We’ve tested our knowledge of mimicry between species, but what about the opposite? Sometimes a single species can look different depending on the conditions in which they live and sometimes these differences lead to subspeciation, or a population with unique characteristics that is mostly separate from, but can still breed with, the main population.
Limenitis arthemis, the Red-spotted Admiral, has different subspecies in different geographic locations.
Which of the butterflies below is the Northern subspecies?
Click below for the answer to this weeks’ quiz!
The butterfly on the right is the Northern subspecies, the White Admiral! The butterfly on the left is the Southern subspecies, the Red-spotted Purple.
The White Admiral has been spotted almost 2000 times on iNaturalist across the state of Vermont, while the Red-spotted Purple has been recorded around 60 times, mostly south of the I-89 highway.
Why the disparity? In the south, the Red-spotted Admiral overlaps ranges with the toxic Pipevine Swallowtail. They have evolved to mimic the blacks and blues of the swallowtail to avoid predation - an advantage not available to the northern Red-spotted Admirals. Currently, there has only been one lone Pipevine Swallowtail sighted in Vermont (on iNaturalist) in Rutland in 2017.
As the climate warms and southern species move north or as Pipevines become feasible to grow in backyard gardens, there may be more Pipevine Swallowtails arriving from their current New York City northern range edge. It will be interesting to see how our local Red-spotted Admiral subspecies react to this change in their community!
White Admiral by Kent McFarland (iNaturalist)
Red-spotted Purple by jlgoch (iNaturalist)
Ready for next weeks’ quiz? Click here!
