Predation by Octopus vulgaris at Cayos Cochinos, Honduras An Analysis of Prey Selection Using the Framework of Optimal Foraging Theory

Caitlin Petro

Date of Award

2011

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Gilchrist, Sandra

Keywords

Optimal Foraging Theory, Octopus, Cayos Cochinos

Area of Concentration

Biology

Abstract

Octopus vulgaris is a major predator of benthic organisms in the intertidal reef at Cayos Cochinos, Honduras. Because they are capable of capturing a variety of species using different foraging techniques, their predatory behaviors can have a significant impact on community trophic structures and population dynamics. Field work was conducted in the intertidal reef at Cayos Mejor as part of a pilot study aimed at characterizing the prey items that were returned to the dens of O. vulgaris. Major prey items were determined based on midden contents and the relative availabilities of prey species were approximated using randomized quadrats. Subsequent lab work was performed to assess the degree to which energetics influence prey selection in the field. Specifically, handling times and energy contents were determined for species of both low and high electivity. Factors such as patch-utilization and predator avoidance were found to play a significant role in the foraging behavior of O. vulgaris, suggesting that O. vulgaris is a time-minimizing forager.

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