A bruchid beetle and a viable seedling from a single diaspore of Attalea butyracea

Seeds of the palm Attalea butyracea (formerly known as Scheelea zonensis in Panamá and Scheelea rostrata in Costa Rica—Bradford & Smith 1977, Forget et al. 1994, Henderson 1995) are contained within stony endocarps. For the purposes of this paper, individual fruits or their seed-bearing endocarps will be referred to as diaspores; all of the seeds of a given fruit are surrounded by the stony wall of a single indehiscent endocarp. Although single-seeded diaspores are the norm for A. butyracea, twoand three-seeded diaspores are also produced. The frequency of multiseeded diaspore production is reported to vary within the geographic range of A. butyracea. Smith (1975) and Bradford & Smith (1977) found that 23% of diaspores were two-seeded and 4% were three-seeded in Guanacaste, Costa Rica, while the respective frequencies for Barro Colorado Island (BCI), Panamá were 5% and 0.2%. They proposed that the frequency of multiseeded fruits in A. butyracea varies geographically as a result of evolutionary responses by populations of A. butyracea to historical differences in the relative risks of attack by rodent vs. insect seed-predators, primarily by beetles in the family Bruchidae (Bradford & Smith 1977, Smith 1975). Bradford & Smith (1977) showed that predation by rodents accounted for a significantly higher proportion of seed mortality for undispersed diaspores found directly beneath adult palms in their Panamanian site as compared to