First Record of Megaselia scalaris (Loew) as a Potential Facultative Parasitoid of Apis mellifera in India

Abstract

Aims: In 2016, suddenly a pile of dead honey bees, Apis mellifera with unfolded wings had been noticed adjacent to the Langstroth bee boxes on the daily interval for a consecutive period of 2-3 months. The present study was an attempt to investigate the reason for this abnormal death. Place and Duration of Study: Department of Agricultural Entomology, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, India between May 2016 and February 2018. Methodology: Forty-eight numbers of sick bees with stiff-unfolded wings and 50 healthy bees were collected and maintained at a temperature of 30 ± 2°C and 70 ± 5% relative humidity. Maggots developed in the unfolded winged bees and adult flies emerged from pupae were examined. Duration of larval and pupal emergence was recorded at a fixed atmospheric condition. Relative mortality and parasitization rate of A. mellifera was also investigated for a period of one year. Results: Parasitoid larvae emerged from the stiff-unfolded winged dead bees were identified as being Megaselia scalaris and further observation revealed that the parasitized bees contained empty body cavities while; normal honey bees were found to be non-parasitized. Matured phorid maggots emerged from the dead honey bees on an average 6 days after collection with the range of 1-14 larvae per honey bee. Maximum 12 pupae per honey bee were found after 18 days of the collection with the emergence of adults at 22nd day. Infestation rate was highest in May and lowest in January. Conclusion: From this study, M. scalaris can be considered as one of the facultative endo-parasitoids of A. mellifera and further research should be done about the impact of phorids in Indian commercial beekeeping.