Paternal response to novel predator exposure correlates with transgenerational response in offspring of threespined stickleback

Abstract

Parental experiences can alter offspring phenotypes via transgenerational plasticity (TGP), which may prime offspring to adaptively respond to novel stressors, including novel predators. However, we know little about the types of sensory cues (e.g. visual, olfactory) that parents use to recognize novel predators and the consequences for offspring. Individuals may respond to novel cues if they mimic historical cues or they may need multiple sensory cues to recognize and respond to novel stimuli. We exposed threespined stickleback (Gasterosteus aculeatus) males to a full factorial of visual and olfactory cues of a novel trout predator prior to fertilization and tested offspring for antipredator behaviour and survival against a live predator. Fathers exposed to visual cues oriented more to and spent time closer to the novel predator post-exposure on the first day. Paternal response to visual cues was echoed in their offspring: offspring of fathers exposed to visual cues were caught faster by a live predator, suggesting that multiple cues are not needed to induce a transgenerational effect. While visual cues elicited responses both within- and transgenerationally, they do not seem to result in adaptive priming in offspring, suggesting the possibility of maladaptive TGP in response to novel cues of predation risk.

Keywords: Gasterosteus aculeatus; multimodal signalling; paternal effect; phenotypic plasticity; predation; transgenerational plasticity.

Figure 1.

Top view of the paternal exposure set-up for each treatment. We housed two stickleback in opposite compartments of a 37.9 l tank divided into three sections and housed the trout individually in an undivided 37.9 l tank. We separated the stickleback and predator tanks visually with a removable opaque divider.

Figure 2.

Paternal time spent in the front of the tank on day 1 due to paternal treatment (data are median with interquartile range, dots correspond to individuals). Orange boxplots show the baseline behaviour of fathers 5 min before treatments were applied. Blue boxplots show paternal behaviour 5 min after treatments were applied. We found a significant interaction between paternal visual cue exposure and the observation period on day 1 for time spent in the front of the tank. Fathers exposed to the visual cue in the visual-only or visual and olfactory treatment spent more time in the front of the tank after exposure compared to control fathers and olfactory-only exposed fathers.

Figure 3.

Offspring survival time in the live-predator assay due to paternal treatment (data are median with interquartile range, dots correspond to individuals). We found that the offspring of fathers exposed to the visual cue in the visual-only and visual and olfactory treatment had reduced survival against a live rainbow trout predator. The data for the figure were log-transformed for visualization only and were not transformed in the model for analysing significance.