To understand mechanisms behind enigmatic declines of tropical reptiles, knowledge of species interactions and how they vary over space and time is important. Some tropical lizard population dynamics can be highly influenced by egg survival. Yet relatively few studies have examined relationships between lizard reproductive success and egg predators across forest and microhabitat types. In this study, we examined variation in probability of egg depredation, predatory ant abundance, prey availability, and the number of lizards and eggs encountered across four different forest types (abandoned agroforestry, abandoned plantation, secondary forest, and old-growth forest) and three microhabitats (buttress, fallen log, and leaf-litter) at La Selva Biological Station, Costa Rica. Based on previous studies, we made three hypotheses about how lizard egg abundance, egg survival, and predatory ant numbers would be related across microhabitat and forest type. Of these hypotheses, only one was supported: we found more lizard eggs in buttress and fallen log microhabitats than leaf-litter. We did not observe any differences in lizard reproduction or numbers of invertebrates by forest type alone. Based on patterns observed in this study, we suggest that future studies investigating tropical leaf-litter lizard declines focus on environmental variation at the microhabitat scale.

Multiple new ant treatment products containing high volumes of sugar have recently been developed specifically for use in ant management programs. The presence of sugar in these products could potentially attract bees, and any such attractancy would likely be fatal given that these products typically contain general insecticides. To determine the risk of such products to bees I present four studies assessing bee attractancy to multiple matrices that are used to make these products. The trials were conducted across multiple years, seasons, and locations, containing various concentrations of sugar in multiple forms, using various experimental setups with many different bee hives, and multiple observers. Not a single bee was attracted to any matrix, nor were bees observed inspecting any matrix, and no bees fed on any matrix, irrespective of whether the matrices were placed close to hives and directly under bee flight paths, or out in areas where bees were feeding. This is in stark contrast to large numbers of bees that were feeding on flowers within the immediate vicinity of all of the matrices in the first two experiments, or flying over the arrays in experiments 3 and 4 travelling to and from other food sources. I present five suggestions for the discrepancy between the trials presented here and the general perception that bees are attracted to sugar. These matrices appear to be acceptable as a basis to make treatment products for broadscale use within ant management programs. However, it should be recognized that bees, and other non-target species, are indeed capable of feeding on these matrices. Therefore vigilance should still be maintained to identify special circumstances where bees may be killed when constituents are added to these matrices that do attract bees, or usage methods can adversely affect bees.

Sacred groves (SGs) of India are islets of forests providing ecosystem and spiritual services to man. Studies suggest that SGs are deteriorating on their quality due to urbanization, invasive species, land-use change, and religious modernization. We explored diversity, community, and abundance of overall and different functional groups of litter ants, including Anoplolepis gracilipes – an invasive ant – on paired SG-neighbouring home garden (HG) sites in rural and urban landscape to (a) assess the quality of SGs and (b) examine whether the variation in ant community of the two habitats was predicted by urbanization and abundance of A. gracilipes. We considered species and local contribution to β-diversity to identify species and sites crucial for conservation of sites. Abundance and richness of overall ants, proportional trap incidence of species, and abundance of A. gracilipes were similar on SG and HG, but species diversity and abundance of certain ant functional groups were higher on SG. Ant community of SG was different from HG, but was not affected by urbanization. A. gracilipes and rural SGs contributed the most to β diversity. A. gracilipes gave little pressure on native ant community. The study concludes that SGs, despite invaded by A. gracilipes, have potential for conserving biodiversity.

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.

In the American continent, the sugarcane borer Diatraea saccharalis (F.) is the main pest in sugarcane producing areas. The objective of this study was to assess the effect of crop residue management on damage by D. saccharalis, its egg parasitoids and the ants associated with sugarcane. The study was carried out during 2011–2012, 2012–2013 and 2013–2014 crop cycles, in three commercial fields located in different regions of Tucumán state, Argentina. Two types of crop residue management (= treatments) were compared: conservation of trash at the soil surface (CT) and trash burning (TB). In ‘trash conservation’ treatment, crop residue was allowed to remain over the soil surface during the whole sugarcane growing season, while the second treatment consisted of complete burning of trash blanket approximately 2 weeks after harvest. The injury level was measured by recording the number of stalks bored and internodes bored. Parasitism was estimated by counting the total number of eggs and number of black eggs (which indicates the occurrence of egg parasitoids). Ants (Formicidae) richness was calculated by two estimators; abundance-based coverage estimator and incidence-based coverage estimator, using the non-parametric richness estimators: Chao 2 and Jackknife. Finally, the indicator value was estimated through the measurement of specificity and fidelity. In all the parameters studied no significant difference was found between TB and CT treatments.

Cultivating plant mixtures is expected to provide a higher productivity and a better control of pests and diseases. The structure of the arthropod community is a major driver of the magnitude of natural pest regulations.

With the aim of optimizing pest management, a study was carried out to determine the effect of the cropping system type (tomato mono-cropping vs. mixed-cropping) on the diversity and abundance of arthropods from three trophic groups (herbivores, omnivores, predators) and the abundance of Helicoverpa armigera. Therefore, the diversity of cultivated plants and arthropod communities was assessed within tomato fields from 30 farmer's fields randomly selected in South of Benin. Results showed that the arthropod abundance was significantly higher in mixed-cropping systems compared with mono-cropping systems, although the crop type did not alter significantly the arthropod diversity, evenness, and richness. At the level of taxa, the abundances of generalist predators including ants (Pheidole spp., and Paltothyreus tarsatus) and spiders (Araneus spp. and Erigone sp.) were significantly higher in mixed fields than in mono-crop fields. Then, the abundances of omnivore-predator trophic groups have a negative significant effect on the H. armigera abundance. This study allowed better understanding of how plant diversity associated to tomato fields structures arthropod's food webs to finally enhance the ecological management of H. armigera.

To maintain savanna vegetation, mid-seasonal fire has been applied since 1961 in the Lamto Savanna (Côte d'Ivoire). However, this prescribed fire has not impeded tree encroachment during recent years, nor have its effects on insect assemblages been documented. Also the impact of tree intrusion on insect assemblages is poorly studied in savanna. To prevent tree density increasing, a change in fire regime might be a solution. In this study, we examined the effect of different fire regimes (early, mid-seasonal and late fires) on leaf-litter ant assemblages in order to suggest appropriate measures for preventing tree invasion without having an effect on insect communities. Sampling was implemented by combining pitfall trapping and leaf-litter sampling before and after three different fire regimes, early, mid-seasonal and late fires. While the ant species richness declined after the passage of early and mid-seasonal fires, significantly more species were found in the burnt savanna after the late fire. However, the losses or gains of species due to different fire regimes did not cause severe changes in the ant species composition. Of the functional groups identified, only the generalists and specialist predators were respectively strongly affected by the early and mid-seasonal fires, certainly due to micro-habitat modification. Based on the trends observed in the present study, we suggest sampling other invertebrate fauna in similar savanna plots to find out if other insect groups have similar reactions to the applied fire regimes.

Seeds of plants naturalized in the United States were examined for the presence of elaiosomes. Seeds of 47 species belonging to 13 families (Asteraceae, Boraginaceae, Dipsacaceae, Euphorbiaceae, Fabaceae, Fumariaceae, Lamiaceae, Liliaceae, Poaceae, Polygonaceae, Resedaceae, Rosaceae, and Solanaceae) were found to have elaiosomes, indicating that these species are probably mymecochorous, i.e., dispersed by ants. These include important rangeland weeds such as bull thistle, Canada thistle, musk thistle, diffuse knapweed, spotted knapweed, and leafy spurge. Myrmecochory in naturalized species may enhance their weediness in areas where they are established and assist their colonization of new and relatively closed communities.

Postdispersal weed seed predation by animals during the summer fallow period may lead to a reduction in the number of weeds that grow in the following winter cropping season. In this study, we investigated the patterns of weed seed removal, the influence of crop residue cover on seed removal, the types of granivores present and their seed preferences in a 16-ha postharvest cropping field in Western Australia during the summer months over 2 yr. Seed removal from caches was extremely variable (from 0 to 100%). Removal rates were generally highest along the edges of the field near bordering vegetation and lowest in the center of the field and within the bordering vegetation. However, there were many deviations from this general pattern. There was no change in rates of predation with different levels of residue cover. Ants or other small invertebrates were found to remove the most seeds. However, seed removal by other animals, such as rodents, was also evident. Annual ryegrass seeds were preferred over wild oat seeds, followed by wild radish pod segments. Seed harvesting was lowest in late January, peaked in February, and decreased in March. Results from this study suggest seed harvesters could reduce the number of surface seeds in the field, reducing the weed seed bank. Management options that increase the activity of the seed harvesters may lead to less variability in seed predation and could, therefore, be incorporated into an integrated weed management program.

Many species of palm produce chambers called domatia that are used by ants as nesting spaces. However, the ecological nature of this association is not well understood, and the information on palm–ant interactions is primarily anecdotal. Here, we conducted a field study in the secondary forest of the Danum Valley Conservation Area, Malaysian Borneo, on 41 individuals of the rattan Korthalsia furtadoana. All studied plants showed signs of a past or present partnership with domatia-nesting ants, as indicated by entry holes in domatia. In 14 plants, our physical disturbance of a stem provoked the appearance of patrolling ants of Camponotus sp. We compared the leaf conditions of rattans with and without patrolling ants, testing whether the presence of ants is linked to improved leaf health. The leaflets of plants with patrolling ants were significantly less physically damaged and less covered by epiphylls. On average, 19% of the leaflets of plants with patrolling ants were damaged (52% in plants without patrolling ants), and the epiphyll cover of their leaflets was 0.2 on our scale of 0–4 (1.3 in plants without patrolling ants). Our results suggest that this poorly studied plant–ant association has a mutualistic character. It seems that the ants take advantage of the nesting space created by the plant partner, while the plants gain protection for their photosynthetic apparatus against herbivores and epiphylls.

Termites are an important component of savannah ecosystems throughout Africa. Despite their importance in the ecosystem, they can be serious pests of structures, houses, rangelands, tropical forestry, and agriculture. For many decades, chemical insecticides have remained popular for termite management worldwide. However, with the growing environmental concerns over pesticides, biological control using entomopathogenic fungi such as Metarhizium anisopliae (Metschnikoff) Sorokin has become an often-considered alternative. Metarhizium anisopliae is an ubiquitous, naturally occurring pathogen, which has been reported infecting over 200 insect species; therefore, there is concern that use of M. anisopliae may affect non-target organisms. The effects of M. anisopliae isolate ICIPE 30 were experimentally tested on the ants which associate with Odontotermes spp. termite mounds. Laboratory bioassays were carried out to assess the effects of direct exposure to M. anisopliae on Crematogaster mimosae and Camponotus spp. In addition, ant diversity was monitored over 18 months from termite mounds treated with M. anisopliae in situ near the Mpala Research Centre in Laikipia District of central Kenya. Results obtained revealed no effects of direct exposure to M. anisopliae isolate ICIPE 30 on the mortality of C. mimosae (F1 = 7.29, P = 0.0072) or Camponotus spp. (F1 = 13.01, P = 0.0004) in the laboratory. No significant difference in Shannon indices of ant diversity from treated and untreated mounds (F1 = 0.016, P = 0.8989) was found. It is evident that M. anisopliae has no negative effects on ants that are associated with Odontotermes spp. termites.

Environmental effects on species interactions can be studied by comparative analyses of network structure. For example, comparison of interaction networks among study sites can provide clues to geographic variation of host breadth. Obligate plant–ant interactions are ideal systems to explore these phenomena because they are long term and can be accurately sampled in the field. We tested two hypotheses: (1) network structure and host specialization do not vary among communities, and (2) the effects of plant extinction do not vary among communities. We sampled 10 or more plants for each of the 30 ant–plant species found in three Neotropical locations. We found that network specialization, H2′, was significantly higher than expected in random networks. The ant or plant specialization index, d′, distribution did not vary among localities, neither varied in link or asymmetry distribution. Plant extinction simulations showed that these interactions are vulnerable to plant loss, and the null model was more robust than the observed networks. This study provides a foundation on which plant and ant phylogenies can be added to explore compartment evolution.

Chinese knotweed (Persicaria chinensis) is of ecological and economic importance as a high-risk invasive species and a traditional medicinal herb. However, the insects associated with P. chinensis pollination have received scant attention. As a widespread invasive plant we would expect P. chinensis to be associated with a diverse group of insect pollinators, but lack of taxonomic identification capacity is an impediment to confirm this expectation. In the present study we aimed to elucidate the insect pollinators of P. chinensis in peninsular Malaysia using DNA barcoding. Forty flower visitors, representing the range of morphological diversity observed, were captured at flowers at Ulu Kali, Pahang, Malaysia. Using Automated Barcode Gap Discovery, 17 morphospecies were assigned to 23 species representing at least ten families and four orders. Using the DNA barcode library (BOLD) 30% of the species could be assigned a species name, and 70% could be assigned a genus name. The insects visiting P. chinensis were broadly similar to those previously reported as visiting Persicaria japonica, including honey bees (Apis), droneflies (Eristalis), blowflies (Lucilia) and potter wasps (Eumedes), but also included thrips and ants.

Although predation is generally seen as one of the key factors determining the abundance and composition of insect herbivore communities in tropical rain forests, quantitative estimates of predation pressure in rain-forest habitats remain rare. We compared incidence of attacks of different natural enemies on semi-concealed and exposed caterpillars (Lepidoptera) in lowland and montane tropical rain forests, using plasticine models of caterpillars. We recorded attacks on caterpillars in four habitats: primary forest, secondary forest and forest fragment in lowlands (200 m asl), and montane primary forest (1700 m asl). We used 300 exposed and 300 semi-concealed caterpillars daily, and conducted the experiment for 6 d in every habitat. Daily incidence of attacks was higher on exposed caterpillars (4.95%) than on semi-concealed (leaf-rolling) caterpillars (2.99%). Attack pressure of natural enemies differed also among habitats. In the lowlands, continuous primary and secondary forests had similar daily incidence of attacks (2.39% and 2.36%) which was however lower than that found in a primary forest fragment (4.62%). This difference was caused by higher incidence of attacks by birds, ants and wasps in the forest fragment. The most important predators were birds in montane rain forests (61.9% of identified attacks), but insect predators, mostly ants, in the lowlands (58.3% of identified attacks). These results suggest that rapid decrease in the abundance of ants with altitude may be compensated by increased importance of birds as predators in montane forests. Further, it suggests that small rain-forest fragments may suffer from disproportionately high pressure from natural enemies, with potentially serious consequences for survival of their herbivorous communities.

Ant–acacia mutualisms are conspicuous biotic associations in Savannah and neotropical ecosystems; however, the effects of tree size and forest structure on ant behaviour and tree traits are rarely examined. We tested two hypotheses related to these effects: (1) ant responses to disturbance are influenced by tree size and forest basal area; and (2) tree traits important to ants are predictable by tree size and forest basal area. We investigated these hypotheses in a dry tropical forest (Ometepe Island, Nicaragua) with the myrmecophytic Collins acacia (Vachellia collinsii Saff.) and the ant Pseudomyrmex spinicola (Emery 1890). We measured trees from three size classes and three basal area classes and quantified resources that are important for ants, including food resources (nectaries and Beltian bodies) and domiciles (thorns), as well as a measure of potential tree reproductive fitness (seedpods). We also evaluated ant responses to experimental disturbances. Three important findings emerged: (1) on average, 1140–1173% more ants responded to experimental disturbances of large trees than small- or intermediate-sized trees, respectively; (2) forest basal area did not affect ant responses to disturbance; and (3) neither tree size nor forest basal area was correlated with branch-level mean numbers of nectaries, food bodies or thorns. Our studies support the hypothesis that tree size is an important factor regarding ant behavioural responses to disturbance, but not forest basal area. Our work suggests that future studies of ant behaviour on myrmecophytes should consider tree size.

Leaf litter invertebrates were sampled at eight sites, approximately 250 m apart in elevation, along an altitudinal transect extending from primary lowland rainforest to cloud forest in western Panama. The study focused on several diverse and numerically important litter invertebrate taxa (e.g., ants, spiders, and beetles) that were effectively sampled using a combination of litter sifting and test tube pitfall traps. The mean altitudinal range of species was around 500 m (standard deviation 370 m) and approximately 50% of the species characteristic of a given elevation dropped out after a 500 m change in elevation in either direction. There was no evidence for distinct altitudinal zonation in leaf litter assemblages. Both species richness and number of individuals of most taxa showed a pronounced decline in the vicinity of the upward transition to cloud forests. The data also suggest a broad mid-elevation peak in sample species richness for the litter invertebrate fauna. The implications of the results for biodiversity conservation are discussed.