Aggregation of mosquitoes on black colour

摘要

Mosquitoes are the nuisance creatures for human being all over the world, as they are the causal agents for spreading various fatal diseases in the human population. Mosquitoes are said to be colour-blind, but, generally it is being observed that in the evening, they aggregate over the head of human beings with black hairs, black cars, and black clothes also. To study, whether there is any relation between the colour and aggregation of mosquitoes, an experiment was designed. Black, blue, green, red, white, orange, yellow, violet, and pink colour’s chambers were used. The used colours have the wave length as; viz. black (0 nm) blue (450-495nm), green (495-570nm), red (620-750nm), white (400 -700 nm), orange (590-620 nm), yellow (570–590 nm), violet (350-450 nm), and pink (0 nm), colours were used as attractant to observe the maximum and minimum attraction of mosquitoes on different colours. The species of Culex and Anopheles mosquitoes were selected for present experiment. Large number of Culex and Anopheles mosquitoes was collected from field by aspirator, brought alive to laboratory in polythene bags, sorted out separately and specific number was released in the central chamber. Two trials were made with 500 10 and 600 10 mosquitoes. In first observation, out of the 500 10 mosquitoes, 465 2 were found to be aggregated on black colour, on blue and green 10 1and 15 2 respectively, while other colours; red, white, orange yellow, violet and pink had no aggregation of mosquitoes. The second observation also showed that out of 600 10 mosquitoes, 565 5 were reported on black colour, while on blue and green colour 20 2, 14 2 respectively, no mosquito were found on the other colours, except the white having a single mosquito only. Which perception stimulates, the olfactory, visual or sensory organs helping in this behaviour? It needs further extensive investigations.