Indosialis Lestage, 1927 is a small and rare megalopteran genus belonging to the family Sialidae and endemic to the Oriental region. The Thai and Lao species of Indosialis are herein revised by an integrative approach combining morphological and molecular evidence, including two species: Indosialis bannaensis Liu, Yang & Hayashi, 2006 and Indosialis siamensis sp. nov. The pupal stage of Indosialis is reported here for the first time. Indosialis siamensis sp. nov. can be distinguished from its congeners by 1) the brown head and prothorax (orange in congeners); 2) the apical tooth of right mandible in male sharply angulated (truncate or almost absent in congeners); and 3) the distinct sac-like structure present in male genitalia (indistinct or absent in congeners). The new species coexists with I. bannaensis in Loei Province, northeastern Thailand. Both species inhabit slow-flowing or sluggish streams that are usually covered by Colocasia esculenta (L.) Schott (Araceae).

Sparsorythus is a genus of Tricorythidae from the Oriental Region. Sparsorythus multilabeculatus Sroka & Soldán, 2008 was described based on a male imago from Vietnam. Unknown nymphs and female subimagines of Sparsorythus and male imagines of S. multilabeculatus were collected from Thap Lan National Park, Khon Buri District, Nakhon Ratchasima Province, Thailand. Nymphs and female subimagines of Sparsorythus were associated with male imagines of S. multilabeculatus by analyzing sequences from the DNA barcoding region of the mitochrondrial gene cytochrome oxidase I. Phylogenetic analysis based on Maximum Likelihood indicated that all unknown specimens are conspecific with male imagines of S. multilabeculatus (bootstrap 100% and genetic distance 0–0.004). Male and female nymphs, female subimago and egg are described for the first time. Nymphs each bear a medial emargination on the hypopharynx, one bristle-like process at the base of the left prostheca, and a bifurcate rudimentary gill on abdominal segment VII. The male usually has smudges and light blotches on its forewings; the penis extends to the basal segment of the forceps and reaches to approximately 1/3 of the second segment of the forceps. Forewings of the female subimago have dark colour over more than half of the basal area, and the distal portion of each wing is translucent. The egg has a rounded pole; the polar cap covers approximately 1/4 of the surface; and the surface is covered with hexagonal structures.

Urbanization is widely recognized as a significant threat to biodiversity. Stingless bees are vital pollinators in the tropics, yet their nesting site preferences in human-modified habitats are still poorly understood. This study aimed to examine the nesting substrate use, nesting tree species and size, nest height, and entrance orientation of Asian stingless bees in urban areas and to investigate whether landscape metrics (built-up area, NDVI, and forest cover) influence stingless bee richness and nest abundance. Using field surveys across 28 sites within four location types—parks, temples, schools, and universities—we recorded 207 nests representing nine stingless bee species across four genera ( Heterotrigona , Homotrigona , Lepidotrigona , Tetragonula ). Over 50% of all recorded nests occurred in man-made substrates, highlighting the bees’ flexibility in utilizing urban infrastructure when natural substrates are limited. The most commonly nesting stingless bee species in urban areas were Tetragonula pagdeni , followed by T. collina and T. fuscobalteata . Stingless bee species richness and nest abundance were higher in larger urban green spaces, including parks and universities; however, smaller sites, such as schools and temples also provided important nesting habitats. Seven stingless bee species collectively utilized 19 tree species and exhibiting variation in preferred tree diameter. The three most frequently used tree families were Moraceae, Fabaceae, and Magnoliaceae. Lepidotrigona satun , Heterotrigona itama , and Homotrigona apicalis tended to nest at relatively high positions, with average nest heights exceeding 2 m. Nest entrance orientations varied among stingless bee species; however, Tetragonula collina and T. fuscobalteata predominantly oriented their nest entrances toward the northwest. Additionally, generalized linear mixed models revealed no significant associations between the landscape variables and bee richness or nest abundance. Our findings highlight the adaptability of stingless bees to heterogeneous urban environments and demonstrate that both green spaces and built structures contribute to supporting their communities.