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
- Lewis, S.M., 1986. The role of herbivorous fishes in the
organization of a Caribbean reef community. Ecological
Monographs 56: 183-200.
- Lewis, S.M., 1985. Herbivory on coral reefs: Algal
susceptibility to herbivorous fishes. Oecologia
- 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.
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:
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.
- Masonjones, H.D. and S.M. Lewis. 2000. Differences
in potential reproductive rates of male and female
seahorses related to courtship roles. Animal Behaviour