Effects of elevated atmospheric carbon dioxide on insect-plant interactions

In the enriched carbon dioxide atmosphere expected in the next century, man y, species of herbivorous insects will confront less nutritious host plants that will induce both lengthened larval developmental times and greater mo rtality The limited data currently available suggest that the effect of inc reased atmospheric CO2 on herbivory will be nor only highly species-specifi c brit also specific to each insect-plant system. Several scenarios can be predicted however. (1) local extinctions will occur; (2) the endangered spe cies status as well as the pest status of some insect species will change; (3) geographic distributions for some insect species will shift with host-p lant ranges; and (4) changes in the population dynamics of affected insect species will influence their interactions with other insects and plants. Fo r insect conservation purposes, it is critical to begin long-term studies o n the effects of enhanced CO2 levels on insect populations. An analysis of the available literature indicates that many orders containing insect speci es important for ecosystem conservation, and even those important as agricu ltural or medical pests, have not been examined. Without a major increase i n research on this topic, we will be unprepared for the species changes tha t will occur, we will lose the opportunity to document just how some insect s adapt to elevated CO2 levels, and we will lack the information necessary for effective conservation efforts.