Abstract:
Ivermectin and spinosad have longevity reducing effects in several insect species, including
disease transmitting mosquitoes after feeding blood contaminated with above toxicants on
hosts. Therefore, this approach could play an enormous role in mosquito control operations by
its use in the female elimination process during mass-rearing, enabling the release of only sterile
males in the context of the sterile insect technique (SIT) and incompatible insect technique (IIT)
with Wolbachia bacterium.
Blood meals of cattle origin were spiked with diffeerenct concentrations (2, 4, 6, 8 and 10 ppm)
of Ivermectin (Ivotec, 1% w/v) and Spinosad (Spinosyn, 12% w/v) and offered to a batch of
adult Ae. aegypti (n = 300) and Ae. albopictus (n = 300) having 1:1 sex ratio in order to obtain
an optimal dose for quick and total female elimination. After 24 hours all remaining females
and males were aspirated out and transferred in to new cages separately. An additional blood
meal with the initially fed concentrations of ivermectin and spinosad was provided after 24
hours, followed by a 48-hour observation of mortality. This experiment was repeated by feeding
cattle blood containing a mixture of ivermectin and spinosad in 1:1 ratio from each
concentration.
Spiked blood with 8 ppm ivermectin and spinosad killed all the fed females of Ae aegypti and
Ae. abopictus within 24 to 48 hours. It was observed that the number of fed females gradually
increased, when decreasing the toxicity in combination of ivermectin and spinosad (1:1) in
blood for both species. Male mortality did not show any significant differences during the study.
Mixed feeding of blood with 8 ppm ivermectin and 8 ppm spinosad have shown as the viable
treatment to eliminate female Ae aegypti and Ae. abopictus from laboratory colonies.
