The seasonal reproductive status of tawny crazy ant queens (Hymenoptera: Formicidae) in Florida

Authors: Oi, David

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2021
Publication Date: 6/5/2021
Citation: Oi, D.H. 2021. The seasonal reproductive status of tawny crazy ant queens (Hymenoptera: Formicidae) in Florida. Florida Entomologist. 104(2):140-142. https://doi.org/10.1653/024.104.0211.
DOI: https://doi.org/10.1653/024.104.0211

Interpretive Summary: The tawny crazy ant is an invasive ant that is spreading in the southern USA. The control of invasive ants requires an understanding of their biology to develop efficient methods of control such as strategically applying ant baits to eliminate queen ants which are vital to the survival of ant colonies. Previous research indicated that in the winter, queens congregated together in nests, but eggs and immature ants were not being produced. Monthly examinations of the ovaries of tawny crazy ant queens revealed that eggs were present in queens throughout the year and over 80% of the queens had mated. These results indicated that despite having fertilized eggs, egg laying was not occurring perhaps because in the winter there is less foraging for food by the colony and limited feeding by queens. This suggests that the strategy of baiting queens consolidated in winter nest sites may not be efficient and and alternative strategies, such as applying bait when egg laying starts, should be evaluated.

Technical Abstract: The tawny crazy ant, Nylanderia fulva (Mayr) (Hymenoptera: Formicidae), is an invasive ant that is spreading in the southern USA. The control of invasive ants requires an understanding of their biology to implement measures of suppression such as strategically applying ant baits to eliminate queens. N. fulva queens were collected monthly in north central Florida and dissected to determine their seasonal reproductive status. The percentages of queens with >50 eggs increased from 26% in winter to a peak of 68% in summer, while queens with less than 10 eggs was below 20% per season. Thus, eggs were present in queens throughout the year. Likewise, mated queens were present in each season, with 81 – 92% of the queens inseminated. While queens were fecund year-round, the lack of brood production in winter may indicate a curtailment of colony foraging to feed queens and larvae which could impede the strategy of baiting queens consolidated in winter nest sites.