PARENT SESSION
Oral Session 67: Mutualism - Parasitism III: Ants.
Presiding: K Mooney
Wednesday, August 4, 8:00 AM to 11:30 AM, Meeting Room D 135.
Effects of ant-aphid mutualisms on arthropod community strucutre & spread of aphid-vectored viruses.
Cooper, Laura *,1, Murphy, John1, Eubanks, Micky1, 1 Auburn University, Auburn, Alabama, USA
ABSTRACT- Mutualisms may play disproportionately large roles in population dynamics, community ecology, and landscape ecology. We are investigating the effects of a fire ant-aphid mutualism on the population dynamics of non-aphid herbivores, arthropod community structure, and the spread of aphid-vectored plant viruses across landscapes. We investigated the effects of fire ants by manipulating densities of red imported fire ants (Solenopsis invicta) in greenhouse and large-scale field experiments. We found that non-aphid herbivores and natural enemies of aphids were more abundant in tomato fields with suppressed densities of fire ants than in fields with high densities of fire ants. In contrast, aphids were 6 times more abundant in fields with large fire ant populations than in fields with small fire ant populations. These results suggest that fire ants are consuming non-aphid herbivores and predators while protecting honeydew-producing aphids. Fire ants may alter landscape ecology by connecting spatially disjunct plant populations via aphid dispersal by increasing alate (winged, dispersal form of aphid) production, thereby increasing the spread of aphid-vectored viruses within and among plant populations. Aphid-vectored viruses affect a broad range of plant species. These viruses can be devastating for many agricultural crops and can also dramatically reduce the fitness of naturally occurring plants. In a greenhouse experiment, we found that aphids dispersed to neighboring plants significantly more frequently in the presence of fire ants than in no fire ant treatments, suggesting that fire ants increase aphid dispersal. In addition, we found that fire ants altered the production of alate aphids in the field. This research suggests that ant-aphid mutualisms may have intensive effects on community structure and alter the movement of aphid-vectored plant viruses across landscapes.
Key words: aphid-vectored viruses, mutualisms, Red imported fire ants