MACH, M.E.; University of Washington: The effects of embryonic heat stress on hatching size and larval growth of the bubble snail Melanochlamys diomedea.
An organism�s growth and survival depends on the environmental conditions it experiences. For organisms with complex life histories, each life history stage may be affected differently by these conditions, and the effects felt by one stage may carry over to the next. Intertidal invertebrates have complex life histories which can experience some of the largest changes in environmental temperature of any organism. We used the bubble snail Melanochlamys diomedea to examine the effects of temperature on one life history stage and its subsequent effects on the next stage. M. diomedea is an intertidal organism with a complex life history that has its embryonic and adult life history stages in the benthos and its larval stage in the plankton. We collected egg masses from mudflats on San Juan Island, WA and incubated them under a series of natural temperature profiles that varied in maximum temperature reached (from 12 to 34oC). Larvae hatched from these different conditions were then raised at a constant temperature of 12oC. High temperatures during the embryonic stage caused variation in hatching size but had no effect on growth rate of larvae. Embryos which were stressed at temperatures above 28oC hatched out at a smaller size then those in non-stressful lower temperatures. After two weeks larvae from temperature stressed embryos were smaller then those from embryos not stressed. The results of this study suggest that temperatures experienced by embryonic invertebrates will have an effect on later life-history stages.
