Irradiation does not affect field dispersal ability in the West Indian sweetpotato weevil, Euscepes postfasciatus

Abstract

The effect of irradiation on the dispersal ability of males and females of the flightless West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae), a major sweet potato pest, was examined in the field using mark-release-recapture techniques. To evaluate the dispersal ability of the weevil, we released 7 619 weevils in two replicates (July and August 2007). Each replicate lasted 5 days from release to sampling and consisted of one weevil release and two weevil samplings. Thirty-two traps were placed in lines corresponding to eight compass directions and in four distance classes (8, 12, 16, and 20 m) in each replicate. We captured 709 (9.3%) weevils in the two replicates. Weevils dispersed at least 20 m from the release point in 2 days, regardless of sex or irradiation. Dispersal was strongly affected by wind direction, and in both replicates most weevils were recaptured in upwind directions. The mean dispersal distance for non-irradiated weevils was about 11 m per 2 days. Although there were some differences between sexes in recapture rate and dispersal distance, there was no consistent difference between irradiated and non-irradiated weevils in dispersal distance. We conclude that irradiation does not affect the dispersal ability of flightless E. postfasciatus in the field.

Effect of low temperature between fractionated-dose irradiation doses on mating of the West Indian sweetpotato weevil, Euscepes postfasciatus (Coleoptera: Curculionidae)

“…The adult E. postfasciatus is unable to fly, and its distribution depends on walking (Raman and Alleyne 1991). Thus, migration ability of this weevil is very low in the field (Kumano et al 2009b). Therefore, the age range of sterile males is broad in the targeted area in the eradication program.…”

Current mosquito-borne disease emergencies in Italy and climate changes. The neem opportunity

“…Other approaches pursue mass-rearing and field release of sterile male insects [21][22][23]. However, since no legal framework exists to authorize the release of such organisms in the nature, sterilization by irradiation remains the most used technique [24][25][26].…”

Female mating failure and the failure of ‘mating’ in sterile insect programs

“…However, irradiation doses of 10 krad diminished dispersal distances (Hamada, 1980). Likewise, in the sweet potato weevils Cylas formicarius Fabricius and Euscepes postfasciatus (Fairmaire), there was no effect of irradiation on dispersal ability (Kumano et al, 2007(Kumano et al, , 2009a. In contrast, in the Caribbean fruit fly, there was no significant difference in the flight duration and flight velocity of irradiated or non-irradiated males (Sharp & Webb, 1977).…”

“…In the codling moth, dispersal of irradiated males is shorter than that of wild males (Vreysen et al, 2010), and mobility decreases with increasing irradiation dose (Bloem et al, 2006), thus limiting male location of females. Although flightless and obviously less vagile, weevil males nonetheless still need to orient toward potential mating partners in the field (Kumano et al, 2009a). Likewise, in the sweet potato weevils Cylas formicarius Fabricius and Euscepes postfasciatus (Fairmaire), there was no effect of irradiation on dispersal ability (Kumano et al, 2007(Kumano et al, , 2009a.…”