Changes in ornithine decarboxylase activity in response to temperature stress and stimulation of juvenile hormone in Anastrepha fraterculus (Diptera, Tephritidae)

Abstract

Ornithine decarboxylase (ODC) activity was analyzed in Anastrepha fraterculus (Diptera) females (4 days old) submitted to temperature stress (6 degrees C and 20/6 degrees C) and the topical application of juvenile hormone (JH). ODC activity and ejaculatory apodeme measurements (length and width) were made in males (15 days old) after 6 degrees C stress. JH dose of 500 ng and incubation of 3, 7, and 18 h increased ODC activity. Females reared at 6 degrees C and 20/6 degrees C had higher ODC activity than those reared at 25 degrees C. The treatment of 6 degrees C and JH incubation for 1 h increased ODC activity when compared to 6 degrees C treatments only. However, the treatment of 20/6 degrees C only after 3 or 18 h of JH incubation resulted in higher ODC activity than controls (20/6 degrees C) or 20/6 degrees C plus 1 h of JH incubation. Males did not undergo differences in ODC activity when reared at 6 degrees C or 25 degrees C but the ejaculatory apodeme measurements was higher in those reared at 25 degrees C than in those reared at 6 degrees C. The results can be considered an adaptive process to environmental changes.