© Royal Entomological Society
Edited By: Jane K. Hill, Francis S. Gilbert and Rebeca B. Rosengaus
Impact Factor: 1.954
ISI Journal Citation Reports © Ranking: 2012: 17/87 (Entomology)
Online ISSN: 1365-2311
Associated Title(s): Agricultural and Forest Entomology, Insect Conservation and Diversity, Medical and Veterinary Entomology, Insect Conservation and Diversity, Physiological Entomology, Systematic Entomology
The Editor's Choice
Plant neighbours mediate bird predation effects on arthropod abundance and herbivory
Brice Giffard, Luc Barbaro, Hervé Jactel and Emmanuel Corcket
Since the iconoclastic days of Dan Simberloff, ecologists have tried much harder to test experimentally whether community-level interactions matter. An abundance of evidence has resulted, first from simple interspecific interactions and then from more complex ones. This nice experiment shows the complexity and conditionality of the tritrophic interactions based on oak trees and involving plant neighbours, insect herbivores and insectivorous birds.
Images - Left: Bird exclusion equipment Right: Caterpillar on an oak leaf
Volume 38 Issue 3
Effects of climate warming on host–parasitoid interactions
Christopher T. Jeffs & Owen T. Lewis
Many insects exhibit parental care and increase the success of their offspring at a cost to themselves. This Review paper examines the hypotheses that have been put forward to explain the evolution of parental care, and reviews the empirical evidence. Parental care is often associated with social interactions, and the paper also examines how factors such as food availability and population density influence social interactions. The authors point out how insects provide great opportunities for carrying out experimental and comparative research to investigate key new questions in the evolution of parental care.
Volume 37 Issue 5
Egg size and composition in an ageing capital breeder – consequences for offspring performance
Heikki Pöykkö, Satu Mänttäri
Click on the image to enlarge the picture.
As entomologists, our research usually focuses on insects at one particular developmental stage during their life cycle: the immature larval period, the nymph or pupae phases, or the adult stage. Yet, many of the attributes we study during these specific phases are influenced and/or determined at the egg stage, a period that has significant "trickle-down effects" on post-hatching success. Egg size as well as egg composition may be significant predictors of offspring survival and developmental rates and ultimately, fitness of progeny. The work by Pöykkö and Mänttäri reminds us that maternal provisioning can be context-dependent, influenced by both intrinsic (i.e. genetics, female age) and extrinsic factors (i.e. female nutritional reserves). Their work addressed first, the question of whether differences in absolute egg size and/or differences in the concentration of certain nutrients were correlated with female age in the capital breeder geometrid moth, Cleorodes lichenari. Secondly, they studied whether these differences affected offspring’s performance. Given the vast diversity of insect species, their corresponding variable life-history traits and the significance that egg “quality” can have on future success of offspring, the study of non-genetic parental contributions (made not only by female but also male adults), ought to make this a fruitful and promising area for future research.
Images - Cleorodes lichenaria first instar larva, Cleorodes lichenaria adult female (both images taken by Ho Heikki Pöykkö)
Evaluating female remating rates in light of spermatophore degradation in Heliconius butterflies: pupal-mating monandry versus adult-mating polyandry
James R. Walters, Christine Stafford, Thomas J. Hardcastle, Chris D. Jiggins
Scientists often have contrasting views about the older literature: either it can be safely ignored because mostly it contains erroneous conclusions arrived at intuitively without the help of statistics; or "there is nothing new under the sun" - modern ideas have all been thought before, and lie hidden in the dusty corners of libraries. So it's reassuring when modern statistical analysis confirms what was concluded from pure observation. This paper reconsiders the idea that female heliconiines that mate while still emerging from the pupa are monandrous, while those that mate when fully post-teneral adults are more promiscuous, a conclusion derived largely from counting spermatophores in the female tract. However, spermatophores are now known to degrade fairly rapidly, putting this conclusion in doubt. Estimating the remating rate required a novel maximum-likelihood model that included age, remating and rates of degradation. Reassuringly, the evolution of pupal mating does indeed appear to evolve in concert with monandry, an important result in the study of just why females mate more than once.
Please click the picture above to access a short video of mating behaviour
Image - Heliconius melpomene mating behaviour – Chris Jiggins
Seasonal patterns of herbivory, leaf traits and productivity consumption in dry and wet Patagonian forests
Noemí Mazía, Enrique J. Chaneton, Cristina Dellacanonica, Luciano Dipaolo, Thomas Kitzberger
The study investigates herbivory in temperate Nothofagus forest in South America, and shows that herbivory is higher in ‘dry’ forest compared with ‘wet’ forest. This was unexpected because foliar production and nutritional quality was much higher in wet forests. The authors conclude that cooler conditions and a shorter growing period in wet forests may explain low herbivory rates.
Images - Left: Nothofagus forest in autumn Middle: Wet forest study site Right: Dry forest study site
Photos by: C. Noemí Mazía
A seed parasitoid wasp prevents berries from changing their colour, reducing their attractiveness to frugivorous birds
Etsuro Takagi, Kazunobu Iguchi, Masanori Suzuki, Katsumi Togashi
Parasites are well known for their ability to manipulate host physiology and behaviour to increase their own survival, dispersal and infective potential. Examples of such direct effects abound. Yet relatively little is known about the indirect effects that parasites have on mutualistic interactions of its host. The research by Takagi et al presents convincing evidence that the parasitoid wasp Macrodasyceras hirsutum disrupts the well-established mutualistic interaction between the plant Ilex integra and its seed-disperser, the frugivorous bird, Hypsipetes amaurotis. The plant produces fruits that normally change coloration from green to red as they ripen on the tree. Such red fruit are preferentially eaten by the birds, and thus, both the plant and the birds benefit from this interaction. Yet, female parasitoid wasps oviposit on the fruit’s seed preventing the fruit from attaining the typical red coloration. Through field exclusion and feeding experiments, the results indicate that the developing wasp larvae inhibit in a density-dependent fashion the coloration change of the fruit, but not its size or shape. The disruption of the plant/bird mutualistic interaction by wasp larvae has important ecological consequences for each member of this tripartite association.
Images - Left: Macrodasyceras hirsutum larva in winter Right: Macrodasyceras hirsutum female inserting ovipositor into an Ilex integra berry
Physical barriers and corridors in urban habitats affect colonisation and parasitism rates of a specialist leaf miner
Guadalupe Peralta, Maria Silvina Fenoglio, Adriana Salvo
Developing an understanding of the ecology of urban areas will become increasingly important as urban development continues to accelerate. Much attention has been focussed on birds and mammals although recent work has also examined the importance of urban areas to insect pollinators. This paper takes a broad ecological approach to understand how the ecology of urban areas might affect leaf miner colonisation and parasitism. The urban environment is detailed as a fragmented and heterogeneous mix of host plants, pavements, walls and yards, with the results showing that pavements act as corridors and constructions as barriers. The distinct physical environment found in urban areas is shown to play a role in the dispersal, colonisation and parasitism found in this system.
Images – Left: Chrysocharis flacilla; Right: C. erecta flower and mined leaf
Dispersal in the Glanville fritillary butterfly in fragmented versus continuous landscapes: comparison between three methods
Rongjiang Wang, Otso Ovaskainen, Yundong Cao, Houqiang Chen, Yan Zhou, Chongren Xu and Ilkka Hanski
Natural habitats are becoming increasingly fragmented and insects occupying these landscapes are showing evolutionary changes in dispersal. Harmonic radar techniques reveal that butterflies from a continuous landscape fly more slowly and have lower optimal temperatures for flight, and that the predicted distance these individuals fly at their optimal temperature is shorter than for individuals from fragmented landscapes. The study combines findings from three different methods – harmonic radar, MRR and rearing studies - to reveal evolutionary adaptations of insects in modern landscapes.
Image - Left: Glanville Fritillary with transponder attached. Right: Harmonic radar equipment used for tracking free-flying butterflies
Effects of different methods of non-lethal tissue sampling on butterflies
Daria Koscinski, Lindsay A. Crawford, Heidi A. Keller and Nusha Keyghobadi
In butterfly genetic studies, it is often assumed that removing legs or clipping wings from living individuals is both non-lethal and not detrimental. Although common practice, this assumption, like so many in ecology, has not been tested. This study tests the effects of these treatments in the field with Pieris rapae and Coenonympha tullia. It shows that such manipulations do not affect survival or flight behaviour, thereby giving credibility to the many studies underpinned by this previously untested assumption and providing a firm foundation for future studies.
Images – Left: Non-lethal tissue sampling (wing clipping) of a cabbage white butterfly (taken by Daria Koscinski); Right: Wing clip sample taken from a cabbage white butterfly (taken by Alan Noon)
Context-dependence in an ant–aphid mutualism: direct effects of tending intensity on aphid performance
Ho Jung S.Yoo and David A. Holway
Mutualistic associations are ubiquitous in nature. A prime example of these interactions includes the widespread phenomenon of aphid tending by ants. Historically, this association has been categorised as mutualistic since both partners of the association appear to draw significant benefits: ants receive nutritious honeydew from their aphids, while aphids benefit from predator protection and/or sanitation from their ants. This study points to the fine line and dynamic balancing act between mutualism and parasitism. By manipulating the per capita tending rates between the aphid Chaitophorus populicola and the ant, Linepithema humile, the authors provide evidence for context- and density-dependent factors influencing the nature of such inter-specific interactions. The work combines greenhouse and field observations and reminds us about nature’s complexity. Sliding back and forth between mutually beneficial and parasitic interactions may be more common than we realise. Considering which intrinsic and extrinsic factors favour one kind of association over another throughout the symbiosis continuum is particularly informative.
Images – Left: Clip cages used to enclose adult and neonate aphids during set-up of experiment; Right: Argentine ants tending poplar leaf aphids on cottonwood trees in the field (both images taken by Ho Jung Yoo)
Many insects have important associations with bacterial symbionts. This paper reviews the role of these important endosymbionts for insect nutritional ecology; for example, in relation to insect-plant interactions, in facilitating insect invasions, and insect immunity. New technological advances through metagenomic approaches open up great opportunities for future research on insects and their endosymbionts.
Images - Left: The ant Polyrachis ypsilon which harbours endosymbiontic bacteria of the genus Blochmannia
Right: Many phloem feeding insects like this membracid harbour primary as well as secondary endosymbionts