ATBC 2008 - Plenary Abstracts 10 June

Plenary Speakers - Abstract - Tuesday 10 June

Kalko, Elizabeth (University of Ulm, Institute of Experimental Ecology, Ulm, Germany and Smithsonian Tropical Research Institute, Balboa, Republic of Panamá)

Biogeography patterns and functional diversity of bats across the tropics

Bats (Chiroptera) constitute one of the most diverse group of mammals. With more than 1,100 species worldwide they fulfill crucial ecological roles and contribute to essential ecological services. Species diversity and functional diversity peak in the tropics where bats act as seed dispersers, pollinators and predators, enhancing for instance regeneration of vegetation and limiting the impact of herbivorous arthropods on plants. During evolution, access to the broad range of resources has been enabled and facilitated for bats by the development of controlled, flapping flight and the integration of a range of senses for foraging, including a keen sense of smell, excellent vision and a complex echolocation system. Interestingly, a trade-off exists where strong emphasis on one sense seems to reduce the performance of other senses, probably associated with energetic bottlenecks. The differences in expression of senses is tightly coupled with phylogeny and ecology. Recent molecular studies convincingly show monophylie of bats and support a distinct biogeographic pattern where families that had been formerly regarded as separate clades and that are restricted in their distribution to the Old World, are indeed closely related. This biogeographic pattern permits detailed pantropical comparisons of bats that differ in phylogeny as well as in sensory abilities but converge in their ecological function. I am comparing structure and function of bats in the neo- and paleotropics and illustrate for plant-visiting and animalivorous species how ensembles in the neootropics relate to their palaeotropical counterparts in ecological diversity, function, and performance. A comprehensive assessment of structure and function of bat ensembles in a biogeographic context combined with a strong emphasis on sensorial and morphological features reflecting differential access to resources is crucial if we are to understand whether and how well bats adapt to changes in environmental conditions and which conditions may lead to reduction in species diversity and hence ecosystem services. This comprehensive approach is crucial to meet current and future challenges in conservation, where management strategies are increasingly exacerbated by global change and the ever growing strain on natural resources from humans including drastic changes in land use and urbanization.

Borges, Renée (Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India)

The scent of a fig: how do birds, bats, wasps and ants like it?

Figs (Ficus: Moraceae) are a familiar feature of many tropical landscapes. Despite their ubiquity, and their keystone status, many aspects of their biology, especially their chemical ecology, are only just being discovered. Figs constitute a nursery pollination mutualism, in which syconia nurture pollinating fig wasps and seeds. Figs attract pollinating wasps by volatile organic compounds (VOCs). The VOCs of the fig syconium change with development stage, and when the fig seeds are ready for dispersal, the VOC profile of the fig attracts seed dispersers such as birds or mammals such as bats. Thus the VOC chemistry of pollen-receptive fig syconia is completely different from that of mature, ripened figs. The scent of mature figs also depends on whether the figs are monoecious or dioecious; in the latter case, the syconia on female trees produce only seeds, and their scent is more attractive to dispersers, compared to those on male trees whose syconia breed only wasps. Figs may even repel dispersers from male trees by repellent compounds in fig odors. The scent of figs is also used by non-pollinating parasitic wasps to locate their hosts which are wasps developing inside the syconium. Predatory ants are also attracted by the scent of figs at particular syconium developmental stages and may use this scent to arrive at fig trees when wasps are expected, thus increasing their prey capture success. Trophobiont-tending ants, however, are indifferent to the scent of figs.