Herbivore responses to climate change

Figure 2 (new, color)

Figure from: E.A. Robinson*, G.D. Ryan* & J.A. Newman (2012).  Tansley Review: A meta-analytical review of the effects of elevated CO2 on plant-arthropod interactions highlights the importance of interacting environmental and biological variables.  The New Phytologist, in press. *Co-first authorship.

This is a broad theme in my lab, and we have used five different approaches:

1. Field and Lab Experiments:  My PhD student, Emily Robinson, and I are currently working on the bean leaf beetle and how rising temperatures may alter over winter survival.  However the mainstay of my experimental work in this field has been the bird cherry-oat aphid and it's responses to rising CO2 concentrations. My most recent work on this subject has been with my PhD student, Gerry Ryan, where we have been trying to link changes in plant host quality brought on by rising levels of CO2 to changes in aphid population dynamics.  Papers relating to this area can be found here.

2. Physiologically-based mechanistic models: This model comprises four sub-models.  The plant sub-model respond mechanistically to changes in CO2, temperature, water availability, soil nitrogen, relative humidity, and photosynthetically active radiation.  There are also simple soil and water sub-models, and a more extensive aphid sub-model.  The aphid model is linked to the plant sub-model through the nutritional quality of the phloem sap.  We have also looked at a couple of examples of tri-trophic interactions by adding aphid predators and parasitoids. Papers relating to this area can be found here.

3. Bioclimatic envelope models: These models combine information about an insect's tolerances for various aspects of the climate and then attempts to map the areas where 'suitable' climate for that insect might be found.  We've published papers on the swede midge and the pea leafminer.  We continue to dabble in this area of work and have a few unfinished projects we are still working on.  Papers relating to this area can be found here.

 4. Degree-day models:  These are models on insect phenology that try to account for development time as a function of how many days occur between the insect's lower and upper developmental threshold temperatures.  We have one paper in review now where we investigate the impacts of warming on thirteen different agronomic pest species in California.  Papers relating to this area can be found here.

5. Critical syntheses:  Here we attempt to systematically review and synthesize the literature on arthropod-plant interactions under climate change, particularly CO2 concentrations. Papers relating to this area can be found here and here.

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