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Article
Geographic variability of Octopus insularis diet: from oceanic island to continental populations
Habitat and Trophic Ecology Collection
  • Tatiana S. Leite, Universidade Federal do Rio Grande do Norte
  • Allan T. Batista, Universidade Federal do Rio Grande do Norte
  • Françoise D. Lima, Federal University of Rio Grande do Norte
  • Jaciana C. Barbosa, Federal University of Rio Grande do Norte
  • Jennifer A. Mather, University of Lethbridge
Document Type
Article
Publication Date
1-1-2016
Abstract

A predator’s choice of prey can be affected by many factors. We evaluated various influences on population dietary composition, individual specialization and size of prey in Octopus insularis populations from 2 continental and 4 insular locations. We expected that habitat diversity would lead to diet heterogeneity. Furthermore, in keeping with MacArthur & Wilson’s (1967) theory of island biogeography, we expected that diet diversity would be lower around islands than on the coast of the mainland. Both predictions were confirmed when prey remains from octopus middens were examined. The 2 continental areas exhibited a richer habitat diversity and a wider variety of prey. Niche widths in the continental areas were 2.42 and 2.03, with the lowest niche widths exhibited by the population from the most distant oceanic islands (1.30, 0.85). We found variation in the proportion of specialist relative to generalist individuals across areas based on the proportional similarity index. The correlation between habitat diversity and niche width (R2 = 0.84) was highly significant, as was distance from the continental shelf and niche width (R2 = 0.89). This study reaffirms the central position of octopuses in the nearshore benthic ecosystem, and supports MacArthur & Wilson’s (1967) prediction of a lower diversity of species on islands—which applies not only to the species themselves, but also indirectly for the diet of their predators.

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© The authors 2016. Open Access under Creative Commons by Attribution Licence. Use, distribution and reproduction are unrestricted. Authors and original publication must be credited.

Citation Information
Leite, T. S., Batista, A. T., Lima, F. D., Barbosa, J. C., & Mather, J. (2016). Geographic variability of Octopus insularis diet: from oceanic island to continental populations. Aquatic Biology, 25, 17-27. DOI: https://doi.org/10.3354/ab00655