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Leroy, C.

Publications and source records attributed to Leroy, C..

10 recordsLinked to original sources
bioRxiv2025

Ongoing coevolution between reintroduced Phengaris teleius butterflies and their Myrmica host ants

Coevolutionary interactions between parasites and hosts are key drivers of biological adaptation. In this study, we explore the evolutionary response of the social parasitic butterfly Phengaris teleius to its host ant, Myrmica scabrinodis, taking advantage of a unique opportunity: the reintroduction of the butterfly in the Netherlands thirty years ago. We compared the degree of host mimicry and behavioural performance of caterpillars between the reintroduced and the Polish source population. After about thirty generations, chemical and vibroacoustical signal profiles have diverged. Chemical mimicry remained limited during the pre-adoption phase for both groups; however, in the post-adoption phase, the source population showed significantly higher chemical similarity to their local hosts. In contrast, reintroduced pre-adoption caterpillars evolved vibroacoustic signals closely resembling local hosts, also resulting in a stronger response from their local host ants. This suggests that adoption is driven by acoustics and subsequently serves as a selective filter promoting post-entry chemical refinement. Behavioural data evince that despite the differences between the different communication channels, the combination of signals remains sufficient to ensure recognition and integration in both host-parasite systems. These results illustrate how social parasites involved in multisensory mimicry can rapidly recalibrate strategies to remain functional in new ecological contexts.

ecology↗
bioRxiv2025

Rainwash eDNA to monitor tropical rainforest biodiversity

Tropical rainforest canopies shelter an under-explored reservoir of biodiversity. In recent years, the amplification and sequencing of taxonomically informative DNA fragments from environmental samples (i.e. eDNA) has revolutionized biomonitoring. Here, we explore the potential of DNA contained in canopy throughfall water to sample the biological diversity of rainforest canopies. By sampling rainwash eDNA in two 1ha-plots, one mature Amazonian forest and a nearby tree plantation, we were able to detect 170 plant taxa, 72 vertebrate taxa including mammals, birds, and amphibians, and 313 insect taxa including e.g. mosquitoes, ants, beetles. The taxonomic composition retrieved in these two plots reflected their different disturbance status, and the plantation exhibited a much lower diversity. We also found that rainwash eDNA persists over ten days in passive eDNA collectors while providing a local picture of the diversity. This suggests that this method can be scaled up for a cost-effective environmental management of rainforest, and more generally of all forests canopies. TeaserRainwash DNA reveals the identity of plants, animals, and insects diversity, offering a practical tool for monitoring canopy biodiversity.

ecology↗
bioRxiv2024

Unique belowground ecological strategies of subtropical and tropical plant species expand the root trait space

Root trait variation may reflect the ecological and evolutionary processes shaping biodiversity, but remains poorly quantified in the (sub)tropics. Here, we aim to further complete our knowledge of belowground functional strategies by assessing the contributions of subtropical and tropical species to global root trait diversity. We gathered root data for 1618 temperate, 341 subtropical, and 775 tropical species. We compared functional diversity among biomes and calculated the unique contribution of each biome to the global root economics space. Further, we determined if the within-variation of subtropical and tropical biomes is shaped by species niches and/or differences in evolutionary history. Root trait expressions differed among biomes, but root functional diversity did not. Furthermore, subtropical and tropical biomes accounted for 40% of the unique root functional space within the global traits space. Species climate niches and phylogenetic turnover explained variation in root traits (e.g., denser root tissue was associated with drier sites) among subtropical but not tropical species. Through their unique root traits, sub(tropical) species strongly expand the current global root trait space. This work underwrites their importance in conceptual models for more complete insights into how various belowground strategies drive plant functional biogeography and biodiversity globally.

ecology↗
bioRxiv2022

Ants act as olfactory bio-detectors of tumour in patient-derived xenograft mice

Early detection of cancer is critical in medical sciences, as the sooner a cancer is diagnosed, the higher the chances of recovery. Tumour cells are characterized by specific volatile organic compounds (VOCs) that can be used as cancer biomarkers. Through olfactory associative learning, animals can be trained to detect these VOCs. Insects, such as ants, have a refined sense of smell and can be easily and rapidly trained with olfactory conditioning. Using urine from patient-derived xenograft mice as stimulus, we demonstrate that individual ants can learn to discriminate the odour of healthy mice from that of tumour bearing mice, and do so after only three conditioning trials. Chemical analyses confirmed that the presence of the tumour changed the urine odour, supporting the behavioural results. Our study demonstrates that ants reliably detect tumour cues in mice urine and have the potential to act as efficient and inexpensive cancer bio detectors.

animal behavior and cognition↗
bioRxiv2022

Within and among population differences in cuticular hydrocarbons in the seabird tick Ixodes uriae.

AO_SCPLOWBSTRACTC_SCPLOWThe hydrophobic layer of the arthropod cuticle acts to maintain water balance, but can also serve to transmit chemical signals via cuticular hydrocarbons (CHC), essential mediators of arthropod behavior. CHC signatures typically vary qualitatively among species, but also quantitatively among populations within a species, and have been used as taxonomic tools to differentiate species or populations in a variety of taxa. Most work in this area to date has focused on insects, with little known for other arthropod groups such as ticks. The worldwide distribution and extensive host-range of the seabird tick Ixodes uriae make it a good model to study the factors influencing CHC composition. Genetically differentiated host-races of I. uriae have evolved across the distribution of this species but the factors promoting sympatric population divergence are still unknown. To test for a potential role of host-associated CHC in population isolation, we collected I. uriae specimens from two of its seabird hosts, the Atlantic puffin (Fratercula arctica) and the common guillemot (Uria aalge) in different colonies in Iceland. Using gas-chromatography and mass-spectrometry, we detected a complex cuticular mixture of 22 hydrocarbons, including n-alkanes, methyl-alkanes and alkenes ranging from 17 to 33 carbons in length. We found that each population had a distinct CHC profile. The host group explained the greatest amount of population divergence, with long-chain hydrocarbons being more abundant in puffin tick populations compared to guillemot tick populations. Future work will now be required to test whether the different CHC signals reinforce assortative mating, thereby playing a role in generating I. uriae population divergence patterns, and to evaluate diverse hypotheses on the origin of distinct population signatures.

ecology↗
bioRxiv2021

Nestmate recognition of early brood in ants

Brood is critically important in social insect colonies. It carries the colonys fitness through delivering future reproductive adults as well as workers that will increase the colonys workforce. Adoption of non-nestmate brood can increase the colony workforce but entails the risk of rearing unrelated sexuals or social parasites. Thus, theory would predict that ant workers will evolve the ability to discriminate between nestmate and alien brood using the chemical cues displayed at the broods surface. This appears especially true for eggs and first instar (L1) larvae, which require more resources before becoming adult workers compared to older brood. However, the chemical signature of ant early brood stages and its recognition by workers remains understudied. To fill this gap, we investigated the chemical basis of early brood nestmate and cross-species recognition in six ant species. We also tested the discrimination behaviour of workers in brood retrieval trials. We observed species-level cues and discrimination against hetero-specific brood. We also found that eggs and most L1 larvae displayed a colony signature. However, only some species discriminated against non-nestmate early brood. Interestingly, these species belong to genera subject to brood parasitism. We hypothesize that non-nestmate brood discrimination could arise from species adaptations against brood parasitism.

animal behavior and cognition↗
bioRxiv2020

Epidermal stem cell compartment remains unaffected through aging in naked mole-rats.

Skin represents an informative and convenient organ for the analysis of the aging process. Naked mole-rats (NMR) are subterranean rodents remarkable for their longevity, with unexplained resistance to skin aging. In middle-aged NMR, extensive in situ analysis indicated that skin compartments and cell types remained similar to young animals. Using single-cell RNA-sequencing, we found three classical cellular states defining a unique keratinocyte differentiation trajectory that did not appear to be altered during aging after pseudotemporal reconstruction. Finally, NMR skin healing closure was strictly comparable between the two age groups. These results indicate that the content in stem cell populations as well as the differentiation process are preserved during aging in NMR and that such properties are related to the healing process.

cell biology↗
bioRxiv2020

Climate influences the response of community functional traits to local conditions

Functional traits determine an organisms performance in a given environment and as such determine which organisms will be found where. Species respond to local conditions, but also to larger scale gradients, such as climate. Trait ecology links these responses of species to community composition and species distributions. Yet, we often do not know which environmental gradients are most important in determining community trait composition at either local or biogeographical scales, or their interaction. Here we quantify the relative contribution of local and climatic conditions to the structure and composition of functional traits found within bromeliad invertebrate communities. We conclude that climate explains more variation in invertebrate trait composition within bromeliads than does local conditions. Importantly, climate mediated the response of traits to local conditions; for example, invertebrates with benthic life-history traits increased with bromeliad water volume only under certain precipitation regimes. Our ability to detect this and other patterns hinged on the compilation of multiple fine-grained datasets, allowing us to contrast the effect of climate vs. local conditions. We suggest that, in addition to sampling communities at local scales, we need to aggregate studies that span large ranges in climate variation in order to fully understand trait filtering at local, regional and global scales.

ecology↗
bioRxiv2019

Targeting MOG to skin macrophages prevents EAE in macaques through TGFβ-induced peripheral tolerance

To study the effect of vaccination on tolerization to the myelin antigen MOG we used a macaque model of experimental autoimmune encephalitis (EAE) in which immunization with recombinant human myelin oligodendrocyte glycoprotein (rhMOG) elicits brain inflammation and demyelination mediated by MOG-specific autoreactive CD4+ T lymphocytes and anti-MOG IgG. For antigen targeting to tolerizing antigen presenting cells, we used a recombinant antibody directed to the Dendritic Cells (DC)-Asialoglycoprotein receptor (DC-ASGPR). The intradermal administration of an anti-DC-ASGPR-MOG fusion protein, but not a control anti-DC-ASGPR-PSA (prostate specific antigen) protein, protected monkeys committed to develop EAE. Although effective treatment did not modify anti-MOG IgG production, it prevented the CD4+ T lymphocyte activation and pro-inflammatory cytokine production. Moreover, animals treated with anti-DC-ASGPR-MOG experienced a rise of MOG-specific CD4+CD25+FOXP3+CD39+ regulatory T cells as well as a TGF{beta}1, TGF{beta}2 and IL-8 upsurge after rhMOG re-immunization. Our results indicate that the pathogenicity of autoantibodies directed to MOG is mitigated in the presence of MOG-specific regulatory lymphocytes. This vaccination scheme appears suitable to treat relapsing autoimmune diseases with identified autoantigens such as that harboring anti-MOG or anti-AQP4 autoantibodies.

immunology↗