Houseflies susceptible strains

Studies with susceptible and selectively bred carbofuran-resistant houseflies (Musca domestica) indicated that LD50 values for susceptible and resistant strains were 0.1 and 1.3 pg/insect, respectively (Dorough 1973). Resistant flies contained up to 34% more cholinesterase than susceptible strains and could excrete carbofuran almost twice as fast (Dorough 1973). Carbofuran resistance among pestiferous insects is not yet widely known or adequately documented. 

Decreased uptake as a mechanism of resistance was also observed in houseflies resistant to organochlorine, organophosphate, and carbamate insecticides. Resistant strains had higher total lipids, monoglycerides, diglycerides, fatty acids, sterols, and phospholipids in the cuticle than did the susceptible strain (Patil and Guthrie, 1979). 

The Swiss product DDT was introduced for housefly control in neutral countries in 1944, and already by 1946 resistance had developed in northern Sweden (of all unlikely places). When housefly resistance appeared near Rome, Italy in 1947, Professor Missiroli considered that it was a different subspecies which he named Musca domestica tiberina at the very same time that Wilson and Lindquist in the USDA Orlando laboratory were producing a resistant strain from a susceptible one by laboratory selection. 

Table 9.7 Metabolism of JH analogs by adult microsomes from insecticide-susceptible (SR) and resistant (Isolan-B) strains of housefly...

Houseflies can metabolise y-BHC. In the case of resistant fly strains this metabolism is more rapid than it is for susceptible ones. In the first step of metabolism 2,3,4,5,6-pentachlorocyclohex-l-ene (32) is formed, which is then converted to conjugates. S-2,4-Dichlorophenyl-glutathione (34), formed in the course of the dehydrochlorination of a conjugate, could be isolated from treated insects. Other metabolites are 1,2,3-trichlorobenzene, 1,2,4,5- and 1,2,3,4-tetra-chlorobenzene and pentachlorobenzene (Oppenoorth, 1954 Bradburg and Standen, 1959 Clark et al., 1966 Reed and Forgash, 1968 1969 1970). 

HJEBOB binding to the head membranes of the dieldrin-resistant (OCR) strain of houseflies was investigated. The OCR houseflies had an alanine-to-serine mutation at the 299-position of the RDL subunit. Scatchard analysis showed that EBOB bound to the head membranes of the OCR houseflies with 4-fold lower affinity than to those of the susceptible (WHO/SRS) strain. The membranes of the OCR strain were found to have 45-fold lower affinity for dieldrin than those of the WHO/SRS strain. By contrast, the membranes of the OCR strain showed only 2-fold lower affinity for fipronil than those of the WHO/SRS strain. The alanine-to-serine mutation does not hinder the binding of fipronil to the housefly GABA receptor. 

We used dieldrin-resistant (OCR) and susceptible (WHO/SRS) strains of houseflies Musca domestica) in the current study. Houseflies possess an RDL... 

---