A Backyard Insect Safari
WILLIAM DUNSON
Too often we think that we have to go to a far country to see fantastic animals. However if you extend your gaze towards the insect world you may find a remarkable menagerie right in your own backyard. Here are some examples from my own yard in Boone, NC, during a month-long period in mid-summer.
This tulip tree silk moth may have fed on nearby tulip poplar trees as a caterpillar but adults live for only a few days and do not eat. They exist only to breed. The right eye spot and a piece of the hind wing are missing, likely the result of bird attacks.
This harmless fly on a black eyed Susan flower is a convincing mimic of a bee and thus presumably obtains some protection from bird attacks. Flies have only one pair of wings compared to two pairs in bees, but birds must be convinced this would be a painful prey anyway due to the realistic coloration.
While sitting on my front porch I witnessed a life and death struggle between a rusty spider wasp and a large and ferocious rabid wolf spider. The wasp expertly stung the spider and paralyzed it so that an egg could be placed on it. Quite a gruesome death to be consumed by a wasp larvae!
One of our most common butterflies is the pipevine swallowtail which feeds on toxic pipevine as a caterpillar. I found a caterpillar in our yard which is black and orange to advertise that it is toxic. The adult is also toxic due to chemicals sequestered by the larva and advertises this by a black and iridescent blue coloration of the inner wings. Several other butterflies such as the red spotted purple and black tiger swallowtail mimic this coloration in order to deter bird predation.
Another method of diminishing the effect of predation is illustrated by a gray hairstreak which was finding nectar on a cone flower in our yard. Note that it has two false antennae and eye spots (making a false head) on the rear of the hindwings. This misdirects the strike of a predatory spider or bird away from the vulnerable head region.
A beautiful monarch stopped to feed on a Brazilian vervain/verbena that we planted. It is famous for retaining toxins from milkweeds which the caterpillar eats and advertises its toxicity by orange and black coloration. A number of other butterflies such as the viceroy mimic this pattern to gain protection from birds.
One of the stranger habits of butterflies comes from their need for sodium which is not common in their plant food. They apparently recognize the smell of sweat on mammals and will drink it to gain this salt. So when I was sitting on my porch after working in the yard, a great spangled fritillary landed on my leg and starting sipping my sweat! They will also drink the fluids from vertebrate feces which may gross us out but provides a vital nutrient for them.
So enjoy the wildlife in your own backyard. There is a wonderful world there at a smaller scale than the "charismatic megafauna" of Africa, but equally intriguing in many ways.
Bill Dunson
Boone, NC and Englewood, FL
http://lemonbayconservancy.org/news-blog/nature-notes-by-bill-dunson/
