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Die Naturwissenschaften

Oliver Hawlitschek, Mark D Scherz, Bernhard Ruthensteiner, Angelica Crottini, Frank Glaw
Cryptic species have been detected in many groups of organisms and must be assumed to make up a significant portion of global biodiversity. We study geckos of the Ebenavia inunguis complex from Madagascar and surrounding islands and use species delimitation algorithms (GMYC, BOLD, BPP), COI barcode divergence, diagnostic codon indels in the nuclear marker PRLR, diagnostic categorical morphological characters, and significant differences in continuous morphological characters for its taxonomic revision. BPP yielded ≥ 10 operational taxonomic units, whereas GMYC (≥ 27) and BOLD (26) suggested substantial oversplitting...
July 20, 2018: Die Naturwissenschaften
Lenka Sentenská, Stano Pekár, Gabriele Uhl
In order to avoid sperm competition, males of many taxa apply physical barriers, so-called mating plugs, into female genitalia. Females may control which males deposit a plug through pre-copulatory mate choice or by influencing plug efficacy to avoid costs imposed by plugging. However, subsequent suitors might remove the plugs. We investigated behavioural and morphological aspects of plug deposition and removal in a promiscuous spider, Philodromus cespitum (Philodromidae). We performed mating trials to investigate factors affecting plugging...
July 20, 2018: Die Naturwissenschaften
Samira Veiga Ravaiano, Wagner Faria Barbosa, Lúcio Antônio Campos, Gustavo Ferreira Martins
The insect immune system faces various challenges; particularly in social bees, caste system and age polyethism expose individuals to numerous environmental and working conditions. However, little is known about how cellular defenses in social bees may be organized to respond to a variety of immune challenges. Here, we describe the morphological features and the total and differential counts of hemocytes in different female classes (newly emerged workers, nurses, foragers, and virgin queens) of the eusocial stingless bee Melipona quadrifasciata...
July 19, 2018: Die Naturwissenschaften
Martin Nyffeler, Çağan H Şekercioğlu, Christopher J Whelan
In this paper, we present an estimate of the predation impact of the global population of insectivorous birds based on 103 (for the most part) published studies of prey consumption (kg ha-1  season-1 ) of insectivorous birds in seven biome types. By extrapolation-taking into account the global land cover of the various biomes-an estimate of the annual prey consumption of the world's insectivorous birds was obtained. We estimate the prey biomass consumed by the world's insectivorous birds to be somewhere between 400 and 500 million metric tons year-1 , but most likely at the lower end of this range (corresponding to an energy consumption of ≈ 2...
July 9, 2018: Die Naturwissenschaften
Brehna Teixeira de Melo, Theo Mota, Clemens Schlindwein, Yasmine Antonini, Reisla Oliveira
Pollinators search for multiple flora resources throughout their life cycle. Most studies, however, only assess how bees discriminate floral cues in the context of nectar foraging. In the present study, we sought to elucidate whether oil-collecting bees discriminate flowers of Byrsonima variabilis (Malpighiaceae) with petals of different colours when foraging for pollen or oil. As the colour of the standard petal changes during anthesis, we characterised the spectral reflectance patterns of flowers throughout anthesis and modelled chromatic perceptual space to determine how these colour patterns are perceived by bees...
July 5, 2018: Die Naturwissenschaften
Alejandro Cantarero, Jesús Carrasco Naranjo, Fabián Casas, Francois Mougeot, Javier Viñuela, Carlos Alonso-Alvarez
Complex body designs, such as plumage ornaments in birds, can be described by fractal geometry. These complex patterns could have a role as visual signals during courtship and social interactions, but an empirical validation in the wild is currently lacking. Here, we investigated whether the fractal dimension (FD) of a complex plumage pattern displayed by red-legged partridges Alectoris rufa could function as a potential sexual signal. We captured wild birds early in the breeding season and tested if mated and unmated birds differed in the FD of their conspicuous melanin-based black bib...
June 29, 2018: Die Naturwissenschaften
Brooke Erin Crowley, Ian Castro, Voahangy Soarimalala, Steven M Goodman
We applied a multi-isotope approach to examine aspects of niche partitioning, competition, and mobility for rodents in the Central Highlands of Madagascar. Specifically, we used carbon (δ13 C), nitrogen (δ15 N), and strontium (87 Sr/86 Sr) isotope ratios in bone to investigate diet and mobility for endemic tufted tail rats (Eliurus spp.), and introduced black rats (Rattus rattus) and house mice (Mus musculus) within and outside a fragment of montane humid forest in the Ambohitantely Special Reserve. There was a clear spatial segregation in trapping success for different species: Eliurus was only in the forest interior and edge, Mus only outside of the fragment in a marsh and park housing complex, and Rattus in all habitats except the housing complex...
June 29, 2018: Die Naturwissenschaften
Alain Dejean, Frédéric Azémar, Frédéric Petitclerc, Jacques H C Delabie, Bruno Corbara, Céline Leroy, Régis Céréghino, Arthur Compin
Because Tachia guianensis (Gentianaceae) is a "non-specialized myrmecophyte" associated with 37 ant species, we aimed to determine if its presence alters the ant guild associated with sympatric "specialized myrmecophytes" (i.e., plants sheltering a few ant species in hollow structures). The study was conducted in a hilly zone of a neotropical rainforest where two specialized myrmecophytes grow at the bottom of the slopes, another at mid-slope, and a fourth on the hilltops. Tachia guianensis, which occurred everywhere, had its own guild of associated ant species...
June 27, 2018: Die Naturwissenschaften
Rien E van Wijk, Michael Schaub, Steffen Hahn, Natalia Juárez-García-Pelayo, Björn Schäfer, Lukáš Viktora, Manuel Martín-Vivaldi, Marko Zischewski, Silke Bauer
The annual cycle of migrating birds is shaped by their seasonal movements between breeding and non-breeding sites. Studying how migratory populations are linked throughout the annual cycle-migratory connectivity, is crucial to understanding the population dynamics of migrating bird species. This requires the consideration not only of spatial scales as has been the main focus to date but also of temporal scales: only when both aspects are taken into account, the degree of migratory connectivity can be properly defined...
June 21, 2018: Die Naturwissenschaften
Marcos G Becerra, Diego Pol, Gertrud E Rössner, Oliver W M Rauhut
New materials of the ornithischian dinosaur Manidens condorensis highlight a strong heterodonty between the upper and lower dentitions and reveal a novel occlusion type previously unreported in herbivorous dinosaurs. The diamond-shaped maxillary teeth have prominent cingular entolophs in a V- to Z-shaped configuration that are absent in dentary teeth. These cingular entolophs bear denticles and serrations with vertical wear that is coplanar with the apical wear facets, supporting their involvement in chewing...
June 14, 2018: Die Naturwissenschaften
Ilya A Volodin, Vera A Matrosova, Roland Frey, Julia D Kozhevnikova, Inna L Isaeva, Elena V Volodina
Non-hibernating pikas collect winter food reserves and store them in hay piles. Individualization of alarm calls might allow discrimination between colony members and conspecifics trying to steal food items from a colony pile. We investigated vocal posture, vocal tract length, and individual acoustic variation of alarm calls, emitted by wild-living Altai pikas Ochotona alpina toward a researcher. Recording started when a pika started calling and lasted as long as possible. The alarm call series of 442 individual callers from different colonies consisted of discrete short (0...
June 11, 2018: Die Naturwissenschaften
Zoltán Rádai, Zoltán Németh, Zoltán Barta
Previous studies on arthropods showed that seasonality and parity in breeding considerably impact the direction of sex differences in immunocompetence, and it has been suggested that life span and the time window available for breeding play key roles in shaping sex-differences in immunity. One proposed mechanism behind this phenomenon is differential investment into life history traits in sexes. Here, we tested whether in a seasonally breeding semelparous arthropod sexes differ in their immunocompetence, predicting that females would show weaker immune response than males...
June 7, 2018: Die Naturwissenschaften
Jia-Ying Zhu, Zhi-Wen Xu, Xin-Min Zhang, Nai-Yong Liu
The ability to sense and recognize various classes of compounds is of particular importance for survival and reproduction of insects. Ionotropic receptor (IR), a sub-family of the ionotropic glutamate receptor family, has been identified as one of crucial chemoreceptor super-families, which mediates the sensing of odors and/or tastants, and serves as non-chemosensory functions. Yet, little is known about IR characteristics, evolution, and functions in Lepidoptera. Here, we identify the IR gene repertoire from a destructive polyphagous pest, Spodoptera litura...
May 22, 2018: Die Naturwissenschaften
B Mortimer, A Soler, C R Siviour, F Vollrath
Spiders are fascinating model species to study information-acquisition strategies, with the web acting as an extension of the animal's body. Here, we compare the strategies of two orb-weaving spiders that acquire information through vibrations transmitted and filtered in the web. Whereas Araneus diadematus monitors web vibration directly on the web, Zygiella x-notata uses a signal thread to remotely monitor web vibration from a retreat, which gives added protection. We assess the implications of these two information-acquisition strategies on the quality of vibration information transfer, using laser Doppler vibrometry to measure vibrations of real webs and finite element analysis in computer models of webs...
May 22, 2018: Die Naturwissenschaften
D Rodríguez-Morales, V Rico-Gray, J G García-Franco, H Ajuria-Ibarra, L T Hernández-Salazar, L E Robledo-Ospina, D Rao
Many animals use body coloration as a strategy to communicate with conspecifics, prey, and predators. Color is a trade-off for some species, since they should be visible to conspecifics but cryptic to predators and prey. Some flower-dwelling predators, such as crab spiders, are capable of choosing the color of flowers where they ambush flower visitors and pollinators. In order to avoid being captured, visitors evaluate flowers visually before landing. The crab spider Mecaphesa dubia is a polymorphic species (white/purple color morphs), which inhabits the flower heads of a dune plant, Palafoxia lindenii...
May 12, 2018: Die Naturwissenschaften
Zuzanna M Rosin, Zbigniew Kwieciński, Andrzej Lesicki, Piotr Skórka, Jarosław Kobak, Anna Szymańska, Tomasz S Osiejuk, Tomasz Kałuski, Monika Jaskulska, Piotr Tryjanowski
Although shell colour polymorphism of the land snail Cepaea nemoralis is a well-known phenomenon, proximate and ultimate factors driving its evolution remain uncertain. Polymorphic species show variation in behavioural responses to selective forces. Therefore, we estimated effects of various environmental factors (temperature, humidity, food availability, (micro)habitat structure and predatory pressure) on behavioural response (frequency of locomotion, climbing and hiding) of C. nemoralis morphs, in experimental and natural conditions...
May 9, 2018: Die Naturwissenschaften
Shiping Gong, Melita Vamberger, Markus Auer, Peter Praschag, Uwe Fritz
Chinese softshell turtles (Pelodiscus spp.) are widely distributed, ranging from the Amur and Ussuri Rivers in the Russian Far East through the Korean Peninsula, Japan, and eastern, central, and southern China to southern Vietnam. In East and Southeast Asia, Chinese softshell turtles are traditionally exploited for food and have been farm-bred in China since the Spring and Autumn Period, more than 2400 years ago. Currently, the annual production of Pelodiscus amounts to 340,000 t in China alone. Using mitochondrial DNA (2428 bp) and five nuclear loci (3704 bp), we examined broad sampling of wild and farm-bred Pelodiscus to infer genetic and taxonomic differentiation...
May 4, 2018: Die Naturwissenschaften
James J Foster, Shelby E Temple, Martin J How, Ilse M Daly, Camilla R Sharkey, David Wilby, Nicholas W Roberts
In "Polarisation vision: overcoming challenges of working with a property of light we barely see" (Foster et al. 2018) we provide a basic description of how Stokes parameters can be estimated and used to calculate the angle of polarisation (AoP).
May 3, 2018: Die Naturwissenschaften
Masahiko Tanahashi, Hiroshi Ikeda, Kôhei Kubota
Wood degradation by insects plays important roles for the forest matter cycling. Since wood is deficient in nitrogen compared to the insect body, wood-feeding insects need to assimilate the nitrogen selectively and discard an excess carbon. Such a stoichiometric imbalance between food and body will cause high metabolic cost; therefore, wood-feeding insects may somehow alleviate the stoichiometric imbalance. Here, we investigated the carbon and nitrogen budgets of the larvae of stag beetle, Dorcus rectus, which feed on decaying wood...
May 3, 2018: Die Naturwissenschaften
Juan Manuel González-García, Carlos Lara, Javier Quesada, Carlos A Chávez-Zichinelli, Martín A Serrano-Meneses
The role of badges as indicators of contest ability has been previously described. In hummingbirds, the exhibition of a badge is expected to save energy expenditure in agonistic interactions and to favor energy intake. Here, we investigate whether variable supercilium size in the white-eared hummingbird has a role in dominance status signaling. Firstly, 45 hummingbird males were captured and their superciliums were photographed to investigate variation in size and any possible allometric relationships. Secondly, 42 male birds were used to analyze whether the supercilium has a role in dominance status signaling in a dyadic contest...
April 3, 2018: Die Naturwissenschaften
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