Watana Sakchoowong

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

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 m2 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.

Observations of immature and adult stages of the myrmecophilous cetoniine beetle Campsiura nigripennis (Coleoptera: Scarabaeidae)

Several cetoniine species are known or speculated to be associated with ants, based on their specialized morphological characters. However, there are only a few species where biological information on the larval and adult stages is available. Field observations revealed that Campsiura nigripennis spends the immature stages inside elephant dung, and that adult females fly to elephant dung for oviposition. In addition, adult beetles of C. nigripennis intruded into arboreal nests of Oecophylla smaragdina. Specialized morphological characters appear to allow them to tolerate attacks from the ants. Furthermore, the distribution of the beetle in continental Asia largely overlaps that of the Asian elephant, indicating that dung of elephants, in conjunction with that of other large mammals, is fundamental to the biology of C. nigripennis.

Myrmecophilous rove beetles (Coleoptera: Staphylinidae) associated with Aenictus hodgsoni (Hymenoptera: Formicidae) from Thailand, with description of two new genera and three new species.

Three species of rove beetles (subfamily Aleocharinae) were collected from colonies of Aenictus hodgsoni Forel, 1901 in Khao Yai National Park, Thailand. They are classified into three genera, including two new genera, and described herein as: Aenictobia siamensis Maruyama, sp. n. (tribe Aenictoteratini), Aenictosymbia cornuta Maruyama, gen. & sp. n. (tribe Lomechusini) and Aenictoxenides mirabilis Maruyama, gen. & sp. n. (tribe Pygostenini). The systematic positions of the new genera are discussed.

Host record of the myrmecophilous carabid genus Cryptocephalomorpha (Coleoptera: Carabidae: Pseudomorphinae) with description of a new species from Thailand

Cryptocephalomorpha siamensis sp. nov. is described from Thailand. The type series was collected from a nest of myrmicine ant, Pheidole singaporensis, which is the first exact host record of the genus Cryptocephalomorpha. Collecting circumstances and observed behavior are reported.