Scaled up differences: new ways to study moth pests using fossilized wing scales
The wings of moths and butterflies are covered in microscopic scales that preserve as fossils in lake sediments dating back as far as 10,000 years. These fossilized scales can be used to indicate the presence of moth pests in the past. We developed a new method using scanning electron microscopy that distinguishes five species of moth pests based on differences in the fine-scale structure (or ultrastructure) of their scales.
Using the ultrastructure of moth scales to distinguish species means that scales that are not in optimal condition, which is often the case when looking at fossils that are thousands of years old, can still be examined.
Read this open access paper on the FACETS website.
We studied five common species of moth pests that outbreak in eastern North America. We found that the ultrastructure from two species, hemlock looper and blackheaded budworm, had clearly distinguishable features that allowed them to be categorically distinguished from the other three species.
We then used statistical analysis to differentiate between the remaining three species (spruce budworm, jack pine budworm, and forest tent caterpillar). We found that scales from the remaining three species could be distinguished with an overall accuracy of 66%.
Canadian forests are home to at least 106 species of insect defoliators — insects that eat leaves or needles — 70% of which are moths and butterflies (Lepidoptera). When moth pests enter epidemic phases known as outbreaks, their numbers dramatically increase, and they can cause severe destruction with their defoliation of host plants.
An abundance of research has been done to understand the outbreak dynamics of past and present populations of these pests, but it remains unknown how they may be affected by climate change. To understand how climate change may affect Lepidoptera pests, we must look back in time and observe the outbreak histories of important pests during different climate periods.
Read the full paper — Distinguishing eastern North American forest moth pests by wing-scale ultrastructure: potential applications in paleoecology by Kristen J. Milbury, Les C. Cwynar, and Sara Edwards.
