Trees of the family Dipterocarpaceae dominate the emergent canopy of most lowland rain forests in Asia (Ashton et al. 1988). The family is, therefore, one of the most ecologically important in South-East Asia. Shorea curtisii Dyer ex King is the most common tree species in the hill dipterocarp forests of Peninsular Malaysia (Burgess 1975, Symington 2004), and is considered a key species for the dynamics of such forests. Currently, most Malaysian hill forests are selectively logged. Trees over 50 cm dbh are harvested, and any subsequent harvests depend on the remaining smaller trees. Such selective logging takes no account of seedling regeneration. Hence, subsequent timber harvests rely on trees derived from the seedlings that are already present and future seeds produced by the residual trees (Appanah & Mohd. Rasol 1994). Existing seedlings of S. curtisii in the forest, therefore, play a significant role in the dynamics of the hill forest. However, the conditions that constitute a suitable habitat for S. curtisii seedling establishment and survival remain unknown.

An important deficiency of the tropical forest data set on above-ground net primary productivity (ANPP) is the paucity of studies where requisite components of forest productivity have been measured at the same location. Missing data on above-ground biomass increment (ABI, which refers to the incremental growth of trees) and fine-litter production (leaves, fruit, flowers, small twigs, but excluding coarse woody debris) is particularly problematic as these are the two major components of ANPP. The fragmentary nature of the data is reflected by the fact that only 13 of 39 (33%) plots reviewed by Clark et al. (2001) and 8 of 104 (8%) plots reviewed by Malhi et al. (2004) had data on both major components of productivity. In an attempt to retain the geographic coverage and replication of data in analyses, researchers have proposed ways to infer missing data. Typically ratios or (more recently) fitted relationships between ABI and litter production have been used for this purpose (Bray & Gorham 1964, Clark et al. 2001, Murphy 1975).

In many plants, the defence systems against herbivores are induced, and may be involved in recruiting the natural enemies of herbivores. We used methyl jasmonate, a well-known inducer of plant defence responses, to manipulate the chemistry of Ficus hahliana along a tropical altitudinal gradient in order to test its ability to attract the enemies of herbivores. We examined whether chemical signals from MeJA-treated trees (simulating leaf damage by herbivores) attracted insect enemies in the complex settings of a tropical forest; and how this ability changes with altitude, where the communities of predators differ naturally. We conducted the research at four study sites (200, 700, 1700 and 2700 m asl) of Mt Wilhelm in Papua New Guinea. Using dummy plasticine caterpillars to assess predation on herbivorous insect, we showed that, on average, inducing plant defences with jasmonic acid in this tropical forest increases predation twofold (i.e. caterpillars exposed on MeJA-sprayed trees were attacked twice as often as caterpillars exposed on control trees). The predation rate on control trees decreased with increasing altitude from 20.2% d−1 at 200 m asl to 4.7% d−1 at 2700 m asl. Predation on MeJA-treated trees peaked at 700 m (52.3% d−1) and decreased to 20.8% d−1 at 2700 m asl. Arthropod predators (i.e. ants and wasps) caused relatively more attacks in the lowlands (200–700 m asl), while birds became the dominant predators above 1700 m asl. The predation pressure from birds and arthropods corresponded with their relative abundances, but not with their species richness. Our study found a connection between chemically induced defence in plants and their attractivity to predators of herbivorous insect in the tropics.

Oil palm (Elaeis guineensis Jacq) is an economically important crop in South-east Asia, especially in Malaysia and Indonesia. In Malaysia, oil palm is the most profitable commodity in the agriculture sector. The future of oil palm lies in obtaining a higher yield that is aligned and directed towards achieving the Sustainable Development Goals (SDG) by 2030. Elaeidobius kamerunicus was introduced into Malaysia during the late 1980s to boost the production of oil palm fruit bunches. Almost 40 years since the introduction of E. kamerunicus, significant improvements have been witnessed in the increase of oil palm yield. Nevertheless, the current concern in the oil palm sector is regarding the decreasing of fruit set that may be affected by E. kamerunicus. The weevil population plays a crucial factor in the pollination of oil palm. Several factors had been reported to reduce the weevil population such as natural enemies, interaction with local insects, pesticides, climate and male inflorescence. These factors have been addressed in this article based on various studies conducted since the first investigation in Cameroon by Syed in 1977. The role of the pollinator in terms of its biology, behaviour and pollination mechanism is also described in this article, together with the population management of the weevils. This review article will provide a summary of the current state of Elaeidobius kamerunicus in Malaysia and other neighbouring oil palm-producing countries.

Sessile organisms interact locally on the scale of their body sizes, and one of the great advances in population and community ecology is the use of individual-based models to examine species interactions (Biondini 2001, Bolker & Pacala 1999, Pacala & Deutschman 1995, Pacala & Silander 1985, 1987; Silander & Pacala 1985). Canopies are often taken as a proxy for body size in the plant literature, even though roots can make up substantial amounts of a plant's biomass, have productivity that equals or exceeds the above-ground parts, and are critical in both competition and mutualisms involving nutrient capture and water balance (Biondini 2001, Casper & Jackson 1997, Casper et al. 2003, Rajaniemi & Reynolds 2004, Robinson 2004). Root zones, however, are seldom incorporated in plant ecological studies because they are exceptionally difficult to measure, and the importance of intra- and interspecific root interactions is little known (Schenk & Jackson 2002).

The change of mound structure of the fungus growing termite, Macrotermes gilvus, which has no clear air passage system in the mound, was examined in relation to the mound growth in a rubber plantation of southern Thailand. The nest proper consisted of the hive with a royal chamber and nursery, and diffused chambers with fungus combs. The location of the hive became higher with the growth of the mound. Therefore, colonies with a very large mound utilize only the upper mound part and this may be due to the lack of air passage systems in this species. A colony with a very large mound is not in reality commensurately large in colony size and this may be the reason why the density of huge mounds of M. gilvus in Thailand is much higher than that of Macrotermes in Africa.

In this study, we determined the effects of plant richness, total plant abundance and abundance of plants with high galling diversity (super-hosts) on the local and regional galling richness in 15 areas of Neotropical savanna in different parts of Brazil. We established in each area 10 plots of 10 × 10 m, where we sampled a total of 131 plant species and 112 galling insect species. We considered all areas at the regional level and plots within each area at the local level. We found that at the regional level a combination of plant richness and plant abundance is the best model to explain the gall-inducing richness. We also found that at the local scale the most important factors are plant abundance and super-host abundance, but the plant richness is irrelevant. These findings confirm recent results that plant richness is an important predictor of galling species richness at the regional level, whereas the vegetation composition and structure act at the local level. Furthermore, this study contributes to the knowledge of the ecology of galling by showing how local factors influence the richness of this insect guild.

Insect-pollinated Laguncularia racemosa has a variable breeding system; some populations are androdioecious, with male and hermaphroditic plants, while others lack male plants. We observed the foraging behaviours of insects in three androdioecious and three hermaphrodite-only populations of L. racemosa in Florida. In each population, insect visitation rates were estimated from 30–108 timed intervals. We recorded the number of flowers visited by 144–224 insects during foraging bouts made to 15–40 male and hermaphroditic plants. Male plants in androdioecious populations had significantly more visitors than hermaphroditic plants, increasing the number of vectors carrying pollen from male plants. Further, many insects visited few flowers during foraging bouts, which should increase outcrossing frequency. According to mathematical models, male plants benefit from these combined factors. Plants in hermaphrodite-only populations had significantly more visitors than hermaphroditic plants in androdioecious populations. Proportionately more insects visited many flowers during foraging bouts in hermaphrodite-only versus androdioecious populations. The increased likelihood of geitonogamous self-pollination could help explain the lack of male plants in hermaphrodite-only populations. Differences in pollinator assemblages and the relative abundances of several species were responsible for differences in foraging behaviours: Apis mellifera, Bombus sp., Melissodes sp., Xylocopa sp., Euodynerus sp. and a calliphorid species.

The relative importance of different bottom-up-mediated effects in shaping insect communities in tropical secondary forests are poorly understood. Here, we explore the roles of vegetation structure, forest age, local topography (valley vs. hill top) and soil variables in predicting fruit-feeding butterfly and tree community composition, and tree community composition in predicting fruit-feeding butterfly community composition, in different-aged naturally regenerating and primary forests of Kibale National Park, Uganda. We also examine which variables are best predictors of fruit-feeding butterfly species richness or diversity. Butterflies (88 species) were sampled with a banana-baited trap and trees (98 taxa) with a 40 × 20-m sampling plot at 80 sampling sites. The environmental variables explained 31% of the variation in the tree community composition, the best predictors being local topography, forest age and cover of Acanthus pubescens (a shrub possibly arresting succession). The fruit-feeding butterfly community composition was better predicted by tree community composition (explaining 10% of the variation) rather than vegetation structure, local topography or soil factors. Environmental variables and tree species richness (or diversity) were poor predictors of butterfly species richness (or diversity). Our results emphasize the importance of tree community to recovery of herbivorous insect communities in tropical secondary forests.

Knowledge on cheetah population densities across their current range is limited. Therefore, new and efficient assessment tools are needed to gain more knowledge on species distribution, ecology and behaviour. Scat detection dogs have emerged as an efficient and non-invasive method to monitor elusive and vulnerable animal species, like cheetahs, due to the dog’s superior olfactory system. However, the success of locating scat using detection dogs can be significantly improved under suitable weather conditions. We examined the impact of temperature, humidity and wind speed on detection rates of scat from cheetahs during a scat detection dog survey in Northern Kenya. We found that average wind speed positively influences the scat detection rate of detection dogs working on leash. Humidity showed no significant influence. Temperature showed a strong negative correlation with humidity and thus was excluded from our model analyses. While it is likely that wind speed is especially invalid for dogs working off leash, this study did not demonstrate this. Wind speed could thus influence the success of monitoring cheetahs or other target species. Our findings help to improve the survey and thus maximise the coverage of study area and the collection of target samples of elusive and rare species.

The functional composition of plant communities in montane regions has been studied for decades, and most recent analyses find that environmentally favourable landscapes at lower altitudes tend to be dominated by species with resource-acquisitive traits, while more resource-conservative taxa dominate higher-altitude communities. However, it is unclear the extent to which this pattern is driven by co-gradient variation within clades or changes in clade representation across the gradient. To test for co-gradient variation, species composition, phylogenetic structure and functional traits were quantified for 97 species within the plant family Melastomataceae at five locations across a 2500-m altitudinal gradient along Volcán Barva in Costa Rica. Average melastome leaf force to punch, specific leaf area and leaf size vary with altitude, while four other functional traits do not. Taxonomic dissimilarity between communities was correlated with altitudinal difference, while phylogenetic dissimilarity was correlated with altitudinal dissimilarity only when measured with a metric that emphasizes shallow turnover of the tips of the phylogeny. These results highlight how species turnover may be more pronounced than functional or phylogenetic variation along altitudinal gradients. In addition, these results highlight the conservation value of lowland tropical forests, which here harbour a disproportionate amount of phylogenetic and functional diversity.

Tree establishment in tropical dry forests is constrained by drought-related seedling mortality during early stages of recruitment. Predicted increases in the duration of growing-season droughts in the future pose a significant threat to these ecosystems that could significantly alter their vegetation structure and composition. Here, we examined drought tolerance in seedlings of seven common dry-forest tree species from the Indian subcontinent. We conducted a dry-down experiment on 3-wk-old seedlings, and asked whether the key plant functional traits, specific leaf area (SLA), leaf dry matter content (LDMC), seed size and stem specific density (SSD) were good predictors of seedling growth under well-watered conditions, and survival during drought. Seedlings displayed substantial drought tolerance with most seedlings surviving for more than 2 wk under protracted drought. Seed size in combination with SLA predicted seedling growth under well-watered conditions and seed size predicted survival under drought. In contrast to our expectations, seedlings with lower SSD survived for longer without water. Our results suggest that dry-forest species will be differentially affected by the predicted increases in the duration of growing-season droughts, and detrimental effects will be more severe for species with smaller seeds.

Bulbul species (family Pycnonotidae) are important seed dispersers in Asian forests, but almost nothing is known of their movement patterns inside intact forest, which are likely to impact forest dynamics. We examined the movement patterns of the forest-dwelling puff-throated bulbul (Alophoixus pallidus) in relation to fruit productivity and distribution of fruiting trees/lianas in an evergreen forest in north-eastern Thailand. Movement patterns of 10 groups were precisely mapped by following colour-ringed individuals in each group 4 h mo−1 for 1 y. We evaluated fruit productivity and dispersion of fruiting trees/lianas based on monthly phenologies. There were clear seasonal fluctuations in fruit availability, which appeared to affect movement patterns, particularly distance moved between fruiting trees, time spent feeding and food selection. When fruit availability was low, bulbuls spent more time on average at a given food plant and moved longer distances between fruiting plants than compared with periods of higher fruit availability (low availability: 58 s, 83.2 m; high availability: 10 s, 43.4 m). This study points to the importance of seasonal availability of fruit resources on frugivore movement patterns. Seasonal dynamics of movement may be useful for understanding interactions between fruiting trees and their dispersers, and forest tree recruitment patterns.

Habitat fragmentation may lead to spatial genetic structuring of plant populations, but the magnitude of this effect differs among species. In this study, the effects of fragmentation on spatial genetic structure of Manilkara maxima, an ecologically important tree species endemic to the Atlantic forest of southern Bahia, Brazil, were examined. To address this issue, 222 individuals were sampled across two large-forest sites (200 and 400 ha) and one site comprising eight small fragments (5, 10 and 25 ha) roughly 35 y old. Five microsatellite loci were used. In general, M. maxima exhibited limited genetic structuring within and across the sites examined. At the landscape scale, genetic structure was not shaped by isolation by distance. Within individual sites, weak to moderate genetic structure was observed for both adults and saplings, which represented pre- and post-fragmentation, respectively. Sapling genetic structure did not clearly vary among the study sites, suggesting fragmentation has not affected spatial genetic structure. High levels of migration were observed, which would help maintain genetic connectivity. Taken together, these results suggest M. maxima, a long-lived tree that naturally occurs in low densities, may have limited spatial genetic structuring both within and across forest patches.

Whole plant form and function vary spectacularly across the seed plants. In recent years, plant evolutionary ecologists have begun to document this diversity on large geographic scales by analysing ‘functional traits’ that are indicative of whole plant performance across environmental gradients (Swenson & Enquist 2007, Wright et al. 2004). Despite the high degree of functional diversity in tropical forests, convergence in function does occur locally along successional or light gradients (Bazzaz & Pickett 1980, Swaine & Whitmore 1988).

Bird species assemblages in isolated Neotropical highland mountains have been moulded by the drastic climatic changes that occurred in late Pleistocene. Palynological evidence indicates that after the Pleistocene the highlands of Costa Rica and western Panama became isolated as climate turned gradually more tropical and highland vegetation retreated to the upper elevations of high mountains, forming highland islands. We surveyed birds at 10 representative sites throughout the Costa Rican highlands in order to determine the species composition of highland endemic assemblages. The area of available highland habitat explains 77% of the variance in species richness of the 36 highland endemics across highland islands, and the composition of these species assemblages have a nested distribution, rather than being independent sets of species on each island. The observed nested pattern is more consistent with a differential extinction model of species assemblages, and less likely to be explained by differential migration. We conclude that the reduction of highland vegetation and the avifauna associated with it, and its subsequent confinement to the summit of high mountains, is a possible explanation for the current distribution of highland endemic species in Costa Rican highland islands.

Ant gardens (AGs) are specialized ant-plant associations where arboreal ants build their carton nests in association with epiphytes that use the carton as a substrate. Most of the epiphytes are planted by ants; therefore, seed selection by ants is a key driver of the epiphyte composition of AGs. However, deterministic post-dispersal factors, such as the surrounding environmental conditions and plant succession, may also influence epiphyte composition. Here we ask whether epiphyte composition on a local scale is associated with dispersal constraints, local environmental conditions (light availability, number of branches and nest height) or AG successional stage. We sampled all epiphyte species in 18 AGs formed by Camponotus femoratus and Crematogaster levior in Central Amazon, Brazil. AGs were located within a range of 1 km and at a maximum of 20 m from the edges of a dirt road within a primary forest. Epiphytic composition showed strong spatial structure, decreasing in similarity with increasing distance. Environmental conditions and AG successional stage were not related to AG floristic composition, suggesting a key role of stochastic processes related to seed dispersal. A combination of seed abundance and attractiveness in neighbouring AGs seems to drive the higher similarity in epiphyte composition among closer AGs.

A honeydew-producing scale insect, Stigmacoccus garmilleri (Margarodidae), is associated with oak trees (Quercus spp.) in highland forests of Mexico. Although feeding by ants on scale-insect honeydew is more frequently documented in the literature, the honeydew produced by feeding instars of S. garmilleri is sufficient to provide nourishment for birds. This study elucidates bird use of honeydew in the tropical montane forests near Chiconquiaco, Veracruz, Mexico, and uncovers patterns in honeydew foraging. Over a 2-mo period, 40 trees harbouring scale insects, located in both forest and pasture areas, were intensely studied (160 h of bird-foraging observations along with quantitative measurements of honeydew production). Fifteen resident bird species and 18 migrant species were observed visiting observation trees. Approximately 72% of the resident bird species and 83% of the migrant bird species observed were recorded to forage on scale-insect honeydew. Audubon's warbler (Dendroica coronata auduboni) was the most active consumer and defender of the resource. Of 118 aggressive chases observed, only 9.65% occurred in forest observation trees, and 90.3% in pasture trees. Audubon's warbler demonstrated preferential defence and territorial patrolling of scale-insect honeydew in scattered pasture trees.

Sacred groves (SG) of south India are either relics of primary or secondary forests or swamps, worshipped by the local communities, and distributed in the countrysides (CS) and forest landscapes of India. Studies suggest that SGs harbour a biodiversity different from that of adjoining CS and have a structural similarity to protected forests. Studies also suggest a negative effect of structural complexity of forests on predation. Considering these two expectations, we compared the predation of artificial caterpillars inside SGs and CSs with the hypothesis that predation will be less in SG than in CS. Examining the predation marks, we identified the likely predator and scored the intensity of predation. Bite marks of arthropods, birds, lizards and mammals were observed on caterpillars of both habitats. The predation rate and predation intensity were similar for overall predators and for each predator taxon in both habitats, despite the fact that mammal predation was mostly encountered in SGs. Because the proportion of predated caterpillars is not different between habitats and the intensity of predation is high in SGs, we conclude that SGs may not have a quality of the expected standard.

Intraspecific synchrony in the phenology of tropical forest trees has implications for satiation of browsers and seed predators, pollination, dispersal and interpreting plant responses to environmental cues and stresses. Community phenological studies have been constrained in their consideration of these issues by the lack of concise quantitative measures of intraspecific synchrony. We propose a novel application of Colwell's predictability indices to overcome this deficiency. Its application is demonstrated by evaluating the leaf and reproductive phenologies of 8–16 individuals of each of 20 monsoon forest tree species from northern Australia monthly for 30 mo. The indices yielded substantial additional information over that provided by summaries averaged amongst conspecifics. Marked intraspecific asynchronies in leaf flush or flowering occurred in five evergreen species and two deciduous fig species, and were associated with prolonged individual commitments to these states. Five partly deciduous species exhibited marked intraspecific variation in the seasonal extent of leaf loss. We interpret the observed variation in intraspecific synchrony in terms of contrasting water-use and pollination strategies. The synchronicity indices are concise and robust to small and variable sample sizes, and may thus enhance studies of species-rich assemblages.