Newly settled Caribbean spiny lobsters, Panulirus argus, undergo an ontogenetic habitat shift from vegetation (algal phase) to crevice shelters (postalgal phase). I experimentally observed the nocturnal behavior and diurnal shelter choice of juveniles across this size range in the absence and presence of conspecifics. Activity and shelter choice was not influenced by conspecifics during the algal phase. Postalgal phase juveniles, in the presence of conspecifics, were induced to greater locomotory activity and shelter sharing. Conspecifics influence produced an ontogenetic habitat shift at a smaller size. / Den sharing behavior by postalgal spiny lobsters has been postulated as a form of cooperation. I examined four hypotheses of how lobsters might benefit from sharing dens and/or being gregarious. By sharing dens, lobsters may increase survival (H$\sb{\rm A1})$ through group defense against predators, or (H$\sb{\rm A2})$ through group defense against interspecific competitors. By being gregarious, lobsters may increase survival (H$\sb{\rm B3})$ through the dilution effect, or (H$\sb{\rm B4})$ through decreased exposure while searching for shelter (guidepost effect). The first two hypotheses provide a benefit for den sharing and constitute cooperation. The last two hypotheses suggest that den sharing is a coincidence of congregation. Each hypothesis makes specific predictions which I tested by den monitoring field surveys, field manipulations and mesocosm experiments. / I found (1) lobsters did not consistently utilize the most defensible dens nor occupy dens to capacity. (2) Den sharing was not correlated with predator or competitor density, but was positively correlated with conspecific density. (3) Lobsters were more often aggregated at a spatial scale larger than a single den. (4) Lobsters did not have higher survival when sharing dens. (5) Lobsters were not better competitors when sharing dens. (6) Lobsters did not have higher survival with higher conspecific density, but (7) lobsters were able to find dens twice as often and three times faster when conspecifics were present. These results support only the guidepost effect (H$\sb{\rm B4})$ hypothesis. Den sharing is a non-advantageous outcome of gregariousness but is not cooperation during the ontogenetic phase when the behavior is first observed. / Source: Dissertation Abstracts International, Volume: 56-12, Section: B, page: 6513. / Major Professor: William F. Herrnkind. / Thesis (Ph.D.)--The Florida State University, 1995.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77634 |
| Contributors | Childress, Michael John., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 179 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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