Both decreases in compositional similarity with increasing geographic distances between sites (i.e. distance–decay relationship) and vertical stratification of species composition are key issues in ecology. However, the intersection between these two trends has scarcely been investigated. Here we use identical sampling methods in the canopy and at ground level in a tropical rainforest remnant on the coast of the Gulf of Mexico to evaluate, for the first time, a distance–decay relationship within vertical strata in insect assemblages. We found that the ant assemblage was vertically stratified; ant species richness was higher at ground level than in the canopy, and the species composition differed between the two vertical strata. Moreover, we observed that β-diversity increased with geographic distance at ground level, but not in the canopy strata. However, contrary to our prediction, there was less species turnover (lower β-diversity) between vertical strata than between trees. These findings may reflect differences in the dispersal capacity and nest habit of ants from each vertical stratum, and also habitat heterogeneity on the horizontal scale, e.g. the species of sampled trees. Our results illustrate the importance of sampling more than one vertical stratum to understand the spatial distribution patterns of biological diversity in tropical rainforests.

To address how seasonality affects the richness and abundance of tropical insects, we compared the canopy and understorey communities of fruit-feeding butterflies in a seasonal Atlantic forest in south-eastern Brazil. Butterflies were sampled over 1 y using a standardized design with baited traps. A total of 2047 individuals in 69 species were recorded (1415 in the canopy, 632 in the understorey). Clear differences were found between canopy and understorey, with significantly higher butterfly abundances in the canopy. We observed two marked peaks of abundance and richness in both strata; one at the transition from dry to the wet seasons, and the other at the transition from wet to dry seasons. We found lower species turnover throughout the year in the canopy. We interpret this as evidence that temperature is more important than rainfall in explaining the yearly variation of abundance in vertical strata. The higher temperatures found in the canopy may allow butterflies to maintain activity in this stratum all year round, whereas the understorey is subject to colder temperatures, thus presenting a higher species turnover. These results improve our understanding of diversity gradients between evergreen and seasonal tropical forests, allowing insights into how climate and beta diversity gradients interact.

A sample of 1834 leaves from 83 plants in 26 families was collected in tropical rain forest in Madagascar from three vertical strata: top of emergent trees (up to 37 m), top of trees in upper canopy (about 22 m), and shrubs and saplings at ground level. These leaves were examined for damage by seven different agents: fungi, epiphyllae, mechanical injury, galls, leaf miners, grazing insects and skeletonizing insects. Fungi affected more than 60% of the leaves and grazing insects 45–65%, with other agents each affecting 3–30%; fewer than 4% of the leaves escaped unscathed by any agent. Individual leaves were attacked by up to five agents. There was a sharp decline in proportion of leaves affected by fungi, leaf miners, epiphyllae and mechanical breakage with increasing category of severity. Grazing insects, mechanical injury, and perhaps galls, had greater impact at ground level than in the canopy, with fungi and skeletonizing insects showing the opposite pattern. Leaf miners had lower incidence in the canopy than elsewhere. The observed vertical stratification means that a tree not only needs to balance its defences to meet multiple threats in any stratum, but must adapt to a different suite of challenges during its lifetime. Attack by grazing insects and fungi are major challenges for saplings at ground level, but with increasing height above the ground fungal attack on leaves becomes more prevalent, but attack by grazing insects less so.

Mistnets were set at ground level and 11–30 m above ground in lowland rainforest at Kuala Lompat in peninsular Malaysia, and Sepilok in Sabah, to compare the abundance of fruit bats in the subcanopy and at ground level. Capture rates in the subcanopy were up to 100 times greater than at ground level, averaging 3–7 bats per net-night. Species diversity was higher in the subcanopy than forest understorey. Two species that were frequently captured in the subcanopy, Megaerops wetmorei and Dyacopterus spadiceus, were previously thought to be rare. The abundance of Old World fruit bats in the subcanopy indicates that their roles in pollination and seed dispersal of Malaysian forest trees may be greater than previously recognized. Further research on foraging ranges, food selection and roosting habits is required to determine the overall importance of fruit bats in forest regeneration through seed dispersal, and the adequacy of existing reserves for their conservation.

This study investigated the vertical stratification of Old World fruit bats (Chiroptera: Pteropodidae) in relation to habitat structure and wing morphology, in a lowland Malaysian rain forest. In total, 352 fruit bats of eight species were captured within the subcanopy of the structurally complex old-growth forest during 72 306 m2 mist net hours of sampling. Fruit bat species that were grouped in relation to capture height were also grouped in relation to wing morphology – with those species predicted to have more manoeuvrable flight (i.e. lower wing-loadings and lower aspect-ratios) captured in increasingly cluttered airspaces. Thus, small differences in wing morphology are likely to be ecologically significant to the vertical stratification of bats. Hence, habitat heterogeneity may be a key factor promoting fruit bat species diversity in old-growth palaeotropical forests.

Didelphids use vertical strata in different ways, suggesting the existence of a wider variety of niches than simply arboreal or terrestrial. This variety could be related to the differential ability to deal with support diameters and inclines, and might be important for the coexistence of species in local assemblages. From data obtained with the spool-and-line technique, the use of the vertical space and above-ground supports is described in four species of an assemblage of didelphid marsupials in south-east Brazil. The stratification in this and other assemblages in the Atlantic forest and in the Amazon is also compared. Animals were trapped in Serra dos Órgãos, state of Rio de Janeiro, and equipped with a spool-and-line device before release. The paths were tracked by measuring variables related to support diameter, incline, distance and height moved above ground. The diameter of supports used was positively related to body size, and the incline to the dominant direction of movement (horizontal vs vertical). The more cursorial species, Metachirus nudicaudatus, only once moved above ground in > 3200 m of paths followed. Didelphis aurita moved mostly on the ground, but was the only species that occasionally reached the canopy. Philander frenata also moved mostly on the ground, occasionally used the understorey, but never reached the canopy. The more arboreal species, Marmosops incanus, moved mostly in the understorey, but never in the canopy. This pattern of stratification is similar to that observed in other sites in the Atlantic forest and in the Amazon.

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.

The vertical stratification of bat communities in primary forests of the Central Amazon (80 km north of Manaus, Brazil) was investigated using capture nets in the canopy (17 to 30 m high) and in the understorey (from 0-2.5 m). Seventeen sites were sampled during one year (3398.5 mistnet-hours) and 936 individuals captured, belonging to 6 families, 29 genera and 51 species. Utilizing Non-Metric Multidimensional Scaling (NMMDS), a well-marked vertical stratification between the communities was verified, the canopy being the more utilized region. Fifteen species were exclusively captured in the canopy, 10 were predominantly captured in the canopy, and 12 species were exclus ively captured in ground nets. Species recorded and the communities they form were analysed using a matrix of guilds. The matrix obtained had 24 cells. A guild composed by background cluttered/gleaning frugivores was the richest in species (19), followed by background cluttered/gleaning insectivores (12 species). The results illustrate that when studying tropical forests it is highly desirable to involve both the lower and the upper part of the forests; otherwise the fauna would be merely subsampled, thus under-estimating the status and abundance of some species.

Seven species of mosquitoes oviposited in open and bored bamboo traps at a site in Peradeniya, Sri Lanka, the most prevalent being Aedes albopictus, Aedes novalbopictus and Armigeres subalbatus. These three species preferred to lay in open than in bored traps. Aedes albopictus and Ar. subalbatus preferred to lay at ground level but Ae. novalbopictus showed no preference between ground level, 3.5 and 7.0 m height. A comparison of two collection series, one with traps in fixed positions and the other with traps interchanged randomly with respect to the positions, showed that individual trap attractiveness is a factor that can have a marked influence on the overall oviposition trends in Ae. albopictus and Ar. subalbatus.

A study of oviposition with respect to height above the water level showed that in Ae. albopictus and Ar. subalbatus, more than 75% of the eggs were laid within about 16 mm of the waterline. However, there was a markedly greater dispersion of eggs in Ae. albopictus, indicating more vertical movement during oviposition in this species than in Ar. subalbatus.