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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
Luis Fernando García, Carmen Viera, Stano Pekár
Predators are traditionally classified as generalists and specialists based on the presence of adaptations that increase efficiency of prey capture and consumption and selection of particular prey types. Nevertheless, empirical evidence comparing foraging efficiency between generalist and specialist carnivores is scarce. We compared the prey-capture and feeding efficiency in a generalist and a specialist (araneophagous) spider predator. By using two related species, the generalist Harpactea rubicunda (Dysderidae) and the specialist Nops cf...
April 2, 2018: Die Naturwissenschaften
Michelle Ramos-Robles, Wesley Dáttilo, Cecilia Díaz-Castelazo, Ellen Andresen
Interactions between fleshy fruited plants and frugivores are crucial for the structuring and functioning of biotic communities, particularly in tropical forests where both groups are diverse and play different roles in network organization. However, it remains poorly understood how different groups of frugivore species and fruit traits contribute to network structure. We recorded interactions among 28 plant species and three groups of frugivores (birds, bats, and non-flying mammals) in a seasonal forest in Mexico to determine which species contribute more to network structure and evaluate the importance of each species...
April 2, 2018: Die Naturwissenschaften
James J Foster, Shelby E Temple, Martin J How, Ilse M Daly, Camilla R Sharkey, David Wilby, Nicholas W Roberts
In recent years, the study of polarisation vision in animals has seen numerous breakthroughs, not just in terms of what is known about the function of this sensory ability, but also in the experimental methods by which polarisation can be controlled, presented and measured. Once thought to be limited to only a few animal species, polarisation sensitivity is now known to be widespread across many taxonomic groups, and advances in experimental techniques are, in part, responsible for these discoveries. Nevertheless, its study remains challenging, perhaps because of our own poor sensitivity to the polarisation of light, but equally as a result of the slow spread of new practices and methodological innovations within the field...
March 27, 2018: Die Naturwissenschaften
Alberto Boscaini, Dawid A Iurino, Guillaume Billet, Lionel Hautier, Raffaele Sardella, German Tirao, Timothy J Gaudin, François Pujos
Several detailed studies of the external morphology of the ear region in extinct sloths have been published in the past few decades, and this anatomical region has proved extremely helpful in elucidating the phylogenetic relationships among the members of this mammalian clade. Few studies of the inner ear anatomy in these peculiar animals were conducted historically, but these are increasing in number in recent years, in both the extinct and extant representatives, due to wider access to CT-scanning facilities, which allow non-destructive access to internal morphologies...
March 27, 2018: Die Naturwissenschaften
G Zięba, M Dukowska, M Przybylski, M G Fox, C Smith
Providing parental care is potentially costly. Costs can arise through elevated energy expenditure or from an increased risk of mortality. A cost of parental care can also occur because a parent is compromised in their ability to forage. We used pumpkinseed Lepomis gibbosus, a fish with an alternative male mating strategy, to test whether parental males differed in their feeding in comparison with females and cuckolder males. To address this question, we examined the stomach contents of female, cuckolder male, and parental male pumpkinseed during the breeding season over an entire diel cycle...
March 26, 2018: Die Naturwissenschaften
Fabian Engel, Kaitlin J Farrell, Ian M McCullough, Facundo Scordo, Blaize A Denfeld, Hilary A Dugan, Elvira de Eyto, Paul C Hanson, Ryan P McClure, Peeter Nõges, Tiina Nõges, Elizabeth Ryder, Kathleen C Weathers, Gesa A Weyhenmeyer
The magnitude of lateral dissolved inorganic carbon (DIC) export from terrestrial ecosystems to inland waters strongly influences the estimate of the global terrestrial carbon dioxide (CO2 ) sink. At present, no reliable number of this export is available, and the few studies estimating the lateral DIC export assume that all lakes on Earth function similarly. However, lakes can function along a continuum from passive carbon transporters (passive open channels) to highly active carbon transformers with efficient in-lake CO2 production and loss...
March 26, 2018: Die Naturwissenschaften
Guilin Li, Yanming Zhang, Yong Ni, Ying Wang, Baohua Xu, Xingqi Guo
It is known that melatonin plays an indispensable role in the defense against some environment-induced stresses. The melatonin receptor (MTNR) is also closely linked to the environmental stress response in mammals. However, little is known about the function of the MTNR in insects, including honeybees. In this study, we identified a MTNR from Apis cerana cerana named AccMTNR1A, which contained a typical seven-transmembrane domain common to this family of receptors. A subcellular localization analysis showed that AccMTNR1A was localized in the cytomembrane...
March 22, 2018: Die Naturwissenschaften
Benjamin J Taylor, Robert L Jeanne
Many social insect species produce signals that either recruit foragers to a specific food source or simply activate more nestmates to become foragers. Both are means of enhancing resource exploitation by increasing the number of individuals devoted to gathering profitable resources. Gastral drumming (GD) has been documented in several species of yellowjackets and hornets (Vespidae: Vespinae). It has been hypothesized that it is a hunger signal, but there is little empirical evidence to support this claim. An alternative hypothesis is that GD recruits workers to forage for food...
March 21, 2018: Die Naturwissenschaften
Denise Aumer, Fiona N Mumoki, Christian W W Pirk, Robin F A Moritz
Social insects are characterized by the division of labor. Queens usually dominate reproduction, whereas workers fulfill non-reproductive age-dependent tasks to maintain the colony. Although workers are typically sterile, they can activate their ovaries to produce their own offspring. In the extreme, worker reproduction can turn into social parasitism as in Apis mellifera capensis. These intraspecific parasites occupy a host colony, kill the resident queen, and take over the reproductive monopoly. Because they exhibit a queenlike behavior and are also treated like queens by the fellow workers, they are so-called pseudoqueens...
March 20, 2018: Die Naturwissenschaften
Sven Thatje
No abstract text is available yet for this article.
March 14, 2018: Die Naturwissenschaften
Carmelo Peter Bonsignore, Umberto Bernardo
The chestnut gall wasp (CGW), Dryocosmus kuriphilus, an invasive pest native to China, has caused severe yield and economic losses to chestnut production in Europe since its arrival in 2002. In Southern Italy, the complex of indigenous parasitoids colonizing CGW was monitored between 2013 and 2015, with the aim of estimating the composition of the indigenous parasitoid complex, its ability to control CGW populations, and the interactions of both factors with several measured environmental parameters. We compared results among three differently managed field types...
March 2, 2018: Die Naturwissenschaften
Sally Hall, Sven Thatje
The objectives of this work are to use gene sequence data to assess the hypothesis that the Lithodinae arose from ancestors with uncalcified abdomens in shallow waters of the North-East Pacific, investigate the monophyly and interrelationships of genera within the Lithodinae and to estimate the scale and minimum number of biogeographic transitions from the shallow environment to the deep sea and vice versa. To do this, phylogenetic analysis from three mitochondrial and three nuclear markers was conducted using minimum evolution, maximum likelihood and Bayesian methods...
February 27, 2018: Die Naturwissenschaften
Branislav Igic, Liliana D'Alba, Matthew D Shawkey
White colouration is a common and important component of animal visual signalling and camouflage, but how and why it varies across species is poorly understood. White is produced by wavelength-independent and diffuse scattering of light by the internal structures of materials, where the degree of brightness is related to the amount of light scattered. Here, we investigated the morphological basis of brightness differences among unpigmented pennaceous regions of white body feathers across 61 bird species. Using phylogenetically controlled comparisons of reflectance and morphometric measurements, we show that brighter white feathers had larger and internally more complex barbs than duller white feathers...
February 14, 2018: Die Naturwissenschaften
E P Badás, J Martínez, J Rivero-de Aguilar, C Ponce, M Stevens, S Merino
Carry-over effects refer to processes that occur in one season and influence fitness in the following. In birds, two costly activities, namely reproduction and moult, are restricted to a small time window, and sometimes overlap. Thus, colour in newly moulted feathers is likely to be affected by the costs of reproduction. Using models of bird vision we investigated male colour change in a free-living population of blue tits (Cyanistes caeruleus) in three sampling occasions: spring 1, winter and spring 2. We related crown, tail, breast and cheek feather colouration after the moult (winter) to the intensity of infections by blood parasites during reproduction (spring 1)...
February 6, 2018: Die Naturwissenschaften
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