Meeting Abstract
Stable environmental conditions in the tropics promote breeding year round in intertidal invertebrates but reproduction is still influenced by abiotic factors. Reproduction often responds to where animals are in the intertidal and larval release is more time-restricted as you move higher up. Biotic factors play a key role and crowding can reduce reproductive effort. We studied a tropical Chthamalus species to see if reproduction varies with tidal height, temperature or crowding. We gathered barnacles from two tidal heights in the Bay of Panama and measured percent brooding, maternal dry weight and brood dry weight. We used animals from three proximity levels to their neighbors. To see if temperature has an effect on reproduction we altered the surface color of various barnacle patches. There was no clear semi-lunar or monthly reproductive cycle. Barnacles in the mid-intertidal were more likely to be brooding than those higher up. Barnacles in the high intertidal had a drop in percent brooding during the week of the new moon in July but not in August. There was an interaction effect of tidal height and crowding on the relationship between brood weight and maternal size. Partially crowded barnacles in the mid-intertidal had a steeper increase in brood size with maternal body weight than massed or solitary animals. Barnacles under reduced temperatures had a greater increase in brood size with maternal body weight than controls or those under increased temperatures. The results suggest that settlement site and temperature have an effect on Chthamalus reproduction. We collected our data in the wet season and it will be notable to see if they show the same pattern during the dry season and if events like the current El Niño affect their reproduction.
