Herbivory through the ages: Revealing effects of global change with historical specimens

Climate warming and drought have increased outbreaks of insect herbivores that eat plants across multiple habitats, including crop systems, forests, and urban areas. However, less is known about how chronic, non-outbreak herbivores respond to changes in the earth’s climate. Chronic herbivores are those that munch on your tomato plant, presumably reducing its growth and fruit production, but not killing it. Chronic herbivory by insects is the most prevalent kind of herbivory worldwide.

In this ongoing project, I use pressed plant 'herbarium' specimens to document chronic herbivory on plants over the last 200 years. The images above show the diversity of herbivore damage on herbarium specimens, from leaf mines to galls to chewing damage. I have mined herbarium specimens to understand: How do urbanization and climate change affect insect damage? Does domestication affect how much plants get eaten? How does leaf-out sensitivity to temperature affect change in insect damage over time? 

This work is housed at the Harvard University Herbaria, the Museum National d' Histoire Naturelle, Paris, and the National Museum of Nature and Science Herbarium, Japan

Aimée ClassenJonathan Davies, Charles Davis, Nate Sanders

NSF Postdoctoral Fellowship Program, NSERC CRSNG, Harvard University Herbaria

Meineke, EK, Davis, CC, Davies, TJ. The unrealized potential of herbaria for global change biology. Ecological Monographs, 2017In Press. doi: 10.1002/ecm.1307. pdf

NOTE: Specimen images above and those I have posted to social media are from the Northeastern Botanical Collection's digitization project of New England plant specimens. For details about this collection, email Mikaela Schmull at or see the Harvard Herbaria digitized collections.