Survival of boll weevil (Coleoptera: Curculionidae) adults after feeding on pollens from various sources

Authors: Greenberg, Shoil; Jones, Gretchen; Eischen, Frank; Coleman, Randy; Adamczyk, John; LIU, T.X - TAES A&M UNIV-WESLACO,TX.; SETAMOU, MAMOUDOU - CITRUS CENTER,A&M UNIV.

Submitted to: Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2007
Publication Date: 11/10/2007
Citation: Greenberg, S.M., Jones, G.D., Eischen, F.A., Coleman, R.J., Adamczyk Jr, J.J., Liu, T., Setamou, M. 2007. Survival of boll weevil (Coleoptera: Curculionidae) adults after feeding on pollens from various sources. Insect Science. 14:503-510.

Interpretive Summary: The boll weevil overwinters in the southern United States in the adult stage. Survival of overwintering boll weevils is a critical determinant in the severity of infestation in the subsequent cotton season and is a principal element in the present area-wide eradication programs. Alternative foraging resources play a significant role in adult boll weevil survival, especially during cotton free periods. Boll weevils are primarily a pollen feeding insect. Plant pollens may provide energy and nutrients that increase boll weevil survival during the absence of cultivated cotton. But effects of alternative foraging resources on overwintering boll weevils have not been thoroughly investigated. Boll weevils are polyphagous pollen feeders and actively feed on pollen from a diverse assemblage of plant species. Boll weevil ingesting and digestion of pollen may be one of the principal evolved survival mechanisms in fall and winter of the Lower Rio Grande Valley of Texas when cotton is not available. This finding is important in understanding how to control and eradicate this pest.

Technical Abstract: The survivablilty of overwintering boll weevils, Anthonomus grandis grandis (Boheman), on non-cotton hosts during extended periods of relatively mild climatic conditions in the Lower Rio Grande Valley (LRGV) of Texas was examined from 2001 through 2006. The success of the Boll Weevil Eradication Program, which was re-introduced in the LRGV in 2005, will depend on controlling overwintering boll weevil populations in a subtropical environment. This study was conducted in the laboratory with boll weevils captured in pheromone traps from September through March. The number of boll weevils captured per trap declined significantly from the postharvest period to the beginning of the spring (3.5 – 4.2 fold). The proportion of trapped males versus females did not differ significantly. Approximately 70.5% of boll weevils captured in September weighed between 10.1 and 20.0 mg while 77.3% captured in October weighed between 5.1 and 15.0 mg. Boll Weevils captured in November through January (82.9%) weighed less than 10.0 mg. The boll weevil is a polyphagous pollen feeder and this may be one of the principal evolved survival mechanisms during fall and winter when cotton is not available. In the laboratory, boll weevils were fed different plant pollens until death. Our data shows that the highest longevity were when boll weevils were fed almond or mixed pollens (mean 72.6 d and 69.2 d, respectively), and lowest when they fed on citrus pollen or a non-food source (mean 9.7 d or 7.4 d, respectively). The highest survival of boll weevils also was on almond and mixed pollens (88.0-97.6% after 1st 10 d feeding, 78.0-90.8% after 3rd 10 d feeding, 55.0-83.6% after 5th 10 d feeding, and 15.2-32.4% after 10th 10 d feeding period). The lowest survival of boll weevils was when they fed on citrus pollen (52.0-56.0% after 1st 10 d feeding, 13.3% after 3rd and 5th 10 d feeding, and 0 after 6th 10 d feeding period). Pollen feeding is apparently not a behavior restricted to boll weevils of a specific sex or physiological state. Studying the ability of the boll weevil to survive on plants other than cotton is important in understanding how to control and eradicate this pest, especially in subtropical regions of the United States and Mexico.