Patterns of Hyperparasitism of Cotesia melanoscela (Hymenoptera: Braconidae) in Southern Ontario

Bourchier, Robert S.; Vincent, Geoffroy

doi:10.1093/ee/21.4.907

Cited by 8 publications

(11 citation statements)

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“…Since the majority of studies showed that hyperparasitoids release insect pest populations from the strong top-down effect of primary parasitoids, it is generally recommended that introduction of hyperparasitoids should be avoided (Sullivan and Völkl, 1999). Although it is possible to exclude them during quarantine assessments of primary parasitoid consignments, primary parasitoids can acquire other obligate hyperparasitoid species once released in the field (Agricola and Fisher, 1991;Bourchier and Nealis, 1992;Kellogg et al, 2003). Since nothing can be done to exclude populations of obligate hyperparasitoids in nature, this predicament puts pressure of biological control practitioners to investigate ways of stabilizing biological control programmes in the light of ecological disturbance from obligate hyperparasitoids.…”

Section: Discussionmentioning

confidence: 99%

“…The presence of both subcategories in a food web can alter the food web structure if those species attacking primary parasitoid pupae also parasitize species attacking larval stages (Carew and Sullivan, 1993;Brodeur, 2000). A majority of studies have shown that presence of obligate hyperparasitoids increases herbivory as insect pest populations are often released from the strong top-down effect of primary parasitoids (Bourchier and Nealis, 1992;Eichhorn, 1996;Boenisch et al, 1997;Lei and Hanski, 1997;Rosenheim, 1998;Brodeur, 2000;Schooler et al, 2011). Further, obligate hyperparasitoids can leave cues on the plant surface that may increase dispersal probability of primary parasitoids, which further reduces mortality of insect pests (Höller et al, 1993;van Veen et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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The effect of obligate hyperparasitoids on biological control: Differential vulnerability of primary parasitoids to hyperparasitism can mitigate trophic cascades

Nofemela

2013

Biological Control

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Highlights-Cotesia vestalis was a dominant primary parasitoid of Plutella xylostella.-It was also a secondary host to three obligate hyperparasitoid species.-At low hyperparasitism, C. vestalis limited hosts available to competitors. -As C. vestalis population declined, competitors parasitized more of available hosts.-Species that are invulnerable to hyperparasitism took over role of the vulnerable. Graphical abstractAbstract : Obligate hyperparasitoids are widely considered an important ecological disturbance to biological control of insect pests, as they develop at the expense of primary parasitoids. However, supporting evidence is largely derived from direct trophic interactions in simple food webs. Yet, a multitude of insect pest populations simultaneously support development of several primary parasitoid species in horticultural and natural systems. Since primary parasitoid species in a community can differ in vulnerability to obligate hyperparasitoids, it is desirable to establish if the invulnerable primary parasitoids can take advantage of reduced competition from affected species by increasing their contribution to total primary parasitism levels thereby mitigating effects of hyperparasitism on biological control. To investigate this question, populations of the diamondback moth, Plutella xylostella (Linnaeus) (Plutellidae), its primary parasitoids and hyperparasitoids were monitored on unsprayed cabbage plots at weekly intervals over six consecutive years. Cotesia vestalis (Haliday) (Braconidae), a dominant primary parasitoid in this system, was a secondary host to three obligate hyperparasitoids: Mesochorus sp. (Ichneumonidae), Eurytoma sp. (Eurytomidae) and Pteromalus sp. (Pteromalidae). The higher efficiency of C. vestalis in utilizing younger host larvae at lower hyperparasitism levels limited host availability to other major primary parasitoids. But, as hyperparasitism levels increased and its populations declined, populations of Oomyzus sokolowskii (Kurdjumov) (Eulophidae) and Diadromus collaris (Gravenhorst) (Ichneumonidae) increased significantly as they parasitized a greater proportion of available hosts. As a consequence, the impact of hyperparasitoids did not result in trophic cascades, as their impact on total primary parasitism levels and infestation levels was insignificant. This study shows that primary parasitoid species that are invulnerable to hyper-parasitism can take over the function of vulnerable ones in communities where interspecific interactions among species are strong. Thus, an approach that considers both direct and indirect effects of hyperparasitoids in primary parasitoid communities improves our understanding of the net impact of hyperparasitism on biological control of insect pests.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The effect of obligate hyperparasitoids on biological control: Differential vulnerability of primary parasitoids to hyperparasitism can mitigate trophic cascades

Nofemela

2013

Biological Control

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“…Gypsy moth neonates were transferred in groups of 50-75 to 188-mL plastic cups (Sweetheart Plastics, Wilmington, MA) containing an artificial diet (ODell et al 1985). Cotesia melanoscela were obtained from field populations of diapausing cocoons collected from various sites in southeastern Ontario (44"N) (Bourchier and Nealis 1992). These cocoons were stored at 2°C for 4 months and then incubated at 20°C to permit eclosion of parasitoid adults.…”

Section: Generalmentioning

confidence: 99%

“…Direct measurement of field populations of C. melanoscela in Ontario, however, shows that most of the first generation enters diapause in mid-to late June so that a second generation is, at most, partial (Bourchier and Nealis 1992). The issue of voltinism is relevant to understanding the ecology of this species because the timing and duration of the diapause stage of C. melanoscela largely determine the extent of hyperparasitism in the species (Bourchier and Nealis 1992) and the extent to which the parasitoid is synchronized with the susceptible stages of its principal host (Weseloh 1976). Both factors affect C. melanoscela's potential as an effective biological control agent of the gypsy moth.…”

Section: Introductionmentioning

confidence: 99%

“…Studies from Connecticut, United States, suggest that all or most of the first generation of C. melanoscela continues development to adult in the same year so there are effectively two complete generations each year (Weseloh 1973(Weseloh , 1976. Direct measurement of field populations of C. melanoscela in Ontario, however, shows that most of the first generation enters diapause in mid-to late June so that a second generation is, at most, partial (Bourchier and Nealis 1992). The issue of voltinism is relevant to understanding the ecology of this species because the timing and duration of the diapause stage of C. melanoscela largely determine the extent of hyperparasitism in the species (Bourchier and Nealis 1992) and the extent to which the parasitoid is synchronized with the susceptible stages of its principal host (Weseloh 1976).…”

Section: Introductionmentioning

confidence: 99%

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THE DIAPAUSE RESPONSE TO PHOTOPERIOD IN ONTARIO POPULATIONS OF COTESIA MELANOSCELA (RATZEBURG) (HYMENOPTERA: BRACONIDAE)

1996

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The diapause response to photoperiod in Ontario populations of Cotesia melanoscela, an introduced parasitoid of the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), was investigated under a series of stationary photoperiods and constant temperature. When the parasitic larval stages of C. melanoscela were exposed to different photoperiods, the insect exhibited a typical long-day response: long days (greater than 18 h) promoted continuous development whereas short days (less than 16 h) resulted in diapause in the cocooned prepupal stage. Within the region of the critical photoperiod (16–18 h) the diapause response was associated with larval development time. Individuals that developed more slowly were more likely to enter diapause. Cotesia melanoscela was sensitive to photoperiod throughout its entire larval period. These individual responses are used to interpret patterns of seasonality of the parasitoid in Ontario and to compare with published information from populations of C. melanoscela in New England.

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Divergent life history strategies in congeneric hyperparasitoids

et al. 2016

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International audienceLife histories can reveal important information on the performance of individuals within their environment and how that affects evolutionary change. Major trait changes, such as trait decay or loss, may lead to pronounced differences in life history strategies when tight correlations between traits exist. Here, we show that three congeneric hyperparasitoids (Gelis agilis, Gelis acarorum and Gelis areator) that have diverged in wing development and reproductive mode employ markedly different life history strategies. Potential fecundity of Gelis sp. varied, with the wingless G. acarorum maturing a much higher number of eggs throughout life compared with the other two species. Realized lifetime fecundity, in terms of total offspring number was, however, highest for the winged G. areator. The parthenogenic G. agilis invests its resources solely in females, whilst the sexually reproducing species both invested heavily in males to reduce competitive pressures for their female offspring. Longevity also differed between species, as did the direction of the reproduction-longevity trade-off, where reproduction is heavily traded off against longevity only in the asexual G. agilis. Resting metabolic rates also differed between the winged and wingless species, with the highest metabolic rate observed in the winged G. areator. Overall, these geline hyperparasitoids showed considerable divergence in life history strategies, both in terms of timing and investment patterns. Major trait changes observed between closely related species, such as the loss of wings and sexual reproduction, may contribute to the divergence in key life history trait

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Patterns of Hyperparasitism of Cotesia melanoscela (Hymenoptera: Braconidae) in Southern Ontario

Cited by 8 publications

References 0 publications

The effect of obligate hyperparasitoids on biological control: Differential vulnerability of primary parasitoids to hyperparasitism can mitigate trophic cascades

The effect of obligate hyperparasitoids on biological control: Differential vulnerability of primary parasitoids to hyperparasitism can mitigate trophic cascades

THE DIAPAUSE RESPONSE TO PHOTOPERIOD IN ONTARIO POPULATIONS OF COTESIA MELANOSCELA (RATZEBURG) (HYMENOPTERA: BRACONIDAE)

Divergent life history strategies in congeneric hyperparasitoids

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