Biology subjects

Renault, D.

Publications and source records attributed to Renault, D..

7 recordsLinked to original sources

bioRxiv2026

AnthropInsect: a global database of insect traits and anthropogenic associations.

Insect research remains hindered by limited data availability and fragmented knowledge compared to other, better-documented taxonomic groups. Yet, both the macroecological and the insect research communities highlight the need to integrate large-scale ecological trait datasets for insects. Insects and humans are interconnected through diverse relationships, ranging from beneficial interactions, such as the use of insects as nutritional resources, to adverse impacts, including their role in to the emergence and spread of biological invasions. Understanding the traits of insects associated with human use, movement and impact is therefore important for linking insects to ecosystem function and global change. We present AnthropInsect, one of the largest database on insect traits to date, which uniquely includes variables describing human-insect associations. AnthropInsect describes species through 35 variables grouped into five categories: (i) taxonomic descriptors; (ii) ecological descriptors (native bioregions and habitat); (iii) human-insect associations (edibility and invasive status); (iv) functional traits (behavior, morphology, life history and feeding); (v) and macroecological descriptors of native-range geography and climate. AnthropInsect currently includes 5867 species across six major orders: Coleoptera, Lepidoptera, Hemiptera, Hymenoptera, Orthoptera and Blattodea. Data extracted from peer-reviewed, grey literature and from existing databases were standardized and validated with expert knowledge to ensure accuracy. By providing traits data with information on insect-human interactions, this rigorously curated resource supports global research in entomology, ecology, conservation, and global change.

ecology↗

bioRxiv2024

Contrasted effect of climate and anthropogenic change on future invasion risk of a solitary bee Amegilla pulchra

Amegilla pulchra is a solitary bee from Australia that has recently been spread throughout many islands of the Pacific. The non-regulated human-driven spread of the species may affect the local pollinator communities and their interactions with host plants. We used an ecological niche modelling approach, accounting for non-equilibrium and anthropogenic spread with the most recently recommended approach, and predicted the potential spread of the species under current and future conditions. We expected climate change and increase in human density to offer new suitable environments for the spread of the species. Invasion risks will increase in the future overall, but more in the non-native regions compared to the native region. In the native region, the projected effect of future environmental change was highly contrasted, with increasing invasion risk in human-dense areas but decreasing elsewhere. We found high risks of invasion in eastern Asia and provided a world ranking of entry points for surveillance priority which accounts for maritime traffic. This study highlights potential contrasted effects between climate and anthropogenic change, with differing projections between the native and the non-native regions. Public awareness and prevention will be the key to prevent further spread and mitigate potential adverse effects of the species on island systems. In regions that are already invaded, we propose that habitat restoration is a promising strategy for both the mitigation of the spread and the conservation of local communities.

ecology↗

bioRxiv2022

Parasites make hosts more profitable but less available to predators

Parasites are omnipresent, and their eco-evolutionary significance has aroused much interest from scientists. Parasites may affect their hosts in many ways with changes in density, appearance, behaviour and energy content, likely to modify their value to predators (profitability) within the optimal foraging framework. Consequently, parasites could impact predators diet and the trophic links through food webs. Here, we investigate the consequences of the infection by the iridovirus Daphnia iridescent virus 1 (DIV-1) on the reproductive success, mortality, appearance, mobility, and biochemical composition of water fleas (Daphnia magna), a widespread freshwater crustacean. We do predation tests and compare search time, handling time and feeding preference between infected and uninfected Daphnia when preyed upon by Notonecta sp., a common aquatic insect. Our findings show that infection does not change fecundity but reduces lifespan and thereby constrains fitness. Infected Daphnia show reduced mobility and increased color reflectance in the UV and visible domains, which potentially affects their appearance and thus vulnerability to predators. Infection increases body size and the amount of proteins but does not affect carbohydrate and lipid contents. Although infected Daphnia are longer to handle, they are preferred over uninfected individuals by aquatic insects. Taken together, our findings show that DIV-1 infection could make Daphnia more profitable to predators (24% energy increase), a positive effect that should be balanced with a lower availability due to the higher mortality of infected specimens. We also highlight that exposure to infection in asymptomatic individuals leads to ecological characteristics that differ from both healthy and symptomatic infected individuals. Recommender: Luis Schiesari Reviewers: Thierry De Meeus and Eglantine Mathieu-Begne Cite as: Prosnier L., N. Loeuille, F.D. Hulot, D. Renault, C. Piscart, B. Bicocchi, M, Deparis, M. Lam, & V. Medoc. (2023). Parasites make hosts more profitable but less available to predators. BioRxiv, ver. 4 peer-reviewed and recommended by Peer Community in Ecology. https://doi.org/10.1101/2022.02.08.479552

ecology↗

bioRxiv2021

Extreme longevity of highly fecund termite queens achieved by mitochondrial and insulin upregulation without harmful lipid signatures or accumulation

Kings and queens of eusocial termites can live for decades, while queens sustain a nearly maximal fertility. To investigate the molecular mechanisms underlying their long lifespan, we carried out transcriptomics, lipidomics and metabolomics in Macrotermes natalensis on sterile short-lived workers, long-lived kings and five stages spanning twenty years of adult queen maturation. Reproductives share gene expression differences from workers in agreement with a reduction of several aging-related processes, involving upregulation of DNA damage repair and mitochondrial functions. Anti-oxidant gene expression is downregulated, while peroxidability of membranes in queens decreases. Against expectations, we observed an upregulated gene expression in fat bodies of reproductives of several components of the IIS pathway, including an insulin-like peptide, Ilp9. This pattern does not lead to deleterious fat storage in physogastric queens, while simple sugars dominate in their hemolymph and large amounts of resources are allocated towards oogenesis. Our findings support the notion that all processes causing aging need to be addressed simultaneously in order to prevent it.

molecular biology↗

bioRxiv2019

Spotlight on the monitoring of the invasion of a carabid beetle on an oceanic island over a 100 year period

The flightless beetle Merizodus soledadinus, originating from the Falkland Islands, was introduced to the sub-Antarctic Kerguelen Islands. We compiled the existing information on ship visits and landings on these islands to confirm the introduction date of M. soledadinus. Using data available in the literature, in addition to collecting more than 2000 presence/absence records of M. soledadinus over the 1991-2018 period, we tracked changes of its abundance and geographical distribution. The range expansion of this nonflying insect was initially slow, but has accelerated over the past two decades in parallel to local increased abundances of the insects populations. Human activities may have facilitated colonization of some localities by M. soledadinus which is now widely present in the eastern part of the Kerguelen archipelago. This predatory insect represents a major threat for the native invertebrate fauna; in particular, the wingless flies Anatalanta aptera and Calycopteryx moseleyi which are locally displaced and/or eliminated by the beetle. If no control measures, let alone eradication, are practicable, it is essential to limit the transport of this invasive insect along with human activities. Since 2006, the Kerguelen Islands have had the status of a nature reserve, making these results of significant interests for the management of this archipelago, and more generally, emphasizing the importance of long-term biomonitoring programmes for assessing and predicting changes in the distribution of invasive organisms. Strict biosecurity measures have now been established at the Kerguelen Islands, with even greater attention paid to visits to remote sites not yet colonized by M. soledadinus.

ecology↗

bioRxiv2019

The distinct phenotypic signatures of dispersal and stress in an arthropod model: from physiology to life history

Dispersing individuals are expected to encounter costs during transfer and in the novel environment, and may also have experienced stress in their natal patch. Given this, a non-random subset of the population should engage in dispersal and eventually show divergent stress-related responses towards new conditions. Dispersal allows escape from stress, but is equally subjecting individuals to it.\n\nPhysiological shifts expressed in the metabolome form a major part of responses to stress exposure and are expected to be associated with the dispersal phenotype, thereby shaping physiological dispersal syndromes. We analyzed how metabolic profiles and life-history traits varied between dispersers and residents of the model two-spotted spider mite Tetranychus urticae, and whether and how these syndromes varied with exposure to a stressful new host plant (tomato). Regardless of the effect of host plant, we found a physiological dispersal syndrome where, relative to philopatric individuals, dispersers were characterized by lower leaf consumption rates and a lower concentration of several amino acids, indicating a potential dispersal-foraging trade-off. As a possible consequence of this lower food intake, dispersers also showed a lower reproductive performance. Responses to tomato exposure were consistent with this plant being a stressor for Tetranychus urticae, including reduced fecundity and reduced feeding by mites. Tomato-exposed mites laid larger eggs, which can be interpreted as a plastic response to food stress, increasing the likelihood of survival to maturity. Contrary to what could be expected from the costs of dispersal and stress resistance and from previous meta-population level studies, there was no interaction between dispersal status and host plant for any of the examined traits, indicating that the impacts of a new stressful host plant are equally incurred by residents and dispersers.\n\nWe thus provide novel insights in the processes that shape dispersal and the putative feedbacks on ecological dynamics in spatially structured populations.

ecology↗

bioRxiv2018

Sex makes them sleepy: change in host reproductive status induces diapause in parasitoids

When organisms coevolve, any change in one species can induce phenotypic changes in traits and ecology of the other species. The role such interactions play in ecosystems is central, but their mechanistic bases remain underexplored. Upper trophic level species have to synchronize their life-cycle to both abiotic conditions and to lower trophic level species phenology and phenotypic variations. We tested the effect of host seasonal strategy on parasitoid diapause induction by using a holocyclic clone of the pea aphid Acyrthosiphon pisum producing asexual and sexual morphs that are viviparous females (i.e. laying embryos) and oviparous females (laying eggs), respectively, the latter being only present at the end of the growing season. Aphidius ervi parasitoids from populations of contrasted climatic origin (harsh vs. mild winter areas) were allowed to parasitize each morph in a split-brood design and developing parasitoids were next reared under either fall-like or summer-like temperature-photoperiod conditions. We next examined aspects of the host physiological state by comparing the relative proportion of forty-seven metabolites and lipid reserves in both morphs produced under the same conditions. We found that oviparous morphs are cues per se for diapause induction; parasitoids entered diapause at higher levels when developing in oviparous hosts (19.4 {+/-} 3.0%) than in viviparous ones (3.6 {+/-} 1.3%), under summer-like conditions (i.e., when oviparous aphids appear in the fields). This pattern was only observed in parasitoids from the harsh winter area since low diapause levels were observed in the other population, suggesting local adaptations to overwintering cues. Metabolomics analyses show parasitoids response to be mainly influenced by the hosts physiology, with higher proportion of polyols and sugars, and more fat reserves being found in oviparous morphs. Host quality thus varies across the seasons and represents one of the multiple environmental parameters affecting parasitoid diapause. Our results underline strong coevolutionary processes between hosts and parasitoids in their area of origin, likely leading to phenological synchronization, and we point out the importance of such bottom-up effects for trait expression, and for the provision of ecosystem services such as biological control in the context of climate change.

ecology↗