What physiological changes occur in the gonotrophic cycle of a female mosquito after a blood meal?

What physiological changes occur in the gonotrophic cycle of a female mosquito after a blood meal?

• A. Blood meal directly triggers egg laying without yolk production.
• B. Blood digestion triggers yolk protein production (vitellogenesis), ovaries mature eggs, leading to oviposition after a period.
• C. Blood meal reduces yolk protein production and delays oviposition.
• D. The midgut shortens, increasing flight speed.

Answer: (B)

The main concept is how a blood meal initiates a hormonal and nutritional cascade that drives yolk production and egg maturation in the ovaries, leading to oviposition—this sequence is the gonotrophic cycle. After a blood meal, digestion releases nutrients that travel through the mosquito’s body. These nutrients, along with hormonal signals, stimulate the fat body to synthesize vitellogenin, the major yolk protein. A rise in the hormone 20-hydroxyecdysone after the blood meal promotes vitellogenin gene expression and its uptake into developing oocytes, a process called vitellogenesis. As yolk proteins accumulate, the ovaries mature and eggs become yolk-filled, and, after a period, the female lays the eggs. This explanation fits the correct choice because it describes yolk production following a blood meal and subsequent egg maturation and laying. The other ideas don’t align with how mosquito reproduction works: eggs aren’t laid without yolk production, yolk production isn’t reduced after a blood meal, and changes to the midgut aren’t the mechanism that drives the gonotrophic cycle.

The main concept is how a blood meal initiates a hormonal and nutritional cascade that drives yolk production and egg maturation in the ovaries, leading to oviposition—this sequence is the gonotrophic cycle. After a blood meal, digestion releases nutrients that travel through the mosquito’s body. These nutrients, along with hormonal signals, stimulate the fat body to synthesize vitellogenin, the major yolk protein. A rise in the hormone 20-hydroxyecdysone after the blood meal promotes vitellogenin gene expression and its uptake into developing oocytes, a process called vitellogenesis. As yolk proteins accumulate, the ovaries mature and eggs become yolk-filled, and, after a period, the female lays the eggs. This explanation fits the correct choice because it describes yolk production following a blood meal and subsequent egg maturation and laying. The other ideas don’t align with how mosquito reproduction works: eggs aren’t laid without yolk production, yolk production isn’t reduced after a blood meal, and changes to the midgut aren’t the mechanism that drives the gonotrophic cycle.