Biology subjects

Fossoy, F.

Publications and source records attributed to Fossoy, F..

3 recordsLinked to original sources

bioRxiv2025

Signatures of genomic adaptation to Cuckoo brood parasitism in Reed Warbler hosts across Europe

Behaviour is a fundamental defence mechanism for animals facing enemies, yet its plasticity makes finding associated genomic evidence for coevolution challenging. As a solution, we apply landscape genomics methods more typically deployed with abiotic variables to a coevolutionary model system: Reed Warblers (Acrocephalus scirpaceus) and their Cuckoo (Cuculus canorus) brood parasites. Using continental sampling of genome-wide data from hosts breeding under varying brood parasitism rates, we reveal that gene flow varies among populations, and, controlling for variation due to environmental differences, identify genomic regions and putative genes that differ with exposure to brood parasitism. Therefore, our results suggest that variable host responses to selection are possible, even by highly mobile and connected populations, supporting long-held assumptions that behavioural defences may reflect genomic adaptation despite their plasticity. Further studies, including those linking genetic variation to individual-level behaviours involved in parental responses to brood parasitism, are required to confirm a genetic basis to specific coevolutionary adaptations, and to test for other biotic or abiotic variables potentially confounding with local parasitism rate.

evolutionary biology↗

bioRxiv2025

High genetic diversity and no detectable founder effects following a rapid range expansion of a long-distance migrant (Acrocephalus scirpaceus)

Many species are currently experiencing range shifts in response to changing environmental conditions, but with potentially serious genetic consequences. Repeated founder events and strong genetic drift are expected to erode genetic variation at the range front, reducing adaptive potential and slowing or even halting the expansion. However, the severity of these consequences for the more common and highly mobile species undergoing environment-driven range shifts (c.f. invasions) is less clear. Here we combined historical observations and contemporary movement data of the common reed warbler (Acrocephalus scirpaceus) with genomic evidence from across its European breeding range to (1) infer the origin and (2) quantify the genetic consequences of a recent and rapid northward range expansion. While there were no reductions in levels of nucleotide diversity or allelic richness, nor a signal of founder effect in the directionality index ({psi}), our combined dataset approach was able to infer an expansion origin from the southwest. Furthermore, we found that private allelic richness retained a slight but significant linear decline along the colonisation route. These results suggest that high dispersal capabilities can allow even philopatric species to avoid the loss of genetic diversity during rapid range expansions. Nevertheless, if multiple lines of evidence enable identification of an expansion pathway, we may still detect genetic signals of expansion.

evolutionary biology↗

bioRxiv2019

Environmental (e)DNA detection of the invasive pink salmon Oncorhynchus gorbuscha during the 2017 Norwegian invasion

The pink salmon Oncorhynchus gorbuscha was introduced from its native range in the Pacific to Northwest Russia several times since the 1950s. While this species has been regularly observed in rivers in Northern Norway since that time, there has been an upsurge in the numbers of odd-year O. gorbuscha individuals observed in rivers in southern Norway in recent years, and particularly in 2017. Although the wide-scale effects of this species presence are currently uncertain, there are concerns regarding potential competition between O. gorbuscha and native species - most notably the Atlantic salmon Salmo salar. Environmental (e)DNA is becoming a widely used tool to monitor rare and invasive species in aquatic environments. In the present pilot study, primers and a probe were developed to detect O. gorbuscha from eDNA samples taken from a Norwegian river system where the species was observed. Water samples were taken at both upstream and downstream locations of the Lysakerelva river during Autumn 2017 (to coincide with spawning) and during late Spring 2018. Autumn samples were positive for O. gorbuscha at both sampling locations, whereas Spring samples showed positive detection of this species in the upstream region of the river, when smolt should have left, or be in the process of leaving the river. These findings reveal that eDNA-based methods can be used detect the presence of O. gorbuscha during their spawning season. This suggests that odd-year populations have the potential to become established in the studied river system. We recommend that eDNA sampling is repeated to determine whether individuals of this odd-year population have survived at sea and return to spawn. Our assay specificity tests indicate that the tools developed in the present study can be used for detection of O. gorbuscha in both Norwegian and other European river systems where presence/absence data is required. We also suggest some modifications to our methodology that may improve upon the detection capabilities of O. gorbuscha using eDNA.

genetics↗