Tritrophic interactions in the context of climate change: a model of grasses, cereal Aphids and their parasitoids

Abstract

Biologists have been challenged to envisage the likely consequences of increases in atmospheric carbon dioxide concentrations, and the suite of accompanying environmental changes (e.g. rising temperature, changing rainfall patterns, etc.) on our biotic systems. Research to date on plant responses has been extensive, but work on herbivore responses has been less complete, and work on higher trophic levels nearly nonexistent. One group of herbivores that has been reasonably well studied is aphids, and at least for this group, researchers have even begun to investigate responses at higher trophic levels, to include parasitoids. In this paper, we develop a mechanistic mathematical model of the general interaction between grasses, cereal aphids and their parasitoids. We used this model to investigate the interacting effects of rising CO 2 and temperature. The model suggests that, while parasitoids do have an impact on the aphid colony population dynamics, they do not fundamentally alter the aphid response to climate change. The model predicts that for both aphids and their parasitoids, the population responses to combined effects of elevated CO 2 and temperature will be more similar to current ambient conditions than we might expect from the individual effects of CO 2 or temperature increases. This interaction has important consequences for the interpretation of results from experiments that study only the effect of rising CO 2 .

Large‐scale migration synchrony between parasitoids and their host

“…In field systems over short time periods, it might be expected that there is a density-dependent effect of aphids on parasitoid communities (Hoover & Newman, 2004;Hance et al, 2007). However, this does not necessarily hold for migration parasitoid-host dynamics.…”

A review of climate-driven mismatches between interdependent phenophases in terrestrial and aquatic ecosystems

“…Trying to find the appropriate temperature cue driving a change in phenology is challenging when different organisms and even different phenophases respond differently to the same rise in temperature and when interdependent phenophases are responding to slightly different temporal trends in temperature. Modelling studies aimed at predicting the impacts of climate change on ecosystems should integrate all these responses to obtain a more realistic picture of all potential effects and assist the development of more robust mitigation policies (Hoover and Newman 2004;Ponti et al 2009). …”

Interactive effects of multiple climate change variables on trophic interactions: a meta-analysis

“…"X" indicates that a climate variable was manipulated in the particular study. All studies are experimental except [33] which is a modeling study. "Temp"= temperature, "Photo"= photoperiod, and "UV"= ultraviolet radiation.…”