Aphid response to elevated ozone and CO₂

Abstract

Numerous reports indicate that pollution stress caused by sulphur dioxide (SO 2 ), oxies of nitrogen or fluorides promote aphid growth on herbaceous and woody plants. At SO 2 exposures, the response curve of aphids is bellshaped having the peak at 100 ppb. This curvilinear response is related to physiological stress responses of host plants exposed to pollutants. On the other hand, observations of aphid performance on ozone-exposed (O 3 ) or elevated carbon dioxide-exposed (CO 2 ) plants have given very variable results. Depending on the duration and concentration of O 3 or elevated CO 2 exposure or the age of the exposed plants, aphid growth on the same plants either decreased or increased in comparison to growth on control plants grown in filtered air. The results of these studies suggest that there is no general air pollution-induced plant stress that triggers aphid outbreaks on plants. Plants grown in elevated CO 2 usually have higher C/N ratios than plants grown in current ambient CO 2 atmosphere. A reduced proportion of nitrogen in the plant foliage decreases growth of chewing herbivorous insects, but the few studies of elevated CO 2 effects on sucking insects such as aphids have not yielded similar consistent effects. The present paper reviews recent studies of elevated CO 2 effects on aphids and discusses the effects of combined elevated O 3 and CO 2 exposures on aphid performance on woody plants using pine and birch aphids as examples.

Climate Change and Tritrophic Interactions: Will Modifications to Greenhouse Gas Emissions Increase the Vulnerability of Herbivorous Insects to Natural Enemies?

“…The effects of increased CO 2 concentrations on sap-feeders vary according to the type of plant tissue that the insect is feeding on . A review by Holopainen (2002) highlights contrasting results for aphid performance when reared on plants under elevated CO 2 conditions, with studies showing increased, decreased, or unchanged performance compared with ambient CO 2 levels. These variable results may be related to the specificity of the plant-insect interactions or to differences in environmental and experimental factors .…”

“…This phytotoxic gas modifies the biosynthetic pathway of important secondary metabolites (Holopainen 2002), leading to changes in plant volatile cues, and subsequently affecting how phytophagous insects locate host plants (Pinto et al 2010). Moreover, secondary plant metabolites are also used as synomones by the natural enemies to find phytophagous insects (Vet and Dicke 1992).…”

“…These direct effects on plants may also have indirect effects on organisms in the higher trophic systems, through the modification of trophic cascades (BidartBouzat and Imeh-Nathaniel 2008). Consequently, interactions between plants and insect herbivores have received greater attention compared with interactions between phytophagous insects and their natural enemies (Coviella and Trumble 1999, Whittaker 1999, Holopainen 2002, Lindroth 2010, DeLucia et al 2012). Yet, the preliminary results remain inconclusive regarding the extent to which modifications in the emissions of greenhouse gases are likely to influence the efficiency of beneficial insects at controlling phytophagous pests.…”

Ethological Study of Flower Visiting Insects in Two Parks, Kolkata, India

“…The difference shown in two different parks may be vary on certain factors such as human interference, as Elliot park is a public park, vehicular air pollution as Elliot park is just beside the road side and landscape change. Insect outbreaks have been observed in the surroundings of polluted industrial areas and along highways (Holopainen, 2002). According to Grimm et al, (2000), human actions dramatically altered the functioning of ecosystems of which humans are a part, and equally, humans are a part of virtually all ecosystems and have been so for millennia.…”

Individual growth rates do not predict aphid population densities under altered atmospheric conditions

“…Furthermore, other traits, such as nutrient assimilation or survivorship, may become positively or negatively affected only when densities increase. Adding additional complexity, aphids may have altered life-history patterns depending on host plant ontogeny (Holopainen, 2002). Athough it is difficult, if not impossible, to examine all the life-history traits of an organism, these results indicate that a multifaceted approach (i.e.…”