Adaptation to artificial rearing during successive generations in the West Indian sweetpotato weevil, Euscepes postfasciatus (Coleoptera: Curculionidae)

An eradication project has been initiated in the southwestern island of Japan to contain the West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire) using the sterile insect technique (SIT). We report here about rearing this insect for >14 successive generations on an artificial diet, an element required for successful use of SIT. The fecundity of reared weevils increased with each generation. Egg hatch (85-95%) and adult yield (30-60%) were consistenetly high throughout the test period. Comparisons of fecundity and preoviposition periods indicated that females from the artificially reared strain at generation 14 oviposited more and earlier in life than those from the base stock. These differences resulted from an increase in frequency (100%) of females that laid eggs without standard oviposition substrates in the artificially reared strain. Adaptation to an artificial diet is discussed in relation to the oviposition behavior of E. postfasciatus and the success of SIT against this weevil.