Factors determining the functional response of the parasitoid <i>Venturia canescens</i>

Trudeau, D.; Gordon, David M.

doi:10.1111/j.1570-7458.1989.tb02306.x

Cited by 25 publications

(17 citation statements)

References 13 publications

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“…6, ANOVA, during the day with a "remaining" (r = 0.77, search (r = 0.73, P < 0.001). No change decreasing egg load P < 0.001) P < 0.001) in their walking speed (r = 0.55, P < 0.001 and see was found (a = 0.05) their Table 6 Pak et al 1985Collins and Dixon 1986Collins and Dixon 1986Trudeau and Gordon 1989 a No statistical effect of age on searching activity was found. Initial egg load was estimated as a function of the egg load determined at the end of an observation and size, i.e.…”

Section: Theorymentioning

confidence: 82%

Egg Load as a Major Source of Variability in Insect Foraging and Oviposition Behavior

Minkenberg¹,

Tatar²,

Rosenheim³

1992

Oikos

256

181

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Section: Theorymentioning

confidence: 82%

Egg Load as a Major Source of Variability in Insect Foraging and Oviposition Behavior

Minkenberg¹,

Tatar²,

Rosenheim³

1992

Oikos

256

181

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“…V. canescens females emerge with mature and immature eggs (Trudeau and Gordon 1989;Harvey et al 2001;Roberts and Schmidt 2004) that mature during the adult lifetime (synovigeny). With continuous sugar access, thelytokous V. canescens can produce up to several 100 eggs over their lifetime (Harvey et al 2001;Roberts and Schmidt 2004).…”

Section: Biological Materials and Culturesmentioning

confidence: 98%

Differential energy allocation as an adaptation to different habitats in the parasitic wasp Venturia canescens

2006

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Environmental pressures are expected to favour organisms that optimally allocate metabolic resources to reproduction and survival. We studied the resource allocation strategies and the associated tradeoffs in the parasitoid wasp Venturia canescens, and their adaptation to the characteristics of the environment. In this species, individuals of two reproductive modes coexist in the same geographical locations, but they mainly occur in distinct habitats. Thelytokous (asexual) wasps are mostly found in anthropogenic habitats, where hosts tend to aggregate and food is absent. Arrhenotokous (sexual) wasps are exclusively found in natural habitats, where hosts are scattered and food is present. We analysed (1) the quantity of energy stored during ontogeny, (2) the tradeoff between reproduction and survival, by measuring egg load and longevity and (3) the host patch exploitation behaviour of the wasps at emergence. Arrhenotokous wasps emerged with more metabolic resources than thelytokous ones, especially glycogen, a nutrient that could be used for flying in search of hosts and/or food. Thelytokous wasps allocated more energy than arrhenotokous wasps to egg production: this would allow them to parasitize more hosts. The tradeoff between egg production and longevity was not revealed within reproductive modes, but when comparing them. At emergence, arrhenotokous wasps tended to exploit host patches less thoroughly than thelytokous wasps, suggesting that by leaving the host patch, they search for food. The results clearly showed adaptations to the characteristics of habitats preferentially inhabited by the two reproductive modes, and suggested a mechanism that facilitates their coexistence in natural conditions.

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“…Experiments have shown that following host encounters, RM-wasps lay fewer eggs initially and more eggs later compared to RP-wasps (Beck et al, 2001). The observed differences in egg deposition strategies may be because of a lower egg load in RM-wasps (Beck et al, 1999), which correlates with lower egg deposition rates (Trudeau and Gordon, 1989).…”

Section: Introductionmentioning

confidence: 99%

Genetic analysis of two distinct reproductive strategies in sexual and asexual field populations of an endoparasitic wasp, Venturia canescens

Zhao

Roberts

et al. 2003

Heredity

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Asexual (thelytokous) females of the parasitoid Venturia canescens, which develop inside another insect, exhibit evolutionarily stable mixtures of life-history strategies, allowing two genetically distinct wasp lines to coexist sympatrically on the same host resources. Since the two asexual lines differ in a virus-like particle protein-coding gene (VLP1), the question is whether the VLP1 gene is genetically associated with the phenotype. The recent isolation of facultative sexual (arrhenotokous) and asexual V. canescens strains from the same location in Southern France has enabled an investigation of the genetic basis for the observed phenotypic differences, by comparing the two asexual lines with the corresponding homozygous VLP1 genotypes in arrhenotokous strains. This analysis showed similar patterns of morphological and functional differences exist in the ovaries of the two asexual VLP1 lines and in the two homozygous VLP1 genotypes from the field, suggesting that the VLP1 gene alteration either causes the ovarian phenotype or is genetically closely linked to the putative gene. However, the VLP1-gene may not be the only gene contributing to the phenotypic effects observed in the asexual lines. Although the two VLP1-alleles segregate with the relative differences in the ovary distribution of eggs, the absolute egg numbers differ in the corresponding asexual and sexual genotypes. This suggests that an additional unlinked gene may be involved in the transfer of eggs from the ovarioles into the oviduct.

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Factors determining the functional response of the parasitoid Venturia canescens

Cited by 25 publications

References 13 publications

Egg Load as a Major Source of Variability in Insect Foraging and Oviposition Behavior

Egg Load as a Major Source of Variability in Insect Foraging and Oviposition Behavior

Differential energy allocation as an adaptation to different habitats in the parasitic wasp Venturia canescens

Genetic analysis of two distinct reproductive strategies in sexual and asexual field populations of an endoparasitic wasp, Venturia canescens

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