Mating Behavior and Gonotrophic Cycle in Anopheles gambiae Complex and their Significance in Vector Competence and Malaria Vector Control

Abstract

Anopheles gambiae complex mosquitoes comprise different morphologically identical species and the most medically important malaria vectors in Africa. Understanding An. gambiae complex mosquitoes’ mating behaviour is a clue for prevention and control of malaria. The factors affecting the mating behavior of An. gambiae complex are age, body size, food finding, type of food, host availability and environmental temperature. An. gambiae complex passes through different and unique mating strategies. The fundamental mechanisms underlying mating behavior of An. gambiae complex are male aggregation before copulation which is called swarming, finding female and insemination. Male in the swarm detects the wing beat of female with which he mates by auditory system. The wing beat frequencies of opposite sex of the same genetic form simply harmonize indicating possible hybridization while that of different genetic forms do not harmonize. The successive mating behavior of female An. gambiae mosquitoes includes, locating a male among the swarm for cupola, friend selection and storage of sperm. Successful female An. gambiae complex mosquitoes mating is accomplished by host seeking, blood feeding and digestion, egg development and oviposition. The sequential process of host finding and blood feeding followed by blood digestion and simultaneously egg maturation and accomplished by searching of oviposition site and oviposition is referred to as gonotrophic cycle. The time period between two successive blood feedings or two successive ovipositions is said to be gonotrophic period. The length of gonotrophic period depends on temperature, number of previous gonotrophic cycle, host and breeding site availability. In addition to population net reproduction of the colony, gonotrophic cycle is also used to estimate female mosquitoes’ age by determining the parity. Finally, understandings of mating behavior and gonotrophic cycle of An. gambiae complex mosquitoes help in malaria vector control strategies and their vector competence.

Gonotrophic stages of Anopheles gambiae and Culex quinquefasciatus and their relationships with climatic conditions in selected school dormitories in Benin City, Nigeria

“…was recorded in Ikpoba Okha LGA in the rainy season month of June (41.7±11.8 %). Relating this finding with the number of eggs a female mosquito is able to lay during oviposition which is up to 200 (Service, 2012;Fereda, 2022) is something to be concerned with -as this could translate to geometric increase in the vector population and disease burden thereafter. Months that had no record of blood digestion stage may have been periods when the dormitory dwellers' were on vacation or the mosquitoes caught were all males that are not used for blood digestion studies.…”

“…After emergence from their pupal stage of development, adult female mosquitoes seek out suitable hosts either animal or human to obtain blood meals necessary for their energy requirement and most importantly the requisite nutrient to aid production of their eggs (Service, 2012;Fereda, 2022). Blood in the abdominal region of blood fed female mosquitoes begin to digest immediately after ingestion; a process that occurs concurrently as their ovaries' development (Charlwood et al, 2000).…”

“…During the process of digestion, blood is actively used to produce eggs. This is shown in the gradual change in the appearance of a completely reddish abdomen of a freshly fed female mosquito compared to an entirely whitish abdomen of a gravid female mosquito with fully developed eggs (Service, 2012;Fereda, 2022). Mosquito-borne diseases are transmitted essentially during blood feeding by the infective mosquito vectors (Lehane, 2005;Scott and Takken, 2012;Service, 2012).…”

“…Also, the presence and number of unfed mosquitoes in the population could be indicative of the existence of nearby viable larval breeding sites and lastly, the occurrence of all the stages could well imply a dearth of effective mosquito vector control tool that targets the freshly fed, half gravid and gravid as they rest and the unfed as they seek suitable host to obtain blood meals.. Weather conditions such as temperature (Maiga et al, 2012), rainfall (Fereda, 2022) and humidity (WHO, 1975) do affect the progression and duration of blood digestion in mosquitoes. This synchronously impacts on their disease transmission risk.…”

“…This synchronously impacts on their disease transmission risk. For instance, the faster rate of digestion of blood meal by malaria mosquito vectors during warmer temperature periods will consequently result in increased frequency of blood feeding and ultimately increased risk of malaria transmission (Fereda, 2022).…”