Abundance and seasonal distribution of filth flies and their hymenopteran puparia parasitoids in Puducherry, India

A survey on filth flies and their natural enemies was carried out at weekly intervals between July 2014 and June 2015. A total of 6 study sites comprising one poultry and five dairy farms in and around Pondicherry were selected for screening abundance of fly and hymenopteran puparia parasitoids. Density of adult flies was monitored using both scudder grill and sweep net technique. Sampling of immature of filth flies was carried out using litre sampling method. The species compositions of flies (n= 22,543) in all the study areas as follows: Musca domestica (89.48%), Stomoxys calcitrans (5.29%), Musca sorbens (2.44%), Calliphora sp. (1.89%), Fannia cannicularis (0.56%), Ophyra sp. (0.13%), Sarcophaga sp. (0.09%) and Hippelates sp. (0.07%). The density of flies (Mean±SD) varied from 18.83±5.4 (Oct.2014) to 58.51±16.5 (Aug.2014) using scudder grill (no/grill/30 sec). The density of flies (Mean±SD) varied between 15.4±3.3 (Nov.2014) to 49.6±17.9 (Aug.2014) using sweep net (no/sweep). Species composition of parasitoids (n= 3,534) during the study period as follows: Spalangia cameroni (46.09%), Spalangia nigroaenea (34.94%), Dirhinus himalayanus (13.80%), Spalangia endius (3.62%) and Pachycrepoideus vindemmiae (1.52%). Rainfall had a significant negative correlation with density of fly (p=0.054) and parasitoid (p=0.015). The results exhibited that the rainfall affected both fly and parasitoid density. The temperature had a positive correlation with density of fly (p= 0.054) and the density was increased when temperature reached above 25⁰C. Therefore, for the effective fly control programme mass release of parasitoids can be done before temperature starts to increase in the summer season.