Emily R. A. Cramer, Terje Laskemoen, Oddmund Kleven, Katie LaBarbera, Irby J. Lovette, Jan T. Lifjeld
No evidence that sperm morphology predicts paternity success in wild house wrens
Behavioral Ecology and Sociobiology July 2013
Postcopulatory sexual selection (PCSS) in internally fertilizing vertebrates is a topic of great interest, yet relatively little is known about the characteristics of sperm and ejaculates that confer an advantage in PCSS. In this study, we investigated several measures of sperm morphology that potentially contribute to fertilization success under PCSS. We tested whether sperm morphology related to success in PCSS (via extra-pair paternity) in house wrens (Troglodytes aedon). We found no evidence that sperm morphology differed between extra-pair sires and the within-pair males they cuckolded, nor that sperm morphology correlated with the proportion of within-pair offspring sired, the number of extra-pair offspring sired, or the total annual reproductive success. Male behavioral strategies may affect the probability that their sperm compete with other males’ sperm and that their sperm succeed under competition. Effects of these behavioral strategies, as well as differences between males in sperm number, could mask the effects of sperm morphology on the outcome of PCSS. Despite moderate levels of extra-pair paternity, selection on sperm may be relatively weak in house wrens. Further work is needed to understand general patterns in how sperm morphology relates to fertilization success within species.
E. Neilson, V. Nijman, K. A. I. Nekaris
Conservation Assessments of Arboreal Mammals in Difficult Terrain: Occupancy Modeling of Pileated Gibbons (Hylobates pileatus)
International Journal of Primatology July 2013
Long-term monitoring programs, wildlife surveys, and other research involving species population assessment require reliable data on population status. Given the logistically challenging nature of some species’ habitats and cryptic behaviors, collecting these data can prove to be a considerable barrier. We used detection/nondetection data from pileated gibbons (Hylobates pileatus) in the Cardamom Mountains of southwest Cambodia to estimate their population occupancy and detectability. We modeled occupancy using elevation, tree height, tree density, tree diversity, and disturbance covariates. Modeling demonstrated that 83% of the sites are occupied by Hylobates pileatus and that the detectability of the species varies positively with elevation. No clear relationship between habitat quality covariates and occupancy of Hylobates pileatus emerged. Effort analysis based on model estimates demonstrated that at high elevations, less than half the number of site visits is needed to attain the same detectability estimate precision as across all elevations. We suggest that human activities at low elevations, which affect forest composition, are the central factors impacting the detectability and occupancy of Hylobates pileatus. Longer sampling durations and/or a higher number of site visits, especially at lower elevations, increase precision of the occupancy estimator for the least effort. For effective future monitoring and research for this and similar species, using this relatively simple method, applied with repeat site visits, would allow a longitudinal comparison of detection at sites in difficult terrain.
Júlio César Bicca-Marques, Ivana Regina Rodrigues Irace Silveira, Leonel de Souza Martins, Rafael Magalhães Rabelo
Artificial nest predation by brown howler monkeys (Alouatta guariba clamitans)
European Journal of Wildlife Research July 2013
Howler monkeys (Alouatta spp.) have long been considered strongly vegetarian primates. Their occasional ingestion of invertebrates has largely been interpreted as unintentional. Recent observations of the consumption of bird eggs by Alouatta caraya living in small and resource-impoverished habitat patches in the state of Rio Grande do Sul (RS), Brazil help to confirm that such behavior by howler monkeys is at times intentional. We report the findings of an experimental study on artificial nest predation by free-ranging Alouatta guariba clamitans in RS and third-party unpublished observations of intentional feeding on animal matter by Alouatta arctoidea in Venezuela and Alouatta palliata in Mexico. A nest station composed of ten artificial nests baited daily with two quail eggs each was placed at six study sites. Each site was monitored from dawn to dusk during 10–12 consecutive days. Individuals (juvenile males and an adult female) from two of the six study groups inspected the nests and ate eggs once. Study subjects from these two groups were the only ones to be supplemented with food (basically fruit) by local inhabitants, a habit that may have decreased their level of neophobia and facilitated their visit to the artificial nests. We suggest that faunivory is an opportunistic and infrequent, but intentional howler monkey feeding behavior.
Sandy Reinhard, Sebastian Voitel, Alexander Kupfer, External fertilisation and paternal care in the paedomorphic salamander Siren intermedia Barnes, 1826 (Urodela: Sirenidae), Zoologischer Anzeiger – A Journal of Comparative Zoology, Volume 253, Issue 1, August 2013, Pages 1-5, ISSN 0044-5231, http://dx.doi.org/10.1016/j.jcz.2013.06.002.
Parental care is widespread in the animal kingdom and enhances offspring survival. Amphibians exhibit an extraordinary diversity of care strategies, including guarding, transport and even feeding of young. Among amphibians, females are usually the carers, but here we present a case of male parental care in the aquatic salamander Siren intermedia, accompanied by records of external fertilisation. Sirenids are a phylogenetically distinct group within basal salamanders, of which the precise systematic position has long been debated. Our observations of external fertilisation and paternal care of S. intermedia lead us to conclude that apparently both internal fertilisation and maternal care evolved after the split between the more basal groups (Cryptobranchoidea and Sirenoidea) and all other salamanders (suborder Salamandroidea).
Quantity matching by an orangutan (Pongo abelii)
Animal Cognition July 2013
An adult male orangutan (Pongo abelii) was presented with a series of delayed matching-to-sample (DMTS) tasks in which he was to match images based on (a) the number of individual animals depicted in the photograph (from 1 to 4), (b) the number of abstract shapes presented in the stimulus (from 1 to 4), or (c) the number of dots presented in the stimulus (from 1 to 4, 4–7, or 7–10). The spatial arrangement of the dots and the background color of the stimuli varied, and the size of the dots was manipulated to control for overall ratio of foreground to background. The subject’s performance was not affected by these perceptual features, but was affected by the absolute difference and ratio between number of elements in the comparison stimuli. However, the relationship between these variables and his performance was not always linear as predicted by the analog magnitude model. In addition, the subject showed a high degree of transfer to novel numerosities up to ten, indicating that orangutans are capable of estimating quantity for a greater number of items than can presumably be subtilized by humans.
Victoria Camilieri-Asch, Ryan M. Kempster, Shaun P. Collin, Ron Johnstone, Susan M. Theiss, A comparison of the electrosensory morphology of a euryhaline and a marine stingray, Zoology, Available online 19 July 2013, ISSN 0944-2006, http://dx.doi.org/10.1016/j.zool.2013.05.002.
The electrosensory system is found in all chondrichthyan fishes and is used for several biological functions most notably prey detection. Variation in the physical parameters of a habitat type, i.e. water conductivity, may influence the morphology of the electrosensory system. Thus, the electrosensory systems of freshwater rays are considerably different from those of fully marine species; however, little research has so far examined the morphology and distribution of these systems in euryhaline elasmobranchs. The present study investigates and compares the morphology and distribution of electrosensory organs in two sympatric stingray species: the (euryhaline) estuary stingray, Dasyatis fluviorum, and the (marine) blue-spotted maskray, Neotrygon kuhlii. Both species possess a significantly higher number of ventral electrosensory pores than previously assessed elasmobranchs. This correlates with a diet consisting of benthic infaunal and epifaunal prey, where the electrosensory pore distribution patterns are likely to be a function of both ecology and phylogeny. The gross morphology of the electrosensory system in D. fluviorum is more similar to that of other marine elasmobranch species, rather than that of freshwater species. Both D. fluviorum and N. kuhlii possess ‘macro-ampullae’ with branching canals leading to several alveoli. The size of the pores and the length of the canals in D. fluviorum are smaller than in N. kuhlii, which is likely to be an adaptation to habitats with lower conductivity. This study indicates that the morphology of the electrosensory system in a euryhaline elasmobranch species seems very similar to that of their fully marine counterparts. However, some morphological differences are present between these two sympatric species, which are thought to be linked to their habitat type.
Paweł Ręk, Soft calls and broadcast calls in the corncrake as adaptations to short and long range communication, Behavioural Processes, Available online 19 July 2013, ISSN 0376-6357, http://dx.doi.org/10.1016/j.beproc.2013.07.009.
Because birds’ acoustic signals function in antagonistic interactions between males and in female attraction, a majority of vocalisations are loud. In contrast, some birds, additionally produce soft vocalisations in escalated agonistic and sexual contexts. Nevertheless, the relationship between the acoustic parameters of such signals and their function is not clear. Here I investigate the sound transmission degradation properties of soft and broadcast (loud) calls in the corncrake using calls with natural and changed amplitude. I show that, if played at the same amplitude, the maximum limit for communication distance with soft calls was significantly shorter than that of broadcast calls, indicating that frequency structure is important in determining the range of both signals independently of their amplitude. At the same time, the values of excess attenuation were lower for soft calls than for broadcast calls at most distances, which suggests that the short transmission of soft calls is achieved mostly due to their low and narrow frequency ranges, promoting their masking by ambient noise. Finally, contrary to soft calls, changes in the energy of tails of echoes in broadcast calls were associated with the distance of propagation, which might be useful in assessing the distance to senders. I suggest that the acoustic structure of soft vocalisations can be used to limit the range of the signal, which might be helpful in eavesdropping avoidance, whereas broadcast calls are designed for long-range transmission.
Hiroko Kagawa, Masayo Soma, Song performance and elaboration as potential indicators of male quality in Java sparrows, Behavioural Processes, Available online 19 July 2013, ISSN 0376-6357, http://dx.doi.org/10.1016/j.beproc.2013.07.012.
Bird songs have evolved under sexual selection pressure. Songs include multiple features that are subject to female preference, but recent comparative research has indicated evolutionary tradeoffs between song performance and complexity in some species. Trill, a repetition of the same sound, is a performance-related song trait; higher trill performance can be achieved at the cost of song complexity at the among-species or population level. The aim of this study was to examine whether such tradeoffs also account for within-species variation in Java sparrow songs, which include both multiple trill types and non-trill parts. We found a great individual variation in trill proportion, trill performance, and song complexity. A positive association between trill performance and body size suggested that trills can serve as an indicator of male quality. However, contrary to the tradeoffs predicted by previous studies based on other passerine species, trill performance and song complexity, i.e. note repertoire, were positively correlated: males in better condition can sing songs with larger note repertoires and higher trill performance, which may explain how trills and non-trill notes are both maintained and have co-evolved by sexual selection in Java sparrow songs.
Zootaxa 3691 (3): 365–376 (22 Jul. 2013)
Nomenclature of African species of the genus Stenodactylus (Squamata: Gekkonidae)
MARGARITA METALLINOU & PIERRE-ANDRÉ CROCHET
The statuses of proposed nomina of the North African species of the genus Stenodactylus have been revised based on the study of their original descriptions and the examination of their name-bearing types. Important nomenclatural actions proposed include the designation of a lectotype for the nomen Stenodactylus guttatus ensuring continuity of the prevailing usage of S. petrii, and the proposal of maintaining prevailing usage of Stenodactylus sthenodactylus by applying to the International Commission of Zoological Nomenclature to set aside the existing name-bearing type and replace it with a neotype corresponding with that usage.
Ribeiro, J. F. and Vieira, E. M. (2013), Interactions between a seed-eating neotropical rodent, the Azara’s agouti (Dasyprocta azarae), and the Brazilian ‘pine’ Araucaria angustifolia. Austral Ecology. doi: 10.1111/aec.12077
We studied the seed predation and scatter-hoarding behaviour of Azara’s agoutis Dasyprocta azarae (Rodentia: Dasyproctidae) in relation to the seeds of the Brazilian ‘pine’, Araucaria angustifolia (Araucariaceae), the rodent’s main winter food source. We compared seed-removal rates, seed-caching rates, cache distances and recovery rates between a summer period of food abundance (with a low demand for A. angustifolia seeds and no such seeds naturally available) and a winter period of food scarcity (with a high demand for A. angustifolia seeds). We investigated whether the relative seed value affected the rodent’s seed-handling behaviour. We predicted that during the high seed-demand period (winter): (1) cache distances would be greater; fewer seeds would be stored; more seeds would be recovered and the seed-recovery time would be lower. In support of our first two predictions, the caching distances were greater in winter (mean ± SE = 15.67 ± 5.11 m) than in summer (9.40 ± 1.59 m), and agoutis hoarded >9 times more seeds in summer (55) than in winter . Our third prediction was not supported, and the proportion of unrecovered caches and buried seed recovery times did not differ between winter (mean ± SE = 3.00 ± 0.00 days, n = 5 seeds) and summer (11.05 ± 3.68 days, n = 20 seeds). The high resource density (during summer) rather than the density of A. angustifolia seeds likely influenced seed fate. Agoutis acted mainly as predators, leaving few intact seeds, caching a low proportion of handled seeds (≅ 8%) and rapidly consuming the caches. Agoutis may cache seeds to keep them safe from competitors on a short-term basis rather than maintaining medium- or long-term reserves for use during food-scarcity periods.
Barelli, C., Matsudaira, K., Wolf, T., Roos, C., Heistermann, M., Hodges, K., Ishida, T., Malaivijitnond, S. and Reichard, U. H. (2013), Extra-pair paternity confirmed in wild white-handed gibbons. Am. J. Primatol.. doi: 10.1002/ajp.22180
Knowledge of the genetic mating system of animal species is essential for our understanding of the evolution of social systems and individual reproductive strategies. In recent years, genetic methods have uncovered an unexpected diversity of paternal genetic contributions across diverse animal social mating systems, but particularly in pair-living species. In most pair-living birds, for example, genetic and behavioral observations have confirmed a previously unknown significance of extra-pair copulations (EPCs) and extra-pair paternity. Among mammals, white-handed gibbons (Hylobates lar) are also known to live in pairs and are traditionally believed to be single-male single-female breeders. However, at Khao Yai National Park, Thailand, behavioral observations have confirmed the occurrence of both EPCs and functional multi-male grouping, but knowledge about the genetic mating system is still unavailable. In this study, we genotyped 89 white-handed gibbons of the Khao Yai population based on fecal samplings and were able to determine paternity for 41 offspring through short tandem repeat analysis. We found that females‘ stable social partners sired the majority (90.5%) of offspring (N = 38), while only a few (7.1%) offspring (n = 2 confirmed cases; n = 1 inferred case) were conceived with extra-pair partners. The paternity of one offspring remained inconclusive (2.4%), because the offspring’s genotype did not mismatch with the genotypes of two potential sires. Like other predominantly pair-living species, gibbons appear to follow a mixed-reproductive strategy. The genetic mating system of wild white-handed gibbons is best described as flexible, primarily monogamous and opportunistically promiscuous.
Sallan, L. C. and Coates, M. I. (2013), Styracopterid (Actinopterygii) ontogeny and the multiple origins of post-Hangenberg deep-bodied fishes. Zoological Journal of the Linnean Society. doi: 10.1111/zoj.12054
The Carboniferous fish family Styracopteridae (Actinopterygii) originated as part of the initial radiation of ray-finned fishes following the end-Devonian Hangenberg extinction. Specimens of Styracopterus fulcratus (Traquair, 1890) have been collected from post-extinction Tournaisian and Visean Scottish sediments for over 100 years, including sites containing some of the earliest ‘Romer’s Gap’ tetrapods. Re-examination of this supposedly long-lived, static species has revealed two genera, Styracopterus and Fouldenia White, 1927, divergent from each other and previous descriptions. Here, we show that styracopterids are among the earliest actinopterygians with durophagous dentition and toothplates, the latter likely to have derived from the ectopterygoids and coronoids. On the basis of this and other traits, such as the presence of an enameloid ‘beak’, the fusiform styracopterids are linked to some, but not all, the deep-bodied actinopterygians previously placed in the suborder Platysomoidei. A new plesion, Eurynotiformes, is erected to contain the styracopterids, the deeply fusiform Eurynotus and the widespread Amphicentrum, among other laterally compressed fishes. This implies that platysomoids are polyphyletic: deep-bodied and/or durophagous fishes evolved multiple times following the Hangenberg event. Reconstructed styracopterid growth series show that trunk depth increased during maturation, mirroring the shape variation observed among the Eurynotiformes. Other ontogenetic changes involve fin-ray differentiation, jaw form, dermal bone ornamentation, and scale morphology; all of these are widely used as actinopterygian diagnostic characters. Further investigation of Eurynotiformes should reveal the extent of evolutionary and ontogenetic change within the earliest actinopterygian radiation, and are likely to rewrite their phylogeny.
Biological Sciences – Psychological and Cognitive Sciences:
Stephanie L. King andVincent M. Janik
Bottlenose dolphins can use learned vocal labels to address each other
PNAS 2013 ; published ahead of print July 22, 2013, doi:10.1073/pnas.1304459110
In animal communication research, vocal labeling refers to incidents in which an animal consistently uses a specific acoustic signal when presented with a specific object or class of objects. Labeling with learned signals is a foundation of human language but is notably rare in nonhuman communication systems. In natural animal systems, labeling often occurs with signals that are not influenced by learning, such as in alarm and food calling. There is a suggestion, however, that some species use learned signals to label conspecific individuals in their own communication system when mimicking individually distinctive calls. Bottlenose dolphins (Tursiops truncatus) are a promising animal for exploration in this area because they are capable of vocal production learning and can learn to use arbitrary signals to report the presence or absence of objects. Bottlenose dolphins develop their own unique identity signal, the signature whistle. This whistle encodes individual identity independently of voice features. The copying of signature whistles may therefore allow animals to label or address one another. Here, we show that wild bottlenose dolphins respond to hearing a copy of their own signature whistle by calling back. Animals did not respond to whistles that were not their own signature. This study provides compelling evidence that a dolphin’s learned identity signal is used as a label when addressing conspecifics. Bottlenose dolphins therefore appear to be unique as nonhuman mammals to use learned signals as individually specific labels for different social companions in their own natural communication system.
Skibins, J. C. and Powell, R. B. (2013), Conservation caring: Measuring the influence of zoo visitors‘ connection to wildlife on pro-conservation behaviors. Zoo Biol.. doi: 10.1002/zoo.21086
Zoos in the 21st century are striving to make effective contributions to conservation. Although zoos are extremely popular and host over 600 million visitors worldwide, one challenge zoos face is how to effectively engage visitors and raise awareness and action for conservation. To this end, zoos commonly rely on charismatic megafauna, which have been shown to elicit a connection with zoo visitors. However, little is known about how to measure a connection to a species or how this connection may influence conservation behaviors. This study had two sequential objectives. The first was to develop a scale to measure visitors‘ connection to a species (Conservation Caring). The second was to investigate the relationship of Conservation Caring to pro-conservation behaviors, following a zoo experience. Pre- (n = 411) and post-visit (n = 452) responses were collected from three sites in order to assess the reliability and validity of a scale to measure Conservation Caring. Structural equation modeling was used to explore the relationship between Conservation Caring and pro-conservation behaviors. Conservation Caring was deemed a valid and reliable scale and was a strong predictor of species oriented behaviors (β = 0.62), for example, “adopting” an animal, but a weak predictor for biodiversity oriented behaviors (β = 0.07), for example, supporting sustainability policies. support the role zoos can play in fostering a connection to wildlife and stimulating pro-conservation behaviors. Additionally, visitors connected to a wide array of animals. On the basis of these results, zoos may recruit a wider assemblage of species as potential flagships.
Stefano S.K. Kaburu, Nicholas E. Newton-Fisher, Social instability raises the stakes during social grooming among wild male chimpanzees, Animal Behaviour, Available online 22 July 2013, ISSN 0003-3472, http://dx.doi.org/10.1016/j.anbehav.2013.06.003.
Explaining cooperative behaviour is a fundamental issue for evolutionary biology. The challenge for any cooperative strategy is to minimize the risks of nonreciprocation (cheating) in interactions with immediate costs and delayed benefits. One of a variety of proposed strategies, the raise-the-stakes (RTS) strategy, posits that individuals establish cooperation by increasing investment across interactions from an initial interaction. This model has received little quantitative support, however, probably because individuals of many social species engage in repeated interactions from a young age. In some situations, however, such as following conflicts, after prolonged absences or during social instability, established relationships may become unreliable predictors of future behaviour, creating an environment for RTS. We investigated grooming interactions among wild male chimpanzees, Pan troglodytes, testing RTS in these specific contexts. We found evidence to support the view that male chimpanzees employed RTS during social instability, but not under the other conditions. However, we also found that the duration of episodes (discrete parcels) of grooming was negatively related to aggression risk and in consequence suggest that the patterning of grooming interactions indicative of RTS was less to do with preventing cheating, and more to do with avoiding the elevated risks of intramale aggression during the period of social instability. We interpret the apparent support for RTS in our data as a by-product of the way chimpanzees cope with fluctuating (here, elevated then diminishing) risks of aggression. We suggest that social instability raises the stakes for grooming by creating a more hazardous marketplace in which to trade.
Kesch, K. M., Bauer, D. T. and Loveridge, A. J. (2013), Undermining game fences: who is digging holes in Kalahari sands?. African Journal of Ecology. doi: 10.1111/aje.12096
The effectiveness of game fencing as a tool to promote coexistence between humans and wildlife is highly dependent on the maintenance of fences. It is vital to identify animal species, which dig holes under fences, and their digging behaviour to maintain game fences appropriately. We provide data on some of southern Africa’s major hole-digging animal species for a simple albeit effective method enabling stakeholders to categorize species that are digging holes underneath game fences in deep sand habitats by species-specific knowledge on sizes and shapes of holes. Using Botswana’s Khutse Game Reserve/Central Kalahari Game Reserve fence as an example, we highlight the temporal aspect in the process of hole digging and enlargement. We present a method to determine the pressure a fence experiences by a number of hole-digging species. Furthermore, we provide data on the time frame of necessary maintenance actions, required to prevent large predators from transgressing this specific fence line. We were especially interested in the effectiveness of fences in excluding African lions from human-dominated areas. The predators proved to be very difficult to fence in and extremely opportunistic. They mostly utilized holes that were initially excavated by other, even very small species.
Říčanová, Š., Koshev, Y., Říčan, O., Ćosić, N., Ćirović, D., Sedláček, F. and Bryja, J. (2013), Multilocus phylogeography of the European ground squirrel: cryptic interglacial refugia of continental climate in Europe. Molecular Ecology. doi: 10.1111/mec.12382
The theory of classical and cryptic Pleistocene refugia is based mainly on historical changes in temperature, and the refugia are usually defined within a latitudinal gradient. However, the gradient of oceanic–continental climate (i.e. longitudinal) was also significantly variable during glacial cycles with important biotic consequences. Range-wide phylogeography of the European ground squirrel (EGS) was used to interpret the evolutionary and palaeogeographical history of the species in Europe and to shed light on its glacial–interglacial dynamic. The EGS is a steppe-inhabiting species and the westernmost member of the genus in the Palaearctic region. We have analysed 915 specimens throughout the present natural range by employing mitochondrial DNA sequences (cytochrome b gene) and 12 nuclear microsatellite markers. The reconstructed phylogeography divides the species into two main geographical groups, with deep substructuring within both groups. Bulgaria is the centre of the ancestral area, and it also has the highest genetic diversity within the species. The northernmost group of the EGS survived in the southern part of Pannonia throughout several glacial–interglacial cycles. Animals from this population probably repeatedly colonized areas further to the north and west during the glacial periods, while in the interglacial periods, the EGS distribution contracted back to this Pannonian refugium. The EGS thus represents a species with a glacial expansion/interglacial contraction palaeogeographical dynamics, and the Pannonian and southeastern Balkanian steppes are supported as cryptic refugia of continental climate during Pleistocene interglacials.