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Tuesday, July 8, 2014

Two Heads Are Better Than One


Juniper Hairstreak, Callophrys gryneus 

Hairstreaks are mainly small butterflies, most with threadlike tails on their hindwings.  They typically fly rapidly, fitting from side to side or in circles, before sticking a landing.  Most perch with their wings closed, and reveal their upper surface only in flight.  Males and females can look quite similar, but the males will often be the more vibrantly colored of the two.  



In central Texas we have three common hairstreak butterflies.  The largest, as indicated by its name, is the Great Purple Hairstreak (Atlides halesus).  Dusky purplish-black below and brilliant blue above with red spots near the base of the wings and a bright orange abdomen, this butterfly flies spring through fall.  It tends to stay well above the ground, and males will sit on trees on hill summits or flat plains to await females, mostly in the afternoon.  Its larval foodplant, or plant upon which the female lays her eggs, is mistletoe species in the genus Phoradendron.  


Great Purple Hairstreak, Atlides halesus 

Another commonly encountered hairstreak is the Gray Hairstreak (Strymon melinus).  It has only one tail on the hindwing and an upperside that is blue-gray with a large reddish-orange spot near the tail.  The male's abdomen is orange and the female's is gray.  In the spring and fall its underside is dark gray, and paler gray in the summer, but it always has a dashed white line, parallel and inset from the wing's edge, bordered with orange.  It flies from February to November and is the most widespread hairstreak in North America.  Males perch all afternoon and into evening on small trees and shrubs to seek receptive females, who lay eggs one at a time on a wide variety of plants including peas, mallows, beans, clovers, and cotton.  



Gray Hairstreak, Strymon melinus

One of our most beautiful hairstreaks is the Juniper Hairstreak (Callophrys gryneus), belonging to a group called Evergreen Hairstreaks, which are widespread and variable.  The upperside of the male is dark brown with an olive-colored sheen, and the female is blackish brown.  Their underside is a vibrant green with two white spots near the base of the forewing and an irregular white line edged inwardly with a reddish-brown.  Males perch on host trees, those in the genus Juniperus like our native Ashe Juniper, awaiting females.  They perch with their wings closed and blend into the junipers so well that they may not be noticed until moving branches cause them to fly.   


Juniper Hairstreak, Callophrys gryneus 

When it comes to survival, hairstreaks have developed an interesting adaptation, much of which has to do with their tails.  Often having distinct markings or spots near these tails, together they form what is known as a 'false head' with the tails looking like antennae.  The illusion is carried further when the hairstreak performs a back-and-forth 'sawing' motion with the hindwings when resting. This motion can distract would be predators such as spiders, causing them to attack the wrong end of the butterfly, leaving the vital structures intact.  



Missing tails and part of the lower portion of the hindwings does not hinder flight, and the butterfly lives to carry on another day.  So it really is true that two heads are better than one!