Location: Bowdoin / Coastal Studies Center / Student Research / Summer 2011 / Daniel Schwab

Coastal Studies Center

Daniel Schwab

College of William and Mary
Advisor: Jonathan Allen
Project: The effect of maternal size on reproduction and larval development in the mud snail Ilyanassa obsolete

Maternal effects occur when the phenotype of an individual is influenced by the phenotype of its mother. Maternal phenotype is partially the result of the environment, and when the maternal environment is an accurate predictor of the offspring’s environment, maternal effects can play an important role in enhancing offsprDanieling fitness. These effects are most frequently mediated by maternal investment, which is often a function of maternal size. The mud snail, Ilyanassa obsoleta, shows high variability in maternal size (14 – 26 mm), and deposits egg capsules on blades of eel grass during the reproductive season. Female I. obsoleta also shows high variability in reproductive traits, such as the number of egg capsules they deposit, the number of eggs per capsule, and egg size. While encapsulated, developing larvae suffer high levels of predation from predators such as the green crab, Carcinus maenas, making them likely targets for adaptive maternal effects. In order to better understand these effects, I will test (1) how egg capsule deposition is mediated by maternal size in the presence of a predator and (2) how larval development is mediated by maternal effects in the presence of a predator. I will expose female mud snails of small (15.00 – 19.00 mm) and large (21.00 – 25.00 mm) size classes to C. maenas cue and quantify egg size, egg number, and egg capsule number, as well as measure various aspects of egg capsule morphology. Additionally, I will rear and measure hatched larvae to determine how predator presence influences larval hatching size and growth rate. This experiment will show how maternal size effects can mediate adaptive responses to predators, as well as how these effects influence growth and development across generations.  

Pecha Kucha

These presentations are in PechaKucha format. PechaKucha is Japanese for ‘chit-chat’. It is a presentation methodology devised in 2003 in which 20 slides are shown for 20 seconds each. The slides auto advance to keep the presentations concise and quick paced. Each presentation is (about) 6 minutes and 40 seconds long.
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