Diversity of pselaphine beetles (Coleoptera: Staphylinidae: Pselaphinae) in eastern Thailand

Abstract

Pselaphine beetles (Coleoptera: Staphylinidae: Pselaphinae) are cosmopolitan, species-rich, and yet poorly studied, particularly in the tropics. We sampled beetles in three types of primary forest and two types of disturbed forest habitats in eastern Thailand to assess the utility of pselaphine beetles as bioindicators of forest disturbance. We simultaneously measured leaf litter mass, soil moisture, soil acidity and canopy cover at each site to infer which environmental factors affect pselaphine beetle diversity and abundance. At each site, pselaphine beetles were extracted from ten 1 m 2 samples of leaf litter and soil with Tullgren funnels. We sampled 1867 adult beetles representing six supertribes, 51 genera and 114 morphospecies; 7% of the genera and 92% of the species were undescribed. Forest types differed significantly in species richness, abundance, diversity and evenness. Primary forest had greater numbers of species and individuals, and higher diversity indices (H′). Teak plantation and secondary forest had substantially fewer individuals and species of pselaphine beetles. Species composition differed between primary and degraded forests. Canopy cover, soil moisture, and leaf litter mass positively correlated with beetle species richness and abundance. Leaf litter mass and soil moisture were the two most important factors affecting the diversity of pselaphine beetle assemblages. Among the 114 morphospecies collected, 43 morphospecies were specific to two or three habitats and 64 morphospecies were found only in a single habitat. Thus pselaphine beetles appear to have rather narrow habitat requirements and their presence/absence was correlated with environmental differences. These traits make pselaphine beetles a suitable bioindicator taxon for assessing forest litter diversity and monitoring habitat change.

Beetle biodiversity in forest habitats in Laos depends on the level of human exploitation

“…This key finding of the present study of higher species richness in less disturbed lowland deciduous forests from Laos agrees with other studies of the subject. For instance, Sakchoowong et al (2008) found that teak plantations and secondary forest had substantially fewer individuals and species of pselaphine beetles in a study conducted in eastern Thailand. Another study showed that abundance, species richness and guild structure of saproxylic beetles were not maintained in a logged and regrowth forest in Queensland, Australia (Grove 2002).…”

Ant diversity as a direct and indirect driver of pselaphine rove beetle (Coleoptera: Staphylinidae) functional diversity in tropical rainforests, Sabah, Malaysian Borneo

“…A Winkler extraction method was used to sample leaf litter macrofauna (see Krell et al, for a discussion on this method). The Pselaphinae beetles (Coleoptera: Staphylinidae: Pselaphinae) inhabit forest leaf litter (Nomura & Mohamed, ; Sakchoowong et al, ), therefore Winkler sampling is appropriate. Sieved leaf litter samples were hung in Winkler bags for 3 days.…”

“…The Pselaphines are a species‐rich group of predatory leaf litter beetles with 9,854 described living species in 1,247 genera worldwide (Parker, ). They are generally small (∼1–3 mm in body length) and are particularly diverse and abundant in the tropics (Chandler, ; Chung et al, ; Parker & Maruyama, ; Nomura & Mohamed, ; Sakchoowong et al, ). In Borneo, 123 species have been recorded (Nomura & Mohamed, ), but many more are yet to be described.…”

“…Pselaphines deviate from the typical staphylinid body plan in possessing a more compact, sclerotized integument that reduces abdominal flexibility. Although a relatively invariant body plan would appear to restrict their movements through the substrate, pselaphines have radiated successfully in the leaf litter, particularly in ant‐dominated tropical forest floors (Chandler, ; Parker, ; Sakchoowong et al, ).…”

“…Their ecological and functional importance have made them suitable candidates for conservation studies particularly concerning the effect of rainforest disturbances on biodiversity (Chung et al, 2000;Edwards et al, 2014;Sakchoowong et al, 2008). Ants and beetles, among other taxa, have proven to be effective bioindicators of the response of other taxa to logging and conversion to oil palm in Southeast Asia (Chung et al, 2000;Edwards et al, 2014;Sakchoowong et al, 2008). Ecosystem disturbances greatly influence the abundance and distribution of functionally important species that contribute to maintaining ecosystem functioning and biogeochemical cycles (Hooper et al, 2005;Loreau et al, 2001).…”