MELATONIN IN 2 SPECIES OF DAMSELFLY, ISCHNURA-VERTICALIS AND ENALLAGMA-CIVILE

We measured melatonin (MEL) with RIA in two species of damselfly, Ischnura a verticalis and Enallagma civile. I. verticalis were sampled over 24 h in ambient outdoor L13.5:D10.5 photoperiod and thermoperiod (15 to 30.5 degrees C), and we found a significant MEL cycle with a peak during scotophase/cryophase. The range of [MEL] was 11.2 to 20.2 pg mg body mass(-1). E. civile were sampled over 24 h at a L12:D12 photoperiod and 25 degrees C and at mid-photophase and mid-scotophase at both 10 and 30 degrees C. Mean [MEL] was 0.957 pg mg body mass(-1), and [MEL] did not differ significantly among times of day or temperatures.