PARENT SESSION
Contributed Oral Session 15: Populations and Genetics: Succession; Reproduction
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 522 A, Level 5, Palais des congrès de Montréal
Maternal effects propagate life-history variation across three generations.
Plaistow, Stewart*,1, Benton, Tim2, 1 University of Aberdeen, Aberdeen, UK2 University of Leeds, Leeds, UK
ABSTRACT- Maternal effects arise when mothers alter the provisioning of their offspring in response to the environment they experience. Offspring life-history trait expression is therefore the product of past and present environments. From a population dynamic perspective, this is important because it means that a populations response to an environmental change may be time-lagged to some degree. The significance of these delays in driving population dynamic patterns is currently debated and will depend upon the size, nature and duration of maternal effects in different environments. Quantifying maternal effects from field data is complicated by the need to separate effects associated with changing offspring quality from effects associated with changes in offspring number and cohort effects. Here we describe an experiment in which we created maternal effects by rearing soil mites,Sancassania berlesei, in three different food environments. Eggs from these parents were reared across all food environments for a further three generations and a suite of life-history traits was measured for all of the offspring in each generation. Effects of the original parental food environment were detectable in all three generations and all food environments. However, the direction of these subtle effects and the traits they influenced varied in different food environments and from one generation to the next. This complexity arises because (a) trait variation is context-dependent, (b) trait co-variation is context-dependent, and (c) because there are significant interactions between great grand-maternal effects, grand-maternal effects, and maternal effects. We propose that this influence of past environmental conditions on life-history expression is likely to contribute to variation in population dynamics over time and may explain why populations still sometimes diverge under similar environmental conditions. Moreover, we suggest that population models that incorporate invariable maternal-effects over a single generation may be too simplistic.
Key words: plasticity, maternal effects, context-dependent trade-offs