Interpopulation variation in prey use and feeding biomechanics in Caribbean triggerfishes

Abstract

The relationships between prey utilization and jaw biomechanics were explored in two Caribbean populations (La Parguera and Mona Island) of four trigger-fishes. The volumetric contribution of major prey types and six biomechanical features of the jaws that characterize biting strength were contrasted between populations. At Mona, Xanthichthys ringens ate 45% benthic organisms, whereas conspecifics at La Parguera fed exclusively on plankton. Balistes vetula at Mona consumed 63% soft and nonelusive invertebrates, in contrast to their La Parguera conspecifics, which consumed 62% hard prey. Differences in diet between populations were associated with differences in jaw biomechanics. Xanthichthys at Mona had jaw muscles, bones, and closing-lever ratios larger than those of fish at La Parguera, indicating a stronger bite. Balistes at Mona had 50% smaller jaw bones, muscles, and closing-lever ratios than their La Parguera conspecifics, indicating a weaker but swifter bite. Melichthys niger and Cantherhines macrocerus ate similar prey at the two locations and showed little difference in trophic anatomy. We hypothesize that the interpopulation differences in morphology are induced by the activities of feeding on different prey and enhance the feeding ability of fishes for locally dominant prey. Plasticity of the feeding mechanism may be a widespread attribute of fish feeding systems that promotes the ability of species to occupy multiple habitat types successfully.

The cerato-mandibular ligament: a key functional trait for grazing in damselfishes (Pomacentridae)

“…A classic example is the trade-off between maximization of force and velocity in mouth closing systems often reported in fishes [50,[58][59][60][61][62]. Grazing in damselfishes has to cope with two different mechanical demands: 1) the quick closing of the mouth on filamentous algae and 2) the development of enough force to extract the algae or to take undesirable objects out of the territory.…”

Genotype × environment interactions in transplanted clones of the massive corals Favia speciosa and Diploastrea heliopora

“…Some phenotypic plasticity is clearly adaptive (Dodson 1989, Scharloo 1989, Newman 1992; however this is difficult to demonstrate empirically (Newman 1992, Dudley & Schmitt 1996. Common in terrestrial taxa, phenotypic plasticity has also been documented in a broad range of marine biota including fishes (Robinson & Wilson 1995, Turigan et al 1995, Vanrooij et al 1995, molluscs (Etter 1996, Trussell 1996, crustaceans (Lively 1986, Hazlett 1995, Mokady et al 1999, echinoderms (Ebert 1996), sponges (Palumbi 1984), bryozoans (Harvell 1992, Okamura 1992 and corals (Foster 1979, Bruno & Edmunds 1997, Muko et al 2000.…”

Chemical defense: Aquatic beetle ( Dineutes hornii ) vs. fish ( Micropterus salmoides )

“…Food ingestion in fish is a complicated process, subject to considerable variation (17)(18)(19). It is not unusual for fish to treat different prey items differently and to subject them to various buccal and pharyngeal preingestive processings (19).…”