Plastic residue shortens mosquito lifecycle, facilitates population explosion: Study

In a study done in the waterlogged canals that run through Thiruvananthapuram, a team of researchers revealed that the residues released into water from plastic wastes unravel a chemical environment which facilitate mosquitoes to complete lifecycle in rapid succession than that in water which is devoid of plastic wastes.

The study was done by RV Ayana Gayathri and DA Evans attached to the Zoology Department of the University College, Thiruvananthapuram.

The study pointed out that Bisphenol A, Bisphenol S and Pthalates are identified as major residues released into water from plastic wastes.

"Quantitative estimation of Bisphenol A (BPA) by Gas Chromatography and Mass Spectroscopy revealed that water samples from mosquito breeding sites possess the compound at a concentration of 1 mg/L (1 ppm). At this concentration BPA can shorten the lifecycle span of mosquitoes from 13 days to 10 days," noted the study.

The lifecycle of mosquito is completed in polluted water and has four stages such as egg, larva, pupa and adult mosquito. Female mosquitoes lay eggs four days after blood meal on the surface of water or on floating wet objects.

The study observed that under the atmospheric temperature range of 26 to 31 degrees, eggs hatch out into larvae after 36 hours.

Technically the study found out that in the presence of BPA hatching time is reduced to 18 hours.

Read | Will we be better off without mosquitoes?

Mosquito borne diseases such as malaria, dengue fever, encephalitis, chikungunya and kyasanur forest disease are major health concern to people living in tropical countries.

The equator of the globe gives ample survival chances to mosquitoes through high rain fall, high humidity and elevated temperature and hence population density of mosquitoes is high in these regions compared to temperate regions.

Anthropogenic factors such as disposal of plastic wastes provide additional chances for mosquitoes for successful completion of lifecycle, as these wastes create stagnation.

Thus the present study revealed that rather than providing additional survival chances, the residues released into water from plastic wastes unravel a chemical environment which facilitate mosquitoes to complete lifecycle in rapid succession than that in water which is devoid of plastic wastes.

"During the peak of summer, atmospheric temperature is elevated to a range of 30 to 38 degrees Celsius, meanwhile mosquito lifecycle is completed within 12 days, which is further shortened to 9 days by BPA. Mosquitoes usually complete two lifecycles in a month and presence of BPA in their breeding sites can facilitate completion of lifecycle in a span of 30 days," noted the study.

They said this can create far reaching consequences on mosquito menace and humans are playing a role as their facilitators.