Environmental Entomology (1996) 25, 859-866

Camille E. Landry and Sherman A. Phillips Jr. (1996)
Potential of ice-nucleating active bacteria for management of the red imported fire ant (Hymenoptera: Formicidae)
Environmental Entomology 25 (4), 859-866
Abstract: Overwintering strategies are important in the survival of insects, and one such strategy involves the regulation of temperatures at which they freeze. Although all insects exhibit some degree of cold tolerance, they can generally be classified as either freeze tolerant or intolerant. Many freeze-intolerant insects seasonally depress their supercooling points, thereby increasing their cold-hardiness in preparation for winter. This study was conducted to assess the influence of cold acclimation on the supercooling ability of the red imported fire ant, Solenopsis invicta Buren. Colonies were consecutively exposed for 7 d each to decreasing temperatures of 10, 5, and 0°C. At the end of each 7-d interval, a thermocouple probe was used to determine whole body supercooling points of randomly selected worker ants from each colony. Analysis of variance indicated a significant difference among supercooling points and acclimation temperatures. In the 1970s, ice-nucleating active bacteria, a new category of biological ice-nucleators, were discovered among other epiphytic bacteria living on the surface of plants. These ice-nucleating bacteria have the capacity to catalyze ice formation at -1 to -2°C. We investigated the effects of topical mist application of the ice-nucleating active bacteria Pseudomonas syringae on the freezing point of minor and media worker ants. Treatment with P. syringae increased the temperature at which the red imported fire ant froze, thus decreasing its supercooling ability.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Solenopsis invicta
Pseudomonas syringae (entomopathogen)	Solenopsis invicta