A great proportion of bats of the New World family Phyllostomidae feed on fruit, nectar and pollen, and many of them present adaptations to feed also on insects and small vertebrates. So far, attempts to examine the diversification of feeding specialization in this group, and particularly the evolution of nectarivory and frugivory, have provided contradictory results. Here we propose a molecular phylogenetic hypothesis for phyllostomids. On the basis of a matrix of feeding habits that takes into account geographical and seasonal variation, we tested different hypotheses of the evolution of feeding specializations in the group. We find strong support for the evolutionary model of a direct dietary diversification from insectivory. The estimates of divergence times of phyllostomid bats and the reconstruction of ancestral states with a Bayesian approach support the parallel evolution of frugivory in five lineages and of nectarivory in three lineages during the Miocene. On the basis of these findings, and recent dietary studies, we propose that during the evolution of phyllostomids switches to new feeding mechanisms to access to abundant and/or underexploited resources provided selective advantages that favoured the appearance of ecological innovations independently in different lineages of the family. We did not find evidences to support or reject the hypothesis that the insectivorous most recent common ancestor of all phyllostomids was also phytophagous.

The latitudinal diversity gradient (i.e. species richness decreases from tropical to extratropical areas) and the difference in species richness between islands and the mainland (i.e. generally islands have fewer species per unit area than the mainland) are two spatial patterns that have interested biogeographers for decades. The diversification rate hypothesis is one of the evolutionary explanations for the latitudinal variation in biological diversity that has received greatest support (Mittelbach et al., 2007). According to this hypothesis, there are higher rates of speciation and lower rates of ABSTRACT Aim Ecological interactions are among the most important biotic factors influencing the processes of speciation and extinction. Our aim was to test whether diversification rates of New World Noctilionoidea bats are associated with specialization for frugivory, and how this pattern differs between the mainland and the West Indies.Location The New World.Methods We reconstructed a time-calibrated molecular phylogenetic hypothesis for the New World genera of the superfamily Noctilionoidea. We compiled data on diet, morphology, geographical distribution and number of ecoregions in which each genus occurs. Then, using the phylogenetic tree constructed, we tested whether diversification was driven by diet (animalivorous and sanguinivorous versus nectarivorous and frugivorous) and specialization for frugivory. Afterwards, we conducted phylogenetic comparative analyses to identify correlates of species richness and net diversification rates. ResultsThe diversification rate was higher in mutualistic than in antagonistic clades in mainland and Antillean biogeographical scenarios, but only strictly frugivorous clades showed a markedly higher diversification rate than the rest of the genera. Geographical range and number of ecoregions were positively associated with species richness and diversification rate in continental and insular lineages. Lower body mass, lower forearm length and specialization for frugivory were significantly positively correlated with higher diversification rates in continental lineages, whereas these parameters were negatively correlated in Antillean lineages. Main conclusionsThe direction of the relationship of intrinsic factors (specialization for frugivory and body size) with diversification of noctilionoid bats depends on the biogeographical context, whereas the direction of the relationship of extrinsic factors (geographical range and number of ecoregions) with diversification is consistent in both mainland and the West Indian lineages.

The mimicry of malpighiaceous oil-flowers appears to be a recurrent pollination strategy among many orchids of the subtribe Oncidiinae. These two plant groups are mainly pollinated by oil-gathering bees, which also specialize in pollen collection by buzzing. In the present study, the floral ecology of the rewardless orchid Tolumnia guibertiana (Oncidiinae) was studied for the first time. The orchid was self-incompatible and completely dependent on oil-gathering female bees (Centris poecila) for fruit production. This bee species was also the pollinator of two other yellow-flowered plants in the area: the pollen and oil producing Stigmaphyllon diversifolium (Malpighiaceae) and the polliniferous and buzzing-pollinated Ouratea agrophylla (Ochnaceae). To evaluate whether this system is a case of mimetism, we observed pollinator visits to flowers of the three plant species and compared the floral morphometrics of these flowers. The behavior, preferences and movement patterns of Centris bees among these plants, as well as the morphological data, suggest that, as previously thought, flowers of T. guibertiana mimic the Malpighiaceae S. diversifolium. However, orchid pollination in one of the studied populations appears to depend also on the presence of O. agrophylla. Moreover, at the two studied populations, male and female pollination successes of T. guibertiana were not affected by its own floral display, and did not differ between populations. The results are discussed in relation to the behavior and preferences of Centris bees, as well as the differential presence and influence of each of the two floral models.

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Low fruit set values in most orchids (especially epiphytic and tropical species) are normally thought to be the consequence of pollination constraints and limited resources. In particular, pollination constraints are modulated by pollinator visitation rates, pollinator visitation behaviour (promoting crossing or selfing), the type and number of pollinia deposited on stigmas (in the case of orchids with subequal pollinia) and the amount of pollen loaded per inflorescence. In order to assess to what extent these factors can affect fruit set in specific orchid-pollinator systems, the repercussions of some of these aspects on reproduction of Broughtonia lindenii were examined in a coastal population in western Cuba. The study focused on plant breeding system, importance of pollen load and type of pollinia on subsequent fruit and seed, limiting factors of seed production and interaction with pollinators. This species presents long-lasting flowers that senesce after all forms of effective visit. Pollinator dependence for fruit production was demonstrated, while hand-pollination experiments revealed self-compatibility and inbreeding depression at seed level. More pollinia on stigmas enhance the proportion of well-developed seeds. In contrast, the pollinia type used in pollination is not important for seed quality of fruits, suggesting that small pollinia are not rudimentary. Natural fruit set in two consecutive years was substantially affected by pollinator activity, and also by systematic depredatory activity of ants and a caterpillar. Considering that this orchid completely lacks nectar and that the local assemblage of pollinators and predators influenced its reproduction, a minor importance of resource constraints in this epiphyte (with long-lasting reserve structures) is confirmed at least for a short time.