Agricultural and Forest Entomology

Agricultural and Forest Entomology Wiley Online Library : Agricultural and Forest Entomologyhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2F%28ISSN%291461-9563John Wiley & Sons, Incen© Royal Entomological Society1461-95551461-95632013-05-01T00:00:00-05:00May 2013152111226Deconstructing the control of the spotted alfalfa aphid Therioaphis maculatahttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12015Deconstructing the control of the spotted alfalfa aphid Therioaphis maculataAndrew Paul Gutierrez, Luigi Ponti2013-05-14T22:25:25.483425-05:00doi:10.1111/afe.12015John Wiley & Sons, Inc.10.1111/afe.12015http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12015Original Articlen/an/aAbstract

The control of insect pests and other taxa may be a result of many factors that are difficult to separate and quantify. Introduced parasitoids, host plant resistance, pathogens and native predators led to the successful control of the spotted alfalfa aphid (SAA; Therioaphis maculata Monell) in California and elsewhere, although the relative contribution of each factor remained largely unknown.
The relative contribution of each control factor was estimated using a weather-driven physiologically-based demographic system model consisting of alfalfa, SAA, its three exotic parasitoids [Aphelinus semiflavus Howard, Praon palitans Muesebeck and Trioxys complanatus (Quilis)], a native coccinellid beetle [Hippodamia convergens (Guérin-Menéville)], a fungal pathogen [Erynia neoaphidis Remaudière & Hennebert (Zygomycetes: Entomophthorales)] and host plant resistance (HPR). Daily weather data for the period 1995–2006 from 142 locations in Arizona and California were used to drive the model.
The factors were introduced to the model singly or in combination to assess their effects in suppressing simulated SAA populations using SAA-days m⁻² year⁻¹ (i.e. density) as the metric of control.
Data from selected runs were mapped using the geographic information system grass (http://grass.osgeo.org). The simulation data across all factor combinations, years and locations were summarized using linear multiple regression, with the dependent variable being log₁₀ SAA-days m⁻² year⁻¹ and the independent variables being the presence–absence (0, 1) of the various factors and their interactions. Marginal analysis of the regression model (∂y/∂x_i) enabled separation of the average effects of the different factors (x_i) given the average effects of the other factors.
Alone, each factor failed to control SAA, as did combinations of the parasitoids and coccinellid predation. Control was predicted across all ecological zones only when all mortality factors were included. The marginal analysis suggests that the order of importance of the mortality factors is HPR > coccinellid beetles > T. complanatus > P. palitans > A. semiflavus > the fungal pathogen. The variability of control by coccinellid beetles and the fungal pathogen was high and hence unreliable.

]]> The control of insect pests and other taxa may be a result of many factors that are difficult to separate and quantify. Introduced parasitoids, host plant resistance, pathogens and native predators led to the successful control of the spotted alfalfa aphid (SAA; Therioaphis maculata Monell) in California and elsewhere, although the relative contribution of each factor remained largely unknown. The relative contribution of each control factor was estimated using a weather-driven physiologically-based demographic system model consisting of alfalfa, SAA, its three exotic parasitoids [Aphelinus semiflavus Howard, Praon palitans Muesebeck and Trioxys complanatus (Quilis)], a native coccinellid beetle [Hippodamia convergens (Guérin-Menéville)], a fungal pathogen [Erynia neoaphidis Remaudière & Hennebert (Zygomycetes: Entomophthorales)] and host plant resistance (HPR). Daily weather data for the period 1995–2006 from 142 locations in Arizona and California were used to drive the model. The factors were introduced to the model singly or in combination to assess their effects in suppressing simulated SAA populations using SAA-days m−2 year−1 (i.e. density) as the metric of control. Data from selected runs were mapped using the geographic information system grass (http://grass.osgeo.org). The simulation data across all factor combinations, years and locations were summarized using linear multiple regression, with the dependent variable being log10 SAA-days m−2 year−1 and the independent variables being the presence–absence (0, 1) of the various factors and their interactions. Marginal analysis of the regression model (∂y/∂xi) enabled separation of the average effects of the different factors (xi) given the average effects of the other factors. Alone, each factor failed to control SAA, as did combinations of the parasitoids and coccinellid predation. Control was predicted across all ecological zones only when all mortality factors were included. The marginal analysis suggests that the order of importance of the mortality factors is HPR > coccinellid beetles > T. complanatus > P. palitans > A. semiflavus > the fungal pathogen. The variability of control by coccinellid beetles and the fungal pathogen was high and hence unreliable. Latitudinal variation in body size of Agrilus planipennis and relationship with fecundityhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12017Latitudinal variation in body size of Agrilus planipennis and relationship with fecundityJordan M. Marshall, Molly A. Miller, Jonathan P. Lelito, Andrew J. Storer2013-05-14T03:12:13.937322-05:00doi:10.1111/afe.12017John Wiley & Sons, Inc.10.1111/afe.12017http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12017Original Articlen/an/aAbstract

For many animals with a wide geographical range, latitude is important in determining body size. Additionally, insect body size often has a direct influence on fecundity. Identifying these relationships for a forest pest can add to population dynamics modelling.
Agrilus planipennis is a pest of North American Fraxinus species.
The relationship between A. planipennis body size and latitude was investigated through field trapping adult A. planipennis in eastern U.S.A., and the relationship between body size and fecundity was investigated through egg production of laboratory-reared A. planipennis adults. Accumulated growing degree days base 10 °C (GDD₁₀) were calculated and used to identify the influence of local climate on A. planipennis body size.
Adult female A. planipennis body size (length and mass) was negatively related to latitude, with larger individuals at southerly sites where the number of days to accumulate 450 and 1000 GDD₁₀ was the lowest.
Using positive linear models relating body size and eggs produced, females from southerly sites would potentially produce twice as many eggs as females from northerly sites.
Agrilus planipennis population latitudes influenced female body size. Because larger A. planipennis females produced more eggs, there is a potential for populations at southerly sites to increase in density and geography more rapidly than northerly populations.

]]> For many animals with a wide geographical range, latitude is important in determining body size. Additionally, insect body size often has a direct influence on fecundity. Identifying these relationships for a forest pest can add to population dynamics modelling. Agrilus planipennis is a pest of North American Fraxinus species. The relationship between A. planipennis body size and latitude was investigated through field trapping adult A. planipennis in eastern U.S.A., and the relationship between body size and fecundity was investigated through egg production of laboratory-reared A. planipennis adults. Accumulated growing degree days base 10 °C (GDD10) were calculated and used to identify the influence of local climate on A. planipennis body size. Adult female A. planipennis body size (length and mass) was negatively related to latitude, with larger individuals at southerly sites where the number of days to accumulate 450 and 1000 GDD10 was the lowest. Using positive linear models relating body size and eggs produced, females from southerly sites would potentially produce twice as many eggs as females from northerly sites. Agrilus planipennis population latitudes influenced female body size. Because larger A. planipennis females produced more eggs, there is a potential for populations at southerly sites to increase in density and geography more rapidly than northerly populations. When genes go wild: highly variable internal transcibed spacer1 and conserved mitochondrial DNA haplotypes used to examine the genetic diversity and dispersal pathways of invasive Hylotrupes bajulus in Western Australiahttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12010When genes go wild: highly variable internal transcibed spacer1 and conserved mitochondrial DNA haplotypes used to examine the genetic diversity and dispersal pathways of invasive Hylotrupes bajulus in Western AustraliaMark A. Castalanelli, Robert J. Cunningham, Matthew B. Davis, David M. Groth, Mike Grimm2013-05-13T22:37:11.288323-05:00doi:10.1111/afe.12010John Wiley & Sons, Inc.10.1111/afe.12010http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12010Original Articlen/an/aAbstract

Hylotrupes bajulus (Linnaeus) is a cryptic insect pest of seasoned coniferous timber. In 2004, an incursion of Hylotrupes bajulus was discovered in Perth, Western Australia.
Two genes, one mitochondrial (cytochrome oxidase subunit I; COI) and one nuclear (internal transcribed spacer 1; ITS1) were used to infer the origin of this incursion, as well as to test the likely dispersal pathways and dispersal distances of H. bajulus.
We sequenced and examined 1003 cloned ITS1 fragments and 170 COI fragments from 14 international and 156 domestic specimens. The ITS1 fragment was extremely variable, with 94% of the sites polymorphic.
To remove the variability and select only the informative polymorphisms principal component analysis was employed. This resulted in the selection of eight informative single nucleotide polymorphisms and seven microsatellites, which were converted into 119 unique ITS haplotypes. In comparison, COI was highly conserved, yielding only four haplotypes.
The data suggest at least three independent incursions, of which two contained the same mitochondrial haplotype but different ITS1 sequences. The datasets were further scrutinized to estimate local dispersal distances. The results suggested that individuals were capable of dispersing > 14 km, which is significantly further than previously reported.

]]> Hylotrupes bajulus (Linnaeus) is a cryptic insect pest of seasoned coniferous timber. In 2004, an incursion of Hylotrupes bajulus was discovered in Perth, Western Australia. Two genes, one mitochondrial (cytochrome oxidase subunit I; COI) and one nuclear (internal transcribed spacer 1; ITS1) were used to infer the origin of this incursion, as well as to test the likely dispersal pathways and dispersal distances of H. bajulus. We sequenced and examined 1003 cloned ITS1 fragments and 170 COI fragments from 14 international and 156 domestic specimens. The ITS1 fragment was extremely variable, with 94% of the sites polymorphic. To remove the variability and select only the informative polymorphisms principal component analysis was employed. This resulted in the selection of eight informative single nucleotide polymorphisms and seven microsatellites, which were converted into 119 unique ITS haplotypes. In comparison, COI was highly conserved, yielding only four haplotypes. The data suggest at least three independent incursions, of which two contained the same mitochondrial haplotype but different ITS1 sequences. The datasets were further scrutinized to estimate local dispersal distances. The results suggested that individuals were capable of dispersing > 14 km, which is significantly further than previously reported. Evaluation of synthetic sex pheromone for monitoring and management of raspberry crown borer Pennisetia marginata (Lepidoptera: Sesiidae)http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12016Evaluation of synthetic sex pheromone for monitoring and management of raspberry crown borer Pennisetia marginata (Lepidoptera: Sesiidae)Carolyn Teasdale, Gary J. R. Judd, Regine Gries, Gerhard Gries2013-04-29T04:09:53.536212-05:00doi:10.1111/afe.12016John Wiley & Sons, Inc.10.1111/afe.12016http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12016Original Articlen/an/aAbstract

(E,Z)-3,13-Octadecadienal (E3,Z13-18:Ald) was recently identified as a sex pheromone component of the raspberry crown borer Pennisetia marginata (Harris) (Lepidoptera: Sesiidae). Although unstable, this pheromone may have utility for monitoring the seasonal abundance and flight phenology of adult P. marginata, as well as for developing control tactics, such as disorienting mate-seeking males. Experiments conducted in raspberry and blackberry crops tested the effect of lure and trap attributes on captures of male P. marginata.
Increasing lure loads (10, 100 or 1000 µg) of E3,Z13-18:Ald significantly increased trap captures.
Freshly prepared lures were significantly more attractive than lures aged for 2–10 days at room temperature.
White wing traps and white delta traps were more effective than green delta or green bucket traps.
Trap height in the crop canopy had no effect on the capture of males.
When sex pheromone components of three other sesiid moth species were added to E3,Z13-18:Ald, the attraction of male P. marginata was reduced and, thus, these components were identified as pheromone antagonists.
Pheromone-based mass trapping with 25 wing traps per hectare reduced captures of males in traps baited with a low-dose (10 µg) pheromone lure by 67–87% in 2011.

]]> (E,Z)-3,13-Octadecadienal (E3,Z13-18:Ald) was recently identified as a sex pheromone component of the raspberry crown borer Pennisetia marginata (Harris) (Lepidoptera: Sesiidae). Although unstable, this pheromone may have utility for monitoring the seasonal abundance and flight phenology of adult P. marginata, as well as for developing control tactics, such as disorienting mate-seeking males. Experiments conducted in raspberry and blackberry crops tested the effect of lure and trap attributes on captures of male P. marginata. Increasing lure loads (10, 100 or 1000 µg) of E3,Z13-18:Ald significantly increased trap captures. Freshly prepared lures were significantly more attractive than lures aged for 2–10 days at room temperature. White wing traps and white delta traps were more effective than green delta or green bucket traps. Trap height in the crop canopy had no effect on the capture of males. When sex pheromone components of three other sesiid moth species were added to E3,Z13-18:Ald, the attraction of male P. marginata was reduced and, thus, these components were identified as pheromone antagonists. Pheromone-based mass trapping with 25 wing traps per hectare reduced captures of males in traps baited with a low-dose (10 µg) pheromone lure by 67–87% in 2011. Assessment of trends in predation pressure on insects across temperate forest microhabitatshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12012Assessment of trends in predation pressure on insects across temperate forest microhabitatsJan Šipoš, Michaela Drozdová, Pavel Drozd2013-04-02T04:08:47.566987-05:00doi:10.1111/afe.12012John Wiley & Sons, Inc.10.1111/afe.12012http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12012Original Articlen/an/aAbstract

Experimental tests of whether predation pressure on insects is sometimes restricted to particular forest microhabitats have been carried out only in one or two vegetation periods and described for only a few predators. In the present study, we describe the seasonal dynamics of a wide spectrum of insect predators among forest microhabitats.
We also examine the impact of weather conditions on insect predation, and predict that forest openness would influence the predation trends among forest microhabitats.
The design of our experiments enabled direct measurement of relative predation pressure on bait (larvae of the blowfly Calliphora vicina) pinned onto selected microhabitats (the base, trunk and leaves of trees) within a temperate floodplain forest (Czech Republic).
The most parsimonious generalized additive model showed significant trends in the predation rate among the forest microhabitats. The highest predation rate for bait was at the base of trees and the lowest predation rate was on leaves.
We also observed significant differences in the species structure of predators in various microhabitats. The most common source of predation on trunks was from birds, whereas wasps were the most common predator on leaves and ants were the most common at the base of trees.

]]> Experimental tests of whether predation pressure on insects is sometimes restricted to particular forest microhabitats have been carried out only in one or two vegetation periods and described for only a few predators. In the present study, we describe the seasonal dynamics of a wide spectrum of insect predators among forest microhabitats. We also examine the impact of weather conditions on insect predation, and predict that forest openness would influence the predation trends among forest microhabitats. The design of our experiments enabled direct measurement of relative predation pressure on bait (larvae of the blowfly Calliphora vicina) pinned onto selected microhabitats (the base, trunk and leaves of trees) within a temperate floodplain forest (Czech Republic). The most parsimonious generalized additive model showed significant trends in the predation rate among the forest microhabitats. The highest predation rate for bait was at the base of trees and the lowest predation rate was on leaves. We also observed significant differences in the species structure of predators in various microhabitats. The most common source of predation on trunks was from birds, whereas wasps were the most common predator on leaves and ants were the most common at the base of trees. Sub-lethal effects of monoterpenes on reproduction by mountain pine beetleshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12013Sub-lethal effects of monoterpenes on reproduction by mountain pine beetlesClayton G. Manning, Mary L. Reid2013-03-31T22:47:12.645603-05:00doi:10.1111/afe.12013John Wiley & Sons, Inc.10.1111/afe.12013http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12013Original Articlen/an/aAbstract

Plant defences may negatively affect the oviposition behaviour of insect herbivores. We exposed adult female mountain pine beetles Dendroctonus ponderosae (Hopkins) to monoterpene vapours and assessed their subsequent oviposition in lodgepole pine Pinus contorta.
Exposure to 31.25 and 125 p.p.m. of α-pinene and limonene for 24 h did not affect the survival or establishment of oviposition galleries compared with controls. Females had fewer, smaller eggs and therefore lower cumulative reproduction after exposure to 125 p.p.m. compared with the other treatments. Limonene negatively affected oviposition more than did α-pinene.
Female body condition, a measure of energetic state, influenced the responses (i.e. significant interactions between condition and monoterpene concentration). With exposure to 31.25 p.p.m., females in better condition tended to have fewer, larger eggs, whereas females in poorer condition tended to have more, smaller eggs, compared with controls. Overall, reproductive investment declined with body condition when exposed to monoterpenes. Egg size and number increased with female body size.
The findings of the present study may indicate the toxic effects of monoterpenes or may be a result of females choosing not to invest in adverse environments depending on body condition. In either case, reduced reproduction when exposed to high plant defences may be increasingly important as climate change affects plant defences.

]]> Plant defences may negatively affect the oviposition behaviour of insect herbivores. We exposed adult female mountain pine beetles Dendroctonus ponderosae (Hopkins) to monoterpene vapours and assessed their subsequent oviposition in lodgepole pine Pinus contorta. Exposure to 31.25 and 125 p.p.m. of α-pinene and limonene for 24 h did not affect the survival or establishment of oviposition galleries compared with controls. Females had fewer, smaller eggs and therefore lower cumulative reproduction after exposure to 125 p.p.m. compared with the other treatments. Limonene negatively affected oviposition more than did α-pinene. Female body condition, a measure of energetic state, influenced the responses (i.e. significant interactions between condition and monoterpene concentration). With exposure to 31.25 p.p.m., females in better condition tended to have fewer, larger eggs, whereas females in poorer condition tended to have more, smaller eggs, compared with controls. Overall, reproductive investment declined with body condition when exposed to monoterpenes. Egg size and number increased with female body size. The findings of the present study may indicate the toxic effects of monoterpenes or may be a result of females choosing not to invest in adverse environments depending on body condition. In either case, reduced reproduction when exposed to high plant defences may be increasingly important as climate change affects plant defences. Ant seed predation, pesticide applications and farmers' income from tropical multi-cropping gardenshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12011Ant seed predation, pesticide applications and farmers' income from tropical multi-cropping gardensIris Motzke, Teja Tscharntke, Navjot S. Sodhi, Alexandra-Maria Klein, Thomas C. Wanger2013-03-28T03:26:16.214453-05:00doi:10.1111/afe.12011John Wiley & Sons, Inc.10.1111/afe.12011http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12011Original Articlen/an/aAbstract

Tropical small-holder farmers rely on sustainable food production. Crop seed predation by ants can cause substantial yield loss and result in high pesticide use.
We conducted field experiments and questionnaire-based surveys aiming to assess the effect of sown-seed predation on four crop species (Cucumis sativus, Daucus carota, Capsicum frutescens and Solanum melongena) in 15 vegetable gardens and the resulting impact on the net income of Indonesian farmers. Furthermore, we tested a commonly applied insecticide and herbicide for seed, seedling and plant protection aiming to understand their effect on ant seed predation.
We found that the mean percentage of seeds removed per garden was 42.0%, 49.4%, 48.0% and 50.6% for C. sativus, D. carota, C. frutescens and S. melongena, respectively, halving the farmers' income after considering initial and operational costs. Insecticide and herbicide treatments did not affect seed predation success or overall ant abundance, although they had positive and negative effects on ant species-specific abundance.
High overall ant abundance caused high seed predation rate in all gardens as a result of a functional redundancy of ant species, which compensated for pesticide-related species loss.
Environmentally-friendly and more sustainable practices such as overseeding or seedling production in nurseries could substitute for these inefficient approaches of chemical pest control, although this requires further research.

]]> Tropical small-holder farmers rely on sustainable food production. Crop seed predation by ants can cause substantial yield loss and result in high pesticide use. We conducted field experiments and questionnaire-based surveys aiming to assess the effect of sown-seed predation on four crop species (Cucumis sativus, Daucus carota, Capsicum frutescens and Solanum melongena) in 15 vegetable gardens and the resulting impact on the net income of Indonesian farmers. Furthermore, we tested a commonly applied insecticide and herbicide for seed, seedling and plant protection aiming to understand their effect on ant seed predation. We found that the mean percentage of seeds removed per garden was 42.0%, 49.4%, 48.0% and 50.6% for C. sativus, D. carota, C. frutescens and S. melongena, respectively, halving the farmers' income after considering initial and operational costs. Insecticide and herbicide treatments did not affect seed predation success or overall ant abundance, although they had positive and negative effects on ant species-specific abundance. High overall ant abundance caused high seed predation rate in all gardens as a result of a functional redundancy of ant species, which compensated for pesticide-related species loss. Environmentally-friendly and more sustainable practices such as overseeding or seedling production in nurseries could substitute for these inefficient approaches of chemical pest control, although this requires further research. Suitability of California bay laurel and other species as hosts for the non-native redbay ambrosia beetle and granulate ambrosia beetlehttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12009Suitability of California bay laurel and other species as hosts for the non-native redbay ambrosia beetle and granulate ambrosia beetleAlbert E. Mayfield, Martin MacKenzie, Philip G. Cannon, Steven W. Oak, Scott Horn, Jaesoon Hwang, Paul E. Kendra2013-03-27T03:45:20.935951-05:00doi:10.1111/afe.12009John Wiley & Sons, Inc.10.1111/afe.12009http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12009Original Articlen/an/aAbstract

The redbay ambrosia beetle Xyleborus glabratus Eichhoff is a non-native vector of the pathogen that causes laurel wilt, a deadly disease of trees in the family Lauraceae in the southeastern U.S.A.
Concern exists that X. glabratus and its fungal symbiont could be transported to the western U.S.A. and cause damage to California bay laurel Umbellularia californica (Hook. & Arn.) Nutt. in California and Washington.
The present study evaluated in-flight attraction, attack density and emergence of X. glabratus and another invasive ambrosia beetle Xylosandrus crassiusculus (Motschulsky) on cut bolts of California bay laurel and eight related tree species in an infested forest in South Carolina. Xylosandrus crassiusculus is not a vector of the laurel wilt pathogen but is a pest of nursery and ornamental trees.
Mean catch of X. glabratus on California bay laurel bolts was not significantly different from catches on bolts of known X. glabratus hosts sassafras Sassafras albidum (Nutt.) Nees and swampbay Persea palustris (Raf.) Sarg. Mean attack density and adult emergence of both beetle species from California bay laurel was equal to or greater than all other tree species tested. Both beetle species readily produced brood in California bay laurel bolts.
The results obtained in the present study suggest that California bay laurel may be negatively impacted by both of these invasive ambrosia beetles if they become established in the tree's native range.

]]> The redbay ambrosia beetle Xyleborus glabratus Eichhoff is a non-native vector of the pathogen that causes laurel wilt, a deadly disease of trees in the family Lauraceae in the southeastern U.S.A. Concern exists that X. glabratus and its fungal symbiont could be transported to the western U.S.A. and cause damage to California bay laurel Umbellularia californica (Hook. & Arn.) Nutt. in California and Washington. The present study evaluated in-flight attraction, attack density and emergence of X. glabratus and another invasive ambrosia beetle Xylosandrus crassiusculus (Motschulsky) on cut bolts of California bay laurel and eight related tree species in an infested forest in South Carolina. Xylosandrus crassiusculus is not a vector of the laurel wilt pathogen but is a pest of nursery and ornamental trees. Mean catch of X. glabratus on California bay laurel bolts was not significantly different from catches on bolts of known X. glabratus hosts sassafras Sassafras albidum (Nutt.) Nees and swampbay Persea palustris (Raf.) Sarg. Mean attack density and adult emergence of both beetle species from California bay laurel was equal to or greater than all other tree species tested. Both beetle species readily produced brood in California bay laurel bolts. The results obtained in the present study suggest that California bay laurel may be negatively impacted by both of these invasive ambrosia beetles if they become established in the tree's native range. Detection and monitoring of forest insects and associated pathogenshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12014Detection and monitoring of forest insects and associated pathogensLeif Martin Schroeder2013-04-16T01:50:17.309668-05:00doi:10.1111/afe.12014John Wiley & Sons, Inc.10.1111/afe.12014http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12014Editorial111112Monitoring of Ips typographus and Pityogenes chalcographus: influence of trapping site and surrounding landscape on catcheshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12002Monitoring of Ips typographus and Pityogenes chalcographus: influence of trapping site and surrounding landscape on catchesLeif Martin Schroeder2012-12-26T22:48:42.856589-05:00doi:10.1111/afe.12002John Wiley & Sons, Inc.10.1111/afe.12002http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12002113119

1
The influence of trapping site (i.e. fresh clear-cuts) characteristics and habitat amount (i.e. area of stands that may hold breeding material) in the surrounding landscape on catches of the bark beetles Ips typographus (L.) and Pityogenes chalcographus (L.) in pheromone-baited flight-barrier monitoring traps was studied.
2
For the two species, the study investigated: (i) the extent of the variation in catches among trapping sites; (ii) the extent of this variation that can be explained by models including trapping site characteristics (clear-cut size, percentage of spruce in the cut stand, altitude) and habitat amounts in the surrounding landscape; and (iii) the spatial scale at which beetles respond to the habitat amount in the landscape.
3
The variation in catches among trap sites was 15-fold larger for I. typographus than for P. chalcographus. There was a positive relationship between the catches of I. typographus and (i) the percentage of the surrounding landscape covered by mature spruce forest at radii 500–4000 m and (ii) the percentage of spruce in stands cut when the clear-cuts used as trapping sites were created. For P. chalcographus, only the second relationship could be demonstrated.
4
Thus, for monitoring of I. typographus: (i) several trapping sites per landscape are required; (ii) the amount of mature spruce forest around trapping sites needs to be considered when choosing trapping sites; and (iii) the trapping sites need to be standardized with respect to the percentage of spruce in the cut stand when fresh clear-cuts are used. For P. chalcographus, fewer trapping sites per landscape are required and only the percentage of spruce in the cut stand needs to be considered.

]]> 1 The influence of trapping site (i.e. fresh clear-cuts) characteristics and habitat amount (i.e. area of stands that may hold breeding material) in the surrounding landscape on catches of the bark beetles Ips typographus (L.) and Pityogenes chalcographus (L.) in pheromone-baited flight-barrier monitoring traps was studied. 2 For the two species, the study investigated: (i) the extent of the variation in catches among trapping sites; (ii) the extent of this variation that can be explained by models including trapping site characteristics (clear-cut size, percentage of spruce in the cut stand, altitude) and habitat amounts in the surrounding landscape; and (iii) the spatial scale at which beetles respond to the habitat amount in the landscape. 3 The variation in catches among trap sites was 15-fold larger for I. typographus than for P. chalcographus. There was a positive relationship between the catches of I. typographus and (i) the percentage of the surrounding landscape covered by mature spruce forest at radii 500–4000 m and (ii) the percentage of spruce in stands cut when the clear-cuts used as trapping sites were created. For P. chalcographus, only the second relationship could be demonstrated. 4 Thus, for monitoring of I. typographus: (i) several trapping sites per landscape are required; (ii) the amount of mature spruce forest around trapping sites needs to be considered when choosing trapping sites; and (iii) the trapping sites need to be standardized with respect to the percentage of spruce in the cut stand when fresh clear-cuts are used. For P. chalcographus, fewer trapping sites per landscape are required and only the percentage of spruce in the cut stand needs to be considered. Quantifying Neodiprion sertifer nucleopolyhedrovirus DNA from insects, foliage and forest litter using the quantitative real-time polymerase chain reactionhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12003Quantifying Neodiprion sertifer nucleopolyhedrovirus DNA from insects, foliage and forest litter using the quantitative real-time polymerase chain reactionPaal Krokene, Inger Heldal, Carl G. Fossdal2012-12-26T22:50:10.207476-05:00doi:10.1111/afe.12003John Wiley & Sons, Inc.10.1111/afe.12003http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12003120125

1
Neodiprion sertifer nucleopolyhedrovirus (NeseNPV) is widely used as a viral bio-insecticide against larvae of the European pine sawfly N. sertifer (Geoff.) (Hymenoptera: Diprionidae), which is one of the most harmful defoliators of pines in Northern Europe. A major obstacle to studying this pathogenic virus in nature is the difficulty of confirming and quantifying the presence of NeseNPV.
2
In the present study, we developed real-time polymerase chain reaction (PCR) primers, based on the caspid gene 39 sequence, for the specific and quantitative detection of NeseNPV. The quantitative real-time PCR (qPCR) assay can detect virus from any substrate tested, including different insect life stages (egg, larval, adult), pine foliage, and litter or ground vegetation. The reproducible detection limit for the real-time assay is 0.013 pg of viral DNA (0.013×10⁻¹² g), corresponding to 136 viral genomes or approximately one to seven virus occlusion bodies per sample.
3
qPCR is a specific, quantitative, sensitive, reliable and flexible procedure, and is a good supplement to conventional microscopy- or bioassay-based methods for detection of the virus. We have used qPCR to quantify the level of NeseNPV in samples collected in the field after aerial application of the virus, and demonstrated significantly higher virus levels in sawfly larvae from sprayed areas compared with unsprayed control areas 4 weeks after spraying.
4
This qPCR assay can be used to determine important aspects of the biology of NeseNPV (e.g. virus levels in different insect life stages and in their microhabitats on pine foliage and in forest litter).

]]> 1 Neodiprion sertifer nucleopolyhedrovirus (NeseNPV) is widely used as a viral bio-insecticide against larvae of the European pine sawfly N. sertifer (Geoff.) (Hymenoptera: Diprionidae), which is one of the most harmful defoliators of pines in Northern Europe. A major obstacle to studying this pathogenic virus in nature is the difficulty of confirming and quantifying the presence of NeseNPV. 2 In the present study, we developed real-time polymerase chain reaction (PCR) primers, based on the caspid gene 39 sequence, for the specific and quantitative detection of NeseNPV. The quantitative real-time PCR (qPCR) assay can detect virus from any substrate tested, including different insect life stages (egg, larval, adult), pine foliage, and litter or ground vegetation. The reproducible detection limit for the real-time assay is 0.013 pg of viral DNA (0.013×10−12 g), corresponding to 136 viral genomes or approximately one to seven virus occlusion bodies per sample. 3 qPCR is a specific, quantitative, sensitive, reliable and flexible procedure, and is a good supplement to conventional microscopy- or bioassay-based methods for detection of the virus. We have used qPCR to quantify the level of NeseNPV in samples collected in the field after aerial application of the virus, and demonstrated significantly higher virus levels in sawfly larvae from sprayed areas compared with unsprayed control areas 4 weeks after spraying. 4 This qPCR assay can be used to determine important aspects of the biology of NeseNPV (e.g. virus levels in different insect life stages and in their microhabitats on pine foliage and in forest litter). Monitoring oak processionary moth Thaumetopoea processionea L. using pheromone traps: the influence of pheromone lure source, trap design and height above the ground on capture rateshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12005Monitoring oak processionary moth Thaumetopoea processionea L. using pheromone traps: the influence of pheromone lure source, trap design and height above the ground on capture ratesDavid T. Williams, N. Straw, M. Townsend, A. S. Wilkinson, A. Mullins2013-02-15T04:53:46.248977-05:00doi:10.1111/afe.12005John Wiley & Sons, Inc.10.1111/afe.12005http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12005Original Article126134Abstract

A field trial conducted in the summer of 2011 evaluated three key parameters that might be influential for determining the number of adult male oak processionary moths (OPM) Thaumetopoea processionea (L.) caught in pheromone traps. Two types of traps (Delta and funnel; Oecos, U.K.) containing one of three different commercially available pheromone lures for OPM were placed out in the lower (3–5 m), mid (5–10 m) and upper (10–15 m) canopy of 72 individual oak trees in Richmond Park, in London, U.K.
The traps were placed out for 8 weeks covering the main flight period of OPM, and significantly more male moths were captured in traps positioned in the upper canopy (76.6%) compared with either mid-canopy (18.6%) or lower canopy (4.8%) positions. Funnel traps caught significantly more male OPM than Delta traps, catching almost six times as many moths over the trapping period.
Traps containing one of the commercially available pheromone lures did not catch any moths, whereas traps with the other two lures caught similar numbers of moths. Chemical analysis revealed considerable differences between the three pheromone lures used in the trial in terms of the initial starting concentration of the primary component (Z,Z)-11,13-hexadecadienyl acetate and its dissipation over a 28-day period.
The results obtained in the present study indicate some of the main factors that need to be taken into account when using pheromone traps to monitor OPM populations and also contribute to the establishment of a standardized monitoring system for this recently established insect pest.

]]> A field trial conducted in the summer of 2011 evaluated three key parameters that might be influential for determining the number of adult male oak processionary moths (OPM) Thaumetopoea processionea (L.) caught in pheromone traps. Two types of traps (Delta and funnel; Oecos, U.K.) containing one of three different commercially available pheromone lures for OPM were placed out in the lower (3–5 m), mid (5–10 m) and upper (10–15 m) canopy of 72 individual oak trees in Richmond Park, in London, U.K. The traps were placed out for 8 weeks covering the main flight period of OPM, and significantly more male moths were captured in traps positioned in the upper canopy (76.6%) compared with either mid-canopy (18.6%) or lower canopy (4.8%) positions. Funnel traps caught significantly more male OPM than Delta traps, catching almost six times as many moths over the trapping period. Traps containing one of the commercially available pheromone lures did not catch any moths, whereas traps with the other two lures caught similar numbers of moths. Chemical analysis revealed considerable differences between the three pheromone lures used in the trial in terms of the initial starting concentration of the primary component (Z,Z)-11,13-hexadecadienyl acetate and its dissipation over a 28-day period. The results obtained in the present study indicate some of the main factors that need to be taken into account when using pheromone traps to monitor OPM populations and also contribute to the establishment of a standardized monitoring system for this recently established insect pest. Influence of sampling effort on saproxylic beetle diversity assessment: implications for insect monitoring studies in European temperate forestshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12008Influence of sampling effort on saproxylic beetle diversity assessment: implications for insect monitoring studies in European temperate forestsGuilhem Parmain, Marc Dufrêne, Antoine Brin, Christophe Bouget2013-03-01T05:53:03.418243-05:00doi:10.1111/afe.12008John Wiley & Sons, Inc.10.1111/afe.12008http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12008Original Article135145Abstract

Saproxylic beetle diversity monitoring provides a tool for estimating the efficiency of forest conservation measures. Flight interception traps are commonly employed to monitor beetle assemblages, although little explicit knowledge of the efficiency of this trapping method is available.
The present study investigated how slight changes in sampling effort can influence species richness and species composition of assemblages in data sets from standard window-flight traps.
At both trap and plot levels, an additional year or an additional trap provided a 50% increase in the number of species detected (a 75% increase for rare species) and resulted in a different estimated composition of the assemblages. Adding 2 or 3 years of sampling gave twice as many species and resulted in assemblages that were 50% dissimilar. Increases in the detection of species and the dissimilarity of assemblages were similarly affected along a gradient of forest conditions, suggesting that changes in sampling effort were not affected by forest condition.
At the forest level, year or trap replication provided smaller increases in species richness (31% and 25%, respectively). Within sites, distance measures in species composition between traps did not differ significantly when based on 1 or 2 years of data. Using two traps per plot compared with one trap influenced comparisons between stand types, based on species richness, in 25% of the cases.
Species detection was similarly increased by either year replication or trap replication. The results of the present study highlight the significant role played by finescale patterns of habitat structure and inter-annual variation with respect to determining catch size and assemblages of saproxylic species.

]]> Saproxylic beetle diversity monitoring provides a tool for estimating the efficiency of forest conservation measures. Flight interception traps are commonly employed to monitor beetle assemblages, although little explicit knowledge of the efficiency of this trapping method is available. The present study investigated how slight changes in sampling effort can influence species richness and species composition of assemblages in data sets from standard window-flight traps. At both trap and plot levels, an additional year or an additional trap provided a 50% increase in the number of species detected (a 75% increase for rare species) and resulted in a different estimated composition of the assemblages. Adding 2 or 3 years of sampling gave twice as many species and resulted in assemblages that were 50% dissimilar. Increases in the detection of species and the dissimilarity of assemblages were similarly affected along a gradient of forest conditions, suggesting that changes in sampling effort were not affected by forest condition. At the forest level, year or trap replication provided smaller increases in species richness (31% and 25%, respectively). Within sites, distance measures in species composition between traps did not differ significantly when based on 1 or 2 years of data. Using two traps per plot compared with one trap influenced comparisons between stand types, based on species richness, in 25% of the cases. Species detection was similarly increased by either year replication or trap replication. The results of the present study highlight the significant role played by finescale patterns of habitat structure and inter-annual variation with respect to determining catch size and assemblages of saproxylic species. Inferring controls on the epidemiology of beech bark disease from spatial patterning of disease organismshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fj.1461-9563.2012.00595.xInferring controls on the epidemiology of beech bark disease from spatial patterning of disease organismsJeffrey R. Garnas, David R. Houston, Mark J. Twery, Matthew P. Ayres, Celia Evans2013-01-07T03:01:17.312898-05:00doi:10.1111/j.1461-9563.2012.00595.xJohn Wiley & Sons, Inc.10.1111/j.1461-9563.2012.00595.xhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fj.1461-9563.2012.00595.x146156

1
Spatial pattern in the distribution and abundance of organisms is an emergent property of collective rates of reproduction, survival and movement of individuals in a heterogeneous environment.
2
The form, intensity and scale of spatial patterning can be used to test hypotheses regarding the relative importance of candidate processes to population dynamics.
3
Using 84 plots across eastern North America, we studied populations of two associated plant parasites, the invasive felted beech scale Cryptococcus fagisuga Lind. and the native Neonectria fungi, which together cause beech bark disease (BBD).
4
We evaluated spatial patterns at the scales of trees within stands, stands within the forest and forests within the landscape to examine four hypothetically important factors in the ecology of the disease: (i) local contagion within stands; (ii) regional contagion, or among patch infection–reinfection dynamics; (iii) variation in host susceptibility linked to genetic and/or environmental heterogeneity; and (iv) climate effects on population growth of BBD organisms.
5
Analyses revealed an unexpected lack of spatial aggregation in BBD populations among trees, stands and forests. This implies that propagule pressure is generally sufficiently high throughout the infested region of North America such that neither trees nor stands are spared from the disease by dispersal limitations of the disease agents. Furthermore, variation in tree and stand level susceptibility has minimal impact on BBD dynamics and climate is not a conspicuous driver of abundance within the core range of BBD.

]]> 1 Spatial pattern in the distribution and abundance of organisms is an emergent property of collective rates of reproduction, survival and movement of individuals in a heterogeneous environment. 2 The form, intensity and scale of spatial patterning can be used to test hypotheses regarding the relative importance of candidate processes to population dynamics. 3 Using 84 plots across eastern North America, we studied populations of two associated plant parasites, the invasive felted beech scale Cryptococcus fagisuga Lind. and the native Neonectria fungi, which together cause beech bark disease (BBD). 4 We evaluated spatial patterns at the scales of trees within stands, stands within the forest and forests within the landscape to examine four hypothetically important factors in the ecology of the disease: (i) local contagion within stands; (ii) regional contagion, or among patch infection–reinfection dynamics; (iii) variation in host susceptibility linked to genetic and/or environmental heterogeneity; and (iv) climate effects on population growth of BBD organisms. 5 Analyses revealed an unexpected lack of spatial aggregation in BBD populations among trees, stands and forests. This implies that propagule pressure is generally sufficiently high throughout the infested region of North America such that neither trees nor stands are spared from the disease by dispersal limitations of the disease agents. Furthermore, variation in tree and stand level susceptibility has minimal impact on BBD dynamics and climate is not a conspicuous driver of abundance within the core range of BBD. Frost increases beech susceptibility to scolytine ambrosia beetleshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fj.1461-9563.2012.00596.xFrost increases beech susceptibility to scolytine ambrosia beetlesSylvie La Spina, Charles De Cannière, Anissa Dekri, Jean-Claude Grégoire2012-12-10T04:36:25.726217-05:00doi:10.1111/j.1461-9563.2012.00596.xJohn Wiley & Sons, Inc.10.1111/j.1461-9563.2012.00596.xhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fj.1461-9563.2012.00596.x157167

1
In the early 2000s, beech forests in Western Europe suffered from a so far unexplained burst of mortality. Necroses, ambrosia-beetle and fungal attacks were observed on the trunks. The symptoms were similar to previous events reported throughout the 20th Century.
2
One current hypothesis is that these phenomena were related to early frost events for which the trees were physiologically unprepared and which made them vulnerable to biotic attacks. In the present study, we aimed to test this hypothesis further, by retrospective meteorological analyses and also by an experimental approach.
3
Our meteorological analyses highlighted the occurrence of cold waves a year before the beech declines were reported in 1929, 1942 and 1998.
4
In our experimental approach, frost injuries were inflicted to mature trees in a beech stand using dry ice. The treated trees were more attractive to insects than untreated controls. Insect attacks were observed in the treated zones on the trees but colonization was not very successful. The galleries had aborted most of the time with only a few larval chambers. Very few insects were caught in emergence traps.
5
The results of these two approaches support and strengthen the hypothesis that frost induced beech dieback. Frost injuries increased tree attraction to ambrosia beetles to the point of inducing attacks. However, the overall success of these attacks was much lower than that observed in the 2000s. These differences might reflect limitations in our experimental approach, where frost wounding was applied locally to the trees.

]]> 1 In the early 2000s, beech forests in Western Europe suffered from a so far unexplained burst of mortality. Necroses, ambrosia-beetle and fungal attacks were observed on the trunks. The symptoms were similar to previous events reported throughout the 20th Century. 2 One current hypothesis is that these phenomena were related to early frost events for which the trees were physiologically unprepared and which made them vulnerable to biotic attacks. In the present study, we aimed to test this hypothesis further, by retrospective meteorological analyses and also by an experimental approach. 3 Our meteorological analyses highlighted the occurrence of cold waves a year before the beech declines were reported in 1929, 1942 and 1998. 4 In our experimental approach, frost injuries were inflicted to mature trees in a beech stand using dry ice. The treated trees were more attractive to insects than untreated controls. Insect attacks were observed in the treated zones on the trees but colonization was not very successful. The galleries had aborted most of the time with only a few larval chambers. Very few insects were caught in emergence traps. 5 The results of these two approaches support and strengthen the hypothesis that frost induced beech dieback. Frost injuries increased tree attraction to ambrosia beetles to the point of inducing attacks. However, the overall success of these attacks was much lower than that observed in the 2000s. These differences might reflect limitations in our experimental approach, where frost wounding was applied locally to the trees. Life-history costs associated with resistance to lambda-cyhalothrin in the predatory ladybird beetle Eriopis connexahttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fj.1461-9563.2012.00599.xLife-history costs associated with resistance to lambda-cyhalothrin in the predatory ladybird beetle Eriopis connexaEmerson S. Ferreira, Agna R. S. Rodrigues, Christian S. A. Silva-Torres, Jorge B. Torres2012-10-29T03:24:14.742817-05:00doi:10.1111/j.1461-9563.2012.00599.xJohn Wiley & Sons, Inc.10.1111/j.1461-9563.2012.00599.xhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fj.1461-9563.2012.00599.x168177

1
The present study assessed the fitness of a lambda-cyhalothrin-resistant population of Eriopis connexa (Germar) with respect to development, reproduction, survival under prey scarcity and prey consumption.
2
Nontreated resistant females (R0) and females recovered after the topical application of 0.05, 0.10 and 0.25 mg active ingredient/mL of lambda-cyhalothrin (R0.05, R0.10 and R0.25) produced, on average, 50% less eggs than susceptible females (S0), irrespective of the applied dose. All of the other traits evaluated remained similar. With respect to developmental characteristics, the larval viability and weight of adult male R0.25 progeny were statistically lower compared with the R0 and S0 progenies. Prey scarcity between days 3 and 13 of adulthood did not affect R0 and R0.25 survival, although egg production was significantly lower for R0 females, followed by R0.25 females, compared with S0 females.
3
The mean consumption of cotton aphids Aphis gossypii Glover over 5 consecutive days was significantly higher for S0, followed by R0 and R0.25, up to day 3 of observation. However, after day 4, prey consumption was similar among the three populations.
4
The results obtained in the present study show that resistant females have a lower reproductive output than susceptible females and that this is not related to the knockdown effect; however, the costs of recovering from knockdown interfere with the survival of offspring and also slightly with prey consumption. Thus, we conclude that the lambda-cyhalothrin-resistant E. connexa population exhibits an egg production disadvantage relative to the susceptible population and that this is increased when the population is subjected to prey scarcity.

]]> 1 The present study assessed the fitness of a lambda-cyhalothrin-resistant population of Eriopis connexa (Germar) with respect to development, reproduction, survival under prey scarcity and prey consumption. 2 Nontreated resistant females (R0) and females recovered after the topical application of 0.05, 0.10 and 0.25 mg active ingredient/mL of lambda-cyhalothrin (R0.05, R0.10 and R0.25) produced, on average, 50% less eggs than susceptible females (S0), irrespective of the applied dose. All of the other traits evaluated remained similar. With respect to developmental characteristics, the larval viability and weight of adult male R0.25 progeny were statistically lower compared with the R0 and S0 progenies. Prey scarcity between days 3 and 13 of adulthood did not affect R0 and R0.25 survival, although egg production was significantly lower for R0 females, followed by R0.25 females, compared with S0 females. 3 The mean consumption of cotton aphids Aphis gossypii Glover over 5 consecutive days was significantly higher for S0, followed by R0 and R0.25, up to day 3 of observation. However, after day 4, prey consumption was similar among the three populations. 4 The results obtained in the present study show that resistant females have a lower reproductive output than susceptible females and that this is not related to the knockdown effect; however, the costs of recovering from knockdown interfere with the survival of offspring and also slightly with prey consumption. Thus, we conclude that the lambda-cyhalothrin-resistant E. connexa population exhibits an egg production disadvantage relative to the susceptible population and that this is increased when the population is subjected to prey scarcity. Influence of the forest caterpillar hunter Calosoma sycophanta on the transmission of microsporidia in larvae of the gypsy moth Lymantria disparhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12000Influence of the forest caterpillar hunter Calosoma sycophanta on the transmission of microsporidia in larvae of the gypsy moth Lymantria disparDörte Goertz, Gernot Hoch2013-01-22T03:47:08.245213-05:00doi:10.1111/afe.12000John Wiley & Sons, Inc.10.1111/afe.12000http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12000178186

1
The behaviour of predators can be an important factor in the transmission success of an insect pathogen. We studied how Calosoma sycophanta influences the interaction between its prey [Lymantria dispar (L.) (Lepidoptera, Lymantriidae)] and two microsporidian pathogens [Nosema lymantriae (Microsporidia, Nosematidae) and Vairimorpha disparis (Microsporidia, Burellenidae)] infecting the prey.
2
Using laboratory experiments, C. sycophanta was allowed to forage on infected and uninfected L. dispar larvae and to disseminate microsporidian spores when preying or afterwards with faeces.
3
The beetle disseminated spores of N. lymantriae and V. disparis when preying upon infected larvae, as well as after feeding on such prey. Between 45% and 69% of test larvae became infected when C. sycophanta was allowed to disseminate spores of either microsporidium.
4
Laboratory choice experiments showed that C. sycophanta did not discriminate between Nosema-infected and uninfected gypsy moth larvae. Calosoma sycophanta preferred Vairimorpha-infected over uninfected gypsy moth larvae and significantly influenced transmission.
5
When C. sycophanta was allowed to forage during the latent period on infected and uninfected larvae reared together on caged, potted oak saplings, the percentage of V. disparis infection among test larvae increased by more than 70%. The transmission of N. lymantriae was not affected significantly in these experiments.
6
Beetles never became infected with either microsporidian species after feeding on infected prey.
7
We conclude that the transmission of N. lymantriae is not affected. Because no V. disparis spores are released from living larvae, feeding on infected larvae might enhance transmission by reducing the time to death and therefore the latent period.

]]> 1 The behaviour of predators can be an important factor in the transmission success of an insect pathogen. We studied how Calosoma sycophanta influences the interaction between its prey [Lymantria dispar (L.) (Lepidoptera, Lymantriidae)] and two microsporidian pathogens [Nosema lymantriae (Microsporidia, Nosematidae) and Vairimorpha disparis (Microsporidia, Burellenidae)] infecting the prey. 2 Using laboratory experiments, C. sycophanta was allowed to forage on infected and uninfected L. dispar larvae and to disseminate microsporidian spores when preying or afterwards with faeces. 3 The beetle disseminated spores of N. lymantriae and V. disparis when preying upon infected larvae, as well as after feeding on such prey. Between 45% and 69% of test larvae became infected when C. sycophanta was allowed to disseminate spores of either microsporidium. 4 Laboratory choice experiments showed that C. sycophanta did not discriminate between Nosema-infected and uninfected gypsy moth larvae. Calosoma sycophanta preferred Vairimorpha-infected over uninfected gypsy moth larvae and significantly influenced transmission. 5 When C. sycophanta was allowed to forage during the latent period on infected and uninfected larvae reared together on caged, potted oak saplings, the percentage of V. disparis infection among test larvae increased by more than 70%. The transmission of N. lymantriae was not affected significantly in these experiments. 6 Beetles never became infected with either microsporidian species after feeding on infected prey. 7 We conclude that the transmission of N. lymantriae is not affected. Because no V. disparis spores are released from living larvae, feeding on infected larvae might enhance transmission by reducing the time to death and therefore the latent period. Ellagitannins: defences of Betula nana against Epirrita autumnata folivory?http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12001Ellagitannins: defences of Betula nana against Epirrita autumnata folivory?Teija Ruuhola, Paula Salminen, Juha-Pekka Salminen, Vladimir Ossipov2013-01-17T04:52:32.455229-05:00doi:10.1111/afe.12001John Wiley & Sons, Inc.10.1111/afe.12001http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12001187196

1
The induced resistance of the subarctic mountain birch Betula pubescens ssp. czerepanovii is a well-characterized phenomenon, whereas the induced responses of Betula nana L., one of the parental species of mountain birch, have not yet been characterized. Betula nana is more resistant to several classes of insectivorous herbivores than the mountain birch, although the mechanisms responsible for the better ability to resist herbivores are not known.
2
The present study aimed to determine the metabolic changes that are induced by early season herbivory in B. nana leaves and to study the effects of rapidly induced resistance on the growth of Epirrita autumnata larvae.
3
Defoliation of B. nana was accomplished by E. autumnata larvae and leaf samples for chemical analyses were collected when the defoliating larvae were at their third and fifth instar. At the same time, laboratory assays for the growth and consumption rates of E. autumnata larvae were conducted.
4
The wounding of leaves by E. autumna larvae induced the production of ellagitannins (ETs) in B. nana. Intriguingly, the concentrations of protein-bound amino acids were also induced by herbivory; however, an increase in proteins was not mirrored in the growth rate of larvae, which was less on the induced foliage. The decreased growth rate of larvae was apparently linked to the increased concentrations of oxidatively-active ETs and the high concentration of ETs may explain the better resistance of this parental species compared with the hybrid mountain birch with its lower levels of ETs.

]]> 1 The induced resistance of the subarctic mountain birch Betula pubescens ssp. czerepanovii is a well-characterized phenomenon, whereas the induced responses of Betula nana L., one of the parental species of mountain birch, have not yet been characterized. Betula nana is more resistant to several classes of insectivorous herbivores than the mountain birch, although the mechanisms responsible for the better ability to resist herbivores are not known. 2 The present study aimed to determine the metabolic changes that are induced by early season herbivory in B. nana leaves and to study the effects of rapidly induced resistance on the growth of Epirrita autumnata larvae. 3 Defoliation of B. nana was accomplished by E. autumnata larvae and leaf samples for chemical analyses were collected when the defoliating larvae were at their third and fifth instar. At the same time, laboratory assays for the growth and consumption rates of E. autumnata larvae were conducted. 4 The wounding of leaves by E. autumna larvae induced the production of ellagitannins (ETs) in B. nana. Intriguingly, the concentrations of protein-bound amino acids were also induced by herbivory; however, an increase in proteins was not mirrored in the growth rate of larvae, which was less on the induced foliage. The decreased growth rate of larvae was apparently linked to the increased concentrations of oxidatively-active ETs and the high concentration of ETs may explain the better resistance of this parental species compared with the hybrid mountain birch with its lower levels of ETs. Positive association between thrips and spider mites in seedling cottonhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12004Positive association between thrips and spider mites in seedling cottonXavier Martini, Natalie Kincy, Kathy Vaughn, Jane Dever, Christian Nansen2013-02-15T04:59:18.579094-05:00doi:10.1111/afe.12004John Wiley & Sons, Inc.10.1111/afe.12004http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12004Original Article197203Abstract

In cotton fields in Texas, spider mites are sporadic pests, whereas thrips are considered as major pests on early stages (before the fourth true leaf stage). Thrips are also important predators of spider mite eggs. In the present study, we tested the hypothesis that the presence of spider mites on seedling cotton may increase the likelihood of the occurrence of thrips.
Based on a greenhouse experiment, it was confirmed that seedling cotton was a suitable host for spider mites. Subsequently, we conducted a 2-year field experiment in which we studied the likelihood of thrips infestation in cotton plants with/without experimental spider mite infestations.
Spider mites established better in 2011 (dry and hot season) than in 2010 (rainy and cooler season), and there was a positive association between spider mites on cotton plants and natural thrips infestation. Thus, we showed that the probability of thrips infestation strongly increased with the presence of spider mites.
To confirm the proposed hypothesis on a larger scale, a second field experiment was performed, in which one half of a field was infested with spider mites. Weekly sampling of thrips and spider mites showed a two-fold increase of thrips immatures on plots previously infested with spider mites.
The results obtained in the present study emphasize the importance of incorporating spider mite population dynamics into risk assessments of thrips infestation in seedling cotton fields in Texas and elsewhere.

]]> In cotton fields in Texas, spider mites are sporadic pests, whereas thrips are considered as major pests on early stages (before the fourth true leaf stage). Thrips are also important predators of spider mite eggs. In the present study, we tested the hypothesis that the presence of spider mites on seedling cotton may increase the likelihood of the occurrence of thrips. Based on a greenhouse experiment, it was confirmed that seedling cotton was a suitable host for spider mites. Subsequently, we conducted a 2-year field experiment in which we studied the likelihood of thrips infestation in cotton plants with/without experimental spider mite infestations. Spider mites established better in 2011 (dry and hot season) than in 2010 (rainy and cooler season), and there was a positive association between spider mites on cotton plants and natural thrips infestation. Thus, we showed that the probability of thrips infestation strongly increased with the presence of spider mites. To confirm the proposed hypothesis on a larger scale, a second field experiment was performed, in which one half of a field was infested with spider mites. Weekly sampling of thrips and spider mites showed a two-fold increase of thrips immatures on plots previously infested with spider mites. The results obtained in the present study emphasize the importance of incorporating spider mite population dynamics into risk assessments of thrips infestation in seedling cotton fields in Texas and elsewhere. Timing and intensity of bush cricket predation on egg batches of pine processionary moth: no evidence of population controlhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12006Timing and intensity of bush cricket predation on egg batches of pine processionary moth: no evidence of population controlJosé A. Hódar, Lucía Torres-Muros, Karim Senhadji2013-03-01T06:20:33.530067-05:00doi:10.1111/afe.12006John Wiley & Sons, Inc.10.1111/afe.12006http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12006Original Article204211Abstract

Bush crickets (Orthoptera, Tettigoniidae) are known predators of egg batches of the pine processionary moth (Thaumetopoea pityocampa Denis and Schiffermüller, Lepidoptera: Notodontidae), a severe pest in Mediterranean pine woodlands. Bush crickets have been proposed as biological control agents of T. pityocampa populations, although their characteristics as generalist predators suggest that this would be possible only during the low-density phases of the processionary population cycle.
We combined observational and experimental approaches aiming to determine the role played by the bush cricket Steropleurus andalusius as a regulator of T. pityocampa.
The synchrony of the phenology of T. pityocampa egg batches and the activity of bush crickets was poor, with the activity of bush crickets being longer than the period during which egg batches were available.
The predation rate of bush crickets reached 23%, varied in time and space, and was independent of T. pityocampa egg-batch density. There was no relationship between the egg-batch densities and bush cricket abundance, and no response to experimental variations in egg-batch density.
Analysis of microhabitat selection suggests that T. pityocampa egg-batch predation is a by-product of the substrate selected by bush crickets for mating, and does not correspond with active searching of egg batches as food.
These findings do not rule out the possibilty of bush crickets being natural regulators of T. pityocampa populations, although they impose limits with respect to their future use in biological control.

]]> Bush crickets (Orthoptera, Tettigoniidae) are known predators of egg batches of the pine processionary moth (Thaumetopoea pityocampa Denis and Schiffermüller, Lepidoptera: Notodontidae), a severe pest in Mediterranean pine woodlands. Bush crickets have been proposed as biological control agents of T. pityocampa populations, although their characteristics as generalist predators suggest that this would be possible only during the low-density phases of the processionary population cycle. We combined observational and experimental approaches aiming to determine the role played by the bush cricket Steropleurus andalusius as a regulator of T. pityocampa. The synchrony of the phenology of T. pityocampa egg batches and the activity of bush crickets was poor, with the activity of bush crickets being longer than the period during which egg batches were available. The predation rate of bush crickets reached 23%, varied in time and space, and was independent of T. pityocampa egg-batch density. There was no relationship between the egg-batch densities and bush cricket abundance, and no response to experimental variations in egg-batch density. Analysis of microhabitat selection suggests that T. pityocampa egg-batch predation is a by-product of the substrate selected by bush crickets for mating, and does not correspond with active searching of egg batches as food. These findings do not rule out the possibilty of bush crickets being natural regulators of T. pityocampa populations, although they impose limits with respect to their future use in biological control. Predicting the distribution of a novel bark beetle and its pine hosts under future climate conditionshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12007Predicting the distribution of a novel bark beetle and its pine hosts under future climate conditionsSteven E. Smith, Ma. G. Mendoza, Gerardo Zúñiga, Kandres Halbrook, J. L. Hayes, D. N. Byrne2013-03-12T04:36:36.020039-05:00doi:10.1111/afe.12007John Wiley & Sons, Inc.10.1111/afe.12007http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111%2Fafe.12007Original Article212226Abstract

Understanding the distribution of key biotic elements of forest ecosystems is essential in contemporary forest management and in planning to meet future management needs. Habitat distribution (niche) models based on known occurrences provide geographical structure for such management as the environmental factors change.
Bark beetles play critical roles in coniferous forest dynamics in western North America. Among these insects, Dendroctonus rhizophagus Thomas and Bright, which occurs in the Sierra Madre Occidental in Mexico, is unique in that it attacks only immature trees (Pinus spp.) and therefore represents a threat to forest regeneration. We developed current habitat distribution models for D. rhizophagus and its Pinus hosts and projected these to future climate scenarios.
Predicted suitable habitat of D. rhizophagus currently covers approximately 119 000 km² of which approximately 11% is occupied, and overlap with suitable habitat for all Pinus hosts exceeds 99.5%. Some suitable habitat occurs isolated from known D. rhizophagus occurrences in Mexico and the south-western U.S.A.
Habitat distribution models were projected to four potential climate scenarios for the period 2040–2060 and this predicted the gains and losses of suitable D. rhizophagus habitat throughout the region. Areas of north-western Mexico maintain large areas of suitable D. rhizophagus and Pinus host habitat in all scenarios. Dispersal to isolated areas of D. rhizophagus habitat appears unlikely.
The results of the present study can be used to target D. rhizophagus monitoring and management activities and may serve as a model for the management of other invasive species.

]]> Understanding the distribution of key biotic elements of forest ecosystems is essential in contemporary forest management and in planning to meet future management needs. Habitat distribution (niche) models based on known occurrences provide geographical structure for such management as the environmental factors change. Bark beetles play critical roles in coniferous forest dynamics in western North America. Among these insects, Dendroctonus rhizophagus Thomas and Bright, which occurs in the Sierra Madre Occidental in Mexico, is unique in that it attacks only immature trees (Pinus spp.) and therefore represents a threat to forest regeneration. We developed current habitat distribution models for D. rhizophagus and its Pinus hosts and projected these to future climate scenarios. Predicted suitable habitat of D. rhizophagus currently covers approximately 119 000 km2 of which approximately 11% is occupied, and overlap with suitable habitat for all Pinus hosts exceeds 99.5%. Some suitable habitat occurs isolated from known D. rhizophagus occurrences in Mexico and the south-western U.S.A. Habitat distribution models were projected to four potential climate scenarios for the period 2040–2060 and this predicted the gains and losses of suitable D. rhizophagus habitat throughout the region. Areas of north-western Mexico maintain large areas of suitable D. rhizophagus and Pinus host habitat in all scenarios. Dispersal to isolated areas of D. rhizophagus habitat appears unlikely. The results of the present study can be used to target D. rhizophagus monitoring and management activities and may serve as a model for the management of other invasive species.