Biology subjects

Caron, S.

Publications and source records attributed to Caron, S..

3 recordsLinked to original sources

bioRxiv2021

Differences in personality / temperament in the endangered tortoise Testudo hermanni and their implications on dispersal and conservation

Behavioural studies are more an more implicated in species conservation. Determining individuals personality in the case of reintroduction operations may be very useful. Actually, indiviuals temperament may be associated to their dispersal capacities and their habilities to adapt to novel environments. Considered as asociable species, few studies have been conducted on reptiles and this is even worse in the case of endangered species. Hermann tortoise, Testudo hermanni, an endemic species from Mediterranean region is endangered because of the lost and modification of its habitats. Before conducting reintroduction actions it is important to have more information on individuals personality traits. We have tested the reaction of three groups of tortoises (domestic, wild and from the SOPTOM center) when confronted to a novel environment and to human presence. The aim was to discriminate individuals with << bold >> and << shy >> behaviours. Behavioural profiles are different between the three groups of tortoises, the domestic group appeared to be bolder than the wild one. Moreover, for the wild group, bold individuals travel longer distances in the field, sometimes outside the protected areas. Thus, it is important to take into account the personality of individuals choosen for translocation projects.

ecology↗

bioRxiv2021

First detection of herpesvirus and mycoplasma in free-ranging Hermann tortoises (Testudo hermanni), and in potential pet vectors

AO_SCPLOWBSTRACTC_SCPLOWTwo types of pathogens cause highly contagious upper respiratory tract diseases (URTD) in Chelonians: testudinid herpesviruses (TeHV) and a mycoplasma (Mycoplasma agassizii). In captivity, these infections are frequent and can provoke outbreaks. Pet trade generates international flow of tortoises, often without sanitary checking; individuals intentionally or accidentally released in the wild may spread pathogens. A better understanding of the transmission of infectious agents from captivity to wild tortoises is needed. Many exotic individuals have been introduced in populations of the endangered western Hermanns tortoise (Testudo hermanni hermanni), notably spur-thighed tortoises (Testudo graeca). We assessed the presence of TeHV and mycoplasma in native western Hermanns tortoises and in potential pet vectors in south-eastern France. Using a large sample (N=572 tortoises), this study revealed, by PCR, the worrying presence of herpesvirus in 7 free-ranging individuals (3 sub-populations). Additionally, Mycoplasma agassizii was detected, by PCR, in 15 of the 18 populations sampled with a frequency ranging from 3.4% (1 of 29 tortoises) to 25% (3 of 12 tortoises). Exotic spur-thighed tortoises showed high frequency of mycoplasma infection in captivity (18.2%) and in individuals (50%) found in native Hermanns tortoise sub-populations, suggesting that this species could be a significant vector. The paucity of information of TeHV on European tortoise URTD in natural settings, especially in combination with mycoplasma, prompts for further studies. Indeed, sick tortoises remain concealed and may not be easily detected in the field. Our results indicate a good health for most infected tortoise but it should be screened in the field as well as in captivity.

zoology↗

bioRxiv2019

The making of an olfactory specialist

The evolution of animal behaviour is poorly understood. Despite numerous correlations of behavioural and nervous system divergence, demonstration of the genetic basis of interspecific behavioural differences remains rare. Here we develop a novel neurogenetic model, Drosophila sechellia, a close cousin of D. melanogaster that displays profound behavioural changes linked to its extreme host fruit specialisation. Through calcium imaging, we identify olfactory pathways detecting host volatiles. Mutational analysis indicates roles for individual receptors in long- and short-range attraction. Cross-species allele transfer demonstrates that differential tuning of one receptor is important for species-specific behaviour. We identify the molecular determinants of this functional change, and characterise their behavioural significance and evolutionary origin. Circuit tracing reveals that receptor adaptations are accompanied by increased sensory pooling onto interneurons and novel central projection patterns. This work links molecular and neuronal changes to behavioural divergence and defines a powerful model for investigating nervous system evolution and speciation.

neuroscience↗