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United States Department of Agriculture

Agricultural Research Service


item Vail, Karen
item Williams, David

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 2/28/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Pharaoh ant Monomorium pharaonis (L.), nest are difficult to locate without causing damage to the structure. Buildings were constructed with modifications (hinged paneling and attic hatches) to allow observation of hidden nests. Large Pharaoh ant colonies ranging from 32,000 to 74,000 workers per colony were introduced into these buildings. Buildings were inspected every 2-4 weeks to determine the following: (1) the size and composition of satellite colonies, (2) Pharaoh ant nest sites indoor and outdoors, and (3) the effects of imported fire ants, on Pharaoh ant nest composition and location. Fire ants severely limited Pharaoh ant colonization and establishment in some of the buildings. The indoor presence of fire ants at food cups ranged from 9-72% of the observation days. On several occasions, fire ants caused the formation of small, ephemeral nests on the paneling facing the interior of the room. Fire ants decreased the biomass, brood, number of females, number of workers per colony, and the mean number of nest per building. Several Pharaoh ant nests were located in the soil under the slab of the buildings. Pharaoh ant colonies would persist outdoors until they encountered fire ants. Fire ants also caused nests to be located further from the food provided. Pharaoh ants will return to a previous nest site after a disturbance or they will occupy previously used nest sites. Fire ants also reduced the percentage of nest sites previously occupied.

Last Modified: 06/22/2017
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