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showing 10 items of 6956 documents
Sexually dimorphic tegumental gland openings in Laniatores (Arachnida, Opiliones), with new data on 23 species
2009
International audience; Sexually dimorphic glands often release sexual pheromones both in vertebrates and invertebrates. Species of Laniatores (Arachnida, Opiliones) seem to depend on chemical communication but few studies have addressed this topic. In this study, we review the literature for the Phalangida and present new data for 23 species of Laniatores. In 16 taxa, we found previously undescribed sexually dimorphic glandular openings on the femur, patella, metatarsus, and tarsus of legs I and metatarsus of legs III and IV. For the other species, we provide scanning electron micrographs of previously undescribed sexually dimorphic setae and pegs located on swollen regions of the legs. We…
Fishery-induced selection for slow somatic growth in European eel
2012
International audience; Both theoretical and experimental studies have shown that fishing mortality can induce adaptive responses in body growth rates of fishes in the opposite direction of natural selection. We compared body growth rates in European eel (Anguilla anguilla) from three Mediterranean stocks subject to different fishing pressure. Results are consistent with the hypotheses that i) fast-growing individuals are more likely to survive until sexual maturity than slow-growing ones under natural conditions (no fishing) and ii) fishing can select for slow-growing individuals by removing fast-growing ones. Although the possibility of human-induced evolution seems remote for a panmictic…
Fish functional traits are affected by hydrodynamics at small spatial scale
2016
The Mediterranean damselfish Chromis chromis is a species with a broad distribution found both in the Mediterranean Sea and Eastern Atlantic as far south as the coast of Angola. We hypothesized that the species may have significant functional morphological plasticity to adapt along a gradient of environmental conditions. It is a non-migratory zooplanktivorous species and spends the daytime searching for food in the middle of the water column. Therefore, local hydrodynamics could be one of the environmental factors affecting traits of C. chromis with repercussions at the population level. We compared the body condition, individual growth and body shapes of damselfish collected under two diff…
Measuring the effects of temperature rise on Mediterranean shellfish aquaculture
2018
Abstract Shellfish aquaculture represents a worldwide valuable segment of the aquaculture market, spreading along the Mediterranean coasts, and is sensitive to the still unforeseen, poorly-known effects of climate change. Threats due to temperature rise can threaten the deployment and development of this sector, up until now recognised as the best candidate to mitigate the effects of fishery overexploitation. Here, we investigate the effects of temperature increase on the model species, Mytilus galloprovincialis, measuring outcomes from valve fragility (thickness) and condition index. Evidence of a reduction in the thickness of valves and the modulation condition of the mussels along with t…
Does trait-based joint species distribution modelling reveal the signature of competition in stream macroinvertebrate communities?
2021
1. The occupancy and abundance of species are jointly driven by local factors, such as environmental characteristics and biotic interactions, and regional‐scale factors, such as dispersal and climate. Recently, it has been shown that biotic interactions shape species occupancies and abundances beyond local extents. However, for small ectothermic animals, particularly for those occurring in freshwater environments, the importance of biotic interactions remains understudied. Species‐to‐species associations from joint species distribution models (i.e. species associations while controlling for environmental characteristics) are increasingly used to draw hypotheses of which species possibly sho…
Environmental filtering and spatial effects on metacommunity organisation differ among littoral macroinvertebrate groups deconstructed by biological …
2018
We examined spatial and environmental effects on the deconstructed assemblages of littoral macroinvertebrates within a large lake. We deconstructed assemblages by three biological trait groups: body size, dispersal mode and oviposition behaviour. We expected that spatial effects on assemblage structuring decrease and environmental effects increase with increasing body size. We also expected stronger environmental filtering and weaker spatial effect on the assemblages of flying species compared with assemblages of non-flying species. Stronger effect of environmental filtering was expected on the assemblages with species attaching eggs compared with assemblages of species with free eggs. We u…
The way wear goes: phytolith-based wear on the dentine–enamel system in guinea pigs (Cavia porcellus)
2019
The effect of phytoliths on tooth wear and function has been contested in studies of animal–plant interactions. For herbivores whose occlusal chewing surface consists of enamel ridges and dentine tissue, the phytoliths might particularly erode the softer dentine, exposing the enamel ridges to different occlusal forces and thus contributing to enamel wear. To test this hypothesis, we fed guinea pigs (Cavia porcellus; n = 36 in six groups) for threeweeks exclusively on dry or fresh forage of low(lucerne), moderate (fresh timothy grass) or very high (bamboo leaves) silica content representing corresponding levels of phytoliths. We quantified the effect of these treatments with measuremen…
Handbook of protocols for standardized measurement of terrestrial invertebrate functional traits
2017
Trait-based approaches are increasingly being used to test mechanisms underlying species assemblages and biotic interactions across a wide range of organisms including terrestrial arthropods and to investigate consequences for ecosystem processes. Such an approach relies on the standardized measurement of functional traits that can be applied across taxa and regions. Currently, however, unified methods of trait measurements are lacking for terrestrial arthropods and related macroinvertebrates (terrestrial invertebrates hereafter). Here, we present a comprehensive review and detailed protocol for a set of 29 traits known to be sensitive to global stressors and to affect ecosystem processes a…
<p><strong><em>Sinostoma</em> <em>yunnanicum</em>, the first nemastomatine harvestman in China (Arachnida: Opilio…
2016
The easternmost Nemastomatinae species, Sinostoma yunnanicum n. gen., n. sp., from northern Yunnan, China is described. It extends the geographic distribution of Nemastomatinae by roughly 3000 km southeastwards. Within Nemastomatinae Sinostoma displays plesiomorphic characters, including the long, basic bulb of the truncus shaft and the extremely short glans of penis, armed with short robust spines. Sinostoma may represent a relict line in the early evolution of nemastomatine harvestmen.
Short-term benefits, but transgenerational costs of maternal loss in an insect with facultative maternal care
2015
A lack of parental care is generally assumed to entail substantial fitness costs for offspring that ultimately select for the maintenance of family life across generations. However, it is unknown whether these costs arise when parental care is facultative, thus questioning their fundamental importance in the early evolution of family life. Here, we investigated the short-term, long-term and transgenerational effects of maternal loss in the European earwig Forficula auricularia , an insect with facultative post-hatching maternal care. We showed that maternal loss did not influence the developmental time and survival rate of juveniles, but surprisingly yielded adults of larger body and force…