20,000 or so years ago the earth was a colder place. Glaciers covered much of North America, including many states that currently are home to Magicicada, and other species of cicadas. There were glaciers in Wisconsin as recently as 9,500 years ago. The area below the glaciers were dominated by taiga, a landscape dominated by sappy evergreens and grasses (mastodon food). Florida was three times the size it was today.
Map from the NOAA.
What I’m curious about is this:
- Where were the Magicicada 20-10 thousand years ago? Did they exist in a primordial form some place in the primordial woodlands of mega-Florida?
- How did deciduous trees (oak, maple, ask, etc) spread northward, and how did the Magicicada spread with them?
- Did the spread of deciduous trees northward into America play a part in the unusual life cycle of Magicicada, including the long lifecycle and 4 year accelerations?
- Were the Neotibicen and Neocicada also living in mega-Florida or perhaps Mexico, and then spread northward as temperatures rose?
- Were Okanagana able to exist in the colder, evergreen-dominated taiga of the time of the last glaciers?
For some reason this stuff intrigues me. Thank goodness my local library has a Jstor account.
Just how far north fragments of temperate deciduous forest (potential Magicicada habitat) managed to persist during the last glacial maximum is a contentious question. The article in the link below has maps focusing on specific plant genera as well as biomes:
http://www.sciencedirect.com/science/article/pii/S0277379199000931
A brief consideration of the northward dispersal question is on page 71 of this paper:
http://www.tandfonline.com/doi/abs/10.1080/00779962.2005.9722688#.VaY3Jbe8Cag