Impact of small variations in temperature and humidity on the reproductive activity and survival of Aedes aegypti (Diptera, Culicidae)
Autor(es): de Almeida Costa, E. A. P.; de Mendonca Santos, E. M.; Correia, J. C.; de Albuquerque, C. M. R.
Resumo: In short space of time increase in temperature and rainfall can affect vector populations and, consequently, the diseases for them transmitted. The present study analyzed the effect of small temperature and humidity variations on the fecundity, fertility and survival of Aedes aegypti. These parameters were analyzed using individual females at temperatures ranging from 23 to 27 C (mean 25 C); 28 to 32 C (mean 30 C) and 33 to 37 C (mean 35 C) associated to 60c8% and 80c6% relative humidity. Females responded to an increase in temperature by reducing egg production, oviposition time and changing oviposition patterns. At 25 C and 80% relative humidity, females survived two-fold more and produced 40% more eggs when compared to those kept at 35 C and 80% relative humidity. However, in 45% of females kept at 35 C and 60% relative humidity oviposition was inhibited and only 15% females laid more than 100 eggs, suggesting that the intensity of the temperature effect was influenced by humidity. Gradual reductions in egg fertility at 60% relative humidity were observed with the increase in temperature, although such effect was not found in the 80% relative humidity at 25 C and 30 C. These results suggest that the reduction in population densities recorded in tropical areas during seasons when temperatures reach over 35 C is likely to be strongly influenced by temperature and humidity, with a negative effect on several aspects of mosquito biology.Original Abstract: Em curto espaco de tempo, um aumento na temperatura e precipitacao pode afetar a populacao de vetores e consequeentemente, as doencas por eles transmitidas. Nesse estudo, analisou-se o efeito de pequenas variacoes na temperatura e umidade, sobre feeundidade, fertilidade e sobrevivencia de Aedes aegypti. Esses parametros foram investigados usando-se femeas individuals nas temperaturas: 23-27 C (media 25 C), 28-32 C (media 30 C) e 33-37 C (media 35 C) associada a umidade relativa: 60 c 8% e 80 c 6%. As femeas responderam ao aumento da temperatura com reducao na producao de ovos, tempo de oviposicao e mudanca nos padroes de postura. A 25 C e 80%, femeas sobreviveram duas vezes mais e produziram 40% mais ovos, que aquelas mantidas a 35 C e 80%. No entanto, nos grupos a 35 C e 60% a postura foi inibida em 45% das femeas e apenas 15% puseram mais de 100 ovos, sugerindo que a intensidade do efeito da temperatura seja influenciado pela umidade. Reducoes graduais na fertilidade a 60% de umidade relativa foram observadas com o aumento da temperatura, embora esse efeito nao tenha sido registrado na umidade de 80%, nas temperaturas de 25 C e 30 C. Esses resultados sugerem que a reducao na densidade populacional nas zonas tropicais durante estacoes, em que a temperatura se eleva acima de 35 C pode ser fortemente influenciada pela interacao temperatura e umidade, afetando negativamente diversos aspectos da biologia do mosquito.
Palavras-Chave: Temperature effects; Relative humidity; Fertility; Population density; Humidity; Oviposition; Aquatic insects; Disease transmission; Abiotic factors; Fecundity; Rainfall; Vectors; Survival; Egg production; Aedes aegypti; Culicidae; Diptera
Imprenta: Revista Brasileira de Entomologia, v. 54, n. 3, p. 488-493, 2010.
Descritores: Aedes aegypti - Transmission ; Aedes aegypti - Dengue ;
Data de publicação: 2010
