Biology subjects

Teulier, L.

Publications and source records attributed to Teulier, L..

3 recordsLinked to original sources

bioRxiv2025

Functional response predicts invasiveness but not trophic impact

Biological invasions are a major driver of biodiversity erosion mainly because invasive species show greater trophic impact than their non-invasive counterparts. The experimental paradigm for assessing this trophic impact is the functional response (FR) test that describes the relationship between per capita consumption rate and resource density. Two key parameters are then assessable and comparable between populations and species: the space clearance rate (attack rate, a) measuring predatory efficiency at low prey densities, and handling time (h) representing the time required to capture, handle, and digest prey. This test is frequently conducted to compare non-invasive and invasive species and shows that invasive species have a higher FR than non-invasive species (characterized by higher space clearance rates and lower handling times) which would explain both their invasion success and their ecological impact. However, it appears that whether FR parameters differ between invasive species sampled in their native versus invasion range has never been tested, implicitly assuming that FR measures can be extrapolated to the entire range of distribution. Using a phylogenetically corrected comparative analysis of 269 FR observations from 45 freshwater fish species (23 non-invasive species and 22 invasive species), we confirm that invasive species exhibited higher FR than non-invasive species. However, this pattern holds true only when considering invasive species sampled in their native range. Invasive species studied in their invasion range displayed functional responses comparable to non-invasive species, with similar space clearance rates and handling times. Additionally, space clearance rates decreased with temperature in non-invasive species but tended to increase in invasive species from invasive introduction ranges, suggesting that climate warming may exacerbate competitive asymmetries. Together, these results indicate that high FR predispose species to invasiveness, but also challenge the assumption that FRs measured in the native range of a species can be directly extrapolated to predict its trophic impacts elsewhere. Our findings call for greater consideration of biogeographic context when using functional responses to assess invasion risk and ecological impact. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/666957v2_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@c9f9aaorg.highwire.dtl.DTLVardef@262f48org.highwire.dtl.DTLVardef@ea5148org.highwire.dtl.DTLVardef@17e84ce_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗

bioRxiv2025

Cannot be male without complex I? Alteration in cellular metabolism involved in cytoplasmic male sterility in snail Physa acuta

Cytoplasmic male sterility (CMS) is a well-known example of mitonuclear genetic conflict over sex determination in hermaphrodite plants, where mitochondrial genes maternally inherited sterilize the male function while biparental inherited nuclear genes restore it. CMS has been recently discovered in wild animals, in the freshwater snail Physa acuta. In this species, CMS is associated with two extremely divergent mitogenomes D and K compared to the classical mitogenome N. D individuals are male-steriles, while male fertility is restored in K individuals. We hypothesized that the extreme divergence of mitogenomes associated with CMS can impact mitochondrial aerobic metabolism, a necessary process in eukaryotic organisms by which energy is transduced from food to ATP. Our results suggest that CMS might be associated with an alteration of co-encoded complex I in D male-sterile individuals, although partly compensated by the nuclear-encoded complex II. K restored hermaphrodites have an unaffected complex I respiration, but exhibit higher mitochondrial proton leak and higher relative anaerobic contribution to cellular metabolism, suggesting an energy cost of bearing CMS and restorer genes, which could underlie the reduced growth of K mitotype. How complex I alteration might induce male-sterility remains to be determined, but could be linked to oxidative stress or a defect in ATP-synthesis rate.

evolutionary biology↗

bioRxiv2024

Temperature-dependant benefits and costs of cytoplasmic male sterility in snail Physa acuta

Cytoplasmic male sterility (CMS) originates from a mito-nuclear conflict where mitochondrial genes induce male sterility and nuclear genes restore male fertility in hermaphrodites. The first observation of CMS in animals was reported recently in the freshwater snail Physa acuta where it is associated with two extremes divergent mitotypes D and K. The D individuals are male-sterile while male-fertility is restored by nuclear genes in K and are found mixed with the most common male-fertile N mitotype in natural populations (i.e., gynodioecy). We compared male and female fitness, growth rate, and metabolism between the three mitotypes at two temperatures as this factor influences CMS in gynodioecious plants via alteration of mitochondrial functioning. Temperature did not affect male-sterility which depended only on the mitotype and the presence of restorers. Our results provided evidence that CMS is beneficial to female fitness in the absence of restorers, while it is costly in their presence, fulfilling a key theoretical condition for the long-term maintenance of gynodioecy. Fitness benefits and costs are mediated by differences in body mass and enhanced at cold temperature suggesting that the system dynamics may vary according to thermal conditions in nature.

evolutionary biology↗