Life-history, host preference and establishment status of Melittia oedipus (Lepidoptera: Sesiidae), a biological control agent for Coccinia grandis (Cucurbitaceae) in the Mariana Islands
G.V.P. ReddyA, Z.T. CruzA and R. MuniappanB
A Agricultural Experiment Station, College of Natural and Applied Sciences, University of Guam, Mangilao, Guam 96923, USA.
B IPM CRSP, OIRED, Virginia Tech, 526 Prices Fork Road, Blacksburg, VA 24061, USA.
Ivy gourd or scarlet gourd, Coccinia grandis (Violales: Cucurbitaceae), is a perennial vine and a native of Africa that has invaded lowland areas of the Hawaiian and Mariana Islands. Failure of mechanical or chemical control techniques to suppress this weed led to the initiation of a biological control program in the Mariana Islands (Guam, Saipan, Rota and Tinian). This follows the success achieved in Hawaii by introducing the natural enemies, Acythopeus cocciniae (Coleoptera: Curculionidae), Acythopeus burkhartorum (Coleoptera: Curculionidae) and Melittia oedipus (Lepidoptera: Sesiidae). Of these three biological control agents, M. oedipus has proven to be effective in suppressing C. grandis in Hawaii.
Life history of M. oedipus has been described. Females laid 144 eggs on average during their lifetime. The mean duration of the egg, larval and pupal stages were 9.4, 43.5 and 21.4 days, respectively. Females lived longer than the males with a mean of 4.5 days and 3.4 days, respectively. This study indicated that M. oedipus is specific to C. grandis and larval development did not occur on Zehneria guamensis (Cucurbitaceae), an endemic plant of Guam and Rota. Field release of M. oedipus in the Marianas resulted in establishment in Guam and Saipan, however the presence of pavement ant Tetramorium bicarinatum (Nylander) (Hymenoptera: Formicidae) on vines in the field in Saipan has hindered establishment there.
Keywords: Melittia oedipus, Sesiidae, Coccinia grandis, Zehneria guamensis, Cucurbitaceae, life-history, host preference, Mariana Islands.
Plant Protection Quarterly (2009) 24 (1) 27-31.