PARENT SESSION
Contributed Oral Session 55: Agroecology: Management
Tuesday, August 9, 1:30 PM - 5:00 PM, Meeting Room 513 A, Level 5, Palais des congrès de Montréal

Impact of food supplements on lifespan and carbohydrate nutrient levels in a parasitic phorid fly.

Fadamiro, Henry^*,1, Chen, Li¹, ¹ Department of Entomology & Plant Pathology, Auburn, AL, USA

ABSTRACT- The phorid fly, Pseudacteon tricuspis Borgmeier (Diptera: Phoridae) has been released in many parts of southern United States for biological control of red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). However, little is known about the nutritional ecology and foraging behavior of phorid flies, and the impact of sugar feeding on their lifespan. We investigated the effect of sugar feeding on the longevity of female and male P. tricuspis. Flies fed 25% sucrose continuously throughout their lifespan have greater longevity than completely starved (provided no water and no sugar solution) flies, sugar starved (provided water only) flies, or flies fed sugar solution only on their first day of adult life. There was no significant effect of sex on longevity. P. tricuspis adults are also able to utilize floral nectar from buckwheat and honeydew produced by cotton aphids, suggesting that availability of supplemental sugar sources near its release sites may enhance the efficacy of P. tricuspis as a biological control agent of imported fire ant. We also compared nutrient levels in flies subjected to different diet treatments. Adult P. tricuspis emerge with no gut sugars, and only minimal amounts of body sugars and glycogen. Levels of body sugars and glycogen decline gradually in sugar-starved flies, whereas high levels of these nutrients are maintained in female and male phorid flies feeding sucrose continuously over the observation period. Honeydew-fed phorid flies also show a slight increase in the levels of body sugars. Lipid levels in sugar-fed flies did not differ significantly from levels in newly emerged individuals, suggesting that adult P. tricuspis are capable of converting dietary sucrose to body sugars and glycogen, but not lipids. These results suggest that conservation of naturally occurring sugar sources in the field may promote P. tricuspis lifespan and possibly, its impact as a biological control agent against imported fire ants.

Key words: Imported fire ants, Habitat manipulation, Phorid fly, Food supplements