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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Publications at this Location » Publication #75866
Title: FEEDING BEHAVIOR OF THE RED AND GRAY SUNFLOWER SEED WEEVILS (COLEOPTERA: CURCULIONIDAE) ON CULTIVATED SUNFLOWER, HELIANTHUS ANNUUS L

Author
item RANA, RICO - UNIV OF NEBRASKA, LINCOLN
item Charlet, Laurence

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Knowing the basic requirements of sunflower seed weevils for survival and reproduction is an important step in managing populations of these insect pests. Adult red and gray sunflower seed weevils use the sunflower plant for food and reproduction. The purposes of this study were to determine the feeding site(s) and types of sunflower tissue consumed by adults and to determine the influence of cultivated sunflower growth stages on development of the female reproductive system. Both male and female gray seed weevils fed more on leaves of sunflower and on disk flowers than on seeds. Mature eggs developed when females were given access to plants in the bud stage. Females feeding only on blooming sunflower heads did not develop mature eggs even after 12 days of feeding. Most red seed weevil females fed on the seeds of sunflower disk flowers, while males fed on the corolla tubes of the disk flowers. Females exposed to prebloom sunflower did not produce mature eggs, but did so when access was prolonged until plants were blooming. Females confined in blooming heads developed mature eggs after four days. Pollen stimulated egg production only when mixed with other foods such as ground sunflower seed, sucrose, or water. The observed preference of sunflower seed weevils for a particular plant tissue, organ, or structure, and growth stage for feeding and reproduction is useful to consider in developing efficient control strategies for these pests.

Technical Abstract: Knowing the basic requirements of sunflower seed weevils for survival and reproduction is an important step towards developing effective control strategies against these insect pests. Adult sunflower seed weevils, Smicronyx sordidus LeConte and S. fulvus LeConte utilize the sunflower (Helianthus annuus L.) plant for food and reproduction. The purposes of this study were to, one, determine the feeding site(s) and types of sunflower tissue consumed by adults; and, two, determine the influence of cultivated sunflower growth stages on maturation of the female reproductive system. Both male and female S. sordidus fed more on leaves of sunflower hybrid '894' and on disk flower corolla tubes than on achenes. Mature eggs developed when females were given access to plant in stages R1 to R3. Females feeding only on blooming capitula did not develop mature eggs even after 12 days. Most S. fulvus females fed on the achenes of sunflower hybrid '894' disk flowers, while males fed on the corolla tubes. Females exposed to the prebloom stages (R1 to R4) did not produce mature eggs, but did so when access was prolonged until the bloom stage (R5.1). Females confined in blooming capitula developed mature eggs after four days. Pollen stimulated egg maturation only when mixed with other foods such as ground sunflower seed, sucrose, or water.