Because seasonality in tropical environments is driven by variation in rainfall, phytophagous tropical organisms are expected to exhibit mechanisms of escape in space and time that allow them to synchronize their breeding efforts with suitably wet periods of the year. This hypothesis was addressed by studying the breeding phenology of the nymphalid butterfly Hypolimnas bolina (L.) in the Australian wet-dry tropics. This species favours small, herbaceous larval foodplants that either die off annually or exhibit marked declines in leaf quality during the dry season. As expected, reproductive activity in H. bolina was broadly correlated with both rainfall and humidity, with individuals spending part of the dry season (early April to late August) sheltering in overwintering sites in a state of reproductive diapause. The timing of the overwintering period was similar between the 2 years, which suggests that individuals respond to seasonally predictable cues such as photoperiod. At least in 1998, the exit of butterflies from overwintering sites was relatively sudden and coincided with the first spring rainfall event. These findings suggest that H. bolina copes with seasonal adversity in the tropics by means of a regularly timed diapause.

Maximum assimilation rate under saturating light level, leaf nitrogen and chlorophyll content and specific leaf mass were measured in forest plants grown under a range of canopy openness. Seedlings from three tree species co-occurring in damar agroforest (Sumatra) were examined: Shorea javanica, Lansium domesticum and Cinnamomum porrectum. A shrub species, Piper hispidum, growing in a different location was also investigated. All species showed pronounced differences in maximum photosynthetic potential when grown under different canopy openness. All tree seedlings showed an increase in maximum assimilation rate (Amax) with canopy openness (CO) until a certain threshold was reached. This saturation threshold varied between species. A steady increase in the maximum assimilation rate over the entire range of canopy openness explored was found only for Piper. Correlation between leaf nitrogen content and Amax was usually highest when expressed on a per unit area basis. However the overall correlation was poor whether expressed per unit mass or per unit area when all species were pooled together questioning the universality of the relationship between both quantities. Potential photosynthetic nitrogen use efficiency, defined as the amount of CO2 uptake per unit leaf nitrogen under saturating light level, was highest in Cinnamomum, supposedly the most light-demanding species, and lowest in Lansium, the understorey specialist.

Thirty-six of the 70 species of bats known from Belize were recorded from the area around Lamanai, Orange Walk County: two in roosts and 34 in about 680 mist net hours that produced 560 captures. Day roosts used by 35 of the species were located using radio-tracking (Sturnira lilium, Platyrrhinus helleri, Centurio senex and Bauerus dubiaquercus) or general searching for roosts (Rhynchonycteris naso, Saccopteryx bilineata, Saccopteryx leptura, Dicli durus albus, Mimon bennettii, Micronycteris schmidtorum, Carollia brevicauda, Carollia perspicillata and Eptesicus furinalis). Data on the day roosts of 23 other species were determined from the literature. Most species reported from Lamanai (19) roosted in hollows, while others used foliage (6), tents (3), sheltered sites (2), crevices (2), open sites (1), and a few species used more than one type of day roost (hollows and crevices (1); hollows and foliage (1); hollows, foliage and tents (1)). The fauna consisted of 13 aerial foragers, 9 gleaners, 11 fruit/leaf eaters, one trawler, one flower-visitor and one blood-feeder. In day roost use and foraging behaviour, the Lamanai fauna did not differ significantly from that of Paracou, French Guiana, but both these locations differed from the bat fauna of Kruger National Park, South Africa, in foraging behaviour.

Human pressure on forest resources in southern Benin has led to a dramatic reduction and disturbance of natural forest patches. The largest remaining forest reserve in southern Benin is the Lama forest, which is known to be a reserve for many endangered species and situated in the boundary between dry forest and savanna. From cluster analysis and hierarchical classification of tree species composition, five forest types were identified in the Lama forest, and ordination techniques were used to determine to what extent these forest types were associated with physiognomic tree characteristics. The geographical position of vegetation plots was used to examine the spatial distribution of the identified forest types. The forest types were interpreted as levels in a successional sequence ranging from either disturbed forest or formerly cultivated farmland to dense forest. Based on the outlined succession sequence it was suggested that reforestation should focus on establishment of Anogeissus leiocarpus, Albizia zygia, Lannea nigritana, Ficus exasperata and Lonchocarpus sericeus as these tree species are associated with the initial forest types.

Wood pieces of a heavy hardwood Neobalanocarpus heimii (King) P. S. Ashton and a light hardwood Shorea macroptera Dyer were used in decomposition experiments with termite-exclusion and control trays on the forest floor of the Pasoh Forest Reserve, West Malaysia to determine effects of wood quality on termite-mediated wood decay. Shorea macroptera had a significant loss of C in the presence of termites while Neobalanocarpus heimii showed no significant termite effect. Neobalanocarpus heimii and S. macroptera both accumulated N in the absence of termites, but S. macroptera lost it when termites were present. The C/N ratio decreased with and without termites as decay proceeded in both species. Neobalanocarpus heimii accumulated P, but S. macroptera lost it with and without termites. The C/P ratio decreased in N. heimii, but did not change in S. macroptera. Decomposition was considerably enhanced by termites in S. macroptera, but not in N. heimii, indicating that termite foraging activity was affected by the different wood qualities of the two trees. The qualities responsible for the differences and how different wood qualities affect nutrient cycling in the tropical rain forest ecosystem are discussed.

The carabid beetle assemblage found feeding on fig fruit falls at night was studied in a terra firme rain forest near Manaus (Amazonia) from July 1991 to August 1996. A total of 8926 carabid beetles were collected on 64 fruit falls from 10 fig species. The most abundant genus was Notiobia with eight species, N. pseudolimbipennis being the most abundant. The Notiobia species comprised 92% of all specimens collected and all feed on small fig seeds. Their species abundance patterns varied considerably between individual fruit falls and during the course of a single fruit fall. However, the species abundance patterns for all Notiobia at all observed fruit falls for each of the two commonest fig species (Ficus subapiculata, F. guianensis), as well as for fruit falls of the remaining fig species, were very similar. Through feeding and breeding experiments and observations of reproductive success by dissection of females, only two of the eight Notiobia species were found to be specialized fig seed feeders, being able to reproduce only on fig fruit falls. The remaining six species of this genus use fig fruit falls as alternate hosts or ‘stepping stones’ between fruit falls of their host trees, which are widely separated both in time and space.

Results of a 3-y study on the populations of three evergreen woody species (Byrsonima crassifolia, Palicourea rigida and Bowdichia virgilioides), from a regularly burnt savanna, in Venezuela, are reported. Tree density, size structure, fruit-seed production per tree of different size classes and soil seed bank were estimated. Viable seed production was one order of magnitude higher in B. crassifolia, which was also the only species with a permanent soil seed bank. Seeds of B. virgilioides germinated readily after dispersal, whilst seeds of P. rigida showed an innate dormancy synchronously released after a year. Both of the latter species seemed to maximize the first growth season by germinating at the beginning of the favourable season. In B. crassifolia, germination proceeds with an early small burst of germination, possibly followed by a second peak at the beginning of the next rainy season and little or no germination thereafter. The results showed that despite the high fire frequency, the studied species produce a substantial number of viable propagules, and have the capacity to germinate in field conditions (readiness depending on the species). Sexual reproduction is expected, therefore, to play an important role, as suggested by their reproductive investment, in long-term population maintenance.

A pollination and breeding system study was conducted on a neotropical palm, Astrocaryum vulgare, in Guyana, South America, to better understand its reproductive character evolution, and test the predictability of pollination syndromes. The pollination syndrome approach was used because it integrates characteristics of flowers and their pollinators into an evolutionary framework that allowed experimental testing of predictions. The flowers of A. vulgare displayed traits that were typical of both beetle and wind pollination syndromes. The protogynous inflorescences produced heat and odour during nocturnal anthesis, had numerous stamens with copious, light pollen, and were visited by hordes of beetles that used the inflorescences as feeding, mating and oviposition sites. In contrast, some of these features, such as numerous stamens with copious, light pollen, a high pollen to ovule ratio, and no obvious production of visitor rewards, were also typical of the wind pollination syndrome. However, floral rewards appeared to be tissues of the fleshy staminate petals and pollen that were readily devoured by the beetles. In addition to the Coleoptera, insect visitors to A. vulgare inflorescences included several species of Hymenoptera, Diptera and Orthoptera. However, only Nitidulidae and Curculionidae beetles were effective insect pollinators. Pollination treatments showed that wind pollination was possible, but fruit set was significantly higher for female flowers visited by beetles. Although a pollen/ovule ratio of 50 000:1 and outcrossing index confirmed an outcrossing breeding system, pollination experiments suggested that A. vulgare had the potential for self pollination. Therefore, the breeding system might be best classified as facultatively xenogamous (cross fertilizing). The predictive value of potential pollinator agents for A. vulgare was inadequate because its floral traits were indicative of both cantharophilous and anemophilous pollination syndromes.

Maintenance of high plant diversity in tropical rain forests has been hypothesized to be related to intense seed predation, and studies have shown that the impact of seed-eaters varies according to seed size, forest type and level of disturbance. The hypothesis that seed survival and seedling recruitment depending on seed size, are related to forest type and the intensity of harvesting and stand refinement was therefore tested at Paracou, French Guiana, for three animal-dispersed tree species. Two forest areas, corresponding to two forest types, were selected based on the occurrence of a dominant species, Eperua falcata (Caesalpiniaceae). Two factors were tested: forest type (E. falcata-rich and E. falcata-poor) and level of harvesting (unlogged, low intensity of logging, low intensity of logging and thinning liberation by tree-poison girdling) within each forest type. Overall, there was no effect of species nor of logging treatment within forest type after 6 wk. There was only a significant effect of forest type on seed survival in the large-seeded Carapa procera, a rodent-dispersed species in the Meliaceae. In the two medium-sized seed species, Pradosia cochlearia and Manilkara bidentata, two frugivore-dispersed Sapotaceae, the effect of treatment was overall significant but was also highly variable between plots within treatments. After 1 y, C. procera showed little seedling recruitment due to low seed removal and dispersal, and high seed-seedling predation under all conditions. Neither forest type, nor treatment nested within forest type, affected seedling recruitment in P. cochlearia whereas M. bidentata seedlings were favoured in unlogged conditions at the E. falcata-poor forest type. These results suggest that species characteristics (such as seed size and palatability), or local tree diversity and resources for granivores select for contrasting patterns in tree recruitment between forest type in the rodent-dispersed tree species, and these interact with level of tree harvesting and stand refinement in the other frugivore-dispersed tree species.

Bromeliads are common as epiphytes in warm neotropical forests (Benzing 1990). Species native to relatively wet forests impound water in a central cup and/or in seperate leaf axils. These tanks receive enough leaf litter and rainwater to support aquatic life (Maguire 1971). In these complex microcosms many groups of freshwater organisms ranging from algae, fungi, bacteria and protozoa through insects to frogs are represented and constitute considerable animal populations (Frank 1983, Laessle 1961, Maguire 1971, Picado 1913, Richardson 1999). Nutrients originating from the decomposition of litter and animal waste are absorbed by specialized trichomes on the bases of the leaves which form the tanks (Benzing 1980, 1990).

Several authors have reported associations between birds and monkeys in tropical forests (Boinski & Scott 1988, Huettmann 1999, Ruggiero & Eves 1998, Terborgh 1990). By such associations birds are considered to get some benefit, such as protection from predators and/or greater feeding efficiency (Terborgh 1990). In Southeast Asia, however, few reports on such interspecific associations have been available (galetti & McConkey 1998). The exception concerns several species of macaques living on Sulawesi Island, Indonesia (Fooden 1969). Associations between birds and Sulawesi macaques have been descibed by researchers as well as bird-watchers (Coates et al. 1997, Jepson & Ounsted 1997, Martarinza et al. 1994, Whitten et al. 1988). Local people in Sulawesi also know of associations between macaques and certain birds, particularly hair-crested drongo (Dicrurus hottentotus) and yellow-billed malkoha (Phaenicophaeus calyrhynchus). The farmers call these birds ‘burung monyet’ (monkey birds) and use the conspicuous calls of drongos and malkohas as signs of macaques' approaches to their fields (S. Matsumara, pers. obs.).