Temperature overrides nutritional cues for optimal oviposition decision in a polyphagous invasive insect

#### Publication title: Temperature overrides nutritional cues for optimal oviposition decision in a polyphagous invasive insect #### Publication authors: Anonymous (added later) #### Code author: Anonymous (added later) #### Last Update: August 2025 This repository houses the code (‘R_script_Step1-4’.R) and data sets that were used for the article ‘Temperature overrides nutritional cues for optimal oviposition decision in a polyphagous invasive insect’. ABSTRACT Oviposition site selection determines the microclimate for the offspring, thereby influencing their development and fitness. Polyphagous insects often rely on multiple cues to select oviposition sites, including substrate temperature and nutritional resources. Optimal conditions do not always align, however, and a thermally optimal oviposition site can be nutritionally suboptimal, and vice versa. Our study evaluated the ability of females to make optimal oviposition site decisions under such mismatch between thermal and nutritional conditions in an invasive polyphagous fly species, Drosophila suzukii. We also tested if symbiotic Wolbachia bacteria modulate oviposition choice. First, we quantified the performance of D. suzukii (i.e., number of eggs laid, offspring development time, survival and mass) on four different fruit purees at three ambient temperatures. Second, we investigated how oviposition choice was affected by substrate temperature or nutritional cues separately. Finally, we designed a multiple-scenario oviposition experiment, forcing females to make choices when temperature and nutrition did not align, to explore which of the two factors were most influential for decision making. While temperature and fruit quality both influenced offspring performance, females consistently prioritised temperatures that were optimal for larval development, resulting in oviposition on less preferred fruits. This choice was in line with the preference-performance hypothesis as temperature had a larger effect than fruit quality on performance in the no-choice experiments. Infection by Wolbachia resulted in higher survival and faster development of offspring. Wolbachia also influenced female oviposition decision, modifying fruit preference and leading to more evenly distributed eggs in complex scenarios, but without altering the preference for thermally favourable oviposition sites. These results support the hypothesis that the invasive success of D. suzukii is in part explained by its ability to select optimal oviposition sites. More generally, this study highlights that animal behaviour needs to be examined under suboptimal conditions to infer the importance of behavioural flexibility for individual fitness and population biology under environmental change. R session info: - R version 4.1.2 (2021-11-01) - Platform: x86_64-apple-darwin17.0 (64-bit) - Running under: macOS 13.1 Metadata for the data files are supplied below: #Step1 Folder File ‘fecundity.csv’, used for fecundity: - ID: id summarising main infos for females D. suzukii - Milieu: G/F/M/C for Viscum / Raspberry / Mahonia / Blackcurrant fruit purees - Temp: 16/20/24 for ambient temperature in °C - Wol: Wm/Wp for Wolbachia uninfected / infected females - Jour: Day of observation - Date: Date of observation - Om: Number of eggs laid by D. suzukii female in the substrate - Ob: Number of eggs laid by D. suzukii female on the box - Pupe: Number of pupae - M_m: Number of emerged male flies - M_f: Number of emerged female flies - M: Total number of emerged flies - Total_O: Total number of eggs laid by D. suzukii female File ‘table_OPM.csv’, used for emergence rate: - ID: id for females D. suzukii - Milieu: V. album/R. idaeus/M. japonica/R. nigrum for Viscum / Raspberry / Mahonia / Blackcurrant fruit purees - Temp: 16/20/24 for ambient temperature in °C - Wol: W-/W+ for Wolbachia uninfected / infected females - O: Number of eggs laid by D. suzukii female - P: Number of pupae - M: Number of emerged flies File ‘DATAdvlpmt_OM_dev_mean.csv’, used for development time: - ID: id for females D. suzukii - Milieu: V. album/R. idaeus/M. japonica/R. nigrum for Viscum / Raspberry / Mahonia / Blackcurrant fruit purees - Temp: 16/20/24 for ambient temperature in °C - Wol: W-/W+ for Wolbachia uninfected / infected females - diff_JOM: Development time from egg to adult (days) - max_OM: Max development time from egg to adult (days) - mean_dev: Mean development time from egg to adult (days) File ‘poids.csv’, used for mass of offspring: - ID: id summarising main infos for females D. suzukii - Milieu: G/F/M/C for Viscum / Raspberry / Mahonia / Blackcurrant fruit purees - Temp: 16/20/24 for ambient temperature in °C - Sex: M/F for male / female - Poids: Mass of emerged offspring #Step2 Folder File ‘FramboiseVSCassis.csv’: - ID: id summarising main infos for females D. suzukii - Milieu: F/C for Raspberry / Blackcurrant fruit purees - Temp: 16/20/24 for ambient temperature in °C - Wol: Wm/Wp for Wolbachia uninfected / infected females - Om: Number of eggs laid by D. suzukii female File ‘GuiVSFramboise.csv’: - ID: id summarising main infos for females D. suzukii - Milieu: G/F for Viscum / Raspberry fruit purees - Temp: 16/20/24 for ambient temperature in °C - Wol: Wm/Wp for Wolbachia uninfected / infected females - Om: Number of eggs laid by D. suzukii female - Total_O: Total number of eggs laid by D. suzukii female File ‘GuiVSMahonia.csv’: - ID: id summarising main infos for females D. suzukii - Milieu: G/F/M/C for Viscum / Raspberry / Mahonia / Blackcurrant fruit purees - Temp: 16/20/24 for ambient temperature in °C - Wol: Wm/Wp for Wolbachia uninfected / infected females - Om: Number of eggs laid by D. suzukii female #Step3 Folder File ‘Step3.csv’: - ID: id summarising main infos for females D. suzukii - Milieu: G/F/M/C for Viscum / Raspberry / Mahonia / Blackcurrant fruit purees - Temp: 16/24 for substrate temperature in °C - Wol: Wm/Wp for Wolbachia uninfected / infected females - Egg: Number of eggs laid by D. suzukii female #Step4 Folder File ‘Step4.csv’: - ID: id summarising main infos for females D. suzukii - Milieu: G/F/M/C for Viscum / Raspberry / Mahonia / Blackcurrant fruit purees - Wol: Wm/Wp for Wolbachia uninfected / infected females - Temp: 16/24 for substrate temperature in °C - Egg: Number of eggs laid by D. suzukii female For any inquiries or bugs, please contact corresponding author Anonymous (added later).