Comparative Demography of Two Cucurbit-Attacking Fruit Flies, Bactrocera tau and B. cucurbitae (Diptera: Tephritidae)

Bactrocera tau (Walker) and Bactrocera cucurbitae (Coquillett) have similar geographic distributions, host ranges, and damage levels in China. The species were similar in duration of immature stages, preoviposition periods, and mean generation time, but differed in survivorship of their immature stages and adults, net reproductive rate, and schedule of egg production. Net reproductive rate was 58.8 and 72.9 for B. tau and B. cucurbitae , respectively. Egg production peaked at an earlier age for B. tau , and B. cucurbitae lacked a clear peak of egg production. B. tau stopped laying eggs at an earlier age than B. cucurbitae . The population growth rates of these two species are similar.