Species turnover and temporal variation of forest insects were used to explain the ecological succession and ecological segregation between efficiently competing species. In this study, species richness, abundance, and beta-diversity of the genus Onthophagus (Coleoptera: Scarabaeidae) assemblages between 2003 and 2007 were described and the diel—flight activity was examined in the disturbed forest and the interior forest of the lowland tropical rain forest at Ton Nga Chang Wildlife Sanctuary in peninsular Thailand. A total of 2,260 individuals of 22 species in 2003 and 2,382 individuals of 24 species in 2007 were collected. Although species richness and abundance did not differ significantly between the two years, all similarity indices were significantly different. The community structure of Onthophagus assemblage in 2003 demonstrated a heterogeneous pattern, whereas there was a tendency for the pattern to shift toward a more homogeneous structure in 2007. The temporal variation showed two distinct diel—flight activities; diurnal and crepuscular patterns. Six species were crepuscular (O. deflexicollis Lansberge, O. orientalis Harold, O. rudis Sharp, O. sp 1, O. sp 2, and O. sp 4), whereas most of Onthophagus species demonstrated diurnal pattern. Remarkably, five species (O. taurinus White, O. pilularius Lansberge, O. punneeae Masumoto, O. laevis Harold, and O. sp 3.) could not be classified as either diurnal or crepuscular species. It was suggested that the species turnover was probably influenced by the recovery of the forest structure and the decrease of anthropogenic disturbance. Resource partitioning was suggested to be a key factor for crepuscular adaptation in Onthophagus species.

Many animal species can produce venom for defense, predation, and competition. The venom usually contains diverse peptide and protein toxins, including neurotoxins, proteolytic enzymes, protease inhibitors, and allergens. Some drugs for cancer, neurological disorders, and analgesics were developed based on animal toxin structures and functions. Several caterpillar species possess venoms that cause varying effects on humans both locally and systemically. However, toxins from only a few species have been investigated, limiting the full understanding of the Lepidoptera toxin diversity and evolution. We used the RNA-seq technique to identify toxin genes from the stinging nettle caterpillar, Parasa lepida (Cramer, 1799). We constructed a transcriptome from caterpillar urticating hairs and reported 34,968 unique transcripts. Using our toxin gene annotation pipeline, we identified 168 candidate toxin genes, including protease inhibitors, proteolytic enzymes, and allergens. The 21 P. lepida novel Knottin-like peptides, which do not show sequence similarity to any known peptide, have predicted 3D structures similar to tarantula, scorpion, and cone snail neurotoxins. We highlighted the importance of convergent evolution in the Lepidoptera toxin evolution and the possible mechanisms. This study opens a new path to understanding the hidden diversity of Lepidoptera toxins, which could be a fruitful source for developing new drugs.

The genus Ngirhaphium Evenhuis & Grootaert, 2002 is reported for the first time from Thailand in particular from mangroves on the coast of the Andaman Sea in southern Thailand. Three species were found: N. murphyi Evenhuis & Grootaert, 2002, N. sivasothii Grootaert & Puniamoorthy, 2014 and N. chutamasae sp. nov. The latter species is described and illustrated and a key to all four known species is provided. COI barcode data showed that the new species is most closely related to N. murphyi with a genetic distance of 7%. The distance with the other species is 11 to 12%.

The species composition of dung beetles in primary forest and secondary forest at Ton Nga Chang Wildlife Sanctuary, Songkhla province, southern Thailand, was compared. Traps baited with pig dung were placed along line transects running through the two forest types. Species diversity and abundance of dung beetles were examined every 2 months from April 1999 to May 2000. Species diversity of dung beetles was significantly higher in the primary forest than in the secondary forest. Seven out of 20 species were found exclusively in the primary forest, namely Microcopris reflexus, Oniticellus tessellatus, Onthophagus near pilularius, O. taeniatus, O. ventralis, O. sp.3 and O. sp.4. Differences in forest structure, native animals present, and physical factors were suggested to be the factors determining species composition in the two forests. More individuals were trapped in the dry season than in the wet season in both forest types. However, seasonal effects on species diversity were not found. Tiniocellus sarawacus and Microcopris reflexus, were recorded for the first time in Thailand. Onthophagus sp.1 and O. sp.2 are expected to be new to science.

Phacaspis (Meuffels and Grootaert 1988) is a true marine dolichopodid fly genus. They are common on the mud flats in the front of mangroves where they deal with extreme conditions. The genus is represented in southern Thailand by Phacaspis mitis (Grootaert and Meuffels 2001) (Diptera: Dolichopodidae). Previous studies have focused on both taxonomy and classification of this genus, but there are a few studies focusing on this species in terms of molecular genetics. The objective of the present study was to investigate genetic variation and phylogenetic relationships of P. mitis using ribosomal DNA subunit 12S, ribosomal DNA subunit 16S, and cytochrome oxidase subunit I of mitochondrial genes. The specimens were collected in six coastal provinces from the Andaman Sea and the Gulf of Thailand. The phylogenetic relationship of combined mitochondrial genes revealed that P. mitis in peninsular Thailand is a monophyletic group that can be divided into two distinct clades. According to the haplotype network, 16 haplotype patterns were observed in P. mitis, but P. mitis was separated into two major haplotype networks. In addition, a positive correlation between genetic distance (FST) and geographical distance (km) was found among the populations of peninsular Thailand. The level of genetic differentiation between populations is influenced by geographic isolation. Moreover, P. mitis arose in late Eocene (35.5 Mya) and it diversified during the Plio-Pleistocene (3.14 Mya). Although, P. mitis is divided into two populations in this study, it is a well-supported monophyletic group.