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Past Research

Coral Reef Ecology 
Our experimental studies on tropical reefs have shown that herbivorous fish play a crucial ecological role as they can mediate competition between reef-building corals and faster-growing seaweeds. When human fishing pressure moves down the food chain, the disappearance of these herbivores causes the degradation of reef communities.

  • Lewis, S.M., 1986. The role of herbivorous fishes in the organization of a Caribbean reef community. Ecological Monographs 56: 183-200. pdf
  • Lewis, S.M., 1985. Herbivory on coral reefs: Algal susceptibility to herbivorous fishes. Oecologia 65:370-375.
  • Lewis, S.M. and P.C. Wainwright, 1985. Herbivore abundance and grazing intensity on a Caribbean coral reef. Journal of Experimental Marine Biology and Ecology 87: 215-228. pdf

Phenotypic plasticity in seaweeds
Some tropical seaweeds show striking phenotypic plasticity as an evolutionary response to the intense herbivory that characterizes healthy coral reefs. Under high grazing pressure, they can persist in a cryptic turf form, rapidly transforming into an upright, macroalgal form whenever and wherever they encounter reduced herbivory.

  • Lewis, S.M., J.N. Norris and R.B. Searles, 1987. The regulation of morphological plasticity in tropical reef algae by herbivory. Ecology 68: 636-641. pdf

Seahorse courtship behavior
Seahorses (genus Hippocampus) have evolved extreme paternal care in which males gestate developing embryos and give birth to live young. Our work on dwarf seahorses demonstrated that in spite of this reversal of parental roles, seahorses display traditional courtship roles. Males compete with one another for access to females, and they also show higher potential reproductive rates because females need more time to mature their eggs.

  • Masonjones, H.D. and S.M. Lewis. 1996. Courtship behavior in the dwarf seahorse, Hippocampus zosterae. Copeia 1996: 634-40. pdf
  • Masonjones, H.D. and S.M. Lewis. 2000. Differences in potential reproductive rates of male and female seahorses related to courtship roles. Animal Behaviour 59: 11-20. pdf