20 February 2006

An upside down butterfly


This is a gray hairstreak (Strymon melinus). The only time I had a chance to photograph this species was last August in my backyard. If you look closely, you will notice that this individual is missing a small portion of its hindwing, including one of the pair of hair-like tails it had. In a previous post I had a picture of a butterfly with wings in much worse condition.


Beth at Fireforest Blog notes that these butterflies seldom leave their wings open when they are nectaring. Nevertheless, she was able to photograph one with its wings partially open.


biosparite said...

It is believed the faux antennae and the color spots at the rear of the hindwing serve to divert birds from pecking anything critical during an attack. You will also notice that when the wings are in the normal, closed position, the butterfly will rub the wings back and forth along the plane of their contact so as to keep the color spots and diversionary antenna structures moving, further inviting a predator to strike at the posterior part of the hindwing. The large numbers of hairstreaks missing their hind structures but still flying are mute testimony to the efficacy of this diversionary strategy.


Yes, I have noticed that hairstreaks have the habit of moving their wings back & forth. But, I wouldn't call that an "invitation"; it wouldn't be very meaningful for an animal to purposefullly invite or provoke a predator to attack it.

biosparite said...

Perhaps diversion is the better word. In case of an attack, losing some posterior wing material is much preferable to being pecked elsewhere.