Diet quality is a key environmental determinant of individual condition. Parental diet is known to have transgenerational effects on offspring traits. For example, individuals in high diet environment may be selected to transfer their good condition to enhance offspring performance (1).
In many species, parental preadult diet has a large influence on offspring traits. In grasshopper, offsprings of parents reared on drought-stressed plants (high-quality diet) had shorter developmental time, higher body mass, laid heavier egg pods and higher peak amplitude (song). Moreover, offspring of parents reared on high-quality plants performed better in both environments (high and poor diet) than offsprings of parents reared on poor diet (2). Insects defend themselves against pathogens and parasitoids by their innate immune system. The experience of a microbial infection can improve the insect immune response to a subsequent exposure to pathogens (i.e. immune priming). Moreover, when the parents are exposed to a parasite or pathogen, offspring immune defences are stronger (i.e. transgenerational immune priming) (3). Investment in immunity can be determined by many environmental factors. For example, in Indian meal moth, Plodia interpunctella, parental larval diet has strong transgenerational effects on offspring immunity. If one parent received the poor diet, reduction in immunity was observed and the lowest offspring immunity was observed when both parents received the poor diet (4). In Drosophila melanogaster, it was found that isocaloric larval diets that differed in ratio of protein and sugar resulted in significant differences in the metabolic pools of protein, glycogen, and triglycerides of newly emerged adults (5). Moreover, offsprings of parents reared on high protein relative to sugar (HPS) had higher reproductive output and different metabolic pools contents compared to the offspring of adults from low protein relative to sugar (LPS). Besides, transgenerational effects also differed among genotypes because isofemale lines varied in their response in all the metabolic pool (6).
Like parental preadult diet, parental adult diet has also carry on effects on offspring traits (7, 8). In D. melanogaster, adults were maintained in two feeding regimes: ‘constant’ and ‘varied’ (‘each day’ and every other day’). Offsprings whose mothers were reared on a constant feeding regime had higher survival than offspring whose mothers were reared on a varied diet, but maternal feeding regime did not affect the number of adult offsprings. However, there was no relationship between a male feeding regime and male pheromone production, although F2 sons were more likely to produce more pheromone than F1 individuals (7). Similarly, in European corn borer, Ostrinia nubilalis, offspring survival was higher when either the grandparents or parents were fed. In addition, silking speed of neonate offspring was faster when either grandparents or parents had fed, while walking speed of neonate was faster only when parents had fed (8).
In many species, resource availability is important function of population density. Thus, transgenerational effects of parental diet on offspring traits are likely to lead to complex population dynamics in ecological system.
References
1. Rotem, K., Agrawal, A. & Laima, 2003. Parental effects in Pieris rapae in response to variation in food quality: adaptive plasticity across generations? Ecol. Entomol. 28: 211-218.
2. Franzke, A. & Reinhold, K. 2012. Transgenerational effects of diet environment on life-history and acoustic signals of a grasshopper. Behav. Ecol.doi:10.1093/beheco/ars205
3. Trauer, U. & Hilker, M. 2013. Parental legacy in insects: Variation of transgenerational immune priming during offspring development. Plos. one. 8(5): e63392. doi:10.1371/journal.pone.0063392
4. Triggs, A. M. & Knell, R. J. 2012. Parental diet has strong transgenerational effects on offspring immunity. Funct. Ecol. doi: 10.1111/j.1365-2435.2012.02051.x
5. Matzkin, L.M., Johnson, S., Paight,C., Bozinovic, G. & Markow, T. A. 2011. Dietary Protein and Sugar Differentially Affect Development and Metabolic Pools in Ecologically Diverse Drosphila. J. Nutr. 141: 1127-1133.
6. Matzkin, L. M., Johnson, S., Paight, C. & Markow, T. A. 2013. Preadult parental diet affects offspring development and metabolism in Drosophila melanogaster. Plos. one. 8(3): e59530. doi:10.1371/journal.pone.0059530
7. Jones, T. M. & Widemo, F. 2005. Survival and reproduction when food is scarce: implications for a lekking Hawaiian Drosophila. Ecol. Entomol. 30: 397-405.
8. Andow, D. A. 2002. Ancestral feeding and survival of offspring in European corn borer. Entomol. Exp. Appli.103: 115-122.