Colony density and breeding structure of underground-nesting fungus-growing termite, Odontotermes formosanus (Blattodea: Termitidae).

Fungus-growing termites both provide essential ecosystem services and are considered agricultural pests in Asia and Africa. Research on such termites has primarily focused on mound-building species; underground-nesting fungus-growing termites remain understudied because of their cryptic behavior. However, molecular tools, such as microsatellite markers, offer an effective means of investigating the ecology of these underground species. In this study, we employed 5 microsatellite markers to accurately identify laboratory-paired colonies of Odontotermes formosanus (Shiraki) (Blattodea: Termitidae) and to determine their breeding structures. Fieldwork was conducted through systematic wood-stake monitoring at the Xiaping Tropical Botanical Garden, where 40 termite colonies were identified across 4 research plots. Most colonies (92.5%) had a foraging distance of <10 m, although the maximum distance recorded was 40 m. The colony density was 16 to 80 colonies per hectare. Of the 40 colonies, 34 contained sufficient samples for breeding structure analysis, which revealed 14 (41.2%) mixed-family colonies and 20 (58.8%) simple-family colonies. The colonies exhibited low levels of inbreeding, with inbreeding coefficients indicating that the reproductives were largely unrelated. Although pleometrosis may enhance colony fitness, it can also reduce genetic heterozygosity, suggesting a trade-off in non-kin cooperation. This study provides key data regarding the colony density, foraging distance, and breeding structure of O. formosanus, offering insights for quantifying ecosystem services, understanding population dynamics, and improving pest management strategies.