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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
Beatriz Sánchez-González, Aimara Planillo, Álvaro Navarro-Castilla, Isabel Barja
Predation is an unavoidable and dangerous fact in the lifetime of prey animals and some sign of the proximity of a predator may be enough to trigger a response in the prey. We investigated whether different degrees of predation risk by red foxes (Vulpes vulpes) evoke behavioural and physiological stress responses in wood mice (Apodemus sylvaticus). We examined the variation in mice responses due to individual factors (sex and reproductive status) and related them to the concentration of the volatile compounds from fox faeces over time...
January 31, 2018: Die Naturwissenschaften
Hideto Yoshimura, Yoshihiro Y Yamada
Independent-founding paper wasps constitute a major group of primitively eusocial insects, and when caste-fate determination occurs in temperate species of these wasps, particularly regarding whether it occurs before or after emergence, remains unclear. No critical morphological differences occur between potential queens of the next generation (often called gynes) and workers in primitively eusocial insects. The gynes of temperate species are characterized by diapausing, and the nutrients available during the larval stage have often been believed to determine caste fate...
January 24, 2018: Die Naturwissenschaften
Sarah A Ohrnberger, Katharina Brinkmann, Rupert Palme, Teresa G Valencak
Breeding of golden hamsters is classically performed at thermal conditions ranging from 20 to 24 °C. However, growing evidence suggests that lactating females suffer from heat stress. We hypothesised that shaving females dorsally to maximise heat dissipation may reduce stress during reproduction. We thus compared faecal cortisol metabolites (FCM) from shaved golden hamster mothers with those from unshaved controls. We observed significantly lower FCM levels in the shaved mothers (F1,22 = 8.69, p = 0...
January 15, 2018: Die Naturwissenschaften
Pauline Provini, Anick Abourachid
Previous studies showed that birds primarily use their hindlimbs to propel themselves into the air in order to take-off. Yet, it remains unclear how the different parts of their musculoskeletal system move to produce the necessary acceleration. To quantify the relative motions of the bones during the terrestrial phase of take-off, we used biplanar fluoroscopy in two species of birds, diamond dove (Geopelia cuneata) and zebra finch (Taeniopygia guttata). We obtained a detailed 3D kinematics analysis of the head, the trunk and the three long bones of the left leg...
January 6, 2018: Die Naturwissenschaften
Sean O'Donnell
Directional climate change (global warming) is causing rapid alterations in animals' environments. Because the nervous system is at the forefront of animals' interactions with the environment, the neurobiological implications of climate change are central to understanding how individuals, and ultimately populations, will respond to global warming. Evidence is accumulating for individual level, mechanistic effects of climate change on nervous system development and performance. Climate change can also alter sensory stimuli, changing the effectiveness of sensory and cognitive systems for achieving biological fitness...
January 6, 2018: Die Naturwissenschaften
Canchao Yang, Qiuli Huang, Longwu Wang, Wei-Guo Du, Wei Liang, Anders Pape Møller
Obligate brood parasites have evolved unusually thick-shelled eggs, which are hypothesized to possess a variety of functions such as resistance to puncture ejection by their hosts. In this study, we tested the hypothesis that obligate brood parasites lay unusually thick-shelled eggs to retain more heat for the developing embryo and thus contribute to early hatching of parasite eggs. By doing so, we used an infrared thermal imaging system as a non-invasive method to quantify the temperature of eggshells of common cuckoos (Cuculus canorus) and their Oriental reed warbler (Acrocephalus orientalis) hosts in an experiment that artificially altered the duration of incubation...
January 2, 2018: Die Naturwissenschaften
G S Balamurali, Elizabeth Nicholls, Hema Somanathan, Natalie Hempel de Ibarra
The spontaneous occurrence of colour preferences without learning has been demonstrated in several insect species; however, the underlying mechanisms are still not understood. Here, we use a comparative approach to investigate spontaneous and learned colour preferences in foraging bees of two tropical and one temperate species. We hypothesised that tropical bees utilise different sets of plants and therefore might differ in their spontaneous colour preferences. We tested colour-naive bees and foragers from colonies that had been enclosed in large flight cages for a long time...
January 2, 2018: Die Naturwissenschaften
Verónica Gomes, Miguel A Carretero, Antigoni Kaliontzopoulou
A central issue in evolutionary biology is how morphology, performance, and habitat use coevolve. If morphological variation is tightly associated with habitat use, then differences in morphology should affect fitness through their effect on performance within specific habitats. In this study, we investigate how evolutionary forces mold morphological traits and performance differently given the surrounding environment, at the intraspecific level. For this purpose, we selected populations of the lizard Podarcis bocagei from two different habitat types, agricultural walls and dunes, which we expected to reflect saxicolous vs ground-dwelling habits...
January 2, 2018: Die Naturwissenschaften
Nikolai W F Bode, Michael J Seitz
The movement of animals in groups is widespread in nature. Understanding this phenomenon presents an important problem in ecology with many applications that range from conservation to robotics. Underlying all group movements are interactions between individual animals and it is therefore crucial to understand the mechanisms of this social behaviour. To date, despite promising methodological developments, there are few applications to data of practical statistical techniques that inferentially investigate the extent and nature of social interactions in group movement...
December 27, 2017: Die Naturwissenschaften
Renata Jach, Stanisław Knutelski, Alfred Uchman, Helena Hercman, Marek Dohnalik
Abundant bog oak trunks occur in alluvial deposits of the Raba River in the village of Targowisko (southern Poland). Several of them contain galleries of the great capricorn beetle (Cerambyx cerdo L.). A well-preserved subfossil larva and pupa, as well as adults of this species, are concealed in some of the galleries. These galleries co-occur with boring galleries of other insects such as ship-timber beetles (Lymexylidae) and metallic wood borers (Buprestidae). A dry larva of a stag beetle (Lucanidae) and a mite (Acari) have been found in the C...
December 27, 2017: Die Naturwissenschaften
Magali Combes, David Pinaud, Christophe Barbraud, Jacques Trotignon, François Brischoux
Severe population declines of amphibians have been shown to be attributed to climate change. Nevertheless, the various mechanisms through which climate can influence population dynamics of amphibians remain to be assessed, notably to disentangle the relative synergetic or antagonistic influences of temperature and precipitations on specific life history stages. We investigated the impact of rainfall and temperature on the egg-clutch abundance in a population of agile frog (Rana dalmatina) during 29 years (1987-2016) on 14 breeding sites located in Brenne Natural Park, France...
December 19, 2017: Die Naturwissenschaften
Min Kong, Fengjuan Wang, Liuying Tian, Hui Tang, Liping Zhang
Glutathione (GSH) fulfills a variety of metabolic functions, participates in oxidative stress response, and defends against toxic actions of heavy metals and xenobiotics. In this study, GSH was detected in Rhodosporidium diobovatum by high-performance liquid chromatography (HPLC). Then, two novel enzymes from R. diobovatum were characterized that convert glutamate, cysteine, and glycine into GSH. Based on reverse transcription PCR, we obtained the glutathione synthetase gene (GSH2), 1866 bp, coding for a 56...
December 15, 2017: Die Naturwissenschaften
Eva Turk, Matjaž Kuntner, Simona Kralj-Fišer
Males and females are often subjected to different selection pressures for homologous traits, resulting in sex-specific optima. Because organismal attributes usually share their genetic architectures, sex-specific selection may lead to intralocus sexual conflict. Evolution of sexual dimorphism may resolve this conflict, depending on the degree of cross-sex genetic correlation (rMF ) and the strength of sex-specific selection. In theory, high rMF implies that sexes largely share the genetic base for a given trait and are consequently sexually monomorphic, while low rMF indicates a sex-specific genetic base and sexual dimorphism...
December 5, 2017: Die Naturwissenschaften
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