Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Influence of egg depth in host plants on parasitism of Scolypopa australis (Homoptera: Ricaniidae) by Centrodora scolypopae (Hymenoptera: Aphelinidae).

Abstract

Parasitism of eggs of Scolypopa australis by Centrodora scolypopae was studied on blackberry, bracken (Pteridium aquilinum var. esculentum), barberry (Berberis darwinii), black bindweed (Polygonum convolvulus [Fallopia convolvulus]), Cyathea sp. and Coriaria arborea in New Zealand during May 1983 and 1984. The average length of the parasitoid ovipositor was 0.60±0.1 mm. The depth at which host eggs were laid in plant stems ranged from 0.30±0.08 mm in Pteridium aquilinum var. esculentum to 0.48±0.01 mm in blackberry. The depth at which eggs were laid was inversely related to parasitism. Different parts of the same plant varied in parasitism levels, with the shallow eggs on the thorns of B. darwinii and racemes of C. arborea having higher levels of parasitism than those in stems. Many eggs laid in plants with soft stems were beyond the reach of the parasitoid, while those laid at shallow depths in hard plant tissues were accessible and were parasitised heavily.