Literature Review: Butterfly Range and Diet

by Carl Strang

This week’s literature review note is about butterflies. Usually we just think of butterflies as delightful, beautiful bits of nature, but those qualities also attract the interest of scientists. The scientists in this case are J. Slove and N. Janz (2011. The Relationship between Diet Breadth and Geographic Range Size in the Butterfly Subfamily Nymphalinae – A Study of Global Scale. PLoS ONE 6(1): e16057. doi:10.1371/journal.pone.0016057). The butterflies they studied are 182 species in the widespread subfamily Nymphalinae. Our local members of this subfamily include such familiar butterflies as the mourning cloak, question mark and red admiral.

Mourning cloaks pass the winter in the adult form, hibernating in a sheltering refuge.

Slove and Janz were interested in seeing if there is a relationship between the diet breadth and the geographic range of these butterflies. They wanted to test a prediction that species which eat more kinds of plants have larger ranges. The diet of interest is not that of the adult butterfly, but rather of the caterpillar.

Mourning cloak caterpillars eat the leaves of trees in several families, so they would be regarded as having a wide diet breadth.

It turns out that the prediction holds. The point is that there are a lot of different kinds of plant-eating insects. Some have broad diets, others have narrow ones. How did this diversity come about? The possibility being considered is that some insects have large geographic ranges, in part because by eating a number of kinds of plants they can spread over the collective ranges of those plants. Over the course of time, circumstances such as climate change (interposing a glacier or desert, for instance), geological events (raising a mountain range or sea, for example) and chance isolations (a few representatives driven to a remote island by a storm, perhaps) divide a wide-ranging species into separate groups that no longer can interbreed. Each group may then specialize on the reduced menu of plants available to them, and over time can evolve into separate species. This is called the oscillation hypothesis, because over a long period of time it predicts an alternation between wide diets and narrow diets within a genetic line.

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2 Comments

  1. Lourdes said,

    July 24, 2015 at 9:30 pm

    can u give a related literature about butterfly? i need it for my thesis pls help me thanks

    • natureinquiries said,

      July 28, 2015 at 5:41 am

      The reference is in the first paragraph of the text.


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