The Biology of a Hyperparasite,Euceros frigidusCress. (Ichneumonidae) and Description of the Planidial Stage

Abstract

For more than a decade the sawfly, Neodiprion swainei Midd., has been a serious defoliator of jack pine, Pinus banksiana Lamb., in the Province of Quebec. In 1955 an intensive research program involving several research officers was initiated at the Forest Biology Laboratory, Quebec, to study the insect. Investigations began near the centre of the infestation at the headwaters of the Gatineau River (47° 55′N., 75° 25′W.). The project dealing with the parasites became the responsibility of the author and constituted approximately 25 pcr cent of the total investigations. Integrated with this project were studies on population dynamics, effect of defoliation on jack pine, and predators of the sawfly with emphasis on the small mammals. The primary object of the parasite studies was to concentrate on the life cycles and descriptions of the immature stages and to publish on each species as sufficient information was obtained. Ultimately, it is planned to publish jointly with other members of the team on the role of parasites in the overall mortality complex of Neodiprion swainei.

Comparative morphology of the planidial larvae of Eucharitidae and Perilampidae (Hymenoptera: Chalcidoidea)

“…Clausen (1940a, p. 19) summarizes the occurrence of active first-instar larvae in parasitoids (the triungulinids of Coleoptera (Rhipiphoridae, Meloidae) and Strepsiptera, and 'planidia' of Diptera (Acroceridae, Tachinidae and Sarcophagidae)) as excellent examples of convergent evolution. Euceros frigidus Cresson (Ichneumonidae) has convergently developed the habit of leaf oviposition and also has an active first-instar larva (Tripp, 1961). The first-instar larva of E. frigidus is heavily sclerotized and has distinct tergites on the thirteen body segments.…”

The life history of Pseudometagea schwarzii, with a discussion of the evolution of endoparasitism and koinobiosis in Eucharitidae and Perilampidae (Chalcidoidea)

“…In contrast, Darling and Miller (1991) and Darling (1992) proposed that because of their unique structure and phylogenetic placement, the term planidium should be reserved for Perilampidae and Eucharitidae, with other [Type I] forms referred to as planidiaform. Type I hypermetamorphic larvae are rare, and appear to have evolved only twice in Hymenoptera, once in Ichneumonidae (Tripp 1961) and in a monophyletic Eucharitidae + Perilampidae . For the Chalcidoidea that oviposit away from the host, not all of their larvae are hypermetamorphic (von Rosen 1956, Parnell 1963, Askew 1980.…”

Parasitiods Utilizing the Same Host: Adaptive Nature of Differences in Size and Form

“…Obligatory hyperparasitoid.-Females lay their stalked eggs on foliage, the planidial first instar larvae attach to the sawfly larvae and do not develop until a primary parasitoid develops in or on the host (Tripp 1961). Therefore, members of this genus may interact with any or all members of other guilds.…”

“…Therefore, members of this genus may interact with any or all members of other guilds. Euceros species have short ovipositors and are capable of massive egg production, having from 50 (Tripp 1961) to about 230 ovarioles per ovary (Iwata 1960).…”