Wednesday, August 3, 2016

Rattlesnake Master or Hairstreak Master??

If there is one species of butterfly that gets the lepidotera-philes scales to stand up on end, it’s the juniper hairstreak, Callophrys g. gryneus.  When I run into folks on the Edge that are seeking out butterfly species, the juniper hairstreak is always on the top of the list.  And usually, it is a butterfly that is seen uncommonly.  In fact, I usually see this small butterfly only a handful of times each year.  But the last 2 years, I have been observing a plant called rattlesnake master, Eryngium yuccifolium, growing along the sidewalk to the Eulett Center, and have been amazed at the species diversity that feeds/visits this plant, one of which is the juniper hairstreak.  I would say this plant is mis-named as I have never seen a rattlesnake around the plant, but it sure attracts hairstreaks.  Now granted, the Eulett Center is surrounded by numerous Eastern red cedar trees, Juniperus virginiana, the host plant of the juniper hairstreak’s caterpillar, but the numbers of juniper hairstreak's this year has been phenomenal.
Juniper hairstreak on rattlesnake master, avoiding the white-banded crab spider, Misumenoides formosipes on the left.
Throughout July, every time I walk the 100 foot long sidewalk of the Eulett Center, I'd check out the 100 or so individual rattlesnake master plant heads.  And this mid-July, it was not hard to find dozens of juniper hairstreaks feeding.  On July 20, 2016 I counted 55 juniper hairstreaks while walking up the path.  10 of them were in one clump of flower heads. 

Numerous juniper hairstreaks on rattlesnake master

Notice the green scales on the wings of our only "green" butterfly.
Rattlesnake master is a prairie plant native to this part of Ohio, and grows commonly in the preserve's prairies.  But this is not a common plant outside of prairie openings in Ohio.  If you want to attract juniper hairstreaks, and you have Eastern red cedars near-by, try planting rattlesnake master on your property.  If there are any juniper hairstreaks around, they will find it.

This plant is incredibly fun to watch blooming in July to see how many flies, wasps, beetles, spiders, moths, bees etc. land on its many flowers.  Below are some interesting species seen visiting rattlesnake master.  
A feather-legged fly, Trichopoda sp.

Great black wasp, Sphex pennsylvanicus
Black and yellow lichen moth, Lycomorpha pholus
Juniper hairstreak near striped lynx spider, Oxyopes salticus
Spotted thyris moth, Thyris maculata
Myzinum wasp, Myzinum sp.
A potter wasp, Monobia quadridens
A paper wasp, Polistes exclamans

Posted by: Mark Zloba