Biology subjects

Cheutin, M.-C.

Publications and source records attributed to Cheutin, M.-C..

3 recordsLinked to original sources

bioRxiv2024

Cadmium ingestion does not disrupt the social transmission of the microbiome in juveniles of a subsocial insect

Symbiotic microbes are essential for host health and fitness. In family-living species, these microbes are often acquired through vertical transmission from parents and horizontal transmission from siblings. However, it is unclear how environmental stressors, such as chemical pollution, influence these contributions to the juvenile microbiome. Here, we tested the independent and interactive effects of social environment and cadmium ingestion - a highly toxic and common heavy metal pollutant - on the microbiome of juvenile European earwigs. We reared 900 juveniles either alone, with siblings or with siblings plus the mother. We exposed them to cadmium-enriched food at 0, 25 or 100mg.L-1, and analysed their microbiome composition and diversity at the end of the family life period. Our results showed that both social environment and cadmium exposure shaped the juvenile microbial community composition (phylogenetic beta-diversity), with no evidence of an interaction between these factors. In contrast, the microbial local richness (alpha-diversity) remained unaffected by either factor or their interaction. Notably, several specific bacterial taxa, including putatively pathogenic (Serratia) and mutualistic (Lactobacillus) symbionts, were more abundant in juveniles reared with family members than in those reared in isolation, reflecting classical patterns observed in social species. Overall, our findings suggest that while both social environment and cadmium shape the microbiome of earwig juveniles, family life neither amplifies nor mitigates the effects of chemical exposure. This highlights the robustness of microbial sharing within families, even under strong environmental stress.

microbiology↗

bioRxiv2024

Microbiome turnover during offspring development varies with maternal care, but not moult, in a hemimetabolous insect

The ecological success of insects often depends on their association with beneficial microbes. However, insect development involves repeated moults, which can have dramatic effects on their microbial communities. Here, we investigated whether and how moulting affects the microbiome of a hemimetabolous insect, and whether maternal care can modulate these effects. We reared European earwig juveniles with or without mothers and used 16S rRNA metabarcoding to analyse the prokaryotic fraction of the core microbiome of eggs, recently and old moulted individuals at four developmental stages and the resulting adults. The 218 samples obtained showed that the microbiome diversity changed non-linearly during development and that these changes were associated with bacterial biomarkers. Surprisingly, these changes did not occur during moulting, but rather between the beginning and end of certain developmental stages. We also found that access to maternal care affected the microbiome of both juveniles and adults, even when the last contact with mothers was two months before adulthood. Overall, these results provide new insights into our understanding of the (in)stability of the prokaryotic microbiome in hemimetabolous insects and its independence from moult. More generally, they question the role of microbiome acquisition through maternal care in maintaining family life in species where this behaviour is facultative.

microbiology↗

bioRxiv2021

How many replicates to accurately estimate fish biodiversity using environmental DNA on coral reefs?

Quantifying the diversity of species in rich tropical marine environments remains challenging. Environmental DNA (eDNA) metabarcoding is a promising tool to face this challenge through the filtering, amplification, and sequencing of DNA traces from water samples. However, the reliability of biodiversity detection from eDNA samples can be low in marine environments because eDNA density is low and certainly patchy in this vast, heterogenous and dynamic environment. So, the number of sampling replicates and filtered volume necessary to obtain accurate estimates of biodiversity in rich tropical marine environments using eDNA metabarcoding is still unknown. Here, we used a paired sampling design of 30L per replicate on 68 reef transects from 8 sites in three tropical regions and identified fish Molecular Taxonomic Units (MOTUs) using a 12S marker. We quantified local biodiversity variation as MOTU richness, compositional turnover and compositional nestedness between replicated pairs of seawater samples. We report strong turnover of MOTUs between replicated pairs of samples undertaken in the same location, time, and conditions. Paired samples contained non-overlapping assemblages rather than subsets of one-another. As a result, localised diversity accumulation curves showed that even 6 replicates (180L) in the same location underestimated local diversity (for an area <1km). However, sampling of regional diversity using [~]25 replicates in variable locations (often covering 10s of km) achieved saturation of biodiversity accumulation curves. Our results demonstrate high variability of diversity estimates perhaps arising from heterogeneous and local distribution of eDNA distribution in seawater or highly skewed frequencies of eDNA traces. This high compositional variability has consequences for using eDNA to monitor temporal and spatial biodiversity changes of local assemblages. Future biomonitoring efforts could be strongly undermined by a high level of false-negative detections under low replication protocols. We reveal the need to increase replicates or increase sampled water volume to better inform management of marine biodiversity using eDNA.

ecology↗