Sexual maturation, mating propensity and remating incidence of Zeugodacus tau (Walker) (Diptera: Tephritidae)

Zeugodacus tau (Walker) (Diptera: Tephritidae) is a serious fruit fly pest of cucurbits. The pest is gaining global attention in recent years due to population expansion and its potential in invading new territory as the species share a similar host range with the melon fly, Zeugodacus cucurbitae. We determined the species' sexual maturation, mating propensity and remating incidence to better understand its basic reproductive ecology. Newly emerged wildish male and female flies were housed with two sexually mature and virgin partners and their first and multiple mating incidences were recorded over 60 days. We show that some females and males of Z. tau began to mate at 16 and 18 days-after-emergence (DAE), respectively; but most adults mated for the first time over a wide age range within a 60-day observation period (male: 26-40 DAE; female: 21-45 DAE). The males demonstrated a higher mating frequency and a lower refractory period (4.8 +/- 0.4 times; 3 days) than the females (1.4 +/- 0.1 times; 14 days). Multiple matings are common in males; with 48.4% remated for at least five times. The ratio of singly-mated females (51.6%) to those multiply-mated (48.4%) was almost 1:1; with one record of a female mated for as many as five times. Under normal circumstances, Z tau was showed to copulate for at least 10-11 h. Further investigation revealed that high female remating incidence was neither due to a shorter copulation duration nor insufficient sperm transferred during mating. Comparison of the dual and multiple-mate choice methods in determining sexual maturity attainment ofZ. tau yielded almost similar results as the profiles generally overlapped when the species is sexually most active (26-45 DAE). These findings provide useful inputs for future behavioural and reproductive investigations, as well as optimization of ecological models in area-wide control of fruit fly pests. (C) 2016 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society. Published by Elsevier B.V. All rights reserved.