Foraging Activity and Food Preferences of the Odorous House Ant (Tapinoma sessile Say) (Hymenoptera: Formicidae)

Foraging activity and food preferences of odorous house ants (Tapinoma sessile (SAY)) were investigated in both the field and laboratory. Foraging activity was examined in the field from April to September 2001 by attracting T. sessile to feeding stations containing a 20% sucrose solution. Ant foraging activity was recorded over a twenty-four hour period along with ambient temperature to examine possible correlations with ant activity patterns. Results indicate that foraging activity may be influenced by both time and temperature. In April and May when temperatures dropped below approximately 10 C, little or no foraging activity was observed. However, in the summer when temperatures were generally higher, foraging activity was greater during relatively cooler times of the day and night. Under laboratory conditions, T. sessile was attracted to feeding stations and foraged throughout the day and night at a constant temperature of approximately 25 C. Evaluations of seasonal food preferences using carbohydrate, protein and lipid samples were also conducted throughout the spring and summer. Results indicated no seasonal shifts in food preference in foraging ants; T sessile consistently preferred sugar and protein rewards over lipids.

Macronutrient choice assays were preformed on T. sessile to evaluate specific food preferences. Several different carbohydrates, proteins, lipids and salts were tested in both liquid and gel formulation. Results indicated significantly greater consumption of sucrose solution at a concentration of approximately 20% compared with other sugars tested (fructose, glucose, trehalose and maltose). In addition, strong feeding responses were observed to both casein hydrolysate and lactalbumin hydrolysate at a 5% concentration. The addition of NaCl to 15% sucrose gel samples also enhanced feeding responses. Lipids were generally ignored by T. sessile and in most cases decreased consumption of the sample. Various amino acids did not enhance feeding responses and were similar to water.