DOI: 10.5061/dryad.8gtht76vv
title: Transgenerational exposure to deoxygenation and warming disrupts mate detection in Gammarus locusta

description: Ocean deoxygenation and warming have been shown to pose a growing threat
 to the health of marine organisms and ecosystems. Yet, the potential for
 acclimation and adaptation remains poorly understood. The aim of this
 study was to evaluate the effects of transgenerational exposure to reduced
 oxygen availability and elevated seawater temperature on the
 chemosensory-dependent mating mechanisms of male amphipods Gammarus
 locusta. Three subsequent generations were exposed to four experimental
 treatments for 30 days: i) present-day scenario, ii) warming; iii)
 deoxygenation; and iv) warming+deoxygenation. After exposure, the number
 of individuals that reached adulthood was gauged, and adult males from F0
 and F1 were subjected to behavioral trials to assess their capacity of
 long-distance female cue detection through quantification of response
 time, first direction of movement, activity rate, and proportion of time
 spent in female scent cues. Ocean-warming-induced mortality and reduced
 oxygen availability had adverse effects on each of the investigated
 behavioral traits, which were amplified when combined with elevated
 temperature. Still, when compared to F0, the F1 generation demonstrated
 more adaptability (i.e., higher activity rate and preference for female
 odors) to the combination of the two stressors, suggesting positive
 carry-over effects. Nevertheless, full recovery to control levels was not
 observed. Altogether, this study indicates that future scenarios of ocean
 deoxygenation and warming have the potential to disrupt
 chemosensory-dependent mate detection in amphipods, but also suggests
 possible behavioral adaptations. We call for greater research efforts on
 long-term impacts of ocean change on the behavioral and physiological
 processes of benthic coastal communities.
description: Our study aimed to investigate the transgenerational effects of
 increased temperature and lower oxygen levels on male gammarids'
 response to female scent signals. For this purpose, we conducted a
 binary-choice experiment using a total of 30 males from the
 F<sub>0</sub> generation and 26 males from the F<sub>1</sub> generation.
 These trials involved direct observations, during which we recorded four
 key traits of male individuals: response time (time to initiate movement
 towards an association zone), proportion of first choice (initial movement
 towards the female-scented association zone), cumulative time spent in
 each association zone, and activity rate (proportion of time spent
 actively moving).  Data analysis of behavioral outputs was
 performed through generalized linear mixed models (GLMM) using the
 negative binomial (number of individuals, response time), binomial (first
 choice), and Gaussian (cumulative time & activity rate) residual
 distributions. All models used temperature, oxygen, and generation as
 categorical fixed factors, and replicate ID as random factors.
 Transgenerational effects of the treatments on these variables were
 considered whenever an interacting effect was observed between Generation
 and Treatment. Full models, with all possible interactions, were tested
 using the function ‘glmmTMB’ from the package ‘glmmTMB’ and the
 function 'Anova' from the package 'car' in R, version 3.4.3. Post-hoc multiple
 comparisons were performed using the package ‘emmeans’ and applying Tukey
 corrections. Model assumptions and performance were validated using the
 package “performance”. Data exploration was conducted using the
 HighstatLibV10 R library from Highland Statistics.
description: # Transgenerational exposure to deoxygenation and warming disrupts mate
 detection in Gammarus locusta
 This dataset comprises a
 code script (script.rmd) with the associated raw data (data*.csv), used in
 the data analysis; and the water parameters registered daily in each
 replicate tank (parameters.xlsx). ## Description of the data and file
 structure Data_beh.csv and Data_population.csv: to be imported into the R
 software, using the R script and changing the directory (setwd()) to where
 the data file is located. Data_beh.csv: Data from behavioral trials (i.e.,
 long-distance female cue detection) with male gammarids from two
 successive generations (F0 & F1) and four treatment groups varying in
 temperature (18 °C & 21 °C) and oxygen levels (90 % & 100 % air
 saturation). Variables (Data_beh.csv): * Temperature; temperature
 treatment in degrees celcius (18ºC - Control, 21ºC - Warming) * Oxygen;
 air saturation (100% - Control, 90% - Deoxygenation) * ID; replicate tank
 ID * Generation; generation of sampled gammarids (F0 and F1) * Resp_time;
 response time in seconds * First_choice; First choice of the male (W -
 natural seawater or F - female scented water) * First_choice_bin; First
 choice of the male (0 - natural seawater or 1 - female scented water) for
 fitting a binomial glm (per replicate) spent in the natural seawater
 (seconds) * Time_F; average time spent in the female scented seawater
 (seconds) * Prop_W; proportion of time spent in the natural seawater *
 Prop_F; proportion of time spent in the female scented seawater * Active;
 average time male gammarids spent moving (seconds) * Prop_active; activity
 rate of male gammarids Data_population.csv: data on the number of
 individuals of *G. locusta* that reached adulthood in two successive
 generations (F1 & F2) exposed to four treatments with distinct
 temperatures (18 °C & 21 °C) and oxygen levels (90 % & 100 % air
 saturation).  Variables (Data_population.csv): * Temperature; temperature
 treatment in degrees celcius (18ºC - Control, 21ºC - Warming) * Oxygen;
 air saturation (100% - Control, 90% - Deoxygenation) * ID; replicate tank
 ID * Generation; generation of sampled gammarids (F1 and F2) * Population;
 total number of gammarids in each replicate tank