Articles: Effect of Body Size on Host Seeking and Blood Meal Utilization in Anopheles gambiae sensu stricto (Diptera: Culicidae): the Disadvantage of Being Small

Abstract

The survival, metabolic reserves, and host-seeking response of unfed Anopheles gambiae Giles sensu stricto females of different size classes were investigated from 1 to 6 d after emergence. In addition, the effect of blood meal size and frequency of feeding on the accumulation of metabolic reserves and reproductive development were investigated during the 1st gonotrophic cycle. Large females survived longer and contained significantly more protein, glycogen, and lipid at emergence than did small females. Over 6 d, the host-seeking response of large mosquitoes was greater than that of small ones. There was no gonotrophic development in unfed small females after emergence, whereas < or = 52% of large females developed oocytes to Christophers stage II. One blood meal, given by enema, resulted in gonotrophic development to stage II in small females, whereas only large females matured oocytes to Christophers stage V. In both large and small females, egg development was related to the size of the blood meal, but large females were better able to utilize the meals. Two successive blood meals enhanced the ability of small females to develop eggs. The pregravid condition commonly observed in An. gambiae appears to be determined by insufficient metabolic reserves at emergence, and the probability for small individuals to be pregravid is greater than for large mosquitoes because of the need to build up sufficient energy reserves before gonotrophic development can occur. The consequence of this behavior in relation to malaria transmission is discussed.

Reactive oxygen species detoxification by catalase is a major determinant of fecundity in the mosquito Anopheles gambiae

“…Female mosquitoes were allowed to mate in normal rearing conditions and then were fed on healthy BALB/c mice at 4, 6, or 8 days PE. A single blood meal is usually sufficient for A. gambiae females to produce an egg batch, particularly when larval nutrition and survival is high, resulting in large-size adults (33)(34)(35), as was the case for our colonies. Twenty-four hours PBM, females of each strain were separated into three groups of 10-12 mosquitoes each and were housed in pint-sized cages.…”

Mating activates the heme peroxidase HPX15 in the sperm storage organ to ensure fertility in Anopheles gambiae

“…gambiae females feed and lay eggs multiple times during their lifetime, and may take multiple blood meals even during the same gonotrophic cycle (5,6). Therefore, the reduction in fertility seen in our experimental settings might be highly relevant to wild mosquito populations.…”

“…gambiae females mate a single time in their lives and must therefore preserve the viability of stored sperm for their lifetime in a specialized sperm storage organ, the spermatheca. As replenishment of sperm stores does not occur, multiple pathways must be in place to nourish and protect sperm in storage in the event of physiological stresses, such as repeated blood feedings needed for egg development during multiple gonotrophic cycles (5,6). The maintenance of sperm viability therefore is a crucial stage in the mosquito life cycle that could be targeted to reduce the fertility of field malaria-transmitting populations.…”

Effect of food types on competitive interaction between Aedes aegypti (LINNAEUS, 1762) and Ae. albopictus (SKUSE, 1894) (Diptera, Culicidae): a proximate level appraisal

“…After eclosion to the adult stage, females with greater energy reserves can utilize them for survival and flight performance; moreover, a substantial proportion can be used to initiate oogenesis if the energy reserves have a threshold lipid content (BRIEGEL & HӦRLER 1993). But smaller females, having lower energy reserves, require blood meals for their survival at a very early part of the adult stage; as a result, multiple feeding in the early days of the adult stage enhance their potential for disease transmission (TAKKEN et al 1998). The consequence of interspecific competition between the two species may therefore have different effects in the adults and thus roles in disease transmission.…”