DISTRIBUTION OF OVIPOSITIONAL ATTACKS BY PARASITOIDS ON OVERWINTERING LARVAE OF THE SPRUCE BUDWORM, <i>CHORISTONEURA FUMIFERANA</i> (LEPIDOPTERA: TORTRICIDAE)

Can. Ent. 122: 585-594 (1990) Interactions between Bacillus thuringiensis Berliner and Apanteles fumiferanae Viereck as mortality factors of the spruce budworm, Choristoneurafumiferana (Clemens), were investigated by placing parasitized and nonparasitized budworm larvae on foliage with and without spray deposits of a commercial formulation of B. thuringiensis. The effect of larval age (and, thus, the timing of spray applications) was examined by using peak thud-instar and peak fourth-instar larvae. We demonstrated that parasitized larvae are more likely to survive exposure to B. thuringiensis because they feed less than nonparasitized larvae and are thus less likely to acquire a lethal dose of the bacterium. THE CANADIAN ENTOMOLOGIST July/August 1990 stade. La survie amtlior& de parasitoides a compenst la mortalitt rtduite des arrosages retardks de B. thuringiensis. Nous avons conclu que I'application de B. thuringiensis aux populations larvaires de la tordeuse la cime du quatrihme stade ou plus tard complkterait au lieu de contrarier les effets avantageux de A. fumiferanae. Les implications a I'tgard des straegies de maniement de la tordeuse sont discutkes. THE CANADIAN ENTOMOLOGIST

Section: Introductionmentioning

confidence: 99%

INTERACTIONS BETWEEN BACILLUS THURINGIENSIS BERLINER AND APANTELES FUMIFERANAE VIER. (HYMENOPTERA: BRACONIDAE), A PARASITOID OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE)

Nealis

Frankenhuyzen²

1990

“…The reasons for this are not clear. The experimental methods insured a surplus of hosts and, moreover, A. fimiferanae will frequently use the same host for repeated oviposition (McLeod 1977). It is possible that the manner in which hosts were offered, as sedentary larvae in hibernacula, was an unnatural or difficult situation for optimum oviposition.…”

Section: Resultsmentioning

confidence: 99%

“…Apantelesfumiferanae appears to be ubiquitous in populations of these budworms. Miller and Renault (1976) found that A. fumiferanae was one of the few species of parasitoid that was present every year over a 12year period of low spruce budworm density in New Brunswick and the parasitoid is routinely found in high-density budworm populations, sometimes at frequencies exceeding 50% (McLeod 1977). Brown (1946) summarized the earlier observations on A. fumiferanae and provided descriptions of the life stages.…”

Section: Introductionmentioning

confidence: 99%

RATE OF DEVELOPMENT, REPRODUCTION, AND MASS-REARING OF APANTELES FUMIFERANAE VIER. (HYMENOPTERA: BRACONIDAE) UNDER CONTROLLED CONDITIONS

Nealis

Fraser

1988

The temperature-dependent rate of development of the post-diapause larval and pupal stages of the spruce budworm parasitoid, Apanteles fumiferanae Vier., was estimated under controlled conditions. Parasitoid larvae required 289.0 degree-days (DD) above a threshold of 8.1 °C to complete development and the pupae required 106.2 DD above a threshold of 9.6 °C to complete development. Longevity of the adult wasp at several temperatures also was examined. Female wasps lived longer than male wasps at all temperatures. Wasps tended to mate more readily under natural than under artificial light conditions.Newly emerged female A. fumiferanae had few, if any, mature eggs in their ovaries. The number of mature eggs increased to a peak of 40–75 eggs, 4–12 days after eclosion of the adult. The pattern in number of ovipositions was similar to this pattern of egg availability. The daily rate of oviposition, however, was only about one-quarter the number of eggs available.These biological measurements are discussed in view of the development of a mass-rearing technique for this parasitoid.

“…Although G. fumiferanae is well adapted to its host it does not parasitize over 25% of them even at high host population levels (Miller 1960;McLeod 1977). Why does it not parasitize a much higher percentage particularly in abundant host populations?…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, if this is so, functional adaptation to survival on sparse host populations may prevent the species from exploiting a sudden or periodic abundance of hosts. In fact, G. fumiferanae is often proportionately less abundant in high host populations (McLeod 1977).…”

Section: Discussionmentioning

confidence: 99%

OVIPOSITION BY GLYPTA FUMIFERANAE (HYMENOPTERA: ICHNEUMONIDAE) IN CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE) LARVAE AND THE EFFECT OF HONEY ON THEIR FECUNDITY AND SURVIVAL

Stairs

1983

Females of Glypta fumiferanae (Viereck) (Hymenoptera: Ichneumonidae) lived 8–28 days and oviposited 42–176 eggs if fed honey but lived only 2–5 days and oviposited 4–89 eggs if unfed. Experiments were done under near natural conditions of temperature and humidity (15°–26 °C and 50–80% R.H.). At low host densities fed adults oviposited live eggs daily and unfed adults, 10. Starved adults at low host densities lived about a day longer than those at high host densities indicating that resorption of eggs may occur in this species. General parasite and host density relationships are discussed.