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

Contributions of Daphnia galeata mendotae diapausing eggs of different ages to population processes.

Fox, Jennifer^{*,1, 2}, ¹ Department of Ecology and Evolutionary Biology, Ithaca, NY, USA² Department of Biology, Madison, NJ, USA

ABSTRACT- Diapausing eggs of Daphnia remaining in lake sediments provide a means of reconstructing population history and fine-scale temporal changes. Differences in the timing of hatching from these "egg banks" of dormant eggs have been used to explain coexistence of different species and similarly could explain the coexistence of different genotypes within a species. The relative impacts on the adult population of eggs of different ages within an egg bank depend on the success and timing of several stages, including the probability of receiving a cue to hatch, probability of hatching once receiving the cue, time of response to the hatching cue, hatchling viability, time to maturity for successful hatchlings, and hatchling reproduction once reaching maturity. Of these, the total development time, from receiving a stimulus to hatch to first reproduction, is perhaps the most important determinant of the contribution of individual clones to the population growth and genetic structure of a population. I quantified the timing of hatching, time to maturity, and survival rates of Daphnia galeata mendotae from older and younger diapausing eggs from Onondaga Lake, New York, to determine how hatching ability and post-hatching survival influence the ability of egg banks to influence ecological and evolutionary dynamics. I found that when the total developmental time was considered, individuals hatched from older or recent eggs may make similar contributions to population processes. The results of this study will help to determine the influence of a standing egg or seed bank on genetic diversity and contribute to our understanding of how genetic variation is maintained in natural populations.

Key words: egg bank, paleoecology, temporal dispersal