Flight polymorphism drives metacommunity structure of aquatic Heteroptera in tropical rock pools

Abstract

Rock pool metacommunities are shaped by the dispersal ability of organisms, which together with environmental heterogeneity, determine whether the metacommunity is structured more by environmental or spatial factors. To understand the effect of interspecific differences in dispersal capacity on beta diversity patterns and metacommunity structure, we studied aquatic Heteroptera (an actively dispersing insect group with species exhibiting flight polymorphism) in the rock pools on three outcrops in the Western Ghats, India. We used an abundance-based gamma diversity partitioning framework to assess the percent contributions of similarity (S) and the decompositions of beta diversity-abundance difference (D) and abundance replacement (R) to community structure for two mobility groups, that is, flying and flightless species. We compared the variation in beta diversity components "D" and "R" within and between outcrops for both mobility groups. We also studied the effects of the local environment on both mobility groups using redundancy analysis. Percent contributions of "S", "D" and "R" changed according to the mobility group, with higher nestedness (S+D) in flying species (74.2%) and higher beta diversity (R+D) in flightless species (76.3%). There was a significant variation in overall beta diversity between outcrops for the respective mobility groups, caused by abundance difference for flying species (p = .003) and by abundance replacement for flightless species (p = .003). Flying and flightless species were not associated with different environmental variables. Our study demonstrates that dispersal capacity is responsible for structuring regional diversity, with distinct sources of dissimilarity being associated with each mobility group: Abundance replacements between assemblages imposed by dispersal limitation for flightless species and abundance differences in assemblages of flying species, which might reflect the carrying capacity of the habitats.

Local‐scale abiotic factors influence the organization of rock pool arthropod communities in a biodiversity hotspot

“…Our results suggest that the passive dispersers were structured by this gradient of dispersal limitation and hydroperiod, highlighting the role of “species sorting” in shaping their communities (Kulkarni et al 2019). Interestingly, Paripatyadar et al (2021) reported the role of species‐specific dispersal in structuring the active disperser communities, thus highlighting the contribution of dispersal mode and its variation in shaping rock pool communities. The high phylogenetic signal suggests that related species responded more similarly to the abiotic covariates than unrelated species, beyond what could be expected due to the studied traits (Ovaskainen and Abrego 2020), supporting the role of niche‐conservatism in the assembly of these communities.…”

“…The rock pools in Australia have been well explored relative to those in tropical regions like Asia, Africa, and South America (Jocque et al 2010 a ). Studies in Asia, including the Indian subcontinent, have largely focused on documenting biodiversity in these pools (Shinde et al 2014), and only a few studies have investigated the drivers of community organization in these habitats (Kulkarni et al 2019; Paripatyadar et al 2021). We identified 34 species of dominant freshwater arthropods (crustaceans and insects) per outcrop and up to 30 species in individual pools.…”

“…The specimens collected from each pool were pooled and preserved in 98–100% ethanol or 4% formalin. Samples were examined under the microscope and identified at the lowest taxonomic level possible using relevant literature ( see Kulkarni et al 2019; Paripatyadar et al 2021 for details).…”