Genetic and environmental factors influence survival and hatching of diapausing eggs
Limnol. Oceanogr., 55(2), 2010, 549-559 | DOI: 10.4319/lo.2010.55.2.0549
ABSTRACT: To test the hypothesis that variation in hatching and survival of Daphnia dormant eggs is fostered by genetic differences among populations, rather than system-specific availability of environmental cues, I measured hatching and egg survival rates for Daphnia from 22 shallow, fishless ponds in the midwestern U.S.A. Although all eggs were incubated at a water depth of 0.75 m or less in their natal pond, hatching rates varied between 5% and 90% and survival rates of eggs remaining in the egg bank ranged from 7% to 72%. There was no significant relationship between hatching and environmental cues such as light, oxygen content, or conductivity, although a negative relationship with depth was observed. Reciprocal transplant experiments quantified genetic and environmental influences on dormancy and survival, revealing strong population-by-host environment interactions. Thus, plasticity to environmental cues and genetic or maternal effects likely interact to determine hatching and survival rates in the field.