Effect of temperature on development, eclosion, longevity and survivorship of malathion-resistant and malathion-susceptible strain of Culex quinquefasciatus.
Density of vectors and development of resistance against insecticides are two important aspects in the control of vector-borne diseases. Here, effect of temperature on different aspects of development of malathion-resistant and susceptible strains of Culex quinquefasciatus was evaluated in the laboratory. Fourth-instar larvae of C. quinquefasciatus were exposed to 37 degrees C, 39 degrees C, 40 degrees C, and 41 degrees C, and their LT(50) values calculated. The fourth-instar larvae were subjected to heat for 4 h at 39 degrees C and live larvae were reared until the completion of life cycle. The larvae of malathion-resistant strain were more tolerant to heat than the larvae of malathion-susceptible ones. The difference in mortality between 37 degrees C, 39 degrees C, 40 degrees C, and 41 degrees C of both the strains of C. quinquefasciatus were highly significant. Pupation percentage of heat-exposed larvae of both the strains was higher and delayed than the control ones. The percentage of adult emergence from the heat-exposed larvae was significantly lower than the control. The adult female of malathion-resistant strain showed increased longevity when exposed to heat at larval stage but reverse was true in case of malathion-susceptible. The highlights of the study would help in the management of resistance of mosquito vectors in the tropics where variable climatic condition is observed.
Swain
V
V
Department of Zoology, University of Delhi, Delhi, 110007, India. vijaylakshmi.swain@rediffmail.com
Seth
R K
RK
Mohanty
S S
SS
Raghavendra
K
K
D000818:Animals; D003465:Culex / Q000187:drug effects* / Q000254:growth & development*; D006358:Hot Temperature; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D008294:Malathion / Q000494:pharmacology*; D013696:Temperature
D007306:Insecticides; D008294:Malathion