OBSERVATIONS ON LARVAL BEHAVIOUR AND AVOIDANCE OF ENCAPSULATION OF PERILAMPUS HYALINUS (HYMENOPTERA: PERILAMPIDAE) PARASITIC IN NEODIPRION LECONTEI (HYMENOPTERA: DIPRIONIDAE)

Abstract

Dissection of 400 diapausing eonymphs of Neodiprion lecontei (Fitch) yielded 149 live planidia larvae of Perilampus hyalinus Say. Of these 87% were embedded in the brain and in the ganglia of the ventral cord, and the remainder in various other internal organs, including the malpighian tubes and silk glands. Numerous encapsulated planidia were found in the haemocoel. To avoid encapsulation in this host, planidia of P. hyalinus must enter an internal organ. Resumption of development of N. lecontei stimulates the emergence of surviving planidia, which commence feeding as ectoparasites. During the second instar, feeding is suspended while the parasite larvae search the body of the host for competitors and destroy them.Some of the eonymphs examined contained larvae of the tachinid Spathimeigenia sp. in addition to planidia. None of these planidia survived, nor did they become hyperparasitic.