Parasitoids as biological control agents – a fundamental approach

Abstract

SUMMARYThis review begins with a description of the parasitoid life-style and the ecological and evolutionary factors which generate the remarkable diversity of insect parasitoids. We then describe the various ways that parasitoids have been used in the biological control of insect pests, and survey their success to date. The use of parasitoids remains largely an art, aided by past experience of success and failure. A more fundamental approach, involving basic research and theory, has not as yet contributed significantly to practical biological control. We explore the potential for such a science of parasitoid use and review basic research on parasitoid ecology and evolution which is of particular relevance to biological control. Mathematical models are used to identify and examine those parasitoid and host attributes which lead to successful biological control. Factors such as parasitoid foraging behaviour, fecundity, larval survival and sex ratio are shown to be important in influencing the depression of host populations and/or the stability of host–parasitoid interactions after depression. Multiple release is discussed and a model for inundative release of parasitoids is explored.

The Effect of Temperatures on the Biological Characteristics of Two Aphid Parasitoids Aphelinus asychis (Walker) and Aphelinus varipes (Förster) (Hymenoptera: Aphelinidae) on Two Aphid Hosts

“…자손세대의 성비는 방사한 포식기생자의 성공과 실패에 영 향을 주는 요인 중의 하나로 (Waage and Hassell, 1982) 온도는 암컷의 비율에 영향을 주는 중요한 환경요인으로 알려져 있다 (Schlinger and Hall, 1959;Raney et al, 1971). …”

Response by Specialist and Generalist Natural Enemies to Agroecosystem Diversification: A Selective Review

“…Most research on natural enemies has been limited to interactions between enemies and victims. Many authors believe that enemies tend to aggregate, on some scales at least, in areas of high victim density (reviewed by Hassell [1978Hassell [ , 1982, but see Morrison and Strong [1980]). By itself, a strong enemy aggregation response might be predicted in some situations to counteract concentration of oligophagous herbivores in simple habitats.…”

“…However, specialist enemies may often be more effective than generalists in controlling herbivore populations, just as oligophagous herbivores are often more effective in exploiting host plants, and comprise the major portion of the herbivore load in many systems (Root 1973, Kogan 1981. The number of successes (Beddington et al 1978, Waage & Hassell 1982 and the rates of success (Hall et al 1980) of biological control introductions using specialist enemies indicate the widespread importance of specialist enemies in natural and agricultural systems. Considering their importance, it is of considerable interest to determine if specialist enemies respond to vegetation texture differently from generalist enemies, just as oligophagous herbivores often respond differently from generalist herbivores.…”

Insect parasitoids : a Canadian perspective on their use for biological control of forest insect pests

“…Askew (1971) estimated that over 200 000 species of the order Hymenoptera were parasitoids; this represents almost 10% of ail animal species. Parasitoid life-styles are found in 87 families from five insect orders (Sweetman 1936) with one genus in Hymenoptera alone accounting for almost 1000 species of parasitoids (Waage and Hassell 1982).…”