Abstract submitted to the Pennsylvania Academy of Science
for inclusion in the April 12-14 1996 meeting held at State College, PA.
Ecdysteroid and Juvenile Hormone production in diapausing female Drosophila
melanogaster.
Nicole H. Purcell* and David S. Richard. Department of Biology, Susquehanna
University, Selinsgrove PA 17870.
Drosophila melanogaster undergoes a female reproductive arrest (diapause)
induced by exposure following adult emergence to low temperatures and short-day
photoperiods. Diapause is associated with a pre-vitellogenic block in oocyte
development, and may be reversed by increasing temperature or application
of juvenile hormones (JH). As part of an ongoing reassessment of the roles
of JHs and of the insect steroid hormones (ecdysteroids) we have examined
ecdysteroid production (by radioimmunoassay) by isolated ovaries in vitro
from diapausing females and from females in which diapause was broken by
exposure to a temperature upshift from 11oC to 25oC
The levels of ecdysteroid production by the ovaries increased within 12h
of the upshift from basal levels (2.0+0.1pg/pair of ovaries/ 5h + SEM) of
to a sustained level of 15+2 pg/ pair/5h. JH production in these animals
did not increase during this period.