Use of a modified Marchand cage to study mating and swarming behavior in Culex tarsalis, with reference to colonization.

Selective pressures in laboratory rearing may account for the poor field mating of laboratory reared Culex tarsalis males. Previous studies of swarming behavior of field collected Cx. tarsalis had to be done in the field since such adults did not exhibit normal swarming in cages. Field collected individuals did not swarm normally nor mate effectively in cages. Normal swarming behavior by field collected mosquitoes, subsequent mating, and insemination were observed in a cage modified from a design by Marchand (1985). The use of such a cage could reduce one type of selective mating pressure involved in the colonization of mosquito species.

The salivary gland chromosomes of Culex tarsalis.

The salivary gland chromosomes of Culex tarsalis are described and briefly compared to similar descriptions of other Culex species previously published. Additional cytogenetic evidence will be needed to make meaningful comparisons and hypothesize speciation relationships.

Three new sex-linked mutants in Culex tarsalis and their relationships in linkage group I.

Three sex-linked mutants are described for the mosquito, Culex tarsalis, Charcoal, char, and ebony, eb, affect body-scale pigment in the adult; wide-wing, ww, gives abnormal wing size and affects the palps in adults. A preliminary map of linkage group I is offered from recombination data involving the sex-linked mutants.

An alternative method for isolating homozygotes of autosomal translocations in the mosquito Culex tarsalis.

An alternative pseudolinkage procedure for isolating homozygotes of autosomal translocations has been developed with the mosquito Culex tarsalis (Coquillet). The first step was to induce a translocation heterozygote in a population that was marked with recessive mutants. Interbred translocation heterozygotes produced translocation homozygotes that were phenotypically different from their translocation heterozygote and normal siblings. Thus, a translocation homozygote line of this species was selected and established in shorter time and with less effort than by prior pseudolinkage procedure.

Selection of a strain of Culex tarsalis highly resistant to infection following ingestion of western equine encephalomyelitis virus.

After prolonged selection, two hybrid strains of Culex tarsalis were evolved that were highly resistant to infection following ingestion of western equine encephalomyelitis virus. These strains were greater than 25,000-fold more resistant than the most susceptible parental strain when fed on viremic chicks. Resistance was associated with a mesenteronal barrier since both refractory and parental strains were equally susceptible to infection by intrathoracic inoculation. Susceptibility was dominant, possibly incompletely dominant, over resistance. Inheritance was probably polyfactorial but this could not be determined with certainty since a small proportion of individuals appeared to become infected by nongenetic mechanisms.

Two sex-linked mutations in Culex tarsalis.

Two sex-linked mutations are described for the Culex tarsalis mosquito. Bleached ocelli (bloc) affects the pigment in the larval and pupal ocelli, and fringe (fr) puts in disarray the costal and vein scales on the adult wing. Their importance is discussed in relation to the basic genetics for this species and the accumulation of multiple-marker stocks needed for the analysis of genetic systems that show potential for control.

The genetics of two new eye color mutants in Culex tarsalis.

Two mutants are described the affect eye pigment in the Culex tarsalis mosquito. The data indicate that carmine eye car, and black eye ble, are each linked to one of the two autosomes. The expression of the two pigment in individuals homozygous for both mutants is unique in that larvae and pupae have car eyes and young adults show both the car and ble phenotypes.