Observations on the ethology and ecology of various Diptera associated with northern California poultry ranches

Different methods of sampling (visual counts, sticky tape and vacuum machine catches) showed similar fluctuations in populations of Fannia canicularis (L.) and Musca domestica L., but weekly changes in magnitudes detected by the different sampling methods often varied considerably. Vacuum collections and visual counts which represented population samples taken only at a single point in time were more subject to error induced by changes in the diurnal dispersion of flies than 24- or 18-hour sticky tape catches. Sticky tape samples could be taken in areas where most of the total ranch populations of F. Canicularis and M. domestica were present for 12–16 hours in a diel. Herein is described methodological advantages of sticky tapes in survey work and a simple, rapid method of collecting the tapes.

All sampling methods showed that populations of most fly species were widely dispersed about ranch premises during the day. Conversely, at night, “outdoor” aggregations of flies were found mainly in tree branches and shrubs, whereas almost all of the “indoor” segments of the fly populations generally aggregated in the ceiling area of poultry houses. At no other time in a diel were such large segments of these populations aggregated in the ceiling area of poultry houses. At no other time in a diel were such large segments of these populations aggregated at only two principal sites. Sticky tapes hung overnight within houses showed that 85% of F. Canicularis and M. domestica were caught within houses. About 90% of Ophyra leucostoma (Wd.) and ichneumonid populations were caught on tapes hung overnight in trees and shrubs near poultry houses. During the day, Stilpnus anthomyidiperda Viereck and Phygadeuon victoriensis Townes and several other presumably parasitic Hymenoptera were captured in large numbers from vacuum samples over droppings. This difference in the nocturnal dispersion of F. Canicularis and M. domestica and certain of their insect enemies suggests one potential approach to an integrated fly control program on northern California poultry ranches.