Sugar and Multivitamin Diet Effects on The Longevity and Mating Capacity of Laboratory-Reared Male Anopheline Mosquitoes.

Successful mating by male mosquitoes is dependent on several factors, with sugar feeding being particularly important. The effect of ingested vitamins on adult male mosquitoes is poorly understood. This laboratory study used 3 anopheline species, Anopheles campestris, An. dirus, and An. sawadwongporni, to study the effect of sugar and vitamins on male longevity, copulation, and fecundity. Males were fed 1 of 5 diets containing different combinations of sugar and vitamins: 10% glucose, 10% sucrose, 10% multivitamin syrup, 10% multivitamin syrup + 10% glucose, and 10% multivitamin syrup + 10% sucrose. The longevity of males was measured for a period of 15 days. Forced mating was used to simulate copulation, and fecundity was measured by counting the number of eggs oviposited and the hatch rate of larvae. The longevity of An. campestris and An. dirus was greatest when fed a diet of 10% multivitamin syrup + 10% glucose, and the longevity of An. sawadwongporni was greatest when fed a diet of 10% multivitamin syrup + 10% sucrose. The 1st mating routinely produced the most viable eggs when males were mated with several females. The diet of 10% multivitamin syrup + 10% sucrose produced numerically greater egg production and larval emergence for all 3 species, although this was not always statistically significant due to variability and small sample size. These results indicate that the addition of multivitamin syrup to sucrose may produce healthier and more fit male anophelines. This has potential implications for increasing insectary operations and improving the fitness of laboratory-reared male mosquitoes that will be released for mosquito and disease-pathogen control studies.

The relationship between wing length, blood meal volume, and fecundity for seven colonies of Anopheles species housed at the Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.

Established colonies of Anopheles campestris, Anopheles cracens, Anopheles dirus, Anopheles kleini, Anopheles minimus, Anopheles sawadwongporni, and Anopheles sinensis are maintained at the Armed Forces Research Institute of Medical Sciences (AFRIMS). Females were provided blood meals on human blood containing citrate as an anticoagulant using an artificial membrane feeder. The mean wing length, used as an estimate of body size, for each species was compared to blood-feeding duration (time), blood meal volume, and numbers of eggs oviposited. Except for An. campestris and An. cracens, there were significant interspecies differences in wing length. The mean blood meal volumes (mm(3)) of An. kleini and An. sinensis were significantly higher than the other 5 species. For all species, the ratios of unfed females weights/blood meal volumes were similar (range: 0.76-0.88), except for An. kleini (1.08) and An. cracens (0.52), that were significantly higher and lower, respectively. Adult females were allowed to feed undisturbed for 1, 3, and 5min intervals before blood feeding was interrupted. Except for An. campestris and An. sawadwongporni, the number of eggs oviposited were significantly higher for females that fed for 3min when compared to those that only fed for 1min. This information is critical to better understand the biology of colonized Anopheles spp. and their role in the transmission of malaria parasites as they relate to the relative size of adult females, mean volumes of blood of engorged females for each of the anopheline species, and the effect of blood feeding duration on specific blood meal volumes and fecundity.

Factors influencing the feeding response of laboratory-reared Aedes aegypti.

We evaluated the effects of membrane surface area (cm2), female density, and container/cage size on feeding response in laboratory-reared Aedes aegypti. Female density did not affect feeding rates at low surface areas, but higher density did significantly increase feeding as surface area increased. Females in large, cloth cages fed less compared to those in large, plastic cups. The rate of feeding was higher when using live, anesthetized mice versus a membrane feeding system. The AFRIMS Insectary will continue to look for innovative ways to improve our membrane feeding system.

Colonization and maintenance of Anopheles kleini and Anopheles sinensis from the Republic of Korea.

Colonization of members of the Anopheles Hyrcanus Group is required to facilitate a better understanding of their roles in the epidemiology, vector competence, transmission potential, and maintenance of vivax malaria in the Republic of Korea (ROK). A total of 158 resting blood-fed wild caught Anopheles species were collected on August 26, 2011 at Tongilchon, near the demilitarized zone, in the ROK and shipped on August 28, 2011 to the Entomology Department, Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. Four of the 5 species of the Anopheles Hyrcanus Group (Anopheles kleini, An. sinensis, An. pullus, and An. belenrae) were identified by polymerase chain reaction. Eggs were obtained from parent populations, and F, progeny provided blood meals using membrane feeding techniques. The mean numbers of eggs/female for An. sinensis and An. kleini were 157 and 146, respectively. Membrane blood feeding rates for An. sinensis (90.6%) and An. kleini (89.0%) were similar for F1-F30 generations. Colonies of An. kleini and An. sinensis were established by force mating techniques and maintained by the Insectary Section, Entomology Department, AFRIMS, to date. This is the 1st report of successful laboratory colonization of An. kleini collected from a vivax malaria high-risk area in the ROK.

Maintenance of mosquito vectors: effects of blood source on feeding, survival, fecundity, and egg hatching rates.

Artificial membrane-feeding techniques have replaced direct feeding on animals for the maintenance of malaria and arbovirus vectors in many laboratories. Membrane feeding facilitates controlled experimentation of pathogen transmission during mosquito feeding. Sheep blood is commonly used due to its availability and low cost. We evaluated the impact of blood source (human, guinea pig, sheep, and hamster via direct feeding) on feeding rates, adult survival, fecundity, hatching rates, and developmental times for five species of laboratory-colonized mosquitoes (Anopheles dirus, An. cracens, An. minimus, An. sawadwongporni, and Ae. aegypti). We found that feeding rates differ among blood sources within mosquito species. Survival, fecundity, and hatching rates were lower in all Anopheles species and Ae. aegypti after membrane feeding on sheep blood. Survival rates seven days post-feeding on sheep blood were significantly lower (P<0.05) for An. dirus (84.2%), An. minimus (67.2%), An. sawadwongporni (51.5%), and An. cracens (35.5%) relative to other blood sources. An. minimus and An. sawadwongporni laid no eggs by seven days post-feeding with sheep blood, while An. dirus and An. cracens produced significantly fewer numbers of eggs and demonstrated significantly lower hatching rates relative to what was observed with the other blood sources. These findings support the conclusion that sheep blood is not a suitable blood source for laboratory rearing of Anopheles spp.