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 and population dynamics: an empirical example.

Benton, Tim ^*,1, Plaistow, Stewart², ¹ University of Leeds, Leeds, UK² University of Aberdeen, Aberdeen, UK

ABSTRACT- The way that mothers provision their offspring can have important consequences for their offspring's performance throughout life. Models suggest that maternally-induced variation in life-histories may have large population dynamical effects, even perhaps driving cycles such as those seen in forest Lepidoptera. The evidence for large maternal influences on population dynamics is unconvincing, principally due to the difficulty of conducting experiments at both the individual and population level. In the soil mite, Sancassania berlesei, we examine the trade-off between a female's fecundity and the per-egg provisioning of protein. The mother's position on this trade-off depends on her current food availability and her age. Populations initiated with the same number of eggs of different mean sizes, or from mothers of different ages, showed significant differences in the population dynamics, converging only after 3 generations. Differences in the growth, maturation and fecundity of the initial cohorts caused differences in the competitive environment for the next generation, in turn, creating differences in their growth and reproduction. Maternal effects in one generation can therefore lead to population dynamical consequences over many generations. Where animals live in environments that are temporally variable, we conjecture that maternal effects could result in long-term dynamical effects.

Key words: maternal effects, population dynamics, perturbation, trade off