Biology subjects

Devineau, O.

Publications and source records attributed to Devineau, O..

3 recordsLinked to original sources

bioRxiv2021

Biogeographic position and body size jointly set lower thermal limits of wandering spiders

Most species encounter large variations in abiotic conditions along their distribution range. Climate, and in particular temperature, varies along clinal gradients, which determines phenotypic plasticity, local adaptations and associated physiological responses of most terrestrial ectotherms, such as insects and spiders. This study aimed to determine how the biogeographic position of populations and the body size of two wandering spiders set their limits of cold (freezing) resistance. Using an ad-hoc design, we sampled relatively large numbers of individuals from four populations of Dolomedes fimbriatus and one population of the sister species Dolomedes plantarius originating from contrasting climatic areas (temperate and continental climate), and compared their supercooling ability as an indicator of cold resistance. Results indicated that spiders from northern (continental) populations had higher cold resistance than spiders from a southern (temperate) populations. Larger spiders had a lower supercooling ability in northern populations. The red-listed and rarest D. plantarius was slightly less cold-tolerant than the more common D. fimbriatus, and this might be of importance in a context of climate change that could imply colder overwintering habitats in the north due to reduced snow cover protection.

physiology↗

bioRxiv2020

Characterization of habitat requirements of European fishing spiders

Wetlands are among the most threatened habitats in the world, and so are their species, which suffer habitat loss due to climate and land use changes. Freshwater species and arthropods receive little attention in research and conservation, and the goals to stop and reverse the destruction of wetlands published 25 years ago in a manifesto by the Union of Concerned Scientists have not been reached. In this study, we investigated the occurrence and habitat requirements at two spatial scales of two species of European fishing spiders Dolomedes, which rely heavily on declining wetland habitats in Sweden and southern Norway. We collected occurrence data for Dolomedes plantarius and Dolomedes fimbriatus, using a live-determination-method. We modelled the placement of nursery webs to describe fine scaled habitat requirements related to vegetation and microclimate. Using a machine learning approach, we described the habitat features for each species, and for co-occurrence sites, to provide insight into variables relevant for the detectability of Dolomedes. We found that habitat requirements were narrower for D. plantarius compared to D. fimbriatus; that the detection of nursery webs can be affected by weather conditions and that nursery placement is mostly dependent on the proximity to water, the presence of Carex sp. (Sedges) and of crossing vegetation structures, and on humidity. Furthermore, co-occurring sites were more similar to D. plantarius sites than to D. fimbriatus sites, whereby surrounding forest, water type and velocity, elevation and latitude were of importance for explaining which species of Dolomedes was present. We provide a detailed field protocol for Dolomedes studies, including a novel live-determination method, and recommendations for future field protocols.

ecology↗

bioRxiv2020

Explicit integration of dispersal-related metrics improves predictions of SDM in predatory arthropods

Fishing spiders (Dolomedes spp.) make an interesting model to predict the impact of global changes because they are generalist, opportunistic predators, whose distribution is driven mostly by abiotic factors. Yet, the two European species are expected to react differently to forthcoming environmental changes, because of habitat specialization and initial range. We used an original combination of habitat and dispersal data to revisit these predictions under various climatic scenarios. We used the future range of suitable habitat, predicted with habitat variables only, as a base layer to further predict the range or reachable habitat by accounting for both dispersal ability and landscape connectivity. Our results confirm the northward shift in range and indicate that the area of co-occurrences should also increase. However, reachable habitat should expand less than suitable habitat, especially when accounting for landscape connectivity. In addition, the potential range expansion was further limited for the red-listed D. plantarius, which is more habitat-specialist and has a lower ability to disperse. This study highlights the importance of looking beyond habitat variables to produce more accurate predictions for the future of arthropods populations.

ecology↗