Journal of Zoology

Cover image for Vol. 301 Issue 2

Early View (Online Version of Record published before inclusion in an issue)

Edited By: Nigel Bennett (Editor-in-Chief), Matt Hayward, Andrew Kitchener, Mark-Oliver Roedel, Jean-Nicolas Volff, Gabriele Uhl. Reviews Editor: Trish Fleming

Impact Factor: 1.819

ISI Journal Citation Reports © Ranking: 2015: 33/161 (Zoology)

Online ISSN: 1469-7998

Associated Title(s): Animal Conservation, International Zoo Yearbook, Remote Sensing in Ecology and Conservation

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  1. 1 - 36
  1. Original Articles

    1. Can the environment influence species home-range size? A case study on Ctenomys minutus (Rodentia, Ctenomyidae)

      B. B. Kubiak, D. Galiano and T. R. O. de Freitas

      Version of Record online: 10 FEB 2017 | DOI: 10.1111/jzo.12444

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      The environment physically limits animal movement and use of space and in the case of subterranean rodents, natural selection is expected to favor burrow structures that minimize energetic costs of digging. We evaluated the home range sizes of two C. minutus populations that inhabit different habitats: sand dunes and sand fields. Our results show that home ranges of C. minutus differ in the two habitats, with average size 1.75 times larger for individuals inhabiting sand dunes. This difference in home range size between habitats is likely associated with differences in resource availability (plant biomass) or soil conditions.

    2. Dietary niche differentiation facilitates coexistence of two large carnivores

      B. du Preez, J. Purdon, P. Trethowan, D. W. Macdonald and A. J. Loveridge

      Version of Record online: 9 FEB 2017 | DOI: 10.1111/jzo.12443

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      Using predator scat analysis and prey survey techniques, we analyze and compare the underlying mechanisms of prey selection – prey body size and group size – between sympatric populations of leopard Panthera pardus and lion Panthera leo, to test for possible means of competitive avoidance between them. Because leopard and lion differ in both size and social structure, we controlled for the differing prey handling ability of each species, and found a significant difference in mean prey body size preference between the two carnivores.

    3. Physical and psychological motivation tests of individual preferences in rainbow trout

      C. M. Maia, B. Ferguson, G. L. Volpato and V. A. Braithwaite

      Version of Record online: 4 FEB 2017 | DOI: 10.1111/jzo.12438

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      To give animals an enriched environment, it is important to assess what they prefer. Preference can be measured by contrasting preferred choices with the effort an animal makes to access these items (motivation). Using Maia and Volpato (2016)'s preference index, we demonstrated that rainbow trout express both physical and psychological motivation to access their preferred background colour, or to access shelters or conspecifics.

    4. Larval and adult nutrition effects on reproductive traits in the red flour beetle

      A. Plesnar-Bielak, K. R. Woch, M. A. Małszycki, A. T. H. Alkhawlany, A. Hołysz, J. F. Assis Correia, N. Turk, M. Ugrin, P. Kramarz and Z. M. Prokop

      Version of Record online: 3 FEB 2017 | DOI: 10.1111/jzo.12440

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      This study investigated how larval and adult nutrition interact in shaping reproductive traits in male and female metamorphic insects. In red flour beetles, we found that male mating activity was affected solely by juvenile diet, whereas for female fecundity the effects of larval and adult diet interacted, suggesting that harmful consequences of juvenile malnutrition can be partially compensated for if conditions improve later in life. Interestingly, path analysis showed that diet effects on reproduction were not mediated by body size in either sex, suggesting that they act via composition, rather than size, of the adult body.

    5. Daily activity patterns in the giant root rat (Tachyoryctes macrocephalus), a fossorial rodent from the Afro-alpine zone of the Bale Mountains, Ethiopia

      T. Vlasatá, J. Šklíba, M. Lövy, Y. Meheretu, C. Sillero-Zubiri and R. Šumbera

      Version of Record online: 2 FEB 2017 | DOI: 10.1111/jzo.12441

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      We radio-tracked 17 giant root rats during two periods of a dry season differing in temperature and food supply. In both periods, they displayed diurnal outside-nest activity with a unimodal pattern positively related to the temperature at the soil surface. Their aboveground activity decreased between the early and late dry season in spite of a decrease of food supply, for which we offer a thermoregulatory explanation.

    6. The gluttonous king: the effects of prey size and repeated feeding on predatory performance in kingsnakes

      D. A. Penning

      Version of Record online: 20 JAN 2017 | DOI: 10.1111/jzo.12437

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      Many snakes are known to feed on a variety of different sizes and quantities of prey. Successful predation may place constraints on subsequent predation performance. Using eastern kingsnakes Lampropeltis getula, I show that prey size alone does not affect constriction performance, but snakes show reductions in predation performance when feeding on multiple prey of ≥7% relative prey mass.

    7. Ritualized fights among foraging cattle egrets following Père David's deer in Dafeng Nature Reserve

      E. V. Fernandez, X. Shi and Z. Li

      Version of Record online: 19 JAN 2017 | DOI: 10.1111/jzo.12435

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      The outcome success of animals competing for food resources may be influenced by their differences in resource holding potential and motivation to acquire these resources. This study investigated the naturally occurring aggressive interactions during ritualized fights of the cattle egret (Bubulcus ibis) following Père David's deer (Elaphurus davidianus), foraging on insects disturbed by the deer's movements, in Dafeng National Nature Reserve, China. The prey capture success rate and the total foraging earnings of resident cattle egrets following a deer with intrusion were significantly higher than those of resident foragers without intrusion. The resident status did not affect the outcomes of the ritualized fights of the cattle egrets, although adult residents or intruders had more cases of winning in contesting ownership of the deer. Thus, age is the major resource holding factor in foraging cattle egrets competing for host ownership.

    8. Reconstruction of the extinct Ezo wolf's diet

      J. Matsubayashi, T. Ohta, O. Takahashi and I. Tayasu

      Version of Record online: 19 JAN 2017 | DOI: 10.1111/jzo.12436

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      We performed carbon and nitrogen stable isotope analysis and radiocarbon dating of the extinct Ezo wolf Canis lupus hattai in Hokkaido Islands, Japan, and estimated the components of the wolves’ diet using an isotope mixing model. The stable isotope analysis revealed that five of the seven wolves exclusively consumed Sika deer, whereas the remaining two wolves clearly depended on marine prey such as salmon and marine mammals. Thus, Ezo wolves had a similar ecological role to Canadian grey wolves, and are a second subspecies shown to have fed on a marine diet, in addition to the ‘coastal wolves’ of British Columbia. Photo credit: Hokkaido University Botanical Garden.

    9. Stage-dependent puma predation on dangerous prey

      L. M. Elbroch, J. Feltner and H. B. Quigley

      Version of Record online: 12 JAN 2017 | DOI: 10.1111/jzo.12442

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      We compared puma (Puma concolor) predation on dangerous adult ungulates and safer juvenile ungulates, as well as two similar-sized rodent species. We found that puma predation was stage-dependent. Dispersing, subadult pumas with limited hunting experience and without territories avoided dangerous but optimally sized adult ungulates, and instead hunted dangerous, suboptimal porcupines more than resident, territorial adults.

    10. Multiple anti-predator mechanisms in the red-spotted Argentina Frog (Amphibia: Hylidae)

      R. Cajade, G. Hermida, J. M. Piñeiro, E. Regueira, L. Alcalde, L. S. Fusco and F. Marangoni

      Version of Record online: 12 JAN 2017 | DOI: 10.1111/jzo.12439

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      The complex anti-predator mechanisms of the casque-headed frog, Argenteohyla siemersi, are described, consisting of (1) behavioural and ecological traits, including secretive and semi-phragmotic habits and posture; (2) morphological features, including cryptic and aposematic colourations, a skull covered with bony dermal spines and protuberances that are associated with two types of granular venom glands; and (3) physiological and chemical traits, such as a highly lethal skin secretion.

    11. Brain size evolution in the frog Fejervarya limnocharis supports neither the cognitive buffer nor the expensive brain hypothesis

      C. L. Mai, J. Liao, L. Zhao, S. M. Liu and W. B. Liao

      Version of Record online: 21 DEC 2016 | DOI: 10.1111/jzo.12432

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      We detected considerable variation in brain size and the sizes of brain structures in the Asian grass frog (Fejervarya limnocharis) among populations. Inconsistent with the predictions of the Expensive Brain Hypothesis (EBH) and the Cognitive Buffer Hypothesis (CBH), individuals living in habitats with medium variation in temperatures and length of growth seasons at middle latitude and/or altitude had a relatively large brain, suggesting that environmental habitat-induced energetic constraints do not play an important role in shaping brain size evolution. Moreover, we also detected a significant intersexual difference in telencephalon size.

    12. From embryos to larvae: seven-month-long paternal care by male Japanese giant salamander

      M. K. Takahashi, S. Okada and Y. Fukuda

      Version of Record online: 19 DEC 2016 | DOI: 10.1111/jzo.12433

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      The current knowledge about salamander parental care is largely limited to pre-hatching attendance by females. By examining videotaped post-hatching behaviours of two male Japanese giant salamanders in situ, we provided the first detailed description and analyses of prolonged and complex parental care behaviours for hatchlings by male salamanders.

    13. Genetic population structure of the long-tailed pygmy rice rat (Rodentia, Cricetidae) at different geographic scales in the Argentinean Patagonia

      N. Ortiz, F. J. Polop, V. C. Andreo, M. C. Provensal, J. J. Polop, C. N. Gardenal and R. E. González-Ittig

      Version of Record online: 15 DEC 2016 | DOI: 10.1111/jzo.12410

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      The population genetic structure of Oligoryzomys longicaudatus colilargo was examined at two geographical scales: (a) regional, including five populations of the Argentinean Patagonia and (b) landscape scale, using five populations from different valleys of the locality of Cholila in the subantarctic forest and a nearby locality of the Patagonian steppe. At the regional scale, several genetic clusters were detected which follow a latitudinal pattern and indicate low levels of current gene flow within the region. At the landscape level, genetic differentiation among the five populations was also found; migration rates were low and asymmetrical between nearby populations. Using a causal modeling approach, we detected landscape features, such as lakes, rivers, urban settlements and roads, which appear to constrain the dispersal of O. longicaudatus at the landscape scale.

    14. Hybridization between a Euro-Siberian (Vipera berus) and a Para-Mediterranean viper (V. aspis) at their contact zone in western France

      G. Guiller, O. Lourdais and S. Ursenbacher

      Version of Record online: 15 DEC 2016 | DOI: 10.1111/jzo.12431

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      Western European vipers are well-defined species with parapatric distributions that reflect contrasting climatic adaptations. The cold-adapted adder (V. berus, subgenus Pelias) is not known to hybridize with the warm-adapted aspic viper (V. aspis subgenus Vipera). Our results in a contact zone in western France demonstrated that hybridization actually occurs and is directional since it involves females V. aspis viper and male V. berus.

    15. Asymmetry of the nasofacial skull in toothed whales (Odontoceti)

      S. Huggenberger, S. Leidenberger and H. H. A. Oelschläger

      Version of Record online: 13 DEC 2016 | DOI: 10.1111/jzo.12425

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      The nasal asymmetry of odontocetes (toothed whales) was analyzed morphometrically using skulls from 12 different species and genera that belong to four odontocete families. The degree of asymmetry tends to be linked with the mechanism of click sound generation in odontocetes. The narrow-banded high-frequency echolocators (e.g. Phocoenidae) show a more symmetric skull than the broad-banded low-frequency species (most delphinids). Exceptions to this tendency are, for example Kogia sima, with narrow-banded high-frequency clicks and a high degree of nasofacial asymmetry, and Feresa attenuata, a delphinid with broad-banded low-frequency clicks and a moderate degree of nasofacial asymmetry. Accordingly, there is no consistent functional correlation between click type and skull asymmetry probably because the nasofacial skull does not strictly reflect the anatomy of the sound generating nasal soft structures.

    16. How the cheetahs' specialized palate accommodates its abnormally large teeth

      G. Steenkamp, S. C. Boy, P. J. van Staden and M. N. Bester

      Version of Record online: 13 DEC 2016 | DOI: 10.1111/jzo.12422

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      Cheetahs have abnormally large teeth for the size of their heads compared to leopards and lions. This macroscopic and microscopic study on cheetah, lion and leopard skulls discovered that the cheetah palate has up to three sets of palatal depressions corresponding to the cusps of the opposing mandibular cheek teeth, showing how their palates are adapted to accommodate their teeth. Larger teeth, we believe, are an advantage for a predator that must consume its prey quickly.

    17. Identifying factors that influence stress physiology of the woylie, a critically endangered marsupial

      S. Hing, E. J. Narayan, R. C. A. Thompson and S. S. Godfrey

      Version of Record online: 10 DEC 2016 | DOI: 10.1111/jzo.12428

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      Measuring faecal cortisol metabolites (FCM) can be used to understand how animals respond to challenges (stressors). We conducted a longitudinal field study of critically endangered woylies and found that season, sex, body condition index and nematode parasite status influence FCM. Knowledge of factors that influence FCM in woylies may be considered when carrying out potentially stressful activities that may influence the species’ future survival.

    18. The effects of soil compactness on the burrowing performance of sympatric eastern and hairy-tailed moles

      Y.-F. Lin, A. Chappuis, S. Rice and E. R. Dumont

      Version of Record online: 10 DEC 2016 | DOI: 10.1111/jzo.12418

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      We investigated how soil compactness affects burrowing performance in two sympatric mole species, eastern moles (Scalopus aquaticus) and hairy-tailed moles (Parascalops breweri). We found that increasing soil compactness impedes tunneling performance as evidenced by reduced burrowing speed, increased soil transport, shorter tunnels, shorter activity time and less time spent burrowing continuously. Eastern moles built longer tunnels than hairy-tailed moles as soil compactness increased. This difference is linked to burrowing for longer times and distances, not higher burrowing speeds or rates of soil transport.

    19. Heterozygosity but not inbreeding coefficient predicts parasite burdens in the banded mongoose

      J. Mitchell, E. I. K. Vitikainen, D. A. Wells, M. A. Cant and H. J. Nichols

      Version of Record online: 9 DEC 2016 | DOI: 10.1111/jzo.12424

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      Less genetically diverse and inbred animals are often noted to be more susceptible to disease and parasitism. In the banded mongoose, we show that pedigree inbreeding does not co-vary with parasite load; however, more genetically heterozygous individuals appear to benefit from reduced overall parasitic infection. Thus, genetic diversity appears to explain some variation in parasite burdens in this cooperative mammal.

    20. Size of nest-cavity entrance influences male attractiveness and paternal provisioning in house wrens

      D. S. Will, E. E. Dorset, C. F. Thompson, S. K. Sakaluk and E. K. Bowers

      Version of Record online: 9 DEC 2016 | DOI: 10.1111/jzo.12429

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      In biparental species in which males provide care for offspring, theory predicts that the effort put forth by males should vary inversely with their sexual attractiveness. We tested this, and found that unattractive males provided an increased level of care for offspring, but that male and female food-provisioning effort was negatively correlated. Although females provisioned less food to offspring as their mates delivered more food, these females also spent more time brooding their nestlings, thereby altering the mode of parental care they provided. These findings suggest that sexual conflict over biparental care may not be as simple as the assessment of food provisioning alone might suggest.

    21. Heterozygosity decrease in wild boar mating system - a case of outbreeding avoidance?

      J. Pérez-González, V. Costa, P. Santos, J. Carranza, A. Zsolnai, P. Fernández-Llario, N. M. Monteiro, I. Anton and A. Beja-Pereira

      Version of Record online: 8 DEC 2016 | DOI: 10.1111/jzo.12426

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      In this work, foetus heterozygosity was used to estimate the genetic relationship between mates in wild boar from Portugal, Spain and Hungary. Foetus heterozygosity was lower than that expected under random mating. We propose outbreeding avoidance as the most likely process able to explain our results.

    22. Intrinsic limb morpho-dynamics and the early development of interlimb coordination of walking in a quadrupedal primate

      F. Druelle, G. Berillon and P. Aerts

      Version of Record online: 8 DEC 2016 | DOI: 10.1111/jzo.12423

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      We question the developmental changes of the temporal aspects of quadrupedal walking in primate, and how these relate to the inertial properties of the limbs and body. For this aim, we studied six captive baboons at two instants in their development, when they just begin foraging independently and when they are autonomous. The main result reveals that the natural pendular period convergence of the limbs has a significant and positive impact on the interlimb coordination pattern. Therefore, while the control of the limbs is in progress through the gradual expression of the corticospinal system, interlimb coordination of quadrupedal walking appears to be (initially) facilitated by intrinsic limb morpho-dynamics, making it an important determinant in the process of quadrupedal learning.

    23. Reproductive behaviour, testis size and faecal androgen metabolite concentrations in the African lesser bushbaby

      J. Scheun, N. C. Bennett, J. Nowack and A. Ganswindt

      Version of Record online: 7 DEC 2016 | DOI: 10.1111/jzo.12420

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      Little is known of the gonadal hormone patterns driving reproduction in male African galagos. As such we aimed to define the androgen patterns accompanying reproductive behaviour as well as changes in testis size, and thus sperm production, in the African lesser bushbaby, Galago moholi. The species displayed a strong degree of reproductive seasonality, with maximum faecal androgen metabolite concentration, testicular volume, and behavioural activity limited to two distinct periods annually. Based on the absence of a significant difference between mating seasons, it is likely that male G. moholi attempt to maximize their reproductive success by utilizing both mating periods equally. This is the first study to describe the reproductive endocrine pattern and its link to physical and behavioural changes in male galagos.

    24. Heavier females produce more sons in a low-density population of red deer

      T. Borowik and B. Jędrzejewska

      Version of Record online: 7 DEC 2016 | DOI: 10.1111/jzo.12430

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      In ungulates, breeding success of males is more variable and often higher than that of females. Thus, sons of mothers in good condition should inherit their condition and attain higher reproductive success than daughters of females in the same condition. In red deer, increasing mother's body mass incremented the chance of female to have male offspring independently of age and population density. This might bring benefit to heavier females in larger number of descendants (grandchildren). (Photo credit: Karol Zub)

    25. Winter sleep with room service: denning behaviour of brown bears with access to anthropogenic food

      M. Krofel, M. Špacapan and K. Jerina

      Version of Record online: 4 DEC 2016 | DOI: 10.1111/jzo.12421

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      Brown bears Ursus arctos regularly use anthropogenic food, but it has remained unclear if human food subsidies affect their hibernation and denning behaviour. We studied denning behaviour of European brown bears in Slovenia, where intensive supplemental feeding with corn is practiced throughout the year. A consistent relationship was observed between latitude, sex and denning period of brown bears across the species’ range. A substantial deviation to this trend (45–56% shortening of denning period) was observed where supplemental feeding of bears with corn is practiced. Availability of anthropogenic food is an important driver of bear denning behaviour and increases the potential for bear interactions with other species, including humans.

  2. Reviews

    1. A different kind of ecological modelling: the use of clay model organisms to explore predator–prey interactions in vertebrates

      P. W. Bateman, P. A. Fleming and A. K. Wolfe

      Version of Record online: 1 DEC 2016 | DOI: 10.1111/jzo.12415

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      Observing predation, particularly in small or cryptic animals, can be very difficult. The use of fake prey made from modelling clay, so that one can vary size, colour and shape of the prey, allows us to explore this otherwise hidden relationship between predator and prey. This paper reviews the research on vertebrates using this technique to date. We discuss both the findings and the failings of this technique and make suggestions for further studies.

  3. Original Articles

    1. Allometry of male sound-producing structures indicates sexual selection on wing size and stridulatory teeth density in a bushcricket

      M. Anichini, S. Kuchenreuther and G. U. C. Lehmann

      Version of Record online: 21 NOV 2016 | DOI: 10.1111/jzo.12419

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      Male sound-producing organs scale with body size in a conditional-dependent manner. As the outcome of song contests is also condition dependent, “sexy males” might be detected by the morphology of their song-producing apparatus.

    2. Deer on the lookout: how hunting, hiking and coyotes affect white-tailed deer vigilance

      S. G. Schuttler, A. W. Parsons, T. D. Forrester, M. C. Baker, W. J. McShea, R. Costello and R. Kays

      Version of Record online: 21 NOV 2016 | DOI: 10.1111/jzo.12416

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      We studied the extent to which perceived predation risk from humans and a newly arrived mesopredator, the coyote, Canis latrans affects white-tailed deer Odocoileus virginianus behavior in the Eastern United States, predicting that deer will be most vigilant in areas hunted by humans which also have the highest levels of coyote activity. We quantified deer vigilance rates in 33 natural areas of which 15 allowed hunting, across six states by evaluating the head posture of 3470 deer photographed at unbaited camera traps. We documented wide variation in coyote activity and human activity, but contrary to our predictions, did not find strong positive relationships between deer vigilance and either of these predators, suggesting neither are functioning as apex predators in the region or that the deer rely on other risk-avoidance behaviors.

    3. Dental microwear texture analysis of extant koalas: clarifying causal agents of microwear

      C. Hedberg and L. R. G. DeSantis

      Version of Record online: 15 NOV 2016 | DOI: 10.1111/jzo.12413

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      Dental microwear, the microscopic wear patterns on teeth, captures dietary information both today and in the past. However, much debate has focused on whether food or grit is the primary agent responsible for microwear formation. Using koalas as model organisms, we demonstrate that dental microwear associated with tough object feeding can be formed in the absence of phytoliths and grit may interact with food to form microwear reflective of diet, as opposed to overprinting dietary signals.

    4. Penny and penny laid up will be many: large Yellow anacondas do not disregard small prey

      E. B. P. Miranda, R. P. Ribeiro-Jr, B. F. Camera, M. Barros, J. Draque, P. Micucci, T. Waller and C. Strüssmann

      Version of Record online: 15 NOV 2016 | DOI: 10.1111/jzo.12417

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      We studied large sexually dimorphic predator, the Yellow anaconda, to learn how influences of sex and size on diet might lead to intersexual niche divergence, so avoiding intraspecific competition. While females (the larger sex) did eat larger prey compared to males, this effect disappeared when we removed the effect of body size. Females ate more frequently than males. Predator-prey size ratios were positively affected by maximum prey size and did not increase minimum prey size. Feeding frequency did not display any ontogenetic effects. While diet composition varied between sexes, overlap was high. This indicates that variations in resource use as a product of sex-based differences in size are negligible in Yellow anacondas.

    5. Contrasting activity budgets of alternative reproductive tactics in male striped mice

      R. Rimbach, M. Wastavino, C. H. Yuen, N. Pillay and C. Schradin

      Version of Record online: 8 NOV 2016 | DOI: 10.1111/jzo.12414

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      Few studies have compared activity budgets and non-sexual behaviour of individuals using alternative reproductive tactics (ARTs) in nature. We studied male African striped mice Rhabdomys pumilio, which can use three ARTs: (1) breeding male in a group of females; (2) philopatrics that remain in their natal group; or (3) solitary living roamers. We conducted focal animal observations on 70 males using the three ARTs. Philopatrics allocated their time towards behaviours that would increase body mass and survival probability, which could improve the probability to switch to a tactic of higher reproductive success. In contrast, breeders and roamers allocated their time towards behaviours that would increase their chances to mate. Using ARTs results in contrasting activity budgets that reflect the differences in reproductive behaviours observed between tactics.

  4. Reviews

    1. Food availability and population structure: How do clumped and abundant sources of carrion affect the genetic diversity of the black-backed jackal?

      R. S. James, D. M. Scott, R. W. Yarnell and A. D. J. Overall

      Version of Record online: 27 OCT 2016 | DOI: 10.1111/jzo.12407

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      Carnivores frequently come into conflict with humans in agricultural and livestock-producing areas around the world. Understanding their fidelity and dispersal patterns in response to food availability is therefore important given the effort invested in conflict mitigation strategies. In this study, we investigated the effect of clumped and abundant sources of food on the migration and dispersal of the black-backed jackal. We found that clumped and abundant sources of food promote population structuring, resulting in subpopulations with limited migration and dispersal when compared with the total population.

  5. Original Articles

    1. Fossorial ánd durophagous: implications of molluscivory for head size and bite capacity in a burrowing worm lizard

      S. Baeckens, R. García-Roa, J. Martín, J. Ortega, K. Huyghe and R. Van Damme

      Version of Record online: 27 OCT 2016 | DOI: 10.1111/jzo.12412

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      Head size is believed to be constrained in limbless fossorial animals, due to the limitations imposed while burrowing, therefore selecting for small heads and, consequently, low bite forces. However, in the burrowing amphisbaenian Trogonophis wiegmanni, we established that small head sizes have remarkably high relative bite capacities. Such biting may be important for their molluscivorous diet. Yet, the wide head necessary to bite hard imposes a limitation towards an alternative snail-feeding strategy: entering the snail's shell via the shell opening and eating the flesh from inside. Our results showed that head size, and consequently bite force, increases the number of gastropods that can be consumed by ‘shell-crushing’, but reduces the number of prey items that can be consumed by ‘shell-entering’, and vice versa. This study implies that the cranial design of (molluscivorous) limbless burrowers may therefore not only evolve under constraints for efficient soil penetration, but also through selection for diet.

    2. Alien versus predators: effective induced defenses of an invasive frog in response to native predators

      E. Pujol-Buxó, C. García-Guerrero and G. A. Llorente

      Version of Record online: 27 OCT 2016 | DOI: 10.1111/jzo.12411

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      We tested the presence and effectiveness of inducible defenses in tadpoles of the invasive frog Discoglossus pictus confronting two native predators, using both lab and mesocosm experiments. Although D. pictus has been introduced from another continent, tadpoles effectively responded to the native predators, and our results match those usually reported in similar native-native predator-prey systems. We believe that the introduced frog is benefiting from a previous knowledge of similar predator populations since its native (African) and invasive (European) ranges are included in the same ecoregion.

    3. Impact of predators and competitors on the depth selection by two invasive gammarids

      J. Kobak, Ł. Jermacz, D. Rutkowska, K. Pawłowska, L. Witkowska and M. Poznańska

      Version of Record online: 27 OCT 2016 | DOI: 10.1111/jzo.12409

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      We evaluated the depth selection by Dikerogammarus villosus and Pontogammarus robustoides (Gammaroidea, Amphipoda, Crustacea), invasive in European waters, with regard to the presence of fish predators and heterospecific gammarid competitors. We exposed gammarids in single- and mixed-species treatments in a depth gradient (10–100 cm) or in a control shallow tank (depth: 10 cm) in the presence or absence of predators. Dikerogammarus villosus always selected deeper locations than Probustoides. Gammarids did not affect each other's depth selection. Dikerogammarus villosus responded to predators only in the depth gradient, retreating to shallower sites. Pontogammarus robustoides moved away from predators in both tank types. The observed differences in depth selection between the studied species are likely to result in their segregation in the field, limiting inter-specific competition and decreasing predatory pressure.

    4. Brood parasite and host eggshells undergo similar levels of decalcification during embryonic development

      B. Igic, M. E. Hauber, C. Moskát, T. Grim, M. D. Shawkey, P. Procházka and M. Honza

      Version of Record online: 26 OCT 2016 | DOI: 10.1111/jzo.12408

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      To increase the likelihood of successful parasitism, common cuckoos lay thicker shelled eggs than their hosts. We tested whether cuckoo eggshells undergo greater degrees of decalcification during embryogenesis than the eggshells of a host that lay similarly sized eggs but with thinner shells, great reed warblers, that may facilitate the cuckoos hatching from an initially thicker shelled egg. To the contrary, we show that cuckoo eggshells retain a greater thickness than warbler eggshells throughout the embryogenesis. A great reed warbler nest with two common cuckoo eggs (on the left) and two warblers eggs (on the right). Credit: Csaba Moskát.

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