Seasonal Mortality and Survival of<i>Pieris rapae</i>(Lepidoptera: Pieridae) in Missouri and the Effect of Introducing an Egg Parasite,<i>Trichogramma evanescens</i>

Parker, Frank D.

doi:10.1093/aesa/63.4.985

Cited by 46 publications

(45 citation statements)

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“…Some of the prominent herbivores, e.g., Pieris rapae (Forbes 1960) and Phyllotreta cruciferae (Milliron 195 3), have invaded the Nearctic Region during the past 150 years. Pieris rapae has a different complement of parasites in North America, which may be less effective in reducing populations than the European parasite complex (Blunck 1951, Parker 1970. Thus the fauna under study is a mixture of species that evolved in different regions.…”

Section: Predators '-P_a_r_a_si_to_i_d_smentioning

confidence: 99%

Organization of a Plant‐Arthropod Association in Simple and Diverse Habitats: The Fauna of Collards (Brassica Oleracea)

Root¹

1973

Ecological Monographs

2,633

147

2,046

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Collards were grown at Ithaca, New York, in two experimental habitats: pure stands and single rows that were bounded on each side by diverse, meadow vegetation. The arthropods associated with these plants were sampled on 20 dates over a 3—year period. The status of the herbivore species was measured by their rank in biomass in each sample. The two most prominent species, Phyllotreta cruciferae and Pieris rapae, maintained high status throughout the investigation, but another important species, Brevicoryne brassicae, was absent for an entire season. Pit feeders usually formed the most important herbivore guild. Nevertheless, the guild spectrum, which describes the functional structure of the fauna, varied widely in time and space. The size distributions of species and of individuals were both highly skewed toward the smaller sizes. Herbivore loads, the mean biomass of herbivores per 100 g of consumable foliage, were consistently higher in the pure stands. Moreover, herbivore loads varied significantly with season in each experimental habitat. Both the number of herbivore species and the diversity of the herbivore load were greater in the diverse habitat. Biomass was more heavily concentrated among the prominent herbivores in the pure stands; increased dominance, rather than differences in species richness, appeared to be the major cause for the lower herbivore diversity in this habitat. The diversity of predators and parasitoids was higher in the pure stands. Most of the abundant species found on collards shared a similar narrow range of hosts. As a result the species in this core group of herbivores and parasitoids were regularly associated with each other. Predators and the less abundant herbivores tended to be less specialized and served to link the collard association with the surrounding community. Plant—arthropod associations are representative of component communities, well—integrated systems that form portions of larger compound communities. This distinction facilitates the analysis of community structure. Microclimates and the effectiveness of "enemies" did not appear to differ sufficiently in the two experimental habitats to account for the observed differences in the herbivore load. The results suggest a new proposition, the resource concentration hypothesis, which states that herbivores are more likely to find and remain on hosts that are growing in dense or nearly pure stands; that the most specialized species frequently attain higher relative densities in simple environments; and that, as a result, biomass tends to become concentrated in a few species, causing a decrease in the diversity of herbivores in pure stands.

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Section: Predators '-P_a_r_a_si_to_i_d_smentioning

confidence: 99%

Organization of a Plant‐Arthropod Association in Simple and Diverse Habitats: The Fauna of Collards (Brassica Oleracea)

Root¹

1973

Ecological Monographs

2,633

147

2,046

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“…Mean displacements for butterflies ranged between .5 and 1.2 kin/day, which corresponds to diffusion coefficients between 0.16 and 0.92 km2day. To convert these daily rates into annual rates, we multiplied by life expectancy for adults (the caterpillar stage is sedentary), which ranges from 10-20 days, and by the number of generations per year, which ranges from 3-7 depending on locale (Harcourt 1966;Parker 1970). The resulting yearly diffusion coeffi-183 cients are between 4.8 and 129 km2/yr.…”

Section: The Match Between Theory and Observed Rates Of Spreadmentioning

confidence: 99%

Spread of invading organisms

et al. 1990

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“…rubecula possesses biological attributes which suggest it may have greater potential in controlling P. rapae than the braconid Cotesia glomerata (L.) (Puttler et al, 1970), which was found to be incapable of suppressing P. rapae populations before economic injury occurred (Parker, 1970). C. rubecula normally exits from, and kills 4 th instar P. rapae, thus preventing most leaf damage (Parker & Pinnell, 1973).…”

mentioning

confidence: 99%

Colonization and hyperparasitism ofCotesia rubecula (Hym.: Braconidae), a newly introduced parasite ofPieris rapae, in Virginia

McDonald

Kok

1992

Entomophaga

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A Yugoslavian strain of Cotesia rubecula (Marshall) (Hymenoptera : Braconidae) was released in spring broccoli for control of the imported cabbageworm, Pieris rapar (L.), in Montgomery Co., Virginia, in 1987. C. rubecula reproduced and parasitized imported cabbageworm larvae in fall broccoli in 1987. It was found in moderate numbers in the summer and fall crops in 1988, and by fall had dispersed 0.8 km from the original release site. However, no C. rubecula were detected in our broccoli plots in Montgomery Country in 1989 or 1990.The hymenopteran hyperparasites lsdromas lycaenae (Walker) (Ichneumonidae), Spilochalcis torvina (Cresson) (Chalcididae), and Tetrastichus galactopus (Ratzeburg) (Eulophidae) were found attacking C. rubecula. Hyperparasites emerged from 31.8 % and 41.1% of the C. rubecula cocoons in 1987 and 1988, respectively. T. galactopus was the most numerous hyperparasite in 1987, but S. torvina was dominant in 1988. Hyperparasite activity was low during early spring, but increased in July in both years. By August 1988, only hyperparasites emerged from the C. rubecula cocoons collected in the field. In spite of C. rubecula's success in overwintering, hyperparasites, especially S. torvina, may be a limiting factor in the establishment of C. rubecula in southwestern Virginia.

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Seasonal Mortality and Survival ofPieris rapae(Lepidoptera: Pieridae) in Missouri and the Effect of Introducing an Egg Parasite,Trichogramma evanescens

Cited by 46 publications

References 0 publications

Organization of a Plant‐Arthropod Association in Simple and Diverse Habitats: The Fauna of Collards (Brassica Oleracea)

Organization of a Plant‐Arthropod Association in Simple and Diverse Habitats: The Fauna of Collards (Brassica Oleracea)

Spread of invading organisms

Colonization and hyperparasitism ofCotesia rubecula (Hym.: Braconidae), a newly introduced parasite ofPieris rapae, in Virginia

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