Research Interest

The focus of this laboratory is the seasonal adaptation in invertebrates. We approach it from a perspective of comparative physiology and we always consider animal’s wild lives and their diversity in the course of studies. Thus, our interests are firmly connected with those of ecologists.

 

A season comes around once a year. There are not only hot summer and cold winter, but also rainy season, dry one and so on. According to these abiotic environmental changes, biotic environment also changes considerably. Because the changes are so serious, almost all the invertebrates adapt their life cycles to these seasonal changes to survive and reproduce. We have been trying to grasp the whole picture of seasonal adaptation at various levels of analyses: individual, cellular and molecular analyses.

Two different courses of research projects are proceeding. The first is the physiological analysis of life cycle; we investigate physiological responses to environmental factors like temperature, daylength or food, underlying an animal’s actual life cycle. Current models used are primarily insects such as flies (Diptera) and stink bugs (Heteroptera), but we are expanding our field covering the tadpole shrimp (Crustacea), the two-spotted spider mite (Arachnida) and the terrestrial slug (Mollusca).

The second is the neuronal and molecular mechanisms of “photoperiodism” that plays a critical role in seasonal adaptations of terrestrial animals. Photoperiodism is the physiological reaction of organisms to daylength. Now we are trying to clarify the mechanisms from the analyses of photoreceptor(s) and endocrine effector systems and, in addition, expressions of circadian clock genes, mostly in flies.