D3175: The effect of ant-produced compounds on microbes

Sociality in insects is linked to efficient, multi-generational brood care, enhanced foraging, and protection against predators through a large number of constituents. Although beneficial, sociality involves crowded conditions that favor quick introduction and transmission of pathogens. The ability for animals that live in group settings to detect and fight potential outbreaks is an essential adaptation for social insects, as evolution selects for the entire colony and not the individual members.

Many ants (Hymenoptera: Formicidae) have evolved chemical defenses to combat viral, bacterial, and fungal infections. Some of these compounds are extremely specialized against certain pathogens, while others are general and serve multiple purposes. Examples include the piperidine venom alkaloids and cuticular hydrocarbons produced by the Red Imported Fire Ant – RIFA (Solenopsis invicta Buren).

We isolated RIFA alkaloids and hydrocarbons through a hexane and water extraction. The solution containing alkaloids and hydrocarbons was pipetted at different quantities onto circular discs. Plates were sprayed with a bacterial suspension of either Bacillus thuringiensis or Bradyrhizobium spp. or with a fungal suspension of Beauveria or Metarrhizium.

The combined effects of the venom alkaloids and cuticular hydrocarbons inhibited Bt, Bradyrhizobium, and Beauveria growth. Further experiments are planned with other microbes.