Dr. Kassai Tibor - Dr. Murai Éva szerk.: Parasitologia Hungarica 6. (Budapest, 1973)

Discussion Although nematodes include dangerous pests causing damages to both animals and plants, certain species can be used beneficially in biological control. Nematodes associated with insects are of great importance as biological agents against insects, therefore the relationships between nematodes and insects are of interest and to be studied. Nematodes have been found attached externally to insects on their abdominal segments, legs, genital segments, beneath the elytra and on the soft tissues between head and thorax. Nematode larvae located on soft tissues feed on them and cause some harm to the insect: if the nematode larvae appear in great numbers, they inhibit host activity and in some cases lead to its death. While these nematodes are harmful to their hosts, those existing beneath the elytra, on the legs and abdominal segments

; are not. Such insects serve as carriers for nematodes and contribute to their distribution among another animal and plant hosts . In the present study a number of 797 beetles were collected and examined both externally and internally as to their infestation with nematodes. 268 specimens of the 797 beetles (33.6 %) were found to be infested with nematodes, all externally (Table 6). 6341 nematode larvae were extracted from 268 infested insects and reared on certain artificial media where adult stages were reached. Nematodes found represented seven species assignable to four families.The family Rhabditidae is represented by three species, Neoaplectanidae by only one, Diplogasteridae by two, and Panagrolaimidae by one species. Rate of infestation ranged from 7.61 % in Anisodactylus virens Dej

. to 59.9 % in Oniticellus pallens Oliv. Liability to infestation by certain nematode species varied among the insect species examined. While Onitis alexis Klug and Pentodon algerinum Herbst were liable to be infested by three