Competition with insectivorous ants as a contributor to low songbird diversity at low elevations in the eastern Himalaya

Abstract

Competitive interactions between distantly related clades could cause complementary diversity patterns of these clades over large spatial scales. One such example might be ants and birds in the eastern Himalaya; ants are very common at low elevations but almost absent at mid‐elevations where the abundance of other arthropods and insectivorous bird diversity peaks. Here, we ask if ants at low elevations could compete with birds for arthropod prey. Specifically, we studied the impact of the Asian weaver ant (Oecophylla smaragdina), a common aggressive ant at low elevations. Diet analysis using molecular methods demonstrate extensive diet overlap between weaver ants and songbirds at both low and mid‐elevations. Trees without weaver ants have greater non‐ant arthropod abundance and leaf damage. Experimental removal of weaver ants results in an increase in the abundance of non‐ant arthropods. Notably, numbers of Coleoptera and Lepidoptera were most affected by removal experiments and were prominent components of both bird and weaver ant diets. Our results suggest that songbirds and weaver ants might potentially compete with each other for arthropod prey at low elevations, thereby contributing to lower insectivorous bird diversity at low elevations in eastern Himalaya. Competition with ants may shape vertebrate diversity patterns across broad biodiversity gradients.

Wheeler’s dilemma revisited: first Oecophylla–Lasius syninclusion and other ants syninclusions in the Bitterfeld amber (late Eocene)

“…It is and the vast majority of its records come from sites classified as having tropical climates (Wetterer, 2017). The highest altitudinal records of Oecophylla in the Himalayas reported by different authors vary from 900 (Supriya et al, 2020) to 1200 (Wetterer, 2017) or even to 1150-1450 m a.s.l. (Collingwood, 1970).…”

Intraspecific trait variability and community assembly in hawkmoths (Lepidoptera: Sphingidae) across an elevational gradient in the eastern Himalayas, India

“…New species, of even distinctive vertebrate taxa, continue to be described from the region (e.g., Athreya, 2006a; Captain et al., 2019; Mirza et al., 2020; Sinha et al., 2005; Sondhi & Ohler, 2011). The entire list of research publications on diversity patterns in the region is a short one: elevational gradient of bird diversity (Acharya et al., 2011; Price et al., 2014; Schumm et al., 2020; Surya & Keitt, 2019), tree diversity patterns and population structure (Bhuyan et al., 2003; Rana et al., 2019), and distribution and abundance of arthropods (Ghosh‐Harihar, 2013; Marathe et al., 2020; Supriya et al., 2020).…”

“…This large species diversity and abundance provides opportunities to understand community assembly with sufficient statistical strength at multiple levels: within a genus, within a family, or across different families. Moth larvae are among the principal (most abundant) herbivores and prey base for insectivores in many ecosystems (Lill & Marquis, 2003; Supriya et al., 2020). The food–plant specificity of moth species makes for an intimate linkage between plant and moth communities.…”

Free-feeding organisms and galling insects (Hymenoptera) interactions on Caryocar brasiliense (Malpighiales: Caryocaraceae) trees, a savanna plant from Brazil

“…The system with a common and economically important Cerrado tree species, C. brasiliense, and its four galling herbivores, and several free-feeding organisms in central Brazil is appropriate to evaluate the hypotheses of competition for free space and food between galling and free-feeding species. Competition between predatory mites, tending ants, and galling insects, among others, has been reported and related to the dispute over food, protection and space (van der Hammen et al, 2012;Macke et al, 2012;Leite et al, 2017;Liu et al, 2020;Supriya et al, 2020).…”