Sucrose intake and percent effort by the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae)

Abstract:
Sucrose intake rate and percent effort (a variable which describes the amount of energy an insect uses to feed on a liquid) was quantified for Solenopsis invicta Buren. In other words, how much energy does the insect gain and how much energy is lost in the feeding event? In order to understand this more closely, two variables important in liquid feeding, viscosity and sucrose concentration, were controlled independently. Three series of solutions were prepared to test these variables separately: base series (BS, no alteration to sucrose solutions), constant viscosity series (CVS, multiple sucrose concentrations all with the same viscosity as a 50% sucrose solution), and constant concentration series (CCS, 30% sucrose solutions with increasing viscosities). Viscosity seemed to affect the solution intake rate of S. invicta more than sucrose concentration of the solution. Percent effort increased with increasing sucrose concentration in the BS and CCS ranging from 17.53 to 95.8% and 40.09 to 100%; however, the sucrose intake rate decreased dramatically in the CCS to less than 2 µg sucrose/min at the highest viscosity level. Levels of solution and sucrose intake rate and percent effort were stable. This information on how viscosity and sucrose concentration affect feeding behavior in ants may assist in future formulations of baits for the control of these pests.