Boll Weevils: Sperm Transfer by Sterile vs. Normal Males; Fecundity and the Use of Sperm by Females

Normal males of Anthonomus grandis Boheman (Coleoptera: Curculionidae), were held unmated and then were mated once. The number of sperm transferred by them increased as they grew older, but with regards to the percentage of the available sperm transferred, the reverse was true. The 4-day-old males transferred ca. 1/5 as many sperm as the 14-day-old males; but the fecundity of the females mated to these males was ca. the same. Males treated with gamma irradiation alone or in combination with diflubenzuron, (l-(4-chlorophenyl)-3-(2,6-diflurobenzoyl)-urea) and held unmated for 5 days transferred ca. ¾of available sperm in a single mating. Both 9-day-old normal males and males treated with 8000 rad + diflubenzuron transferred ca. 1.5 million sperm to the females; however, the females mated to treated males had only ca. ½ as many sperm in their spermathecae as females mated to normal males. This is the 1st indication that irradiation lowers the quality of boll weevil sperm. Sperm from the spermathecae were utilized by the females at a much faster rate during the 1st 4 days after mating than during the 5th through the 10th day.