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Truncation Of Screwworm (Diptera: Calliphoridae) Development By Irradiation Of Embryos., David Taylor, Robert Mangan

David B. Taylor

Gamma irradiation of screwworm, Cochliomyia hominivorax (Coquerel), embryos was used to truncate the life cycle at the prepupal stage. Egg hatch and larval survival were not reduced by dosages ≤8 kilorads (kr). Pupariation and adult emergence were inhibited by dosages ≥2.8 and 1.2 kr, respectively. Larvae, irradiated as embryos with dosages ≤8 kr, successfully infested wounded sheep, although larval weight was lower than normal. A dosage of 5.8 kr was sufficient to prevent pupariation, while permitting larval development to the third instar. Truncation of screwworm development permits the use of artificially wounded and infested animals for screwworm population surveillance and …

Genetic Compatibility Of Aedes (Protomacleaya) Triseriatus With A. (P.) Brelandi And A. (P.) Hendersoni (Diptera: Culicidae)., David B. Taylor

David B. Taylor

Interspecific hybridization was used to examine reproductive compatibility of Aedes (Protomacleaya) triseriatus (Say) with Aedes (P .) brelandi Zavortink and Aedes (P.) hendersoni Cockerell. Most male progeny were sterile intersexes when A. brelandi or A. hendersoni males were crossed with A. triseriatus females. Female hybrids, and males from the reciprocal crosses, were morphologically normal and fertile. Varying percentages of intersex males were observed among progeny when normal F₁ hybrids were crossed to either parental species or with other hybrids. Egg and female sterility resulting from a partial incompatibility between A. triseriatus cytoplasm and …

Unidirectional Reproductive Incompatibility Between Aedes (Protomacleaya) Brelandi And A. (P.) Hendersoni (Diptera: Culicidae)., David Taylor, George Craig

David B. Taylor

Forced mating was used to determine reproductive compatibility between two species in the Triseriatus Group of Aedes (Protomacleaya). In the cross between A. hendersoni Cockerell females and A. brelandi Zavortink males, only 7% of the females laid eggs that developed embryos. Furthermore, <5% of the eggs from single-female clutches in which one or more eggs did embryonate were fertile. In the reciprocal cross, A. brelandi females crossed to A. hendersoni males, 70% of the females laid fertile eggs and >80% of the eggs from those females became embryonated. Approximately 80% of the females were inseminated in both of the reciprocal crosses. No chromosomal abnormalities were observed in the hybrids. Incompatibility between the A. brelandi male genome and the A. …

Speciation In The Aedes Triseriatus Species Complex., David B. Taylor

David B. Taylor

Interspecific hybridization was used to determine the genetic relationships between the four species of mosquitoes in the Triseriatus and Zoosophus groups of the aedine subgenus Protomacleaya (Diptera : Culicidae) . Four factors were investigated : 1) fertility of intra- and interspecific crosses, 2) morphology of the interspecific hybrids and the genetic bases of morphological characters, 3) modes of postcopulatory reproductive isolation and 4) types of chromosomal changes occurring during and subsequent to the divergence of the species .

Hybrid progeny were produced in 11 of the 12 possible crosses between the four species . Only the Aedes zoosophus female X …