Accumulation of Glucosinolates by the Cabbage Aphid Brevicoryne brassicae as a Defense Against Two Coccinellid Species

Abstract

Brassica nigra plants, characterized by high levels of sinigrin, and artificial aphid diets to which sinigrin was selectively added were used to rear the crucifer specialist, Brevicoryne brassicae. Aphids were provided as a food source to two species of polyphagous ladybird, Adalia bipunctata and Coccinella septempunctata. First instar A. bipunctata were unable to survive when fed with B. brassicae reared on B. nigra or diets containing 0.2% sinigrin, but when fed with aphids reared on diets containing 0% sinigrin, survival rates were high. By contrast, first instar C. septempunctata were able to survive when fed with aphids reared on B. nigra or artificial diets containing up to 1% sinigrin. However, the presence of sinigrin in the aphid diet decreased larval growth and increased the time necessary for larvae to reach second instar for this species of ladybird. These results indicate that the presence of sinigrin in the diet of B. brassicae makes this aphid unsuitable as a food source for A. bipunctata but not for C. septempunctata, although for this ladybird species, there appear to be costs associated with feeding on aphids that contain this secondary metabolite.

Aphid-plant interactions affect the suitability of Myzus spp. as prey for the two spot ladybird, Adalia bipunctata (Coleoptera: Coccinellidae)

“…with elevated levels of glucosinolates. Similar results were obtained by Pratt et al (2008) who fed A. bipunctata and Coccinella septempunctata L. with Brevicoryne brassicae (L.) reared on diets with varying levels of sinigrin; higher levels had greater negative impact on the former species. One obvious contrast between the two host plants employed in this study is the presence of nicotine in tobacco that has insecticidal activity against aphids (Thurston et al, 1966) and the lack of any analogous allelochemicals in pepper.…”

Defence mechanisms of Brassicaceae: implications for plant-insect interactions and potential for integrated pest management. A review

“…It was further added that the semiochemicals from plants, directly or through herbivore prey, must be considered as a potential toxin or reliable infochemical in relation to the efficacy of pest control by natural enemies. In another study either B. nigra plants (characterised by high levels of sinigrin), or an artificial aphid diet to which sinigrin was selectively added, were used to rear the specialist B. brassicae and aphids were provided as a food source to two species of polyphagous ladybirds, A. bipunctata and C. septempunctata (Pratt et al, 2008). The results indicated that the presence of sinigrin in the diet of B. brassicae makes this aphid unsuitable as a food source for A. bipunctata, but not for C. septempunctata.…”

Influence of different species of aphid prey on the immature survival and development of four species of aphidophagous coccinellids (Coleoptera: Coccinellidae)

“…erflies and lacewings (Francis et al, 2001b;Vanhaelen et al, 2002;Tsaganou et al, 2004;Kazana et al, 2007;Pratt, 2008;Chaplin-Kramer et al, 2011;Kos et al, 2011Kos et al, , 2012. The cabbage aphid, B. brassicae, is a specialist herbivore that sequesters glucosinolates from its host plant as a defense against its predators (Francis et al, 2002;Kazana et al, 2007;Pratt, 2008;Kos et al, 2011Kos et al, , 2012.…”

“…The cabbage aphid, B. brassicae, is a specialist herbivore that sequesters glucosinolates from its host plant as a defense against its predators (Francis et al, 2002;Kazana et al, 2007;Pratt, 2008;Kos et al, 2011Kos et al, , 2012. It contains an endogenous myrosinase, which is stored separately from the glucosinolates but when attacked by a predator the sequestered glucosinolates come into contact with the aphid myrosinase resulting in the formation of hydrolytic products that are toxic for aphid predators (Jones et al, 2001;Bridges et al, 2002;Francis et al, 2002;Kos et al, 2011Kos et al, , 2012.…”