Sunday, January 8, 2017

Where are they now?

Everyone seems to be pretty well informed about the migrations of monarch butterflies in North America. Long distance southbound fliers end up in southern states in the east and in refuges in California and Mexico in the west. In spring, northbound females lay eggs that hatch into butterflies that fly north and lay eggs, reaching further north with each generation until the far reaches of monarch territory are repopulated for the year. So their current whereabouts are accounted for.  But what about other kinds of butterflies?                     
The common cabbage white butterfly, Pieris rapae, for instance. Cabbage whites are still here. They are hunkered down for the winter in the chrysalis stage. Click to enlarge.
Red-spotted purple butterflies, Limenitis arthemis, spend the winter in the caterpillar stage. The caterpillar makes a little shelter called a hibernaculum from a leaf and attaches it with silk to one of its food plants. When it wakes up in spring it is close to a food source and ready to start eating. 
Question mark butterflies, Polygonia interrogationis, like this one hibernate as adults in sheltered spots like hollow trees or crevices and in human built structures. 
There are even some butterflies that overwinter as eggs. So for every stage of the butterfly life cycle, there are species that spend the winter that way -- as an egg, larva, pupa (chrysalis), or adult. You can find them on plants, in leaf litter, under tree bark, in your garage, and wherever they decide to shelter. They're out there in the cold right now, under the snow, and on branches bending in the winter wind. On this 20 degree day in New York City it is reassuring to be reminded that spring is coming.

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