Jadeja, S., Prasad, S., Quader, S. and Isvaran, K. (2013), Antelope mating strategies facilitate invasion of grasslands by a woody weed. Oikos. doi: 10.1111/j.1600-0706.2013.00320.x
Intra and interspecific variation in frugivore behaviour can have important consequences for seed dispersal outcomes. However, most information comes from among-species comparisons, and within-species variation is relatively poorly understood. We examined how large intraspecific differences in the behaviour of a native disperser, blackbuck antelope Antilope cervicapra, influence dispersal of a woody invasive, Prosopis juliflora, in a grassland ecosystem. Blackbuck disperse P. juliflora seeds through their dung. In lekking blackbuck populations, males defend clustered or dispersed mating territories. Territorial male movement is restricted, and within their territories males defecate on dung-piles. In contrast, mixed-sex herds range over large areas and do not create dung-piles. We expected territorial males to shape seed dispersal patterns, and seed deposition and seedling recruitment to be spatially localized. Territorial males had a disproportionately large influence on seed dispersal. Adult males removed twice as much fruit as females, and seed arrival was disproportionately high on territories. Also, because lek-territories are clustered, seed arrival was spatially highly concentrated. Seedling recruitment was also substantially higher on territories compared with random sites, indicating that the local concentration of seeds created by territorial males continued into high local recruitment of seedlings. Territorial male behaviour may, thus, result in a distinct spatial pattern of invasion of grasslands by the woody P. juliflora. An ex situ experiment showed no beneficial effect of dung and a negative effect of light on seed germination. We conclude that large intraspecific behavioural differences within frugivore populations can result in significant variation in their effectiveness as seed dispersers. Mating strategies in a disperser could shape seed dispersal, seedling recruitment and potentially plant distribution patterns. These mating strategies may aid in the spread of invasives, such as P. juliflora, which could, in turn, negatively influence the behaviour and ecology of native dispersers.
Flores, E. E., Stevens, M., Moore, A. J., Blount, J. D. (2013), Diet, development and the optimization of warning signals in post-metamorphic green and black poison frogs. Functional Ecology. doi: 10.1111/1365-2435.12084
1. Many prey species are chemically defended and have conspicuous appearance to deter predators (i.e. aposematism). Such warning signals work because predators pay attention to the colour and size of signals, which they associate with unprofitability.
2. Paradoxically, in early life stages, aposematic species are often warningly coloured, but their chemical defences are lacking because they have yet to be acquired through the diet or synthesized endogenously. This state of being conspicuous yet poorly defended must place individuals at increased risk of predation, but how they minimize this risk during development is unclear.
3. We reared larval green and black poison frogs (Dendrobates auratus) on a relatively low or a higher food supply and tested the hypothesis that individuals with more resources should grow larger while reducing their investment in warning signals at metamorphic completion. We also assayed markers of oxidative balance (malondialdehyde, superoxide dismutase and total antioxidant capacity) to ascertain whether there were resource-allocation trade-offs that differed with diet treatments.
4. Low-food froglets were relatively small, and their body size and signal luminance (perceived brightness) were positively correlated. In contrast, in high-food froglets body size and warning signal luminance were negatively correlated, suggesting either a resource-allocation trade-off or alternatively a facultative reduction in luminance exhibited by larger froglets.
5. The reduction in luminance in relatively large, high-food froglets did not appear to arise because of oxidative stress: signal luminance and markers of oxidative stress were positively correlated in high-food froglets, but were negatively correlated in low-food froglets suggesting a trade-off.
6. Our results highlight developmental plasticity in body size and coloration as affected by resource (i.e. food) supply. Such plasticity seems likely to minimize predation risk during the vulnerable period early in life when individuals are warningly coloured and must make the transition from an undefended phenotype to a mature aposematic state.
Michelle Brown, Food and range defence in group-living primates, Animal Behaviour, Available online 4 March 2013, ISSN 0003-347
Why do some primate groups contest access to food resources primarily at territorial borders (periphery defence), whereas others are more likely to contest resources in the centre of the home range (core defence)? One possibility is that central areas contain more food resources and so are more important for core-defending groups, whereas peripheral areas are more valuable for groups that defend territorial boundaries. I tested this hypothesis by analysing the distribution of resources in home ranges and aggressive intergroup interactions for six groups of grey-cheeked mangabeys, Lophocebus albigena, and six groups of redtail monkeys, Cercopithecus ascanius, at the Ngogo site in Kibale National Park, Uganda. Neither mangabeys nor redtails exhibited core or boundary defence in this study; instead, both species appeared to defend discrete feeding sites, and neither the core nor peripheral home range areas consistently contained greater quantities of food. I also compared variables that are frequently used to characterize primate food availability (the feeding value of the interaction site versus food abundance, distribution and patch size) to determine if they are equally accurate in predicting aggressive food defence. Whereas site feeding intensity predicted aggression by redtails, aggression by mangabey males correlated with the abundance and distribution of resources. These results demonstrate the importance of testing multiple aspects of food availability, which can vary in importance among different primate populations. I conclude by proposing a new model of food and range defence in group-living primates that predicts specific relationships between various food characteristics and core, patch and periphery defence.
Hans Slabbekoorn, Songs of the city: noise-dependent spectral plasticity in the acoustic phenotype of urban birds, Animal Behaviour, Available online 4 March 2013, ISSN 0003-3472, 10.1016/j.anbehav.2013.01.021.
Urbanization leads to homogenization of avian communities through local extinction of rare bird species and increasing numbers of the same common urban bird species over large geographical areas. Successful city birds often persist through some sort of behavioural plasticity that helps them survive and reproduce close to humans, in built-up areas, with all the typical urban feasts and hazards. In this review, I address whether behavioural plasticity of the acoustic phenotype can be an additional factor in explaining which species end up as urban survivors. Anthropogenic noise has been shown to negatively affect avian distribution and reproduction, especially for species that rely on relatively low-frequency songs for mediating territorial conflicts and attracting partners for mating. Spectral differences between songs of city and forest populations of the same species and correlations between individual song frequency use and local noise levels suggest that many successful city species shift song frequency upward under noisy urban conditions. Experimental evidence has confirmed the ability of several species to show rapid spectral adjustments as well as perceptual benefits of singing at higher frequency in noisy habitats. However, empirical evidence of fitness benefits for birds showing the ability and tendency of noise-dependent spectral adjustment is still lacking. Furthermore, depending on the species and the underlying mechanism for spectral change, there may also be fitness costs through a compromise on signal function. These two aspects are only two of many remaining avenues for future studies. The acoustic phenotype of urban birds provides a great model system to study fundamental processes such as causes and consequences of environmentally induced signal changes, ‘cultural assimilation’, and the relationship between phenotypic and genotypic evolution. Furthermore, the current and expected rate of urbanization remains high at a global scale, which will lead to further spread in time and space of artificially elevated noise levels. This should guarantee the continued interest of scientists, politicians and conservationists for many years ahead.
John A. Rossow, Sonia M. Hernandez, Scarlett M. Sumner, Bridget R. Altman, Caroline G. Crider, Mallory B. Gammage, Kristy M. Segal, Michael J. Yabsley, Haemogregarine infections of three species of aquatic freshwater turtles from two sites in Costa Rica, International Journal for Parasitology: Parasites and Wildlife, Available online 5 March 2013, ISSN 2213-2244, 10.1016/j.ijppaw.2013.02.003.
Twenty-five black river turtles (Rhinoclemmys funerea) and eight white-lipped mud turtle (Kinosternon leucostomum) from Selva Verde, Costa Rica were examined for haemoparasites. Leeches identified as Placobdella multilineata were detected on individuals from both species. All turtles sampled were positive for intraerythrocytic haemogregarines (Apicomplexa:Adeleorina) and the average parasitemia of black river turtles was significantly higher compared to white-lipped mud turtles). No correlation was found between parasitemia and relative body mass of either species or between black river turtles from the two habitats. In addition, one scorpion mud turtle (Kinosternon scorpioides) examined from La Pacifica, Costa Rica was positive for haemogregarines (0.01% parasitemia). Interestingly, parasites of the scorpion mud turtle were significantly smaller than those from the other two species and did not displace the erythrocyte nucleus, whereas parasites from the other two species consistently displaced host cell nuclei and often distorted size and shape of erythrocytes. This is the first report of haemogregarines in turtles from Central America and of haemogregarines in K. leucostomum, K. scorpioides, and any Rhinoclemmys species. Additional studies are needed to better characterise and understand the ecology of these parasites.
Karis H. Baker, A. Rus Hoelzel, Fluctuating asymmetry in populations of British roe deer (Capreolus capreolus) following historical bottlenecks and founder events, Mammalian Biology – Zeitschrift für Säugetierkunde, Available online 5 March 2013, ISSN 1616-5047, 10.1016/j.mambio.2013.02.001.
The potential impact of population bottlenecks and founder events on genetic diversity and indirect measures of fitness (such as fluctuating asymmetry; FA) has important conservation implications. Here we take advantage of historical events that generated a remnant roe deer (Capreolus capreolus) population in the north of the British Isles that retained diversity, while populations in the south were apparently extirpated during the early mediaeval era. The southern population was later re-established from small founder populations of introduced European roe deer starting in the 19th century. We assess the impact of these events, using the northern remnant population as a reference, based on measures of FA at 16 bilateral cranial traits. Comparing the northern and southern populations we find evidence of differential impact on both the level of FA and the relationship between FA and levels of genetic diversity.
Zootaxa 3620 (2): 245–259 (6 Mar. 2013)
A lost species or the loss of stripes? The case of Contomastix lizards from Cabo Polonio, Uruguay, with observations on C. lacertoides (Duméril & Bibron) and Cnemidophorus grandensis Cope (Squamata, Teiidae)
CLAUDIO BORTEIRO, FRANCISCO KOLENC, CARLOS PRIGIONI, MARIANA L. LYRA & DIEGO BALDOThe main goal of this manuscript is the reevaluation of the taxonomic status of the teiid lizard Contomastix charrua, known only from Cabo Polonio, a small coastal rocky outcrop in southeastern Uruguay. This species was erected on the basis of the presence of a second pair of ceratobranchials and longer cornua in the hyoid bone, in addition to a reduced expression of the pattern of coloration as compared with C. lacertoides. Nevertheless, we found that both species have indistinguishable hyoid morphology, bearing C. lacertoides a noticeable second pair of ceratobranchials. Besides, we realized that the pattern of coloration in this species is more variable than previously considered. As a result of the present work, C. charrua is included in the synonymy of C. lacertoides. In addition, we provide some observations on the holotype of Cnemidophorus grandensis, a junior synonym of C. lacertoides.
Zootaxa 3620 (2): 273–282 (6 Mar. 2013)
Redescription of Parapercis macrophthalma (Pietschmann, 1911) and description of a new species of Parapercis (Pisces: Pinguipedidae) from Taiwan
HSUAN-CHING HO & JEFFREY W. JOHNSON
Parapercis macrophthalma is confirmed as a valid species and redescribed on the basis of the holotype and other specimens collected from the type locality, Taiwan, and Japan. It is morphologically similar to P. muronis Tanaka, 1918, but differs in having five vertical transverse bars that extend well below the lateral line versus five oblique transverse bars, with the third to fifth bars ending on or above the lateral line. A new species is also described on the basis of a specimen collected from southwestern Taiwan. It is distinct in having numerous pores interconnected by canals on the head, forming 10 vertical or oblique rows on the cheek and opercular apparatus, predorsal scales extending to the level of the posterior margin of the eye, four dorsal-fin spines, six oblique bars laterally on the body, and a combination of other characters. A key to species of Parapercis with narrow transverse bars on the upper body is provided.
Steyaert, S. M.J.G., Kindberg, J., Swenson, J. E., Zedrosser, A. (2013), Male reproductive strategy explains spatiotemporal segregation in brown bears. Journal of Animal Ecology. doi: 10.1111/1365-2656.12055
1. Spatiotemporal segregation is often explained by the risk for offspring predation or by differences in physiology, predation risk vulnerability or competitive abilities related to size dimorphism.
2. Most large carnivores are size dimorphic and offspring predation is often intraspecific and related to nonparental infanticide (NPI). NPI can be a foraging strategy, a strategy to reduce competition, or a male reproductive strategy. Spatiotemporal segregation is widespread among large carnivores, but its nature remains poorly understood.
3. We evaluated three hypotheses to explain spatiotemporal segregation in the brown bear, a size-dimorphic large carnivore in which NPI is common; the ‘NPI – foraging/competition hypothesis‘, i.e. NPI as a foraging strategy or a strategy to reduce competition, the ‘NPI – sexual selection hypothesis’, i.e. infanticide as a male reproductive strategy and the ‘body size hypothesis’, i.e. body-size-related differences in physiology, predation risk vulnerability or competitive ability causes spatiotemporal segregation. To test these hypotheses, we quantified spatiotemporal segregation among adult males, lone adult females and females with cubs-of-the-year, based on GPS-relocation data (2006–2010) and resource selection functions in a Scandinavian population.
4. We found that spatiotemporal segregation was strongest between females with cubs-of-the-year and adult males during the mating season. During the mating season, females with cubs-of-the-year selected their resources, in contrast to adult males, in less rugged landscapes in relative close proximity to certain human-related variables, and in more open habitat types. After the mating season, females with cubs-of-the-year markedly shifted their resource selection towards a pattern more similar to that of their conspecifics. No strong spatiotemporal segregation was apparent between females with cubs-of-the-year and conspecifics during the mating and the postmating season.
5. The ‘NPI – sexual selection hypothesis’ best explained spatiotemporal segregation in our study system. We suggest that females with cubs-of-the-year alter their resource selection to avoid infanticidal males. In species exhibiting NPI as a male reproductive strategy, female avoidance of infanticidal males is probably more common than observed or reported, and may come with a fitness cost if females trade safety for optimal resources.
Mendonça, F. F., Oliveira, C., Gadig, O. B. F. and Foresti, F. (2013), Diversity and genetic population structure of the Brazilian sharpnose shark Rhizoprionodon lalandii. Aquatic Conserv: Mar. Freshw. Ecosyst.. doi: 10.1002/aqc.2342
1. Similar to many small, range-restricted elasmobranchs, the Brazilian sharpnose shark (Rhizoprionodon lalandii) is listed as ‘data deficient’ by the International Union for the Conservation of Nature (IUCN). Data on stock assessment and sustainability are scarce, and there is no information on population structure. This constitutes a management problem because this shark comprises approximately 50% of the catch of small coastal sharks in Brazil.
2. In this study, populations of R. lalandii distributed from the Caribbean to southern Brazil were investigated using sequences from the mitochondrial DNA control region. Analysis of molecular variance revealed strong structuring between population samples from the Caribbean and those from the Brazilian coast (ФST = 0.254, P < 0.0001). Significant differences in the rates of genetic diversity between these major areas were also detected. The observed levels of population structuring are likely to be driven by female phylopatry.
3. Therefore, the identification of both mating and nursery areas with parallel ban/restriction of fishing in these areas may be critical for the long-term sustainability of these populations.