Native male population, new recruits (young indigenous and immigrant flies), and survival rate of oriental fruit fly,Bactrocera dorsalis(Hendel), were estimated, by mark-release-recapture technique using methyl eugenol–baited traps, in two villages in Penang Island, Malaysia. Population size and new recruits were significantly higher in Tanjong Bungah (TB) than in Batu Uban (BU). This was caused by the higher number of fruits damaged in TB, although BU had more varieties of fruit trees. However, survival rate of fruit flies in both villages was the same. The most important component of the environment affecting adult populations ofB. dorsalisin the tropics is the availability of suitable host fruits. In both villages, among a variety of host plants grown, starfruit played the most important role in this regard. The abundance of damaged fruits fluctuated and lagged behind estimated populations and new recruits ofB. dorsalismales by 3–5 and 2–4 wk, respectively. Peak numbers ofB. dorsalismales and host fruits occurred entirely within the wet seasons of the year. During dry seasons, the fly population declined because of less fruit. However, rainfall (as well as temperature, relative humidity, and wind speed) had no significant correlation with estimatedB. dorsalismale population parameters or host fruit abundance.