Male Culex Research Articles

Diversity in patterns of coital contact of mosquitoes: A scanning electron microscopic study.

Specimens, representative of each of the major taxa of mosquitoes, were fixed in copula and the external genitalia examined by scanning electron microscopy. The periphery of the basin-like everted aedeagus of Aedus aegypti precisely matches that of the everted atrial membrane of the female. These structures are appressed during coitus and sealed by pressure of the paraprocts, aedeagal pouch and proctiger. When everted, the aedeagus of male Culex pipiens reveals a ridged dome that surrounds the genital opening. This dome seals itself laterally into a gutter formed by pad-like extensions of the female's genital lips and is sealed dorsally by pressure of the aedeagal apodeme. The aedeagus of another culicine species, Wyeomyia smithii, bears the gonopore at the apex of a spined tube. This tube is inserted between the female's genital lips and is sealed within the genital atrium. The aedeagus of the toxorhynchitine species Toxorhynchitis brevipalpus is immobile and is inserted deep within the genital atrium of the female where it is sealed by pressure of the atrial walls. Males of each of these mosquitoes deliver a mixture of semen and sperm to the copulatory bursa of the female. After withdrawal of the aedeagus, sperm is transferred to the spermathecae. In contrast, sperm of Anopheles quadrimaculatus are delivered directly to the spermathecal duct. The tube-like aedeagus is positioned by its leaflets during sperm transfer and is driven deep into the atrium, where a mixture of semen and sperm is ejaculated. The significance of mechanical barriers to mating between species is discussed.

Genetic incompatibility and hybridization studies on two members of the Culex pipiens complex.

No fertile eggs were produced when male Culex pipiens pallens from Hokkaido were crossbred with female Culex pipiens fatigans from Ishigaki, Ryukyu Islands. This genetic incompatibility could be used in an attempt to eradicate the latter, a vector of filariasis, from selected Islands. The reverse cross produced a hybrid, which gave a high egg hatch rate when backcrossed to pallens and a very low rate in the backcross to fatigans.

豚舎付近における3種採集法による蚊季節消長についての検討

A survey on the nature of mosquitoes was made at a pigsty in Kayou Town, Joubou District, Okayama Prefecture. Mosquitoes were collected with three methods i.e. light trap, dry ice-trap, and hand-capture once a week from June 15 to October 15 in 1969. A fluorescent lamp (20 W) was used for the light-trap. A mosquito-net, about 180cm×230cm×190cm in size was used for the dry ice-trap. The light-trap and the dry ice-trap were settled for two and a half hours starting from 30 minutes before sunset. The hand-capture was used to collect resting mosquitoes on the pillars of the pigsty for 30 minutes from 1 hour after sunset. We obtained the following data:1. Culex tritaeniorhynchus were collected most with any method, and then the next Anopheles sinesis, Culex vishnui, Culex pipiens, and Armigeres obturbans. The ratio of Anopheles sinensis to the other species in number, with the dry ice-trap, was smaller than that with the light-trap or the hand-capture.2. In the case of the light-trap, the appearance of Culex tritaeniorhynchus and Anopheles sinensis were influenced by the minimm temperature for the collecting time.3. Male Culex tritaeniorhynchus acts freely when the temperature is above 23°C and female at the lower temperature than that.4. Concerning the resting mosquitoes collected by the hand-capture, it was the season when mosquitoes appeared most that the number of engorged was greater than that of the unengorged. This phenomenon was clear in Anopheles sinnsis than in Culex tritaeniorhynchus.5. Some Culex vishnui were collected, but the number was small and the period was short, so it is not so important as a Japanese encephalitis virus vector.

Feeding habits of male southern house mosquitoes on 32P-labeled and unlabeled plants.

Male Culex pipiens quinquefasciatus Say were able to pick up some type of plant substances from the threeseeded mercury plant, Acalypha spp., and nut grass labeled with 32P. Most of the radioactivity was found in the body of the insect, not on or in the proboscis or legs, indicating ingestion. However, the ingestion of this exudate from these labeled plants was insufficient to sustain the life of the mosquitoes. Of 30 unlabeled plants offered to male mosquitoes, 3 plants, saw palmetto, tetter bush, and Japanese pittosphorum, provided the necessary nutrients for prolonged longevity. Also, honeydew of aphids provided the substances necessary to sustain life for prolonged periods.

Culex Rooti, a New Culex from Panama (Diptera: Culicidae)

On November 24, 1934, a number of mosquito larvae and pupae were collected from ground pools a few miles east of Panama City, R. de P. The mosquitoes found were Anopheles neomacnlipalpiis , Curry, Culex conspirator , Dyar & Knab., C. iolambdis , Dyar, C. pilosus , D. & K., and two male Culex of which no description could be found. Mr. W. H. W. Komp, who has recently had the opportunity to examine the types of the genus Culex in the U. S. National Museum, declared that this is a new species, and also made suggestions concerning the description. I am naming this mosquito in memory of the late Dr. F. M. Root, whose untimely death is deeply mourned by all those who have had the pleasure of knowing him and working with him.