Deno, J. | bioRxiv Science

bioRxiv2020

The specificity of sperm-mediated paternal effects in threespined sticklebacks

Parental effects can help offspring cope with challenging environments, but whether these effects are unique to specific environmental conditions is largely unknown. Parental effects may evolve via a core pathway that generally prepares offspring for risky environments or could be stimuli-specific, with offspring developing phenotypes that are tailored to specific environmental challenges. We exposed threespined sticklebacks (Gasterosteus aculeatus) fathers to a potentially threatening stimulus (net) versus native predator (sculpin). Offspring of sculpin-exposed fathers were more responsive (greater change in activity) to a simulated predator attack, while offspring of net-exposed fathers were less responsive (lower plasma cortisol and fewer antipredator behaviors). To evaluate offspring response to native and non-native stimuli, we sequentially exposed offspring of net-exposed, sculpin-exposed or control fathers to a net, native sculpin model, or non-native trout model. Paternal treatment did not influence offspring response to stimuli; instead, offspring were more responsive to the native sculpin predator compared to nets or non-native trout predator. Collectively, we demonstrate that sperm-mediated paternal effects in response to different, potentially stressful stimuli result in distinct offspring phenotypes. This specificity may be key to understanding the evolution of adaptive parental effects and how parents prime offspring for encountering both evolved and novel environmental stimuli.Competing Interest StatementThe authors have declared no competing interest.View Full Text

animal behavior and cognition↗

bioRxiv2019

Sex-specific transgenerational plasticity in threespined sticklebacks

O_LITransgenerational plasticity (TGP) or parental effects - when parental environments alter the phenotype of future generations - can influence how organisms cope with environmental change. An intriguing, underexplored possibility is that sex -of both the parent and the offspring - plays an important role in driving the evolution of transgenerational plasticity in both adaptive and nonadaptive ways. C_LIO_LIHere, we evaluate the potential for sex-specific parental effects in a freshwater population of threespined sticklebacks (Gasterosteus aculeatus) by independently and jointly manipulating maternal and paternal experiences and separately evaluating their phenotypic effects in sons versus daughters. We tested the adaptive hypothesis that daughters are more responsive to cues from their mother, while sons are more responsive to cues from their father. C_LIO_LIWe exposed mothers, fathers, or both parents to visual cues of predation risk and measured offspring antipredator traits and brain gene expression. C_LIO_LIPredator-exposed fathers produced sons that were more risk-prone, while predator-exposed mothers produced more anxious sons and daughters. Further, maternal and paternal effects on offspring survival were nonadditive: offspring with a predator-exposed father, but not two predator-exposed parents, had lower survival against live predators. There were also strong sex-specific effects on brain gene expression: exposing mothers versus fathers to predation risk activated different transcriptional profiles in their offspring, and sons and daughters strongly differed in the ways in which their brain gene expression profiles were influenced by parental experience. C_LIO_LIWe found little evidence to support the hypothesis that offspring prioritize their same-sex parents experience. Parental effects varied with both the sex of the parent and the offspring in complicated and nonadditive ways. Failing to account for these sex-specific patterns (e.g., by pooling sons and daughters) would have underestimated the magnitude of parental effects. Altogether, these results draw attention to the potential for sex to influence patterns of TGP and raise new questions about the interface between transgenerational plasticity and sex-specific selective pressures, sexual conflict, and sexual selection. C_LI

evolutionary biology↗