The Genetics of Dietary Experience in a Restricted Natural Population

Abstract

The sources of individual differences in human and non-human animals remain controversial. We demonstrate that diet and genetics interact in determining the ontogenetic trajectory of chemosensory and prey preferences in the common garter snake, Thamnophis sirtalis, a dietary generalist. In litters of neonate snakes from a single small field in an earthworm-ingesting population, initial responses to chemical cues from fish and worm were similar, with zero heritabilities. After 12 meals on fish, however, the heritability of both fish and worm chemosensory responses increased markedly, the change in response to fish but not worm chemicals was heritable, the relative preference for fish versus worm was heritable, and the change in relative preference was heritable. In addition, growth rates on each diet were related to changes in chemoreceptive responses. Such genetic-environment variation that emerges only after equivalent ontogenetic experience may be a factor in responses to environmental change in many species.

Application of microsatellite DNA markers to discriminate between maternal and genetic effects on scalation and behavior in multiply-sired garter snake litters

“…Garter snakes and their allies exhibit variation among litters in virtually all aspects of morphology, scalation, behavior, growth, and physiology that have been investigated (reviews in Brodie and Garland 1993;Burghardt and Schwartz 1999; see also King 1997;Burghardt et al 2000). This variation is often thought to reflect underlying genetic variation, and estimates of the heritability of and genetic correlations among many of these traits have been reported.…”

Natural History of Neonatal Green Anacondas (Eunectes murinus): A Chip Off the Old Block

“…The paucity of data is particularly noteworthy with snakes, where data from field studies are particularly lacking. There have been some studies on antipredator behavior (Herzog and Burghardt, 1986;Placyk and Burghardt, 2005;Gregory et al, 2007;Mori and Burghardt, 2008), snakes' innate dietary preferences (Burghardt, 1992;Burghardt and Krause, 1999;Burghardt et al, 2000), their ontogenetic switches (Mushinsky and Lotz, 1980;Savitzky and Burghardt, 2000), the ontogenetic changes in vipers' venom (Mackessy et al, 2003;Wray et al, 2015), and neonatal social behavior (Burghardt, 1983;Greene et al, 2002;Holycross and Fawcett, 2002;Cobb et al, 2005;Jellen and Kowalski, 2007;Reiserer et al, 2008;Howze et al, 2012). Only one field study seems to have addressed the natural history of neonatal basal snakes (Pizzatto et al, 2009).…”

“…The view that neonatal reptiles are miniature replicas of adults and undergo few ontogenetic behavioral changes outside of reproduction that are not mere consequences of changes in body size has been challenged by evidence of significant ontogenetic changes in diet (Mushinsky and Lotz, 1980) and other behavioral changes associated with learning in early stages of development (Gove and Burghardt, 1975;Burghardt and Krause, 1999;Burghardt et al, 2000;Waters and Burghardt, 2013). Neonatal animals are expected to have higher energetic requirements than adults (Nagy, 2000) and different metabolic requirements due to the scaling of metabolic processes (Calder, 1996).…”

Heritable variation in testosterone levels in male garter snakes (Thamnophis sirtalis)

“…King, unpublished data), but by including mass as a covariate in our analyses, differences in testosterone levels among families are evident independent of differences in body size. Family effects, such as those on testosterone reported here, have been found consistently for a wide range of morphological, physiological and behavioural traits of natricine snakes (garter snakes and their allies) (reviewed by Brodie & Garland, 1993;Burghardt & Schwartz, 1999; see also King, 1997;Burghardt, Layne & Konigsberg, 2000). Patterns of variation within and among families have been used previously to estimate heritability via full-sib analysis as used here (Brodie & Garland, 1993).…”