December, '22] Richardson: house fly and carbon dioxide 425 



IS THE HOUSE-FLY IN ITS NATURAL ENVIRONMENT 

 ATTRACTED TO CARBON DIOXIDE? 



By Charles H. Richardson and Eva H. Richardson 



Several years ago, experiments with ammoniimi carbonate and certain 

 other compounds were reported ^'^ which indicate that the female house- 

 fly (Musca domestica L.) is attracted to fermenting organic substances 

 largely by the odor of ammonia. These experiments were conducted 

 in the open i,n places habitually frequented by house-flies. All indica- 

 tions pointed to the fact that the oviposition responses of these flies 

 were normal. Since then, Crumb and Lyon ^' ■* using a somewhat 

 different method have concluded that carbon dioxide induces the house- 

 fly to oviposit in fermenting substances, but that ammonia does not 

 possess this attracting influence. The authors carried out their ex- 

 periments in a large wire cage in which the reactions of flies that had 

 previously been captured in traps were observed. Furthermore, bran 

 was employed as the nidus, a substance not used in our work referred to 

 above. In view of these differences, it seemed desirable to test the 

 attractiveness of carbon dioxide with bran as a nidus under outdoor 

 conditions. In addition, the attractiveness of bran containing am- 

 moniimi carbonate was investigated, a combination which as Baum- 

 berger^ has already shown will induce egg-laying. The experiments 

 described below were made at Clarendon Virginia from July 13 till 

 August 18, 1922. 



The location selected for these experiments was the southwest side of 

 a dwelling house in a place not subject to strong air currents. It was 

 shaded till midday and lightly shaded during a part of the afternoon. 

 One series of experiments was placed in a different location which re- 

 ceived more sunlight during the morning and at midday. 



The experimental receptacles (funnels or dishes) were placed on a 

 wooden shelf in a linear series 2 feet apart. A shelf below this held 

 the carbon dioxide generators. In each series there were always more 

 carbon dioxide than ammoniimi carbonate experiments. The position 



iRichardson, C. H. A chemotropic response of the house-fly {Musca domestica L ) 

 Science n. s. 43, 613-6 (1916) 



2 The response of the house-fly {Musca domestica L.) 



to ammonia and other substances. N. J. Agric. Expt. Stations Bull. 292, 19 pp 

 (1916). 



'Crumb, S. E. and Lyon, S. C. The effect of certain chemicals upon oviposition in 

 the house-fly {Musca domestica L.) J. Econ. Entom. 10, 532-6 (1917). 



* Further observations on the effect of certain chemicals 



upon ovipositon in the house-fly {Musca domestica) J. Econ. Entom. 14, 461-5 

 (1921). 



^Baumberger, J. Percy. A nutritional study of insects, with special reference to 

 microorganisms and their substrata. J. Exptl. Zool. 28, 1-81 (1919), 



