Effect of elevated CO 2 on interactions betwe en the western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae) and the common milkweed, Asclepias syriaca

Abstract

We measured the effect of elevated CO on populations of the western flower thrips, Frankliniella occidentalis and on the amount of leaf damage inflicted by the thrips to one of its host plants, the common milkweed, Asclepias syriaca. Plants grown at elevated CO had significantly greater aboveground biomass and C:N ratios, and significantly reduced percentage nitrogen. The number of thrips per plant was not affected by CO treatment, but the density of thrips (numbers per gram aboveground biomass), was significantly reduced at high CO. Consumption by thrips, expressed as the amount of damaged leaf area per capita, was significantly greater at high CO, and the amount of leaf area damaged by thrips was increased by 33%. However overall leaf area at elevated CO increased by 62%, more than compensating for the increase in thrips consumption. The net outcome was that plants at elevated CO had 3.6 times more undamaged leaf area available for photosynthesis than plants at ambient CO, even though they had only 1.6 times the overall amount of leaf area. This study highlights the need for measuring the effects of herbivory at the whole-plant level and also the importance of taking herbivory into account when predicting plant responses to elevated CO.

Influence of Elevated Co2 Associated With Chickpea on Growth Performance of Gram Caterpillar, Helicoverpa Armigera (Hüb .)

“…Similar observation was reported by Hughes and Bazzaz (1997) If the nutritional quality of the food is low, it would try to compensate through higher consumption and intake.…”

Effects of carbon dioxide and nitrogen enrichment on a plant–insect interaction: the quality of Calluna vulgaris as a host for Operophtera brumata

“…Such growth stimulation has been shown to result in a dilution of tissue N in C. vulgaris (Woodin et al, 1992, Whitehead, Caporn & Press, 1997 and many other species (e.g. Hughes & Bazzaz, 1997 ;Schappi & Ko$ rner, 1997), thereby reducing the nutrition quality of the plant for herbivores (Lincoln, Fajer & Johnson, 1993). Furthermore, the carbon\nutrient balance hypothesis (Bryant, Chapin & Klein, 1983) predicts that the increase in internal C availability will trigger an increase in the synthesis of C-based secondary defence chemicals, which can further reduce plant quality for herbivores (e.g.…”

“…When significant effects of host CO # enrichment on insect development are found, they are usually negative. Although it is clear that CO # enrichment can cause a reduction in plant tissue N concentration, many insect herbivores can compensate for this reduction by increasing consumption (Lincoln et al, 1993 ;Watt et al, 1995 ;Docherty et al, 1997 ;Hughes & Bazzaz, 1997). Previous studies of O. brumata on sycamore (Acer pseudoplatanus) and beech (Fagus sylvatica) have found no significant effect of CO # enrichment on larval development, whilst on CO # -enriched plants of Sitka spruce (Picea sitchensis), O. brumata showed reduced larval growth rate, but no change in consumption or development time (Watt et al, 1996).…”

Decreased Leaf-Miner Abundance in Elevated CO 2 : Reduced Leaf Quality and Increased Parasitoid Attack

“…Most work to date on elevated CO 2 has focused on the effects of CO 2 on vegetation (e.g., Potvin andVasseur 1997, Wilsey et al 1997). The effects of elevated CO 2 on vegetation are both direct, including an increase in plant photosynthetic rates, reduced foliar nitrogen, and increased C/N ratios (Ceulemans and Mousseau 1994, Wilsey 1996, Hughes and Bazzaz 1997, and indirect, via herbivory. For example, under elevated CO 2 , herbivores grow more slowly, take longer to develop, and consume more plant material (Watt et al 1995, Hughes andBazzaz 1997).…”