Abstract
The two-spotted spider mite Tetranychus urticae is a cosmopolitan agricultural pest with an extensive host plant range. The species shows clear photoperiodism. Adult females reproduce under long days, whereas they enter reproductive diapause in response to short days. Diapausing females terminate diapause and start oviposition under long days, whereas they maintain diapause under short days. Physiological mechanisms underlying photoperiodism are considered to be divided into 4 processes (photoreceptor, photoperiodic time measurement, counter, endocrine system), and now we accumulate much information on each of the processes in this species. In this review, we introduce recent advances in our knowledge on physiological and genetic mechanisms governing photoperiodism of T. urticae.
