Cacauhy (Theobroma speciosum) is a common tree in Amazonian Brazil whose decaying flowers attract flies. The flies utilize various parts of the plant, including the flowers, which are used for food and as breeding sites. This study is a comparison between the pollination systems of two widely separated populations of T. speciosum, each population growing in an area representing a different biodiversity conservation strategy: ex situ and in situ. Fieldwork took place between 2000 and 2002 in the "Addison O'Neil" genrnplasm collection of the Brasilian Agroforestry Research Institute's Center for Humid Tropical Research (ex situ site) and in the "Emílio Goeldr Natural History Museum's "Ferreira Penna" Research Station (in situ site). This investigation included studies of population structure and phenology of T. speciosum, field observations of insect behavior, the collection of flowers and their insect visitors, analyses of pollen load, and the identification of insects collected and those emerging in the lab from collected flowers. Both populations of cacauhy studied flowered during the driest part of the year and produced fruit during the wettest. The lack of juveniles and subadults in the ex situ (i.e., cultivated) population indicates zero population turnover and demonstrates the fragility of the system established. The inflorescences of T. speciosum are utilized by a wide variety of invertebrates. Individuals from 9 insect orders and at least two other invertebrate orders were observed visiting T. speciosum flowers. Most visitors were in the Hymenoptera, Thysanoptera, Diptera, and Coleoptera. The insect visitors were classified as opportunists, predators, and pollinators. Drosophilids were the observed to be the principal pollinators, with the possibility that some phorids also participated in pollination. The drosophilid guilds were different in the two areas and were most diverse in the in situ area. Four species were common to both areas. The loss of diversity and alteration in the composition of the guild of pollinators in the ex situ area does not seem to have effected the population of T. speciosum. Although the pollination system was greatly altered the ex situ population of T. speciosum still shows signs of viability.
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