cology describes the physical context in which morphology, behavior, and performance interact to mediate interactions between organisms and their environment. We focus on two fundamental ecological questions relating to fruit bats: How do fruit bats living in the same areas partition available fruit resources? And, What role do fruit bats play in the life cycle and evolution of figs? We address these questions by integrating data gathered in the laboratory with data collect from field sites in Central America and Papua New Guinea.
We use information about plant resources and the morphology, behavior, and performance (bite force) of bats to approach the question of resource partitioning in frugivore communities. When we are in the field, our days are spent collecting fruits that bats eat and measuring their size, hardness, color, and location within the forest. We have found that fruits eaten by bats vary significantly -- they can be bright or dull in color, and either small and soft or quite large and hard. By studying fruit samples that we bring back to the lab, we have also documented that fruits vary significantly in nutrient and mineral content.
During our evenings in the field, we document feeding behaviors used by different species of bats as well as the bite forces they can produce. This provides an indication of the relative abilities of bats to consume fruits of different texture. When we return to the laboratory we compare biomechanically relevant aspects of the morphology of the masticatory (feeding) apparatus among sympatric frugivore species. Differences among species are often clearly associated with specializations for consuming fruits of different texture.
In collaboration with Dr. George Weiblen, we are studying a unique interaction between pollinating fig wasps, seed-dispersing bats, and dioecious figs in Papua New Guinea. Among figs, dioecy is a derived breeding strategy in which male and female sexual functions are carried out by separate plants called "gall" and "seed" figs, respectively. Essentially, the life cycle of pollinating wasps is inextricably linked with gall figs; gall figs provide food and shelter for the wasps and the wasps disperse the pollen produced by the fig. In contrast, frugivores exhibit a strong preference for seed figs.
We have suggested that wasps and bats impose opposing selective pressures on figs at different stages of the fig life cycle. While similarities between gall and seed figs may increase the chances of pollination by wasps, increased attractiveness of ripe seed figs to frugivores may both enhance seed dispersal and protect developing pollinators from damage. We are continuing to study the ecological and evolutionary interactions among wasps, bats and dioecious figs by evaluating the specificity of their interactions and by investigating the roles of pollination and seed dispersal in the population structure of figs in Papua New Guinea.
