The Assessment of Morphometric Variation of Aedes aegypti Larvae with the Seasonal Environment Temperature Inversion in Selected Areas of Lahore, Pakistan

Abstract

| Temperature is one of the critical abiotic environmental factors that can influence biological and physiological processes, including mobility, development, and reproduction in poikilotherms. Due to the medical importance of Aedes aegypti as a vector of several medically important pathogens, evaluating the body length variation of Aedes aegypti larvae with the changing seasonal temperature is important. The study was conducted to observe the difference in body size and different body structures of Ae. aegypti larvae in two seasons, i.e., southwest monsoon (June through September) and retreating monsoon (October and November). The fourth instar larvae were collected from areas of district Lahore. The collected larvae were preserved in formalin and transported to the laboratory of the Department of Environmental Science and Engineering at the Government College University Faisalabad for further analysis. The larval morphological measurements were carried out using a stereomicroscope, which included changes in head length and width, thoracic length and width, abdominal length and width, and total length of the larva. Every month, the fourth instar larvae (n=36) were investigated for body size measurement. The results showed that low temperatures of breeding water significantly increase (P≤0.05) the body size, head, thorax and abdomen of larvae. The results convinced that temperature inversion affects the immature development stages of Ae. aegypti . This study concluded that, Ae. aegypti larvae’s body size depends upon seasonal temperature inversion in the breeding water. These findings can help in predicting the variation in the development rate of Ae. aegypti larvae under different seasonal temperatures.