THE CONTROL OF BLOWFLIES INFESTING SLAUGHTER‐HOUSES I. FIELD OBSERVATIONS OF THE HABITS OF BLOWFLIES

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Abstract
The habits of blowflies infesting slaughter‐houses have been studied to determine the conditions under which control measures are most likely to be effective. Flies found in such numbers as to be considered pests of economic importance were: Calliphora erythrocephala (Meig.) and C. vomitoria (L.); Lucilia caesar (L.), L. illustris (Meig.) and L. sericata (Meig.); and Phormia terrae‐novae (R.‐D.). All were found breeding profusely on slaughter‐house refuse.The reactions of adult blowflies to weather and the working conditions at the slaughter‐house are recorded; the three genera react in differing degrees to relatively minor changes in weather conditions, and redistribution of populations caused by these changes is so rapid as to make difficult the accurate assessment of degree of infestation. It was found that blowflies normally do not settle on the internal fabric of slaughter‐house buildings but tend rather to congregate on nearby vegetation. The preferences were studied of adult flies for certain types of meat, for particular parts of carcasses, and for meat exposed to sunlight.Conditions favouring rapid development of larvae were determined and the rates of breeding recorded for the three genera when in natural competition and when breeding independently. The larvae of P. terrae‐novae were found to be predacious on other species and each other. Lucilia sericata was found to oviposit and breed successfully in vegetable matter.Blowflies overwinter as fully grown larvae which pupate only a short while before emerging in the spring.Various methods are discussed whereby the findings of this investigation into the life history and habits of blowflies can be utilized in the control of these pests.