The relationships between body size and host specificity were studied in leaf-chewing and sap-sucking insect communities, including 792 species, feeding locally on 15 species of Ficus in a lowland rain forest in Papua New Guinea. A negative correlation between body size and host specificity, i.e., the tendency for large species to feed on numerous Ficus hosts and those smaller to have a more restricted host range, was found within both the sap-sucking and the leaf-chewing community. A more detailed analysis, which divided herbivorous species into three sap-sucking and four leaf-chewing guilds, revealed that the correlation between body size and host specificity was caused by differences in these traits between the guilds, while no such correlation was detected within any of the guilds. As the changes in feeding mode, defining various guilds, were unique evolutionary events, it is uncertain whether there is a functional relationship between feeding mode, body size and host specificity, or whether their correlation is only coincidental. It is suggested that, in the sap-sucking community at least, the positive body size versus host specificity correlation is a coincidental by-product of the causal relationship between the feeding mode and both the body size and host specificity. The causes of analogous patterns in a leaf-chewing community require further investigation. Methodological problems in the analysis of tropical insect communities, dominated by rare species, are discussed.

Information on the feeding habits of the the lesser dog-faced friut bat, Cynopterus brachyotis, was obtained by the collection of food remains directly beneath daytime and feeding roosts. The bats were found to feed on the fruits of 54 plant species, the leaves of 14 species and the flower parts of four species. The seasonal phenological differences among congeneric plant species led to steady production of fruit throughout the year and the data suggets that Ficus spp. are a key component in the diet. Judging from its wide selection of fruits, C. brachyotis, is considered to be an important seed disperser. Folivory in C. brachyotis appears to be more common than previously thought. Of the leaves consumed by the bats, seven species belonged to the family Leguminosae, followed by Myrtaccae, Moraccae, Rhizophoacae and Euphorbiaccae. Friuts in general, provide an energy rich diet for phytophagous bats but most are low in protein. In contrast, leaves consumed by bats have a relatively high protein content. We suggest that folivory (by leaf fractionation) should be energetically more advantageous than the ingestion of large amounts of low protein friut or the active pursuit of mobile insects.

Density and biomass of four ungulate species, elephant (Elephas maximus) and seven other mammal species were estimated in an area of about 50 km2 in a dry tropical forest in Huai Kha Khaeng Wildlife Sanctuary, western Thailand. Density estimations employed line transects, using either direct sightings or indirect signs. Total biomass of these ungulates and elephant was 1450 kg km–2 which was lower than that found in a well protected and managed area of similar forest, Nagarahole National Park, in India. This is due to the intensive poaching activity and the lack of wildlife management in this study site. Three species of ungulate, banteng (Bos javanicus), gaur (Bos gaurus) and sambar deer (Cervus unicolor), contributed over 70% of the estimated herbivore biomass. This situation is similar to that found in other parts of Asia. The high biomass of a subterranean mammal, Cannomys badius, has not been documented elsewhere in Asia; this species probably influences the forest dynamics and ecology of small carnivores in this area.

Vertical stratification of vascular epiphytes is frequently attributed to niche partitioning along microclimatic gradients but experimental confirmations of this notion are rare. This study investigates the role of the regeneration phase for the stratification of five bromeliad (Catopsis sessiliflora, Guzmania subcorymbosa, Tillandsia anceps, T. bulbosa and Werauhia gladioliflora) and seven aroid species (Anthurium acutangulum, A. brownii, A. clavigerum, A. durandii, A. friedrichsthalii, A. hacumense and A. scandens) in a Panamanian rain forest. We documented gradients of temperature, vapour pressure deficit and light (n = 10 d) as well as species height distributions (n = 11–120). Microclimatic gradients were substantial (maximal T and RH differences between strata: 5 °C and 18%, respectively) and mean attachment heights of the study species (range = 4–21 m) differed significantly. We tested sensitivity to recurrent drought (four treatments) during germination (all species, cumulative germination of 20 seeds, n = 3) and seedling growth (four aroid species, n = 25). Seedling survival of six aroid species transplanted to three heights (n = 27) was monitored in situ. Some species did not germinate under severe recurrent drought while others germinated at the same rate in all treatments. Seedlings of the most exposed species grew fastest under intermediate recurrent drought while those of the other three species grew fastest when kept constantly wet. Survival of transplanted seedlings did not depend on species attachment height, but this may be attributable to insufficient statistical power. Taken together, the results suggest that the stratification can be explained to a large degree by differential sensitivity to the vertical moisture gradient during the regeneration phase.

A population of the giant leather fern Acrostichum danaeifolium was observed during an 18-mo period at La Mancha (19°36′00″N, 96°22′40″W), Veracruz, Mexico. The study site was 230 m from a brackish-water lagoon, in the understorey of the mangroves, which are dominated by Avicennia germinans (Avicenniaceae). Acrostichum danaeifolium showed a clumped distribution pattern, and one third of the population became fertile during this time. Plants had a mean number of 9.4 ± 0.45 sterile leaves, which developed continuously at a rate of 14.6 ± 0.44 leaves y-1. The mean life span of sterile leaves was 7.7 mo. Although soil water was always available, phenological patterns of fertility, leaf production and leaf growth were strongly correlated with the seasonal climate. Individual leaf growth and leaf size increased significantly during the rainy season. Fertile leaves emerged exclusively from April to August and had a mean life span of 4.1 mo. Spore release was restricted to the wet season, when conditions for germination were favourable. Environmental triggers of fertility are discussed and phenological patterns are compared with ferns and angiosperms from other habitats.

Although plant species that attract multiple species of pollinators predominate in tropical plant communities, pollination specialists appear to be at a greater advantage in tropical ecosystems in which pollinators are numerous and many plants flower synchronously. The present study determined the breeding system and legitimate pollinators of Oroxylum indicum Vent. in Songkhla and Patthalung Provinces, Thailand. Oroxylum indicum exhibits steady-state flowering, with one or two flowers per inflorescence opening each night. Flowers open in the evening and drop off shortly after midnight, while its bilabiate stigma is highly sensitive, and quickly close upon being touched. Oroxylum indicum is self-incompatible. Hand-cross pollination and open pollination yielded the highest pollination success (47.7% and 31.2% respectively, n = 7 trees). About 900 pollen grains are needed for initiating fruit set. It is confirmed that a fruit bat, Eonycteris spelaea, is the legitimate pollinator. Bats are responsible for all pollen load and the pollen load from only one visit is generally sufficient to initiate fruit set. Although Eonycteris spelaea is effective, it is an inefficient pollinator. Compared with plant species pollinated by multiple animal species, the likelihood of pollination failure resulting from the decline in populations of Eonycteris spelaea will be much more intense in Oroxylum indicum.

Our study examines the effect of seasonal rains on soil organic C dynamics in a tropical deciduous forest ecosystem in Western Mexico. At the end of the wet season, an accumulation of labile nutrient forms developed and was maintained during the dry season. This accumulation enhances microbial activity in the first rains of the wet season. For example, the litter samples of the dry season had a higher C and N mineralization than those of the wet season. Similarly, the January soil samples had higher C mineralization than October soil samples (55 and 34 μg C g-1 d-1, respectively). These results suggest that the quality of C is strongly affected by the seasonality of rains, which in turn influences microbial activity. This seasonality also influences nutrient redistribution between soil aggregate fractions. Chemical changes across seasons suggest that soil organic matter associated with macro-aggregates represents the main source of energy for microbial activity at the beginning of the wet season, while micro-aggregates protect the labile nutrient forms during the growing season.

Structure and demographics in many tropical forests is changing, but the causes of these changes remain unclear. We studied 5 y (2005–2010) of species turnover, recruitment, mortality and population change data from a 20-ha subtropical forest plot in Dinghushan, China, to identify trends in forest change, and to test whether tree mortality is associated with intraspecific or interspecific competition. We found the Dinghushan forest to be more dynamic than one temperate and two tropical forests in a comparison of large, long-term forest dynamics plots. Within Dinghushan, size-class distributions were bell-shaped only for the three most dominant species and reverse J-shaped for other species. Bell-shaped population distributions can indicate a population in decline, but our data suggest that these large and long-lived species are not in decline because the pattern is driven by increasing probabilities of transition to larger size class with increasing size and fast growth in saplings. Spatially aggregated tree species distributions were common for surviving and dead individuals. Competitive associations were more frequently intraspecific than interspecific. The competition that induced tree mortality was more associated with intraspecific than interspecific interactions. Intraspecific competitive exclusion and density-dependence appear to play important roles in tree mortality in this subtropical forest.

Bukit Belalong, Brunei, is a small mountain (913 m) of uniform shale lithology with continuous primary rain forest from its base to its summit. Three 0.25 ha plots were established at each of three altitudes (200, 500 and 850 m) to investigate the altitudinal zonation of the soils and the vegetation. One soil profile from each altitude is described and chemical analyses of the soils indicate that they are similar at all altitudes. In each plot all trees ≥10 cm dbh were measured and identified as far as possible. Maximum tree height was greatest at 200 m (60 m) and least at 850 m (33 m). Tree density (number of individuals ha−1) increased with altitude. The forest at 850 m was the most species- and family-rich, but since the ratio of species to individuals did not vary significantly among altitudes, the higher species richness is attributed partly to the larger number of trees sampled. The Dipterocarpaceae was the most important family in terms of basal area at all altitudes, but its proportion of basal area was much smaller at 850 m than at the other altitudes. The Dipterocarpaceae was the most diverse family at 200 m and 500 m, but at 850 m its diversity was exceeded by the Lauraceae, Myrtaceae and Euphorbiaceae and equalled by the Clusiaceae. The forests at 200 m and 500 m are classified as lowland rain forest and that at 850 m is classified as a lower montane forest.

A 272-ha grove of dominant Microberlinia bisulcata (Caesalpinioideae) adult trees ≥50 cm stem diameter was mapped in its entirety in the southern part of Korup National Park, Cameroon. The approach used an earlier-established 82.5-ha permanent plot with a new surrounding 50-m grid of transect lines. Tree diameters were available from the plot but trees on the grid were recorded as being ≥50 cm. The grove consisted of 1028 trees in 2000. Other species occurred within the grove, including the associated subdominants Tetraberlinia bifoliolata and T. korupensis. Microberlinia bisulcata becomes adult at a stem diameter of c. 50 cm and at an estimated age of 50 y. Three oval-shaped subgroves with dimensions c. 850 m×1350 m (90 ha) were defined. For two of them (within the plot) tree diameters were available. Subgroves differed in their scales and intensities of spatial tree patterns, and in their size frequency distributions, these suggesting differing past dynamics. The modal scale of clumping was 40–50 m. Seed dispersal by pod ejection (to c. 50 m) was evident from the semi-circles of trees at the grove's edge and from the many internal circles (100–200 m diameter). The grove has the capacity, therefore, to increase at c. 100 m per century. To form its present extent and structure, it is inferred that it expanded and infilled from a possibly smaller area of lower adult-tree density. This possibly happened in three waves of recruitment, each one determined by a period of several intense disturbances. Climate records for Africa show that 1740–50 and 1820–30 were periods of drought, and that 1870–1895 was also regionally very dry. Canopy openings allow the light-demanding and fast-growing ectomycorrhizal M. bisulcata to establish, but successive releases are thought to be required to achieve effective recruitment. Nevertheless, in the last 50 y there were no major events and recruitment in the grove was very poor. This present study leads to a new hypothesis of the role of periods of multiple extreme events being the driving factor for the population dynamics of many large African tree species such as M. bisulcata.

Neotropical bats occupy a large variety of trophic niches, and represent locally abundant, species-rich communities. As such, they are highly suited as a model group for the study of temporal and spatial dynamics of animal communities. However, despite this important research potential, data on the dynamics and turnover rates of Neotropical bat communities are lacking. We here study both aspects for bats inhabiting two natural forests surrounded by savanna in Bolivia. Over a period of 8 y, both bat communities showed high rates of species turnover. As predicted, species relying on fluctuating food resources were more likely to be absent in particular years, whereas species relying on more predictable food supplies were present in all years.

Perceptual range is used as a measure of the ability of animals to perceive the landscape, and can be used to infer functional connectivity between habitat patches such as forest remnants. A relationship of perceptual range with body mass was proposed by Mech and Zollner, but effects of life-history traits and environmental conditions were also acknowledged. We evaluated perceptual ranges and the influence of body mass, wind speed and direction, and grass height in four marsupial species of the Atlantic Forest of south-eastern Brazil. Release experiments were conducted and orientation towards the forest was determined using the spool-and-line technique. In 111 animals released, Didelphis aurita had the highest perceptual range (200 m), followed by Philander frenatus and Micoureus paraguayanus (100 m), and by Marmosops incanus (< 100 m). None of the species presented homing behaviour, and there was no difference in orientation abilities between sexes. Perceptual range was overestimated based on the equations of Mech and Zollner, but species were ordered in perceptual range according to their body size. Distance to the forest was a common determinant of the orientation in P. frenatus and M. paraguayanus, but grass height and wind direction were also important. Orientation of Didelphis aurita was determined by wind direction, showing anemotactic behaviour. Body mass is likely to affect perceptual ranges in didelphid marsupials, but only in interspecific comparisons. Within a species perception depends on the environmental context. Variables other than distance must be considered to estimate functional connectivity of the landscape based on perceptual range.

Rainfall fluctuation influences the physiology and leaf production of the trees in tropical rain forests (Burslem et al. 1996, Condit et al. 1995, Reekie & Wayne 1992, Reich 1995), and consequently it may have an impact on the community of herbivores that depend on forest trees for their food resources (Aide 1988, 1992; Basset 1991, Coley 1998, Lowman 1985, van Schaik et al. 1993).

To assess the influence of microhabitat and season on predator growth and survival and prey community structure, first instars of native Toxorhynchites haemorrhoidalis, a predatory mosquito, were released into Heliconia bracts, bamboo internodes, and the axils of two species of Aechmea bromeliads during wet and dry seasons in a lowland rain forest in eastern Venezuela. Experimental and control microhabitats were compared by complete censusing of macroscopic invertebrates 10 and 20 days after releases.

Survival of T. haemorrhoidalis differed significantly among habitats and was reduced by desiccation in dry-season bamboos and in Aechmea nudicaulis and by the presence of a predatory damselfly (Odonata: Zygoptera) in bromeliads. Developmental rate differed among habitats in the wet but not in the dry season; rapid wet-season maturation was associated with increased prey abundance in Heliconia.

Larvae of T. haemorrhoidalis consumed particular taxa and size categories of dipterous prey. Predation significantly reduced the abundance and skewed size-class distributions of Culicidae, Ceratopogonidae, Psychodidae, and pooled samples of Thaumaleidae plus Chironomidae. In bamboos, instar distributions of other mosquitoes were skewed in the presence of T. haemorrhoidalis even though a significant reduction in mosquito abundance was not detected. A decrease in species richness of aquatic Diptera was associated with intense predation by Toxorhynchites in Heliconia and A. nudicaulis.

Toxorhynchites theobaldi was recognized as the naturally occurring predator in local bamboos, and released larvae caused significant reductions in abundance or size-class frequency shifts among three families of Diptera. Niche segregation between these sympatric Toxorhynchites is maintained by oviposition preferences: the larger species, T. theobaldi, oviposits in bamboos and the smaller T. haemorrhoidalis occurs in plant bracts and axils.

Seeds of Dryobalanops aromatica and D. lanceolata (Dipterocarpaceae) were sown in gaps and understorey on a ridge and a valley in a Bornean rainforest. Germination rates were 92–100% regardless of site and species. On the ridge, the proportion of seedlings that opened primary leaves was larger in D. aromatica (19–30%) than in D. lanceolata (7–19%) due to higher root predation on D. lanceolata. In the valley, on the other hand, the proportion was larger in D. lanceolata (71–74%) than in D. aromatica (56%). After primary leaf production, seedlings of both species had higher survivorship in the gaps than in the understorey. Interactions between predators, soil conditions and light environment and their effects on seedling establishment are discussed.

The abundance of epiphytes has been assumed to be important in explaining the high diversity of tropical canopy arthropods. In this study we assessed the possible role that the presence of epiphytes may have on the diversity and abundance of canopy insects in an experimental study conducted in a coffee plantation in Coatepec, Veracruz, Mexico. Epiphytes were removed from trees in one of two plots in two sites of the coffee plantation. In each plot we collected insects from three Inga jinicuil trees by knockdown insecticide fogging. Insects were sorted to morphospecies, counted and measured. Trees with epiphytes had significantly higher numbers of species and individuals and insects larger than 5 mm were also more species-rich and abundant in trees with epiphytes. The magnitude of the enhancement was surprisingly large with the epiphyte plot samples having on average 90% more individuals and 22% more species than plots without epiphytes. These differences were even greater for large (>5 mm) insects (184% and 113% respectively). Our results support the tenet that epiphytes provide valuable resources to arthropods, which we have illustrated for canopy insects in shade trees of coffee plantations.

Termite species and functional groups differ among regions globally (the functional-diversity anomaly). Here we investigate whether similar differences in biomass and abundance of termites occur among continents. Biomass and abundance data were collected with standardized sampling in Cameroon, Malaysia and Peru. Data from Peru were original to this study, while data from Cameroon and Malaysia were compiled from other sources. Species density data were sampled using a standardized belt transect (100 × 2 m) while the biomass and abundance measurements were sampled using a standardized protocol based on 2 × 2-m quadrats. Biomass and abundance data confirmed patterns found for species density and thus the existence of the functional diversity anomaly: highest estimates for biomass and abundance were found in Cameroon (14.5 ± 7.90 g m−2 and 1234 ± 437 ind m−2) followed by Malaysia (0.719 ± 0.193 g m−2 and 327 ± 72 ind m−2) and then Peru (0.345 ± 0.103 g m−2 and 130 ± 39 ind m−2). The biomass and abundance for each functional group were significantly different across sites for most termite functional groups. Biogeographical distribution of lineages was the primary cause for the functional diversity anomaly with true soil-feeding termites dominating in Cameroon and the absence of fungus-growing termites from Peru. These findings are important as the biomass and abundance of functional groups may be linked to ecosystem processes. Although this study allowed for comparisons between data from different regions further comparable data are needed to enhance the understanding of the role of termites in ecosystem processes on a global scale.

Myrmecophytic species of the Paleotropical plant genus Macaranga (Euphorbiaceae) have hollow stems that are almost always occupied by ants of the genus Crematogaster and scale insects of the family Coccidae (Hemiptera: Coccoidea). The coccids have a cryptic endophytic lifestyle and are confined to this microhabitat. They are much more diverse than previously recognised. First data are presented on the diversity, prevalence, specificity and distribution of the coccids associated with myrmecophytic Macaranga species. Twenty-two species of Coccidae in total, including 15 previously unknown from Macaranga, were discovered from 19 species of Macaranga in Peninsular Malaysia and Borneo. The original describers tentatively assigned the known coccid species to Coccus (Coccinae) but the Macaranga coccids still require taxonomic research to establish their correct placing. The coccids varied in their host-plant specificity from species that occurred in most of the sampled Macaranga to one species that was found almost exclusively only on a single host species. In addition to their occurrence on Macaranga, only three species, C. macarangae and C. secretus and morphospecies C. 214 were found on rare occasions in the stem interior of a few other myrmecophytes and in a non-myrmecophytic liana, but did not regularly colonise these plants. Most of the coccids can be regarded as highly specific at the plant genus level.

Despite the progress made in understanding the ecophysiology of tropical plants during the past two decades (Lüttge 1997, Mulkey et al. 1996), questions regarding relationships between the environment and physiological diversity remain. It is now recognized that tropical climate can be quite variable (see Coen 1983) which could lead to significant functional diversity (increased variation in life history traits) among species due to the tight association between gas exchange physiology and the environment (see Enquist & Leffler 2001, Guehl et al. 1998, Huc et al. 1994, Martinelli et al. 1998, Sobrado 1993). It remains unclear, however, how the subtleties of variation in tropical climate and tree life history traits are related to the functional diversity of tropical communities (Borchert 1994, 1998).