Tung Grayson A, Fonseca Dina M
Center for Vector Biology, Rutgers University, New Brunswick, New Jersey, USA.
Arch Insect Biochem Physiol. 2025 May;119(1):e70066. doi: 10.1002/arch.70066.
Blood avidity in female mosquitoes has been shown to be regulated by cycles of hormone production that determine both egg development and distinct behaviors. Specifically, juvenile hormone (JH) drives early egg development until a bloodmeal is acquired, and JH titers are positively correlated with active host seeking and blood feeding behaviors. After a bloodmeal, JH levels fall, and female mosquitoes become refractory to host seeking and biting. While JH analogs (JHAs) are commonly used as larvicides for mosquito control, the effects of these compounds on adult mosquitoes are not well understood. If JH levels are directly implicated in blood acquisition, adult exposure to JHAs might cause nonbiting female mosquitoes to take a blood meal. To test this hypothesis, in laboratory experiments we exposed gravid Culex quinquefasciatus mosquitoes to s-hydroprene, a JHA, both through direct topical application and a simulated environmental exposure. We found a significant increase in the likelihood of gravid Cx. quinquefasciatus taking a bloodmeal after exposure to JHAs at levels we hypothesize they may encounter in the field. We also measured the fertility of females that had taken a second bloodmeal while gravid and found a significant negative effect on both the number and hatch rate of eggs. Our results support the expectation that JH levels regulate female blood feeding behaviors. They also suggest that application of JHAs for larval control can unintentionally lead to additional blood feeding events per gonotrophic cycle, with potential increases in the transmission of disease agents.
雌性蚊子的血液嗜性已被证明受激素产生周期的调节，这些周期决定了卵子发育和不同行为。具体而言，保幼激素（JH）驱动早期卵子发育，直至获取血餐，并且JH滴度与积极寻找宿主和取食血液的行为呈正相关。在摄取血餐之后，JH水平下降，雌性蚊子对寻找宿主和叮咬变得不应答。虽然JH类似物（JHAs）通常用作控制蚊子的杀幼虫剂，但这些化合物对成年蚊子的影响尚未得到充分了解。如果JH水平直接与获取血液有关，那么成年蚊子接触JHAs可能会导致不叮咬的雌性蚊子取食血液。为了验证这一假设，在实验室实验中，我们通过直接局部应用和模拟环境暴露，使妊娠的致倦库蚊接触一种JHAs，即烯虫酯。我们发现，妊娠的致倦库蚊在接触我们假设它们在野外可能遇到的水平的JHAs后，取食血餐的可能性显著增加。我们还测量了妊娠时摄取第二顿血餐的雌性蚊子的繁殖力，发现对卵子的数量和孵化率均有显著的负面影响。我们的结果支持了JH水平调节雌性取食血液行为这一预期。它们还表明，应用JHAs进行幼虫控制可能会无意中导致每个生殖营养周期出现额外的取食血液事件，并可能增加病原体的传播。
