Effect of Pb, Cd and Cu on survival and development of Culex quinquefasciatus (Diptera: Culicidae)

ABSTRACT

The present research aimed to determine the lowest levels of three heavy metals (Pb, Cd and Cu) to which the larvae of Southern House Mosquito, Culex quinquefasciatus are susceptible in water. The study also aimed to investigate the effects of these heavy metals on the development of Cx. quinquefasciatus at concentrations set by Pakistan Environmental Protection Agency (Pak-EPA) as permissible levels for liquid industrial effluents. The 2nd instar larvae of Cx. quinquefasciatus were exposed to different concentrations of Pb, Cd and Cu and their effects on oviposition preference, egg hatching rate and larval development were studied. The LC₅₀ values of Pb, Cd and Cu were 12.6, 6.3 and 2.6 ppm, respectively. Gravid female mosquito adults deposited a significantly lower number of egg rafts in containers containing 0.50 ppm Pb or 1.0 ppm Cu in water. Each of the heavy metals in water resulted in significantly (p < 0.05) lower egg hatching rate, prolonged time to pupation, lower pupation rate, prolonged time to adult emergence, lower adult emergence rate and higher female to male ratio. It is concluded that the 2nd instar larvae of Cx. quinquefasciatus are susceptible to Pak-EPA permissible levels of Pb, Cd and Cu in municipal and liquid industrial effluents.

KEYWORDS:

• Culex quinquefasciatus
• heavy metals
• larval development
• permissible levels
• susceptibility

Acknowledgements

The authors are thankful to Mr Mirza Gul for donating mosquito cages for this research. The authors are also thankful to Mr Afzal Hussain for his help in collection of mosquito larvae from stagnant water at the campus of University of Malakand for establishing laboratory colonies of Cx. quinquefasciatus.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes on contributors

Ikram Ilahi has done a Master in Zoology with specialization in Entomology from University of Peshawar while a PhD in Zoology with specialization in Environmental Toxicology from Islamia College Peshawar. Currently he is working as Associate Professor and Chairman at Department of Zoology, University of Malakand. His research interest is on Medical and Environmental Entomology, Environmental Physiology, and Environmental Toxicology.

Ali Muhammad Yousafzai has done a Master in Zoology from University of Peshawar while a PhD in Zoology with specialization in Environmental Toxicology from University of the Punjab. Currently he is working as Professor and Chairman at Department of Zoology, Islamia College Peshawar. His research interest is on Environmental Toxicology.

Hazrat Ali has done a Master in Chemistry with specialization in Physical Chemistry from University of Peshawar while a PhD in Chemistry with specialization in Environmental Chemistry from University of Malakand. Currently he is working as Associate Professor at Department of Chemistry, University of Malakand. His research interest is on Environmental Chemistry, Ecotoxicology and Applied Ecology.

ORCID

Hazrat Ali http://orcid.org/0000-0002-6822-6925