The structure, composition and reproductive phenology of a bat assemblage were investigated in the tropical region of Los Tuxtlas, Mexico. A 90-km2 landscape, originally occupied by rain forest, consisted of forest fragments and natural corridors of vegetation surrounded by pasturelands. Artificial strips of vegetation also were present as live fences. Bats were sampled with mist nets set at ground level in 52 forest fragments, three corridors, nine shaded plantations, six unshaded plantations and three live fences. We sampled each site twice, each time for a 5-h period for two consecutive nights. Bats were captured and released and the species identity and reproductive condition of adult females were recorded. Annual fruiting phenology and fruit production was measured with fruit traps in a forest site in three 500 × 20-m transects. We captured 4799 bats of 39 species. At forest sites we recorded 97% of the species and captured 44% of the bats. In corridors we captured 76% of the species and 16% of the total individuals. In the plantations we captured 71% of the species and 32% of the individuals. In the live fences we captured 32% of the species and 8% of the individuals. Three species, Pteronotus parnelli, Carollia brevicauda and Glossophaga soricina, accounted for 52% of all bat captures. Fruit-eating species and fruit-eating insectivores accounted for 65% of captures. Fleshy fruits were available year-round, but a seasonal pattern was evident. Presence of lactating females seemed to be associated, in general, with rainfall and fruiting seasonality, but individual species displayed different patterns ranging from aseasonal polyoestry to seasonal bimodal polyoestry, seasonal polyoestry and seasonal monoestry. Despite extensive fragmentation of the original rain forest, a species-rich bat assemblage still exists in the landscape studied. Short distances among remaining forest fragments and man-made habitats seem to facilitate persistence and reproductive connectivity among members of this bat assemblage.

With 86 species, Iwokrama Forest in central Guyana has the highest reported bat biodiversity for a protected area in the world. Using standardized capture data for 73 of these 86 species, we document community structure of bats in terms of species diversity, relative abundance, gross biomass, feeding guilds, vertical stratification and a trophic-size niche matrix. Based on faunal surveys in 1997, with similar amounts of effort in the forest canopy and at ground level, the greater fruit-eating bat (Artibeus lituratus) was by far the most ecologically dominant species in terms of frequency of capture and biomass. In total, frugivores comprised 70% of the species diversity and 78% of the biomass. The most common species of bat were fully partitioned in a resource niche matrix of size and trophic guild when vertical stratification was included as a variable. We conclude that resource partitioning and species packing differentially affect relative size in tropical bats, and are better summarized and analysed in three dimensions.

Above- and below-ground morphology of seedlings (up to 98 cm in height) were compared by allometric analyses in tropical heath forest and peat-swamp forest in Central Kalimantan. Thirteen abundant species were selected, including two species found in both forests. In above-ground morphology, heath forest seedlings invested more in leaf mass, while peat-swamp forest seedlings invested more in stem mass, stem height, crown area and leaf area. In below-ground morphology, heath forest seedlings invested more in root mass and depth, while peat-swamp forest seedlings invested more in lateral development of the root system. Both specific leaf area and area per leaf of heath forest seedlings were lower than those of peat-swamp forest seedlings. This differentiation in seedling morphology between forest types was evident as a plastic response in the two shared species. Heath forest seedlings on coarse-textured bleached sand with low water retention suffer occasional drought whereas peat-swamp forest seedlings on waterlogged peat rarely experience drought. We concluded that seasonal water limitation brought about the convergence in seedling morphology within heath forest because average understorey irradiances and soil nutrient concentration were assumed to be similarly low in both forests.

Features of microhabitats used by tadpoles of 17 anuran species were recorded in 16 streams in the montane meadows of the Serra do Cipó, southeastern Brazil. Month of occurrence of tadpoles, from November 1998 to February 2000 (16 months) was also recorded. The most important ecological features in differentiating tadpole species were position in the water column, time of occurrence and water depth. Tadpole species were then compared based on their microhabitat preferences, and it was tested whether phylogenetically closer species use microhabitats in a more similar way. In hylids, microhabitat use patterns were not influenced by proposed phylogenetic relationships, and many convergences in ecomorphological types may exist. On the other hand, leptodactylids may have undergone a conservative evolutionary history, as they formed a relatively homogeneous group concerning ecomorphological types and microhabitat preferences.

Like many other palms, Iriartea deltoidea undergoes ontogenetic transitions in leaf morphology. It has been asked whether the transition to adult leaf form in Iriartea was a fixed developmental pattern or a more plastic response to changes in environmental conditions, but studies so far have not resolved the question. We re-examined the question by taking measurements on palms growing under the full range of conditions experienced in the natural environment. Using trunk height as a surrogate variable for ontogenetic stage, we found that individual palms undergo the transition to adult morphology over a wide range of heights from < 10 m to > 20 m. Palms growing in gaps undergo the transition early, whereas those growing under a closed canopy undergo the transition late. Noting this, we asked whether the transition occurred in individuals that were growing faster than a critical minimum rate, and found no correlation between growth and morphological stage. A post-hoc hypothesis, that structural support of the crown (measured as trunk diameter) could limit or delay the transition, was confirmed. Our results indicate that multiple conditions must be satisfied before the transition can be completed. The complex requirements for leaf morphogenesis in Iriartea confer an ability to respond flexibly to spatially and temporally varying environmental conditions.

Understanding the pattern in which adult drosophilids of different species are distributed across and within different vegetation types is necessary for accurate interpretation of their local ecology and diversity. Such studies have been conducted mainly in temperate regions, and there is no basis for extrapolating their conclusions to tropical areas. This study describes the vertical distribution (0-20 m) of drosophilids attracted to banana baits in five different vegetation types in subtropical eastern Australia including open woodland, and rain-forest types. The distribution of most of the 15 common species could be characterized three-dimensionally by vegetation type and height above forest floor. Only one species, Scaptodrosophila lativittata, was common in all vegetation types and it was a canopy species in rain forests and a ground-level species in open woodland. Vertical distribution of some species clearly matched that of their larval hosts, but it did not in others. For example, the fungivore Leucophenga scutellata was mostly trapped well above the forest floor, yet it breeds at ground level, suggesting behavioural mode can influence vertical distributions. We conclude that the vertical dimension, although still poorly understood in relation to drosophilid habitats, needs to be taken into account when conducting and interpreting studies aimed at understanding drosophilid populations and communities in the subtropics.

Floral trait correlations were compared between the two flower morphs of a distylous Ophiorrhiza napoensis population in a subtropical evergreen forest at the Defu Natural Animal Preserve, Guangxi, China. Common principal component analyses indicated that overall patterns in correlations among floral traits were morph specific in the study population. Strong positive correlations (r > 0.9) between anther height and corolla-tube length were found in both morphs. Stigma height correlated positively with corolla-tube length in the long-styled morph (r = 0.843), but not in the short-styled morph (r = −0.018). Flower-morph-specific correlation suggests that natural selection by pollinators has moulded trait covariance among floral traits. Because morph-specific correlations are expressed as the patterns of within-morph variation among multiple traits, putative genes responsible for the stigma-corolla tube correlation should not link to the supergene for sex-organ reciprocity between the morphs, but their expression is limited in the long-styled morph.

The influence of gamma- (γ) and beta- (β) diversity on modern pollen rain is assessed using data from three Amazonian forests. Pollen rain of 79 forest locations was collected in modified Oldfield pollen traps between 1991 and 1993. Pollen diversity in the traps was high with > 280 palynomorph types recognized. Gamma diversity was assessed by comparing lowland terra firme forests in Cuyabeno, Ecuador, with two terra firme forests near Manaus, Brazil. The influence of β-diversity on local pollen rain was investigated using samples collected from neighbouring terra firme forests, seasonally flooded forests, and Mauritia-rich forests at Cuyabeno, Ecuador. Multivariate analyses revealed that γ-diversity produces a stronger signal in the pollen rain than β-diversity. However, β-diversity is accurately reflected in the pollen rain when the diversity is an expression of strong environmental gradients.

The pollination ecology and reproductive phenology of a dioecious palm, Chamaedorea alternans were studied at Los Tuxtlas Biological Station in Veracruz state, Mexico during the 1995-96 flowering season. The sexes flower synchronously from October to January. Field observations investigated reproductive phenology, flower visitors and inflorescence and fruit production. Males produce more flowers and inflorescences than females. Seed-set was 13%, indicating low reproductive efficiency. Individual plants showed a great variation in number of inflorescences produced. Five female and eight male plants (out of 25 and 37 plants, respectively) produced 45% of all inflorescences in the population studied. These five females also produced c. 75% of all fruits. Seed production did not show significant differences between insect-excluded and open-pollinated inflorescences, in experiments to test the efficiency of wind pollination. Flowers of this species are wind-pollinated but a great activity of undetermined species of thrips (Thysanoptera) was observed in male inflorescences.

Lizards mainly eat arthropods, fruit, nectar, pollen and animal scats (Pérez-Mellado & Casas 1997, Whitaker 1987), using their sense of smell and good colour vision while foraging (Vinson & Vinson 1969). Although several papers have contributed to the knowledge on the relationship between lizards and floral resources, this topic is often still regarded as anecdotal. However, a few detailed ecological studies on lizard and flower interactions have been conducted, e.g. in New Zealand and the Balearic Isles (Eifler 1995, Sáez & Traveset 1995, Traveset & Sáez 1997,Whitaker 1987). Pollination by lizards was rendered likely by the following findings: first, Mediterranean lacertid lizards and New Zealand geckos have pollen adhering to their belly, throat and labium; second, they may carry pollen for several hours, and thus also transport pollen some distance away from a pollen donor plant. New Zealand geckos carry pollen up to 72 m away from donors. Good experimental evidence of lizard pollination was produced by Pérez-Mellado & Casas (1997). They showed that an umbellifer species produced less viable seeds if Podarcis lilfordi lizards were excluded from flowers.

Most butterfly species forage for nectar, which provides them with carbohydrates and to some degree other nutrients, such as lipids and amino acids (Boggs 1987). A small number of genera feed exclusively on rotting fruits and plant sap (DeVries et al. 1999). Some 40 passion vine butterfly species, belonging to the genus Heliconius Kluk and a closely related monospecific genus Laparus Billberg gather nutrients from pollen feeding (Brown 1981, Gilbert 1972). Although common in bees, wasps, flies and beetles (Roulston & Cane 2000, Thorpe 2000), pollen feeding is rare among lepidopterans. In order to collect pollen, adults scrape anthers with the proboscis and gather the grains. The pollen is then incubated in solution and the amino acid-rich solution is ingested. The empty pollen grains are eventually discarded (Gilbert 1972, Krenn & Penz 1998). Pollen feeding provides amino acids that are used for egg production and somatic maintenance in adult Heliconius (Dunlap-Pianka 1979, Gilbert 1972, 1991). The most common sources of pollen are flowers of species in the genera Psiguria Neck. ex Arn. and Gurania (Schltdl.) Cogn. (Cucurbitaceae). The home range of an individual Heliconius will encompass one to many pollen plants (Murawski & Gilbert 1986).