Different socialities affect habitat preferences in the coexisting wood-feeding cockroaches Panesthia angustipennis spadica and Salganea esakii

Abstract

Abstract Wood-feeding cockroaches generally have long nymphal periods and adult lifespans. Especially for social species, stable and durable habitats may be required for taking care of their offspring in the same place. We compared the preferences of habitats, colony composition, and reproduction in two coexisting wood-feeding cockroaches, the gregarious P. angustipennis spadica and the subsocial S. esakii, in a temperate forest. Colonies of P. angustipennis spadica were more frequently found in wood at higher decay stages, while the number of individuals of S. esakii was larger in wood at lower decay stages. In P. angustipennis spadica, nymphs in all size classes were found without adults, suggesting that dispersed nymphs prefer more highly decayed wood, which is easy to digest and nutrient-rich. On the other hand, S. esakii form larger colonies with multiple broods, indicating that they may prefer less-decayed wood for maintaining colonies over several years. Thus, the different intensities of sociality in wood-feeding insects may play a role in the decomposition process of decayed woods in forests.