While on a walk at Amberjack Preserve in SW FL we noticed an interesting phenomenon – a mating pair of walkingsticks. This appears to be the large two striped walkingstick, but there are northerly species also. This cousin of the grasshoppers is peculiar for its resemble to a stick, which probably serves it well as camouflage against attacks by predatory birds. The necessity for it to take on this disguise also tells us how persistent and successful birds are in searching for insect prey. But birds that attacks this seemingly defenseless creature are in for a rude surprise- this bug has an attitude and a weapon to defend itself! It can accurately squirt a fluid containing terpene dialdehyde into the eyes and mouth of an attacker and this can cause intense pain and temporary blindness. Here is one account of the effects on a human:
The victim was observing a pair of Anisomorpha buprestoides . . . with his face within two feet of the insects, when he received the discharge in his left eye. . . The pain in his left eye was immediately excruciating; being reported to be as severe as if it had been caused by molten lead. Quick, thorough drenching with cool water allayed the burning agony to a dull aching pain. The pain eased considerably within the course of a few hours. Upon awakening the next morning the entire cornea was almost a brilliant scarlet in color and the eye was so sensitive to light and pressure for the next forty-eight hours that the patient was incapacitated for work. Vision was impaired for about five days.” Symptoms gradually disappeared and there were no lasting effects.
Another interesting aspect of this pair of insects is the disparity in size between the tiny male and the much larger female. Since in humans the male is generally much larger and stronger, this reversal in sizes of the sexes might seem curious. However it is probably more common in animals for the male to be smaller and assume his primary role, that of a “sperm bag” whose main purpose is to inseminate the female. Species with larger males generally are involved in male combat for territory and females. But it is obvious that the larger a female, the more young it can produce.
So let us learn from the humble walkingstick- speak softly, hide in the bushes, and squirt your attackers with a powerful toxin!
Bill Dunson, Englewood, FL & Galax, VA