Preferred Technique for Adult Sex Determination of the Boll Weevil (Coleoptera: Curculionidae)

Determining the sex of boll weevil adults is complicated by the lack of a discreet, gender-specific, externally visible character. However, the posterior edge of the male's 8th tergite is distinctively notched and can be revealed by gentle probing. Although completely accurate as originally described 35 yr ago, this method has not gained wide acceptance because of the perception that it is too slow for processing large numbers of weevils, and because the original illustrations are not entirely adequate. Here we illustrate the tergal-notch method of sexing with photographs and interpretive drawings. This method is quickly learned and fast enough for most applications. Experienced users in our laboratories routinely sex 200–300 weevils per hour. The common alternative technique of sexing by relative snout characteristics is only 88–90% accurate.