Parents interact with offspring in myriad ways and can change offspring gene expression and traits through parental effects. These non-genomic alterations of offspring phenotypes can facilitate rapid transgenerational responses to novel and changing environments. We have two major projects related to parental effects. One investigating the impacts of parental effects on mating preferences and decisions and a second looking at transgenerational effects of maternal age on offspring fitness.
Mating decisions directly impact the maintenance of species boundaries and the generation of biodiversity. So, parental effects on mate preferences and choice could change the sexual selection landscape. Threespine sticklebacks are an ideal study system for this work because both mothers and fathers make independent, but important contributions to offspring development. So we can probe the separate (maternal and paternal) and combined (joint parental) effects of parental experience on offspring reproduction. We recently demonstrated for the first time that environmentally-induced parental effects do extend through development to affect reproductive decisions of their daughters. Maternal and paternal predator exposure independently yield offspring who choose less conspicuous mates with duller nuptial coloration and who court less vigorously. Parental effects can thus relax (paternal) or reverse (maternal) the typical preference for conspicuous males. In ongoing work we are probing the adaptive nature of these parental effects on reproduction as well as their mechanistic underpinnings. This work is supported by NSF through a DDIG to PhD student Whitley Lehto.
Aging is associated with declines in an individual’s performance and breeding success, but how advanced parental age affects offspring viability and reproductive performance is less clear. And transgenerational impacts of maternal age remain largely unknown. In humans and some laboratory-reared organisms, there are well-established negative relationships between maternal age and offspring fitness. Life history theory predicts similar trade-offs between maternal age and offspring fitness, but older females at the end of life might also allocate more resources and energy into reproduction than do younger females. With funding from the Knoebel Institute for Healthy Aging and collaborator Shannon Murphy, we are testing whether and how advanced maternal age influences offspring fitness and immunocompetency, and investigating transgenerational fitness effects and their epigenetic underpinnings.
Selected related publications:
Lehto, W. and Tinghitella, R.M. In Press. Predator-induced maternal and paternal effects independently alter sexual selection. Evolution.
Lehto, W.* and Tinghitella, R.M. 2019. Joint maternal and paternal stress increases the cortisol in their daughters’ eggs. Evolutionary Ecology Research.
Wilson, J.D.*, Anner, S.C.**, Murphy, S.M. & Tinghitella, R.M. In Press. Consequences of advanced maternal age on reproductive investment of male offspring. Journal of Orthoptera Research.