Biology subjects

Siberchicot, A.

Publications and source records attributed to Siberchicot, A..

3 recordsLinked to original sources

bioRxiv2022

Larval density in the invasive Drosophila suzukii: immediate and delayed effects on life-history traits

The immediate and delayed effects of density are key in determining population dynamics, since they can positively or negatively affect the fitness of individuals. These effects have great relevance for polyphagous insects for which immature stages develop within a single site of finite feeding resources. Drosophila suzukii is a crop pest that induces severe economic losses for agricultural production, however little is known about the effects of density on its life-history traits. In the present study, we (i) investigated the egg distribution resulting from females egg-laying strategy and (ii) tested the immediate and delayed effects of larval density on emergence rate, development time, sex ratio of offspring, fecundity and adult size (a range of 1 to 50 larvae was used). We showed that most of fruits contain several eggs and aggregate of eggs of high density can be found in some fruits. This high density has no immediate effects on the emergence rate, but has effect on larval developmental time. This trait was involved in a trade-off with adult life-history traits: the larval development was reduced as larval density increased, but smaller and less fertile adults were produced. Our results should help to better understand the population dynamics of this species and to develop more successful control programs.

ecology↗

bioRxiv2021

rbioacc: an R-package to analyse toxicokinetic data

O_LI rbioacc is an R-package dedicated to the analysis of experimental data collected from bioaccumulation tests during which organisms are exposed to a chemical (exposure phase) and then put into a clean media (depuration phase). Internal concentrations are regularly measured over time all along the experiment. C_LIO_LI rbioacc provides ready-to-use functions to visualize and fully analyze such data. Under a Bayesian framework, this package fits a generic one-compartment toxicokinetic (TK) model automatically built from the data. It provides TK parameter estimates (appropriate uptake and elimination rates) and bioaccumulation metrics (e.g., BCF, BSAF, BMF). All parameter estimates, bioaccumulation metrics as well as predictions of internal concentrations into organisms are delivered with their uncertainty. C_LIO_LIBioaccumulation metrics are primarily provided in support of environmental risk assessment, in full compliance with regulatory requirements required to approve marketing applications of chemical substances. C_LIO_LIThis paper gives brief worked examples of the use of rbioacc from data collected through standard bioaccumulation tests, and publicly available within the scientific literature. These examples constitute step-by-step user-guides to analyze any new data set, uploaded in the right format. C_LI

ecology↗

bioRxiv2021

Taking full advantage of modelling to better assess environmental risk due to xenobiotics

In the European Union, more than 100,000 man-made chemical substances are awaiting an environmental risk assessment (ERA). Simultaneously, ERA of chemicals has now entered a new era. Indeed, recent recommendations from regulatory bodies underline a crucial need for the use of mechanistic effect models, allowing assessments that are not only ecologically relevant, but also more integrative, consistent and efficient. At the individual level, toxicokinetic-toxicodynamic (TKTD) models are particularly encouraged for the regulatory assessment of pesticide-related risks on aquatic organisms. In this paper, we first propose a brief review of classical dose-response models to put into light the on-line MOSAIC tool offering all necessary services in a turnkey web platform whatever the type of data to analyze. Then, we focus on the necessity to account for the time-dimension of the exposure by illustrating how MOSAIC can support a robust calculation of bioaccumulation factors. At last, we show how MOSAIC can be of valuable help to fully complete the EFSA workflow regarding the use of TKTD models, especially with GUTS models, providing a user-friendly interface for calibrating, validating and predicting survival over time under any time-variable exposure scenario of interest. Our conclusion proposes a few lines of thought for an even easier use of modelling in ERA. Graphical art O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/436474v3_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@d98a72org.highwire.dtl.DTLVardef@1066b4org.highwire.dtl.DTLVardef@c6eef3org.highwire.dtl.DTLVardef@71c528_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗