Ac. Kotze, INDUCED INSECTICIDE TOLERANCE IN LARVAE OF LUCILIA-CUPRINA (WIEDEMANN) (DIPTERA, CALLIPHORIDAE) FOLLOWING DIETARY PHENOBARBITAL TREATMENT, Journal of the Australian Entomological Society, 34, 1995, pp. 205-209
Insecticide tolerance in the Australian sheep blowfly, Lucilia cuprina
, was examined using an enzyme-induction approach. The effects of diet
ary phenobarbital administration on detoxification-enzyme activities a
nd insecticide tolerances were measured using first and second instars
. The LC50 of butacarb to blowfly larvae increased 85-fold following p
henobarbital treatment. Tolerance to diazinon and diflubenzuron also i
ncreased considerably, with LC50s 12- and I-fold higher, respectively.
Tolerance to deltamethrin only increased slightly (1.4-fold). The deg
rees of tolerance towards butacarb and diazinon increased with increas
ing concentrations of phenobarbital in the larval diet. Phenobarbital-
treated larvae showed significantly enhanced cytochrome P450 levels re
lative to controls. Aldrin epoxidase, P450 reductase and glutathione t
ransferase activities were enhanced 168-, 1.7- and 2.2-fold, respectiv
ely, in treated larvae. The induced monooxygenase and glutathione tran
sferase systems appear to equip the larvae with the ability to degrade
increased amounts of various types of insecticides.