Bats get two innings in the rain forest
Those of us whose research is largely lab-based and focused on a small range of model species, forget all too easily that there is a huge range of botanical biodiversity 'out there'. Much of this is inadequately described or even unknown and there is still enormous scope for careful observation and recording in the field. The paper by Sazima et al., from Campinas, Sao Paulo, Brazil (pp. 725-730) illustrates this beautifully. They describe aspects of the reproductive biology of Dyssochroma viridiflorum, an epiphytic member of the Solanaceae that grows in the Atlantic rain forest. This species is pollinated by nectar-seeking-bats, which are attracted by a 'mushroom-like' scent. The flowers open early in the night and are available for visiting for about 48 h. During the day, the flowers may also be visited by hummingbirds but these do not act as pollinators. Instead, they 'steal' the nectar by making a hole in the base of the corolla (the corolla tube in D. viridiflorum being too long for the particular hummingbird species). Furthermore, the dependence on bats does not finish with pollination. The fruits of D. viridiflorum are also attractive to bats, but to frugiverous species as opposed to the nectarivous pollinators. The seeds embedded in the fruit pass through the bats' alimentary system and are dispersed in the faeces. Three different bat species, one pollinator and two seed dispersers are thus involved in the reproductive biology of D. viridiflorum. However, the story does not end there. This species produces flowers all the year round and thus flowers and fruit are usually present together, so that an individual plant may be visited by nectar-seeking and fruit-eating bats at the same time. This must be a remarkable sight, a phenomenon that ensures that we lab-based botanists cast our gaze from time to time at a wider botanical world.
Professor J.A. Bryant
University of Exeter, UK
j.a.bryant{at}exeter.ac.uk
