Abstract:
In pest management programmes that incorporate the sterile insect technique
(SIT), the ability of mass-reared insects to tolerate dry conditions may influence their
survival after release in the field. In the present study, desiccation resistance of adult
mass-reared Queensland fruit flies, Bactrocera tryoni (Frogatt) (Diptera: Tephritidae),
that are routinely released in SIT programmes was compared with that of wild flies at
1, 10 and 20 days after adult eclosion. Under dry conditions without access to food or
water, longevity of mass-reared B. tryoni was significantly less than that of their wild
counterparts. Desiccation resistance of mass-reared flies declined monotonically with
age, but this was not the case for wild flies. The sharp decline in desiccation resistance
of mass-reared flies as they aged was likely explained by decreased dehydration
tolerance. As in an earlier study, desiccation resistance of females was significantly
lower than that of males but this was particularly pronounced in mass-reared
females. Female susceptibility to dry conditions corresponded with declining
dehydration tolerance with age and associated patterns of reproductive development,
which suggests that water content of their oocyte load is not available for
survival during periods of water stress.
