Wadriann Horne, 2017

Howard University

Determining the impact of conopid parasitoid flies on bumblebee longevity

Conopid flies are parasitic insects that kill their bumble bee host in order to mature into adults. Because they can be very abundant, infecting up to 80% of the bumble bee population, they could have substantial impact on bumble bee longevity. However, they take 10 -14 days to kill their host, so they would only hurt their host if the host lived long enough to get killed by the conopid. In order to understand how much conopids reduce host lifespan in free-foraging situations (subject to other mortality risks), we used a product to clear conopid fly infection. By doing this, we can determine how long bumblebees can live in field conditions without the influence of conopid flies. This information will tell us how much conopid flies influence the rate of mortality in bumblebees. Cyromazine was the product used to clear conopid infections. Cyromazine is an insect growth regulator used to control fly outbreaks in aquaria. There is preliminary data confirming that cyromazine may help reduce bee death from conopid flies, but because this product is an insect growth regulator, it cannot be placed in a colony of bees for fear it will kill the larval bees in the colony as well as larval flies in bees. This is why it must be given to only the adult bees and is also why the bees receiving the cyromazine treatment must be extracted from the colony to receive treatment.

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