Heritable effects on caste determination and colony-level sex allocation in termites under field conditions

Mamoru Takata; Shuya Nagai; Tatsuya Inagaki; Yusaku Ohkubo; Eisuke Tasaki; Kenji Matsuura

doi:10.1016/j.isci.2023.106207

Heritable effects on caste determination and colony-level sex allocation in termites under field conditions

iScience. 2023 Feb 15;26(3):106207. doi: 10.1016/j.isci.2023.106207. eCollection 2023 Mar 17.

Authors

Mamoru Takata¹, Shuya Nagai¹, Tatsuya Inagaki^{1

2}, Yusaku Ohkubo^{3

4}, Eisuke Tasaki^{1

5}, Kenji Matsuura¹

Affiliations

¹ Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto Universit, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan.
² School of Life Science and Technology, Tokyo Institute of Technolog, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
³ Center for Data Assimilation Research and Applications, Joint Support Center for Data Science Research, Research Organization of Information and Systems, 10-3, Midori-cho, Tachikawa, Tokyo, Japan.
⁴ The Institute of Statistical Mathematics, Research Organization of Information and Systems, 10-3, Midori-cho, Tachikawa, Tokyo, Japan.
⁵ Department of Biology, Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan.

Abstract

The ecological success of social insects is attributed to the division of labor, where newly hatched offspring differentiate into either fertile progeny or functionally sterile worker castes. There is growing evidence for the heritable (genetic or epigenetic) effects on caste determination based on laboratory experiments. Here, we indirectly demonstrate that heritable factors have the principal role in caste determination and strongly affect colony-level production of both sexes of fertile dispersers (i.e., alates) in field colonies of the termite Reticulitermes speratus. An egg-fostering experiment suggests that the colony-dependent sex-specific caste fates were almost entirely determined before oviposition. Our investigation of field colonies revealed that such colony-dependent sex-specific caste fates result in the intercolonial variation in the numerical sex ratio of differentiated fertile offspring and, eventually, that of alates. This study contributes to better understanding the mechanisms underlying the division of labor and life-history traits in social insects.

Keywords: Ecology; Environmental science; Evolutionary biology; Evolutionary ecology.