Convergence in the use of resources may occur between distantly related organisms. A major ecological resource in which members of various taxa may be interested is a cavity for nesting. A variety of social hymenopterans and vertebrates may nest within tree cavities in tropical ecosystems. We used 241 nest-boxes placed in seven Kenyan localities to investigate the use of nesting cavities by members of distant taxa and discuss whether interaction between them is a potential factor shaping cavity-nester communities in tropical regions. The nest-boxes were occupied by social insects (ants, bees and wasps) (30.1% of nest-boxes in April–May and 33.1% in September–October) and vertebrates (birds and mammals) (20% and 7.7%, respectively). Hymenopterans were more abundant in forest boxes (36.2% of nest-boxes occupied in April–May and 37% in September–October), whereas savannas had lower figures (21.7% and 31.3%, respectively). Among vertebrates, most occupants of nest-boxes in savanna were birds (17.8% of nest-boxes occupied vs. 8% in mammals), while mammals predominated in forests (4.9% of the nest-boxes occupied vs. 0.3% in birds). Spatial and temporal patterns of occupation highlight the potential that interaction between distant taxa may have on the access to nesting cavities. More nest-boxes remained unoccupied in forested areas than in savanna areas suggesting that a shorter supply of nesting sites in the savanna may be a source of competition. The simultaneous occupation of a nest-box by two different taxa was exceptional, also supporting the hypothesized inter-taxon competition.

Invasive weeds like Lantana camara have a range of effects on animals such as elephant. These plants are not edible by the Asian elephant (Elephas maximus). They also compete for space with elephant food plants and take over large areas of elephant habitat. We tested whether the addition of L. camara to a model consisting of measured environmental variables improved predictions of habitat use by elephant in Mudumalai Tiger Reserve, India. Elephant dung density was used to assess elephant habitat use from 62 line transects 1-km in length. Results indicated that habitat and impact of human settlements significantly influenced elephant habitat use at a landscape scale. However, we found no evidence for the hypothesis that the addition of L. camara significantly predicted elephant habitat use at the landscape level. We then tested the association of L. camara on elephant habitat use in the dry deciduous forest (DDF) where there was a significant interaction between DDF and L. camara. In the DDF, L. camara significantly predicted elephant habitat use. We conclude that while no significant effects of L. camara were seen at the level of an entire reserve, at a finer scale and in specific habitats negative effects of this invasive plant on elephant habitat use were observed.

Hurricanes are major disturbance events in Neotropical mangrove communities, potentially affecting the reproductive success of mangrove species. This was the first investigation of changes in mangrove pollinator assemblages following hurricanes, and the effect of these changes on the mating system of Laguncularia racemosa. Insect pollinator assemblages were investigated in three Florida mangrove communities in 2001–2003, 2005 and 2009; two hurricanes affected the area in 2004. Visitation rates were estimated from 1445 insects observed during 272 10-min intervals; the number of flowers visited by each insect was also recorded. Pollinator diversity was estimated with the Shannon Index. Following the hurricanes, species richness was reduced by 43–65% and diversity declined by 36–70%. Significant declines in insect visitation to L. racemosa resulted in reduced outcrossing frequencies in 2005. Laguncularia racemosa flowers autogamously self-pollinate without insect visitors, so fruit set still occurred. Visitation rates returned to pre-hurricane levels by 2009, but foraging behaviours differed from pre-hurricane patterns; outcrossing was further favoured by reduced frequencies of long foraging bouts and increased frequencies of short foraging bouts. The mixed mating system of L. racemosa provides reproductive assurance following hurricane disturbances, when pollinator abundance is low.

Abundance and physiology of three understorey tree fern species were compared in a Mexican cloud forest. We hypothesized that the distribution of species would be associated with canopy openness and leaf physiological characteristics. In gullies (1–2% full sun), Alsophila firma was abundant, Cyathea divergens was distributed in moderately open places (4–9%), and Lophosoria quadripinnata preferred more open canopy (9–30%). Although 11 leaf traits of five plants of each species growing under closed and open canopies over 1 y did not differ within species, there were significant interspecific differences. Alsophila firma had comparatively low maximum electron transport rate ETRmax (26.8 ± 1.81 μmol m−2 s−1) and ETR light saturation point (ETRLSP: 261 ± 36.1 μmol m−2 s−1), high specific leaf area (SLA), thin leaves and decreased quantum yield during a leaf desiccation experiment. Cyathea divergens had relatively high maximum quantum yield (0.84 ± 0.004), ETRmax (37.3 ± 1.8 μmol m−2 s−1) and ETRLSP (409 ± 40.0 μmol m−2 s−1). Lophosoria quadripinnata had comparatively thick leaves, low SLA, high predawn water potential, high density (606 ± 25.5 mm−2) and small length (0.026 ± 0.002 mm) stomata. The results support the hypothesis that light sensitivity shapes tree fern distribution in the cloud forest.

Spatial and temporal variation of tropical insect communities has rarely been studied, although such variation influences estimates of global species richness. Therefore, we compared spatial and temporal variation of herbivorous insect communities on Neoboutonia macrocalyx trees among seven sites over 1 y in a primary tropical rain forest in Kibale National Park, Uganda. The distance between the study sites varied from 4.8 to 31.2 km and altitudinal differences ranged from 20 to 242 m. Permutational multivariate analysis of variance (PERMANOVA) revealed significant spatial changes in community composition of the herbivorous insects and study sites differed also in insect abundance (6.9–26.2 individuals m−2 of leaf area). This is likely to be caused by differences in vegetation, altitude and microclimate among the study sites. The similarity of insect species composition was negatively correlated with geographic and altitudinal distances among sites and positively correlated with the similarity of tree community composition. Species richness varied significantly between sampling dates, ranging from 33 to 41 species. Also community compositions changed between sampling dates, which likely follows from marked seasonal changes in climate and the phenology of other host plants used by the generalist insect species also living on Neoboutonia macrocalyx. In general our study supports the idea of high variability of herbivorous insect communities in primary rain forests even at a small spatial scale. This should be considered when estimations of insect biodiversity are made.

Many landscape features represent geographic barriers to gene flow, and promote genetic discontinuity. Rivers are effective barriers. However, most studies on this subject have focused on animals and only a few have focused on plants. We studied the genetic structure and gene flow of the tropical tree Handroanthus ochraceus (Bignoniaceae) on both banks of the São Francisco River in a Brazilian seasonally dry tropical forest. The São Francisco is located in eastern Brazil and is 600 m wide at the study site. Our hypothesis was that the river is a geographic barrier to gene flow of H. ochraceus trees. We sampled two populations on the left bank and one population on the right bank. We used seven microsatellites to genotype 212 individual plants. All populations had low polymorphism and genetic diversity, but high inbreeding. There was no genetic differentiation among populations and, consequently, the estimated gene flow was high for all pairs of populations. The genetic relatedness among individuals from populations of the same margin did not differ from the relatedness among individuals from populations of opposite margins. Hence, the São Francisco River is not an effective geographic barrier to gene flow among H. ochraceus populations.

Interspecific kleptoparasitism (the stealing of already-procured items from other species) has received little attention in tropical reptiles. We report here the second case of kleptoparasitism in tropical lizards, and the first known case of pollen theft by a vertebrate species. Phelsuma inexpectata, a gekkonid lizard endemic to Réunion, was observed robbing pollen pellets from honeybees (Apis mellifera) foraging on Latania lontaroides flowers. Video-records were used to obtain reliable information on gecko-honeybee interactions occurring on L. lontaroides inflorescences. During the 19 observation periods (total duration 140 min) a total of 78 attempts were recorded, at least 40% were successful. Both males and females displayed kleptoparasitic behaviour. A high level of gecko kleptoparasitism occurred, with an average one-robbery attempt every 2 min. Behaviour of both the kleptoparasitic P. inexpectata and its host A. mellifera are described.

Although the dioecious palm, Mauritia flexuosa plays a pivotal role in Amazonian ecology and economy, little is known about its flowering and fruiting patterns. We investigated the role of habitat and inter-annual precipitation in the phenology of M. flexuosa. We calculated sex ratios and recorded phenology for 20 mo in four populations (N = 246) of savanna–forest ecotone (two sites) and forest (two sites) habitat in Roraima, Brazilian Amazonia. Sex ratios were significantly female-biased, and >98% of females set fruit. No significant relationship was found between habitat and sex. Flowering occurred at the wet/dry season interface (August–November), and fruit maturation occurred during the wet season (May–August). Males and females flowered synchronously, and neither the onset nor termination of flowering differed significantly between habitats. Flowering was negatively associated with present precipitation and positively correlated with prior precipitation (3 mo). Fruiting was positively associated with present precipitation and unrelated to prior precipitation (3 mo). We conclude that habitat has an insignificant effect, although short-term climatic variation may influence phenology of this species in northern Amazonia. These results highlight the need for long-term studies relating flowering and fruiting events, and inter-annual climatic variation.

The activity of the water opossum Chironectes minimus was studied in Atlantic forest rivers in south-eastern Brazil using radiotracking, from October 2004 to October 2008. There were 439 nocturnal fixes of 11 males and four females. Activity patterns of the water opossum were compared among sexes and seasons, using linear and generalized linear mixed models. The water opossum is active mostly at night, showing a unimodal pattern, with activity increasing after sunset and decreasing thereafter along the night. Females were more active in the first quarter of the night and males in the second one. The activity period of males was longer in the dry season, while for females it was longer in the wet season. Sex and season were important determinants of the water opossum activity patterns, mainly because of different sex strategies in a promiscuous/polygynous mating system. However, despite those influences the overall distribution of activity along the night was similar to most Neotropical marsupials. Therefore, similarities in the activity patterns are probably due to phylogenetic constraints and to the absence or weakness of selective pressures modifying the activity of the water opossum.

Leaf anatomical and carbon isotope ratio (δ13C) data from previous studies suggest that the species of the Melastomataceae perform C3 photosynthesis and that leaf anatomical features of some epiphytic taxa resemble the characteristics found in CAM plants. The δ13C values of 67 species of neotropical Melastomataceae (including epiphytes) were obtained from herbarium material deposited at the California Academy of Sciences for assessing the presence of the CAM pathway. The δ13C values obtained from leaves (−23.4‰ to −34.5‰) were congruent with C3 photosynthesis (< −20‰), and the δ13C data from terrestrial (56 samples) and epiphytic species (11 samples) were not statistically different. Our results suggest that CAM photosynthesis is not found in neotropical Melastomataceae. The leaf anatomical features found in some species of Melastomataceae represent adaptations to cope with water stress and are not necessarily correlated with CAM photosynthesis. Photosynthetic pathways can be assessed with the use of leaf anatomical and δ13C data, but further biochemical assays are warranted to corroborate the absence of the CAM pathway in the Melastomataceae.

We studied density, size structure, and establishment sites of Coussapoa microcarpa in the Brazilian Atlantic rain forest. This species is a hemiepiphyte that begins its life in the tops of trees and survives the death of its host to become a free-standing tree. All individuals of C. microcarpa already rooted in the ground were recorded in a 3.43 ha (1.75 ha in lowland and 1.68 ha in submontane) sample of forest plots. Data on total height, root diameter at breast height, host height and diameter at breast height, as well as height, type and diameter of the establishment site were collected. Coussapoa microcarpa present a high density (36.5 ind. ha−1) and the population studied was composed mainly of young individuals. Young and adults differed in establishment sites. The diameter of establishment sites of young was narrower than the diameter of establishment sites of adults, which points out to a limiting factor (diameter of establishment site) regulating the establishment of C. microcarpa.