Ontogenetic changes in pharyngeal morphology correlate with a diet shift from arthropods to dreissenid mussels in round gobies (Neogobius melanostomus)

Greg Andraso, James Cowles, Rose Colt, Jay Patel, Michael Campbell

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

The potential of predators to regulate populations of dreissenid mussels (Dreissena polymorpha and Dreissena rostriformis bugensis) has been addressed since early in the dreissenid invasion of North America. Round gobies (Neogobius melanostomus) larger than approximately 60. mm have been shown to prey extensively on dreissenids, whereas smaller round gobies feed mainly on aquatic insects and crustaceans. We propose that ontogenetic changes in pharyngeal morphology may contribute to this diet shift in round gobies. Pharyngeals of 69 round gobies ranging from 31 to 164. mm total length were investigated using light microscopy and scanning electron microscopy. Areas of lower pharyngeals and pharyngobranchial 2 increased allometrically with fish length. Pharyngeals of round gobies smaller than 50. mm contained narrow (<. 0.1. mm diameter) papilliform teeth that are consistent with eating soft-bodied prey. By the time round gobies reached approximately 80. mm in length, pharyngeals contained larger diameter (0.3-0.5. mm) molariform teeth typical of those found in molluscivorous fish. Pharyngeal teeth of the largest round gobies also showed considerable wear. Although changes in pharyngeal morphology may contribute to the previously described diet shift in round gobies as they age, genetic and environmental factors both likely influence pharyngeal remodeling and therefore merit further investigation.

Original languageEnglish (US)
Pages (from-to)738-743
Number of pages6
JournalJournal of Great Lakes Research
Volume37
Issue number4
DOIs
StatePublished - Dec 2011

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Ecology

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