The performance of Brevicoryne brassicae on ornamental cabbages grown in CO 2 -enriched atmospheres Ali Reza Amiri-Jami a, ⁎, Hussein Sadeghi a , Mahmoud Shoor b a Department of Plant Protection, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran b Department of Horticulture, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran abstract article info Article history: Received 1 October 2011 Revised 6 January 2012 Accepted 9 January 2012 Keywords: Climate change Rising CO 2 Aphid Cabbage The effect of different atmospheric CO 2 concentrations on life table parameters and the biology of the cabbage aphid, Brevicoryne brassicae, when fed on two cultivars of ornamental cabbage, was studied in a greenhouse designed for CO 2 studies. Aphid performance was influenced by increasing atmospheric CO 2 levels, signifi- cantly affecting the intrinsic rate of increase (r m ), finite rate of increase (λ), mean generation time (T), dou- bling time (DT), and pre-reproductive period. The longest pre-reproductive period was observed for aphids grown at 380 ppm CO 2 . The intrinsic rate of natural increase was highest for aphids at 1050 ppm CO 2 , because of their faster development, high daily rate of progeny production, and higher survivorship. Future elevated CO 2 concentrations will enhance aphid population outbreaks and consequently increase the damage caused. © Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society, 2012. Published by Elsevier B.V. All rights reserved. Introduction The rise in global atmospheric concentration of carbon dioxide (CO 2 ) has been a great concern for ecologists over recent years. As a result of human activities, atmospheric CO 2 levels rose to 379 ppm in 2005 and double the current level is expected to occur by end of this century (IPCC, 2007). Such an increase in CO 2 levels will affect the biology of living organisms, including plant–herbivore interactions (Guerenstein and Hildebrand, 2008). Elevated atmospheric CO 2 in- creases photosynthesis rates, above-ground biomass, yield and carbon: nitrogen ratios, and reduces nitrogen concentrations; thus, impacting the production of plant nutrients (Cotrufo et al., 1998; Pritchard et al., 1999; Agrell et al., 2000; Hartley et al., 2000). In turn, lower foliar nitro- gen and protein concentrations cause reductions in leaf nutritional quality (Johns and Hugher, 2002) and increase the carbohydrate con- tent of some plants (Barbehenn et al., 2004; Taub et al., 2008). Responses of herbivorous insects to changes in host plants are vari- able. For example, several studies have found that leaf-chewing insects generally consume more foliage from plants grown under elevated CO 2 conditions rather than at ambient CO 2 (380 ppm), but insect growth and development generally are not affected or suppressed (Lincoln et al., 1984; Weste et al., 1987; Lincoln, 1993; Lindroth et al., 1995; Bezemer and Jones, 1998; Brooks and Whittaker, 1998; Williams et al., 1998; Yin et al., 2010). Populations of six leaf-miner species on oak decreased in elevated CO 2 (Stiling et al., 1999), and a trend toward decreased larval size occurred for another leaf miner (Pegomya nigri- tarsus Zetterstedt) on dock (Rumex spp.) (Salt et al., 1995). Popula- tions of a spittlebug (Neophilaenus lineatus L.) feeding on xylem of Juncus squarrosus L. decreased after exposure to elevated CO 2 (Brooks and Whittaker, 1999). In contrast, reproduction of Myzus per- sicae (Sulzer) on groundsel (Senecio vulgaris L.) and annual blue grass (Poa annua L.) increased with CO 2 enrichment (Bezemer et al., 1998). The same was true for Aulacorthum solani (Kalt.) on bean (Awmack et al., 1996) and Sitobion avenae (F.) on winter wheat (Awmack et al., 1996). A consistent, although not significant, trend in population increase occurs for Aphis fabae Scopoli on cardamine (Salt et al., 1995). However, populations of Phyllaphis fagi L. on beech, and Drepanosiphum platanoidis (Schrank) and Periphyllus testundinaceus (Ferni) on sycamore are not sig- nificantly affected by CO 2 enrichment (Docherty et al., 1997). Carbon di- oxide enrichment causes a trend for increased reproduction of M. persicae on Brussels sprouts (Brassica oleracea L.) but significantly decreases re- production of Brevicoryne brassicae (L.) on the same species. Bezemer et al. (1998) suggested that such controversial results imply that the herbi- vore response to elevated CO 2 is dependent on both the host plant and herbivore species. A literature review of the effect of elevated CO 2 on ar- thropod dynamics (Newman et al., 2003; Coviella and Trumble, 1999; Whittaker, 1999) and on aphid performance (Holopainen, 2002; Sun and Ge, 2011) suggested that aphid response to elevated CO 2 cannot be generalized and that every aphid–plant interaction is unique. Knowledge of host–plant effects on the life table of insect pests is essential for population dynamic studies and pest management pro- grams. The degree of plant suitability for herbivores can be measured by variations in insect performance on the host. The intrinsic rate of increase is a measure of performance commonly used to assess the effect Journal of Asia-Pacific Entomology 15 (2012) 249–253 ⁎ Corresponding author. Tel.: + 98 9155255583; fax: + 98 511 87888757. E-mail addresses: Alirezaamirijami@hotmail.com (A.R. Amiri-Jami), Sadeghin@ferdowsi.um.ac.ir (H. Sadeghi). 1226-8615/$ – see front matter © Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society, 2012. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.aspen.2012.01.001 Contents lists available at SciVerse ScienceDirect Journal of Asia-Pacific Entomology journal homepage: www.elsevier.com/locate/jape