MARTINEZ, G.M.; Univ. of New Hampshire: Early mantle function in embryonic squids.

Abstract: The muscular mantle of squids has two primary functions:locomotion and respiration. In squid embryos, the mantle is able to contract well before hatching. The mantle contractions seen in early squid embryos are mainly attributed to incipient respiration and the movement of water across the gills; however, video data suggest the initial function of the mantle changes from strictly respiratory movement to include preliminary locomotory movement as embryonic development progresses. In order to determine the developmental stage this transition in function occurs, I collected high speed video footage of the different mantle contractions exhibited by Loligo pealii and Loligo opalescens embryos from Arnold stage 24 to hatching. These data were then used to create a model of mantle function based on maximum and minimum mantle length and width measurements at different points during the contractions. I used this model to determine a quantitative difference between respiratory and locomotory contractions based on changes in volume expulsion. The results of the model show a distinct difference in volume output between respiration and locomotion contractions in both species of squid. Moreover it establishes when during development this transition occurs. Supported by a Sigma Xi Grant-in-Aid of Research and by University of Washington Blinks and Wainwright Fellowships.