Effects of an invading coccinellid on native coccinellids in an agricultural landscape

Abstract

Seven native coccinellid species inhabited alfalfa, corn, and small grain fields in eastern South Dakota prior to invasion and establishment of Coccinella septempunctata L. Six species occurred in all crops, however, Adalia bipunctata (L.) occurred only in corn. The structure of native coccinellid communities differed significantly for years prior to compared with years after establishment of C. septempunctata in fields of the three agricultural crops. Differences in community structure were accounted for mainly by reduced abundance of two species, C. transversoguttata richardsoni Brown and Adalia bipunctata (L.). Annual abundance of C. transversoguttata richardsoni averaged 20-32 times lower during post-invasion years than in years prior to invasion, depending on crop; while annual abundance of A. bipunctata averaged 20 times lower in corn after invasion. Addition of C. septempunctata to the community did not result in a significant increase in total abundance of coccinellids in the crops. Coccinellid abundance in agricultural crops may be limited by the total abundance of prey or by the availability of other requisites in the landscape as a whole. Therefore, introduction of a new species, while resulting in reductions in native species populations, may not increase total coccinellid abundance, and may therefore have no net effect on biological control of aphid pests.

Harmonia axyridis: a threat to Brazilian Coccinellidae?

“…As an invasive species, H. axyridis may cause negative impacts, including the displacement of natural native enemies and the suppression or extinction of non-target prey species (Elliot et al 1996). In the United States, this species was observed competing with Coleomegilla maculata DeGeer, 1775, an important native predator that feeds on many aphid species, as well as other arthropods and insect eggs (Hodek & Honek 1996).…”

Fates of Rare Species under Siege from Invasion: Persistence of Coccinella novemnotata Herbst in Western North America alongside an Invasive Congener

“…Another introduced species of much concern is Coccinella septempunctata L. This Eurasian species became established in North America in the 1970s and 1980s (Angalet et al, 1979;Obrycki et al, 2000) and soon thereafter came to be regarded as invasive and a likely threat to native North American lady beetles (Schaefer et al, 1987;Ehler, 1990;Elliott et al, 1996). Wheeler and Hoebeke (1995) carefully and thoroughly reviewed the case of Coccinella novemnotata Herbst, detailing that this species (once common throughout North America; Gordon, 1985) declined precipitously in its abundance in northeastern North America in the 1980s and early 1990s at the same time that the ecologically very similar, introduced C. septempunctata was rapidly increasing to very high numbers.…”

Harmonia axyridis: What will stop the invader?

“…To our knowledge, no aphidophagous predators exploit a single 1916-1980Gordon (1985 Africa South Africa 2007 Stals and Prinsloo (2007) aphid species, but instead feed on an array of different prey species (euryphagous), on different host plants and in different environments (eurytopic) (Iablokoff-Khnozorian 1982;Hodek and Honěk 1996). They are also good competitors (Elliott et al 1996;Ellis et al 1999;Alyokhin and Sewell 2004;Evans 2004) which could allow all these species to invade new environments. Moreover, one may invoke the neutral theory of biodiversity (Bell 2005;Hubbell 2001Hubbell , 2005Hubbell , 2006 which suggest that all species are identical and compete equally, once all species can develop on a site.…”