Within‐tree distribution of nest sites and foraging areas of ants on canopy trees in a tropical rainforest in Borneo

Abstract

It has been argued that canopy trees in tropical rainforests harbor species-rich ant assemblages; however, how ants partition the space on trees has not been adequately elucidated. Therefore, we investigated within-tree distributions of nest sites and foraging areas of individual ant colonies on canopy trees in a tropical lowland rainforest in Southeast Asia. The species diversity and colony abundance of ants were both significantly greater in crowns than on trunks. The concentration of ant species and colonies in the tree crown seemed to be associated with greater variation in nest cavity type in the crown, compared to the trunk. For ants nesting on canopy trees, the numbers of colonies and species were both higher for ants foraging only during the daytime than for those foraging at night. Similarly, for ants foraging on canopy trees, both values were higher for ants foraging only during the daytime than for those foraging at night. For most ant colonies nesting on canopy trees, foraging areas were limited to nearby nests and within the same type of microhabitat (within-tree position). All ants foraging on canopy trees in the daytime nested on canopy trees, whereas some ants foraging on the canopy trees at night nested on the ground. These results suggest that spatial partitioning by ant assemblages on canopy trees in tropical rainforests is affected by microenvironmental heterogeneity generated by three-dimensional structures (e.g., trees, epiphytes, lianas, and aerial soils) in the crowns of canopy trees. Furthermore, ant diversity appears to be enriched by both temporal (diel) and fine-scale spatial partitioning of foraging activity.

Experimental suppression of ants foraging on rainforest vegetation in New Guinea: testing methods for a whole-forest manipulation of insect communities

“…This observation corresponds with the generally low activity of ground‐nesting ants on trees in the area (Janda, 2007). It is known that some ant species have nocturnal activity in tropical forests (von Aesch & Cherix, 2005; Tanaka et al , 2010) but we assume these species were affected by our treatment because bait stations were also operated overnight.…”

Competition can lead to unexpected patterns in tropical ant communities

“…We chose P. tomentella which, being of similar height and appearance provided standard microhabitats for epiphytic ferns. Along with other ferns, A. nidus is one of the most common epiphytes large enough to provide nesting space for ants in Southeast Asian rainforests (Tanaka et al, 2010). We distinguished 90 ferns from each of two heights: understorey (3e4 m) and canopy (45e50 m).…”

Vegetation connectivity increases ant activity and potential for ant‐provided biocontrol services in a tropical agroforest

“…Therefore, foraging and discovery of food resources is strongly constrained by the need to construct and follow trails along vegetation (Farji‐Brener et al., ; Gordon, ; Yanoviak, Silveri, Stark, Van Stan, & Leiva, 2017). This is particularly relevant for ants using the arboreal stratum as their primary foraging space (Apple & Feener, ; Hashimoto, Morimoto, Widodo, & Mohamed, ; Powell et al., ; Tanaka, Yamane, & Itioka, ). For instance, the availability of vegetation connections (e.g., branches, leaves, vines, lianas, bark, and moss) can maximize ants’ foraging efficiency, locomotion, and velocity (Clay, Bauer, Solis, & Yanoviak, ; Fewell, ; Torres‐Contreras & Vasquez, ), as well as contribute to changes in community composition and species richness (Adams et al., ; Lassau et al., ; Yanoviak & Schnitzer, ).…”