The diverse life forms omnipresent in the ecosystem have evolved via adaptation to their respective habitats through interactions with each other. Understanding the sophisticated biological functions that have resulted from these processes is not only of basic biological interest but also has been utilized for applied purposes in a variety of ways.

AIST Researchers, in collaboration with the University of Tokyo, have shown that in the stinkbug Plautia stali, for which the gut symbiotic bacteria are essential for survival, (i) the morphology and function of the symbiotic organ developed at the posterior end of the digestive tract differ between nymphs before metamorphosis and adults after metamorphosis, (ii) the transition of the symbiotic organ from the nymphal to adult form is controlled by metamorphosis-regulating genes, (iii) the nymphal symbiont is specialized for retention of the gut symbiotic bacteria, whereas the adult symbiont is, in addition, involved in food digestion and absorption, (iv) the adult symbiont synthesizes large amounts of amino acids necessary for eggshell formation, and (v) these metamorphosis-associated changes of both the stinkbug host and the bacterial symbiont support the vigorous reproductive capacity of adult stinkbugs, which consume large amounts of food and lay an egg mass every few days.

This study demonstrates that metamorphosis, one of the factors that support insect diversity and prosperity, regulates the function of not only the insects themselves but also the symbiotic bacteria therein. This is an important achievement that uncovers a high degree of functional integration of different organisms in a symbiotic relationship, and may contribute to the development of pest control technologies targeting the mechanisms of metamorphosis and symbiosis.