Professor Vanderbilt University Nashville, Tennessee
Insects mount a multifaceted immune response to infection. A key humoral immune response is melanization, which is a biochemical cascade that deposits melanin molecules on the surface of pathogens in a manner that encases and isolates them. The strength of the melanization response is altered by both insect age and by environmental temperature. Although there is some understanding of the independent effects of temperature and age on melanization, how these two factors interact to shape this immune response is unknown. Here, we investigated how temperature, adult age, and their interaction alter the melanization immune response in the African malaria mosquito, Anopheles gambiae. We reared mosquitoes at 27ºC, 30ºC, and 32ºC and evaluated the melanization potential of hemolymph from adult females at each temperature in four age groups (1-day, 5-day, 10-day, and 15-day-old adults), each under four immune treatments (naïve, injured, E. coli infected, and M. luteus infected). Preliminary data suggest that warmer temperatures and older ages individually reduce the melanization potential of mosquitoes. Overall, the data suggest that temperature and age interact to alter melanization, with warmer temperatures accelerating the age-dependent decline in the melanization immune response.