Predation of a cave fish (Poecilia mexicana, Poeciliidae) by a giant water-bug (Belostoma, Belostomatidae) in a Mexican sulphur cave |
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Authors: | MICHAEL TOBLER INGO SCHLUPP MARTIN PLATH |
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Institution: | Zoologisches Institut, Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland;, Department of Zoology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, U.S.A.;, Biozentrum Grindel, Martin-Luther-King Platz 3, D-20146 Hamburg, Germany;, Institut für Biochemie/Biologie, Universität Potsdam, Karl-Liebknecht Str. 24–25, D-14476 Potsdam, Germany |
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Abstract: | Abstract. 1. Caves are often assumed to be predator-free environments for cave fishes. This has been proposed to be a potential benefit of colonising these otherwise harsh environments. In order to test this hypothesis, the predator–prey interaction of a belostomatid (predator) and a cave fish (prey) occurring in the Cueva del Azufre (Tabasco, Mexico) was investigated with two separate experiments. 2. In one experiment, individual Belostoma were given a chance to prey on a cave fish, the cave form of the Atlantic molly ( Poecilia mexicana ), to estimate feeding rates and size-specific prey preferences of the predator. In the other experiment, population density of Belostoma was estimated using a mark–recapture analysis in one of the cave chambers. 3. Belostomatids were found to heavily prey on cave mollies and to exhibit a prey preference for large fish. The mark–recapture analysis revealed a high population density of the heteropterans in the cave. 4. The absence of predators in caves is not a general habitat feature for cave fishes. None the less predation regimes differ strikingly between epigean and hypogean habitats. The prey preference of Belostoma indicates that cave-dwelling P. mexicana experience size-specific predation pressure comparable with surface populations, which may have implications for life-history evolution in this cave fish. |
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Keywords: | Cave ecology cave fish predator–prey interactions prey preferences |
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