University of Florida, Gainesville, Florida, senior, major: Entomology

Mentor: David Oi

Transovarial Transmission, Queen Weight, and Brood Development in Vairimorpha invictae infected Fire Ant Colonies

Abstract:  Vairimorpha invictae is an entomopathogen of the red imported fire ant, Solenopsis invicta and is currently being researched as a potential biological control agent. Five queens from an uninfected polygyne S. invicta colony and five queens from V. invictae positive colonies were isolated for 48 hrs with = 20 uninfected callow workers. The uninfected queens weighed 0.0118 grams and laid approximately 500 eggs per queen. Queens from V. invictae infected colonies weighed 0.0079 grams and produced approximately 75 eggs per queen. At the conclusion of the 24 day study, eggs from only one V. invictae infected colony queen developed into larvae. A second study added uninfected 4th instar larvae along with the queens and callows. Uninfected queens weighed 0.0153 grams and laid approximately 700 eggs per queen while queens from V. invictae colonies weighed 0.0096 grams and laid approximately 50-75 eggs per queen. After 15 days, 60 and 30% of the uninfected and V. invictae replicates contained brood, respectively. V. invictae was not detected by PCR in any of the surviving brood, thus transovarial transmission was not evident in this study.

"Say cheese!" Melissa Oliver at dissecting scope.

Melissa counting fire ant larvae.

Melissa meticulously separating larval instars of fire ants.