Friday, May 6, 2011

Cloudless Sulphur

Cloudless Sulphur laying eggs on Senna, Cassia spp.
Early Instar of Cloudless Sulphur on Senna
Munching Senna leaf, Cloudless Sulphur caterpillar
Cloudless Sulphur sheltering in Senna leaf
Killed by Wasp:  Decapitated Cloudless Sulphur caterpillar on Senna leaf
Beautiful Cloudless Sulphur caterpillar, chewing Senna. "Frass" is the word for caterpillar droppings.
Did you see that yellow butterfly?   What kind was it? 
Those lemony flashes are Sulphur butterflies.  If you prefer, you may use the "f" word and spell it "Sulfur".  They are fast, flitty and rarely alight long enough for my little camera to focus. There are different types of Sulphurs and each has a specific larval host plant.  Larval hosts include:   legumes, partridge pea, senna, acacia, clovers and alfalfa.  Adults will enjoy nectaring at your flowers. 

I have a shrubby senna tree (Cassia spp.).  It froze to the ground during our cold snap, but has cheerfully re-grown from the roots.  During April, this made my garden very popular with female Cloudless Sulphurs, Phoebis sennae.  Notice that the larval host is part of its scientific name.  You have to look closely to spot these caterpillars which are the same shade of green as the senna leaves.  The senna also offers physical protection for the larvae;  in the evening, the leaves fold together like butterfly wings, forming a shelter over the caterpillar. 

I was worried that the short plant could never support all the caterpillars I was seeing.  I needn't have worried because the wasps obliterated the caterpillars.  One day there were scores of larvae, in various instars, covering the senna.  A few days later, despite camouflage and hiding, only two remained.  I hope they were able to survive to pupate.  Timing is important.  When the next female Sulphur lays her eggs, the senna will be larger and the wasps may not be nesting.

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