|Rogers Jr, Hugo|
|Prior, Stephen - Steve|
Submitted to: Agricultural and Forest Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/2/2004
Publication Date: N/A
Interpretive Summary: The level of CO2, a by-product of fossil fuels use, continues to rise in the atmosphere. Plants, which absorb CO2 for photosynthesis, may be affected by these higher levels through changes in the chemical composition of their leaves. Insects that have a plant diet could also be affected changes in leaf quality. In this study, red-headed pine sawflies consumed longleaf pine needles grown under high or normal CO2 levels. Early survival rates of larvae consuming high CO2-grown needles was reduced, but larval development of survivors was not impacted by high CO2. These finding suggest that this insect could adapt quickly to leaf quality changes in a future high CO2 environment.
Technical Abstract: Longleaf pine (Pinus palustris Mill.) seedlings were grown in a model regenerating ecosystem in open-top chambers under two atmospheric CO2 regimes: ambient, 365 ppm and elevated, 720 ppm. Several feeding experiments were conducted using red-headed pine sawfly larvae (Neodiprion lecontei Fitch; Diprionidae: Hymenoptera) to assess the effects of CO2-enriched diets. Needle chemistry (macro- and micronutrients, total phenolics, condensed tannins) did not differ significantly between CO2 treatments. Most measures of larval performance (growth rates, consumption rates, length of time to pupation) were unaffected by CO2-enriched diets when feeding trials were conducted with third instar larvae. Initial larval survival, however, was greatly reduced for larvae that were exposed to CO2-enriched foliage from nascence. Nevertheless, subsequent larval development of surviving larvae was not affected by elevated CO2. We predict that red-headed pine sawfly populations will be able to adapt quickly to changes in foliar chemistry caused by rising atmospheric CO2.