Tuesday, March 8, 2016

Another Sign of Spring

Spring Azure - REK
Spring Azure female - Bob Moul
We have been seeing lots of Goatweed Leafwing and Mourning Cloak butterflies over the last 3 warm weeks.  These are butterflies that overwinter as adults, sheltering under loose bark and coming out on warm days to stretch their wings and look for a snack of tree sap.  Last week a few anglewings also appeared but Saturday the most welcome sight was the appearance of Spring Azures flitting along the gravel drive in front of my sniffing terrier.

Spring Azures, Celastrina ladon, are to butterflies like the Harbinger of Spring, Erigenia bulbosa,  is to wildflowers, a tiny message from nature that spring is officially here regardless of what the calendar says.  Watching these two tiny creatures measuring less than an inch leading us down the drive I could almost hear them giggling in delight at the prospects ahead.

Violacaea form - Bob Moul
There are three identifiable forms (color patterns) among Spring Azures.  Violacea has scattered dark spots.  The marginata form has a dark band on the hindwing while lucia has dark borders on both wings and a prominent dark splotch in the middle of the hind wing.  While these names are catnip to the butterfly aficionado, to me they simply mean there is a confusing color variation in the species.

Marginata form with dark band on hindwing - Bob Moul

Lucia form - Tom Murray

Early spring is a delicate balancing act between flora and fauna.  No one knows for sure what prompts a shrub to bud at a certain time but early butterflies are gambling that it will occur in time for the eggs they are ready to deposit.  It is even a bigger gamble for these specimens as there doesn't seem to be a source of nectar in sight.

Zebra Swallowtail egg already perched on an unfolding leaf - REK
This delicate timing reminded me of an early April day two years ago when I walked through a dense pawpaw grove.  In all those trees there were only three buds that were open, but there glistened a yellow egg of a Zebra Swallowtail, whose caterpillar soon would munch on the tender leaf as it unfolded.  Timing is everything at this time of year.  How they do it without a calendar or weather forecast is another of nature's great mysteries.

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