| dc.description.abstract | The main goal of this investigation was to determine if the parasitic hymenopteran Muscidifurax raptor displayed any host preference. Research conducted through twelve generations seems to suggest that this parasite displays no specific host over another when it is presented with equal numbers of Musca domestica, Stomoxys calcitrans, and Haematobia irritans pupae. Therefore, it has not been possible to develop a strain of the parasite, through artificial selection, which will parasitize only the pupae of one of the aforementioned dipterans and ignore the other two. On a more positive note, I have determined that the species of dipteran pupae parasitized by M. raptor does have a major influence on how long it will take the parasite to complete it's life cycle. This is due to the fact that it takes the parasite 17.46 days to go from the egg stage to the larval stage when this parasited attacks house fly pupae, 16.34 days to do likewise when it parasitizes stable fly pupae and only 15.43 days when it parasitizes horn fly pupae.
The horn fly (Haematobia irritans) is a small, bloodsucking fly. It is blackish with gray powdering and the thorax has three black bands on it. The wing venation is very similar to that of the stable fly (Stomoxys calcitrans). The mouthparts of the horn fly also resemble those of the stable fly (Smith et al., 1943). The horn fly obtains blood from cattle, usually by resting and feeding on the back and shoulders. The damage occasioned by the horn fly is chiefly through irritation and annoyance, which in dairy animals results in disturbed feeding, causing loss of flesh and improper digestion (James et al., 1969).
The stable fly (Stomoxys calcitrans), like H. irritans, is also a bloodsucking fly. It is very similar to the house fly (Musca domestica) in appearance. However, unlike the horn fly, it breeds mostly in decaying straw instead of dung. Another similarity that S. calcitrans and M. domestica have in common is that they are both a member of the family Muscidae. However, the house fly breeds in filth of all kinds and has sponging mouthparts whereas the stable fly has no sponging mouthparts but instead has mouthparts which are capable of causing a wound which exposes the blood of the animal (Borror et al., 1976).
The fourth insect that I studied was Muscidifurax raptor. M. raptor is an ectophagus, pteromalid parasite that attacks various filth-breeding dipterans such as the three aforementioned species (Legner 1969). M. raptor was studied to determine whether or not members of this species would display host preference when offered equal numbers of M. domestica, B. irritans, and S. calcitrans pupae. It was hoped that if M. raptor displayed host preference that three strains of this parasite could be developed through artificial selection which would then attack only one species of dipteran pupae and would ignore the other species when offered equal amounts of each. It should be noted that M. raptor is more correctly called a parasitoid since the larval stage actually causes the death of the host. The adult female parsite will oviposit on the pupae and the larval stage emerges from the egg the female has inserted into the pupae with her ovipositor which is more commonly referred to as the stinger. | en |
