Predation upon the oblique-banded leafroller, Choristoneura rosaceana (Lepidoptera: Tortricidae), by two aphidophagous coccinellids (Coleoptera: Coccinellidae) in the presence and absence of aphids

Éric Lucas,Daniel Coderre,Charles Vincent,Sophie Demougeot

doi:10.14411/eje.2004.009

Abstract

Our goal has been to determine the effect of the presence of aphids on voracity (measured as number of prey eaten and biomass consumed) of Coccinella septempunctata L. and Harmonia axyridis Pallas (Coleoptera: Coccinellidae) feeding upon the oblique-banded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae). For each coccinellid predator, treatments using a single prey species, with either 30 first instar C. rosaceana or 100 third instars Aphis pomi DeGeer (Hemiptera: Aphididae), were compared with two-prey treatments in which the two prey species were present simultaneously. For both predators, the total number of prey killed (total prey species pooled) and the total biomass consumed were significantly higher when both prey were pre- sent than in single-prey treatments. The voracity of C. septempunctata on C. rosaceana larvae was not affected by adding A. pomi, whereas that of H. axyridis declined; the voracity of both predators on A. pomi increased when C. rosaceana larvae were added. The preference for the aphids over C. rosaceana was confirmed for both coccinellid species.

Highlights

The oblique-banded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), feeds on a wide range of plant species including rose (Rosa spp.), dewberry (Rubus flagellaris L.), raspberry (Rubus idaeus L.), blueberry (Vaccinium corymbosum L.), apple (Malus domestica Borkh.), peach (Prunus persica Botsch), pear (Pyrus communis L.), cherry (Prunus avium L.), European hazel (Corylus avellana L.), pistachio (Pistacia vera L.), and forest trees (Chapman & Lienk, 1971)
H. axyridis was more voracious than C. septempunctata (F1,160 = 26.4, p < 0.0001), eating a total of 40.8 (± 3.4; mean ± SE) and 27.3 (± 3.0) prey in 24 h, respectively
The biomass consumed by H. axyridis (8.64 mg) in 24 h was significantly greater than the biomass consumed by C. septempunctata (5.22 mg) (F1,164 = 53.4, p < 0.0001)

Summary

Introduction

The oblique-banded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), feeds on a wide range of plant species including rose (Rosa spp.), dewberry (Rubus flagellaris L.), raspberry (Rubus idaeus L.), blueberry (Vaccinium corymbosum L.), apple (Malus domestica Borkh.), peach (Prunus persica Botsch), pear (Pyrus communis L.), cherry (Prunus avium L.), European hazel (Corylus avellana L.), pistachio (Pistacia vera L.), and forest trees (Chapman & Lienk, 1971). Among the aphidophagous coccinellid (Coleoptera: Coccinellidae) species found in orchards of eastern Canada (Tourneur et al, 1992), the seven spotted ladybeetle, Coccinella septempunctata L., and the asiatic ladybeetle, Harmonia axyridis Pallas, are the most common. They constitute potential biocontrol agents, owing to their ubiquity and competitive abilities. 100 prey species including aphids, psyllids, coccids, thrips, leaf beetles and lepidopteran larvae (Iablokoff-Khnzorian, 1982; Kring et al, 1985; Kareiva, 1987; Horn, 1991) It is abundant in apple orchards of North America, including Michigan (Maredia et al, 1992) and Quebec (Tourneur et al, 1992). H. axyridis is reported to be one of the most polyphagous coccinellid species (Hodek, 1996; Lucas et al, 1997, 1998b)

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