Fig-eating by vertebrate frugivores: a global review

The consumption of figs (the fruit of Ficus spp.: Moraceae) by vertebrates is reviewed using data from the literature, unpublished accounts and new field data from Borneo and Hong Kong. Records of frugivory from over 75 countries are presented for 260 Ficus species (approximately 30% of described species). Explanations are presented for geographical and taxonomic gaps in the otherwise extensive literature. In addition to a small number of reptiles and fishes, 1274 bird and mammal species in 523 genera and 92 families are known to eat figs. In terms of the number of species and genera of fig-eaters and the number of fig species eaten we identify the avian families interacting most with Ficus to be Columbidae, Psittacidae, Pycnonotidae, Bucerotidae, Sturnidae and Lybiidae. Among mammals, the major fig-eating families are Pteropodidae, Cercopithecidae, Sciuridae, Phyllostomidae and Cebidae. We assess the role these and other frugivores play in Ficus seed dispersal and identify fig-specialists. In most, but not all, cases fig specialists provide effective seed dispersal services to the Ficus species on which they feed. The diversity of fig-eaters is explained with respect to fig design and nutrient content, phenology of fig ripening and the diversity of fig presentation. Whilst at a gross level there exists considerable overlap between birds, arboreal mammals and fruit bats with regard to the fig species they consume, closer analysis, based on evidence from across the tropics, suggests that discrete guilds of Ficus species differentially attract subsets of sympatric frugivore communities. This dispersal guild structure is determined by interspecific differences in fig design and presentation. Throughout our examination of the fig-frugivore interaction we consider phylogenetic factors and make comparisons between large-scale biogeographical regions. Our dataset supports previous claims that Ficus is the most important plant genus for tropical frugivores. We explore the concept of figs as keystone resources and suggest criteria for future investigations of their dietary importance. Finally, fully referenced lists of frugivores recorded at each Ficus species and of Ficus species in the diet of each frugivore are presented as online appendices. In situations where ecological information is incomplete or its retrieval is impractical, this valuable resource will assist conservationists in evaluating the role of figs or their frugivores in tropical forest sites.     

Photosynthetic acclimation to shade: probing the role of phytochromes using photomorphogenic mutants of tomato

Photomorphogenic mutants of tomato were used to probe the possible involvement of phytochrome A in photosynthetic acclimation to shade. Plants of wild-type Lycopersicon esculentum, the near isogenic mutants aurea (au, deficient in phytochrome A, and also possibly other phytochromes) and high pigment (hp, exhibiting exaggerated photomorphogenic responses), and the au/hp double mutant were grown in a greenhouse under either unfiltered daylight, or daylight attenuated by neutral density filters or green filters that simulated the spectral effects of vegetation shade. Growth and photosynthetic parameters were measured over a growing period of 15 d. Typical effects of simulated vegetation shade on extension growth were observed only in the wild-type and hp strains; the presence of the au lesion resulted in reduced capacity to respond to vegetation shade by increased extension. Photosynthetic light saturation curves obtained using infrared gas analysis at 15 d indicated that neither the au nor the hp mutations caused serious reductions in maximum net photosynthetic rate in plants acclimated to full daylight, although the au/hp double mutant showed a significantly reduced maximum rate. In the wild-type and hp strains grown under both neutral and simulated vegetation shade, the photosynthetic light saturation curves were similar. Plants with the au lesion showed a significantly lower capacity to acclimate to vegetation shade, as seen by their reduced maximum rate of net photosynthesis. However, in situ measurements of photosynthetic rate in the greenhouse were indistinguishable between the four strains. Thylakoid stoichiometry measurements revealed a very large increase in PSII/PSI ratio under simulated vegetation shade as compared with either unfiltered daylight or neutral density shade. These increases were not diminished in the phytochrome-deficient au strains, and were even larger in the hp strains. The results indicate that the au lesion has little effect on the capacity of tomato to exhibit photoadaptation to simulated vegetational shade when measured at the thylakoid level. On the other hand, net leaf photosynthesis under vegetation shade can be significantly affected by the phytochrome deficiency caused by the au mutation, implying a possible role for one or more of the phytochromes in photoadaptation at the leaf level.     

Injuries and wounds of the esophagus; a classification

A new working classification of esophageal injuries and their complications is presented. The immediate recognition of perforations and ruptures is of prime importance. In some cases the rents heal with conservative therapy. It is emphasized, however, that early surgical exposure and direct repair will result nearly always in uncomplicated cure without the development of prolonged, costly, debilitating and sometimes fatal complications.