Mutualism can facilitate the colonization, establishment, and spread of invasive species. By modifying interactions with third parties, mutualisms can have cascading community-wide effects. Both native and invasive ants are capable of forming mutualisms with hemipteran insects, preying on non-hemipteran herbivores and indirectly affecting primary production. Comparative research on the effects of both native and invasive ant exclusions on multitrophic interactions is therefore crucial for understanding the invasive potential of ants, along with any ecological consequences that invasions may have. We performed a quantitative review of the multitrophic effects of invasive and native ants on insect–plant food webs. Herbivorous insects are the most common food source for both invasive (comprising 56% of prey species caught) and native ants (55% of the prey species caught), followed by predators (31% for invasive ants, 45% for native ants). Excluding both invasive and native ants significantly reduced hemipteran abundance, and excluding invasive ants had a greater negative impact on hemipteran abundance than native ants. Native ant predation significantly reduced herbivore abundance, but excluding invasive ants had no effect. Cascading effects of native ants on plant fitness were significantly positive, but there was no significant impact of invasive ants. These findings suggest a weak relationship between the presence of invasive ants and non-hemipteran herbivore abundance. We suggest that the hemipteran–ant mutualism could represent a ‘symbiotic invasion’. The ecological dominance of invasive ants is often facilitated by hemipteran insects. This association requires invasive ant control strategies to expand beyond ants to consider mutualists.

Network analysis helps reveal the details of community organization by holistically assessing species diversity and the relationships contained therein. In this study, we collected arboreal ants from their host trees at three sites (Nabanhe, Menglun, and Bubeng) in the Xishuangbanna National Nature Reserve. Following computation of species diversity, network metrics, and community metrics, we compared the ant-tree bipartite networks between the three sample sites. Network metrics were evaluated using Z values standardized according to two different null models. Tree species composition differed across the three experimental sites, and the ant communities were correspondingly diverse. Ant and tree species number and 研究报告the tree heterogeneity index (Shannon-Wiener diversity index, Simpson diversity index) were highest in Menglun, and lowest in Bubeng. Extinction slopes showed the same trends as the indices for ant and tree species number and tree heterogeneity, but did not display the same pattern as ant species heterogeneity. Evaluated parameters included: weighted nestedness metrics (WNODF), links per species, specialization, modularity, connectance, extinction slope exponent, and niche overlap. The absolute Z values of these parameters were highest in Menglun and lowest in Bubeng. In conclusion, tree species number and heterogeneity determine the ant-tree network stability, which is measured by extinction slope. WNODF and links per species are positively correlated with community stability. In specialized and modular networks, species populating higher trophic levels experience extinction events in direct correlation with those in lower trophic levels.

Insect pollinators play a vital role in plant sexual reproduction. Pollinators facilitate cross-pollination that in turn promotes genetic diversity, mediates plant speciation, and contributes to ecosystem stability. However, the abundance, diversity and health of wild pollinators are threatened by human activities such as anthropogenic climate impacts, habitat destruction and environmental pollutants, and the impact of these human activities on ecosystems is likely to increase. Despite recognizing the importance of wild pollinators and the implementation of targeted conservation programs, the contemporary threats of wild insect pollinators remain poorly understood. For the giant honey bee (Apis dorsata), an important wild pollinator and honey producer in tropical rainforests and agricultural areas across Asia, here we describe nest characteristics, colony migration and pollination role and review threats to their conservation. We found that A. dorsata nests featured a single honeycomb hanging from the branches of large trees. The bees undertook long distance migrations to locate seasonally ephemeral forage sources but regularly returned to previous nesting sites. We identified several anthropogenic activities that posed significant threats to A. dorsata conservation: harvesting entire colonies, deforestation, pesticide and herbicide utilization, parastioids, mites, pathogens and climate change. Based on our study, we recommend several conservation initiatives to promote wild A. dorsata populations, which include artificial domestication, developing ecological agriculture, establishing of ecological corridors, inspection and quarantine controls on domesticated colonies, and sustainable utilization of the floral resources used by A. dorsata. We hope that this review will stimulate future research on giant honey bees whilst playing a significant role in their conservation and sustainable utilization.