Research

Insect social behavior, particularly with respect to resource sharing

Asymmetries in resource distribution within colonies in termites

The hallmark of social insects is their caste-based division of labor; only a small fraction of individuals monopolize reproduction, while the others conduct non-reproductive tasks. Such social systems are built on asymmetries of resource distribution within colonies. Studying the regulation of such asymmetries in resource distribution is crucial for understanding the maintenance of social systems in insects, although the molecular background is poorly understood. 

Konishi T, Tasaki E, Takata M, Matsuura K (2023) King- and queen-specific degradation of uric acid contributes to reproduction in termites. Proceedings of the Royal Society B 290:20221942 Link 

We focused on nitrogen compounds, the key to reproduction requiring protein synthesis. We found that king- and queen-specific degradation of uric acid (a major product of nitrogen metabolism) contributes to reproduction in the subterranean termite Reticulitermes speratus. The urate oxidase gene, which catalyzes the uric acid degradation, was highly expressed in mature kings and queens. Suppression of uric acid degradation decreased the number of eggs laid per queen. Uric acid was shown to be provided by workers to reproductive castes. Our results indicate that king- and queen-limited capability to use certain compounds enables colony resources to concentrate in reproductive castes.

Aggressive behavior dependent upon social context in termites

Many social insects can distinguish nestmates from non-nestmate conspecifics, thereby ensuring that altruistic behavior is directed toward close relatives and preventing the loss of colony resources. In termites, however, colonies exhibit various responses to non-nestmates: from killing to accepting as a colony member. Why and how termite colonies adopt closed versus open societies remain largely unknown, while it is presumably related to not only genetic but also social-environmental factors.

Konishi T, Matsuura K (2021) Royal presence promotes worker and soldier aggression against non-nestmates in termites. Insectes Sociaux 68:15–21 Link 

We found that kings and queens play a key role in maintaining high aggression levels of workers and soldiers toward non-nestmate intruders in the subterranean termite Reticulitermes speratus. The level of aggression toward non-nestmate conspecifics was significantly lower in “royal-absent” colonies compared to “royal-present” colonies. This study provides further empirical evidence that taking account of the social context is important when conducting ecological studies using termites.

Social information use during egg-laying decision making in longhorn beetles

For insects whose larvae are incapable of moving between food resources, the selection of oviposition sites by females is critical to the survival and development of their offspring. In such insects, it is known that females utilise and benefit from conspecific cues for oviposition choice. Studying how information from the behaviour of conspecifics affects egg-laying decision making is crucial for understanding the biology of insects, which can lead to novel strategies for pest management. 

Konishi T, Uemori K, Tamura S, Taki H, Shoda-Kagaya E (2025) The avoidance of conspecific cues during egg-laying decision making in the Asian long-horned beetle Anoplophora glabripennis. Bulletin of Entomological Research 115:511–516 Link

We focused on the reproductive behaviour of the Asian long-horned beetle Anoplophora glabripennis, which has become an invasive pest species throughout the world. We showed that A. glabripennis avoids sites already containing conspecific cues during egg-laying decision making. The field survey measuring the distance between neighboring oviposition scars (in this species, females make scars through the bark of host branches for laying eggs) suggested that the selection of oviposition sites by females is not random. In laboratory oviposition-choice bioassays, females made less oviposition scars on branches containing scars made by other females than those without scars. Our results indicate that avoiding sites containing conspecific traces realizes fitness benefit such as reducing resource competition among larvae.