Search results for "anima"
showing 10 items of 22401 documents
Hemocyanin genes as indicators of habitat shifts in Panpulmonata?
2018
Hemocyanin is the primary respiratory protein for the majority of the Mollusca and therefore directly interfaces with the physiological requirements of each species and the environments to which they are adapted. Hemocyanin is therefore likely to have been evolutionarily imprinted by significant habitat shifts. In the gastropod clade Panpulmonata (>30,000 species) major realm transitions have occurred multiple times independently and may have contributed to the diversification of this group. Yet, little is known about the adaptive changes linked to these habitat shifts. In order to gain deeper insight into the evolution of panpulmonate hemocyanins and to infer possible impacts associated wi…
Genomic stability through time despite decades of exploitation in cod on both sides of the Atlantic
2021
Significance Both theory and experiments suggest that fishing can drive the evolution of an earlier maturation age. However, determining whether changes in the wild are the result of fisheries-induced evolution has been difficult. Temporal, genome-wide datasets can directly reveal responses to selection. Here, we investigate the genomes of two wild Atlantic cod populations from samples that pre- and postdate periods of intensive fishing. Although phenotypic changes suggest fisheries-induced evolution, we do not find evidence for any strong genomic change or loss of genetic diversity. While evolution could have occurred through undetectable frequency changes at many loci, the irreversible lo…
Evolutionary history of two cryptic species of northern African jerboas
2020
Abstract Background: Climatic variation and geologic change both play significant roles in shaping species distributions, thus affecting their evolutionary history. In Sahara-Sahel, climatic oscillations shifted the desert extent during the Pliocene-Pleistocene interval, triggering the diversification of several species. Here, we investigated how these biogeographical and ecological events have shaped patterns of genetic diversity and divergence in African Jerboas, desert specialist rodents. We focused on two sister and cryptic species, Jaculus jaculus and J. hirtipes, where we (1) evaluated their genetic differentiation, (2) reconstructed their evolutionary and demographic history; (3) tes…
Experience and dominance in fish pairs jointly shape parasite avoidance behaviour
2018
There is increasing evidence that the composition of a social group influences the fitness of its members. For example, group member identities can determine the exposure risk to contact-transmitted parasites and consequently impact the health of all group members. Here, we propose that group composition may also affect host exposure to parasite propagules prevailing in the environment via collective parasite avoidance behaviours. We explored the spatial avoidance of a trematode parasite, Diplostomum pseudospathaceum, using the simplest form of host groups, pairs of sea trout, Salmo trutta trutta. These pairs showed either (1) between-group heterogeneity in their experience with the parasit…
Hierarchical networks of food exchange in the black garden ant Lasius niger
2020
In most eusocial insects, the division of labour results in relatively few individuals foraging for the entire colony. Thus, the survival of the colony depends on its efficiency in meeting the nutritional needs of all its members. Here, we characterise the network topology of a eusocial insect to understand the role and centrality of each caste in this network during the process of food dissemination. We constructed trophallaxis networks from 34 food-exchange experiments in black garden ants (Lasius niger). We tested the influence of brood and colony size on (i) global indices at the network level (i.e. efficiency, resilience, centralisation and modularity) and (ii) individual values (i.e. …
Toxicity of five Cry proteins against the insect pest Acanthoscelides obtectus (Coleoptera: Chrisomelidae: Bruchinae).
2019
Abstract The beetle Acanthoscelides obtectus (Say) causes severe post-harvest losses in the common bean (Phaseolus vulgaris). Under laboratory conditions, the susceptibility of A. obtectus to five coleopteran-specific Cry toxic proteins from Bacillus thuringiensis (Cry1Ba, Cry1Ia, Cry3Aa, Cry7Ab, and Cry23/37) was evaluated. After 30 days exposure, Cry proteins demonstrated high activity against A. obtectus adults (100% mortality). Proteins showed statistical differences in toxicity parameters compared to the control treatment, but the parameters were similar among them, and indicated that the final toxic effects can be observed after the 24th day. The toxic effects on A. obtectus larvae we…
Do small mammals prey upon an invasive ectoparasite of cervids?
2012
Predation is often considered an important factor for population regulation and in some cases for the invasion success of prey. Small mammalian predation may be a major force in the population regulation of many ground-dwelling in- vertebrate species. The deer ked (Lipoptena cervi (L., 1758)) is an ectoparasitic fly of cervids. The species has a large distri- bution area and it has relatively rapidly spread in northern Europe during the previous four decades. The factors possibly regulating the distribution and invasion of this fly are poorly known. During the off-host stage of several months, pupae of deer ked are likely exposed to many ground-dwelling predators. To study whether small mam…
Dynamics of small-mammal communities along an elevational gradient
2019
Elevation is one of the most important natural gradients that is strongly shaping communities across relatively small areas. However, few studies have followed the temporal dynamics of elevational patterns, even in organisms for which population and community fluctuations have been extensively studied, such as rodents. Here we report the multiannual dynamics of small-mammal communities along an elevational gradient in the Southern Carpathians. During a 5-year survey, we conducted live-trapping in forested and shrubby habitats, at elevations between 820 and 2040 m. We used partial constrained multivariate analysis and mixed-effects models to test the effect of elevation, year, and their int…
Changing of the guard: mixed specialization and flexibility in nest defense (Tetragonisca angustula)
2019
Abstract Task allocation is a central challenge of collective behavior in a variety of group-living species, and this is particularly the case for the allocation of social insect workers for group defense. In social insects, both benefits and considerable costs are associated with the production of specialized soldiers. We asked whether colonies mitigate costs of production of specialized soldiers by simultaneously employing behavioral flexibility in nonspecialist workers that can augment defense capabilities at short time scales. We studied colonies of the stingless bee Tetragonisca angustula, a species that has 2 discrete nest-guarding tasks typically performed by majors: hovering guardin…
Tooth tales told by dental diet proxies: An alpine community of sympatric ruminants as a model to decipher the ecology of fossil fauna
2021
Abstract Paleobiologists tend to use dietary information as an ecological indicator because diet is a fundamental link between an organism and its environment. However, the ecological information from fossilized hard tissues is often difficult to interpret, because links between environment, diet, and hard tissue biology are insufficiently studied in modern communities. To address this dilemma, we investigated dietary proxies commonly used by paleobiologists in a 4-ruminant community from the French Alps. Dental microwear texture analyses are applied to 82 specimens of roe deer, red deer, chamois, and mouflons. Intra-tooth serial enamel stable carbon and oxygen isotope analyses of the struc…