Living Sanibel: Florida Ivory Millipede plays vital role in ecological cycle
Florida Ivory Millipede
There are more than 10,000 species of millipedes worldwide. The largest of these, the giant African millipede can grow to 11-inches. Almost all millipedes are detritivores, eating little else than decaying leaves and other dead plant matter. Fossil records indicate that the first known land creature was a 1 centimeter long (0.39 in.) millipede that ate mosses and decaying plants some 428 million years ago, during the Silurian geologic period. The basic shape and diet of this species has changed very little since then.
In the past decade the Florida ivory millipede has become increasingly populous on Sanibel and Captiva. They can be seen in the Bailey Tract, as well as the Sanibel Gardens Preserve, from Wulfert Point to the Lighthouse. The juveniles are roughly an inch long while the mature millipedes can grow to be 4-inches long. They have the unwelcome tendency to get into garages, workrooms and even into houses where, lacking the detritus they need to survive, they soon curl up and die. Sweeping up dead ivory millipedes has become a common chore for many islanders.
Millipedes play a vital role in the ecological cycle of life. They turn decaying wood and plant life back into soil and rid the under story of excess thatch. They are also heavily preyed upon by snakes, birds and reptiles. Fire ants will also overwhelm these slow crawling insects, biting them into a state of shock, then consuming them. They are completely harmless to people, but some millipedes do contain defensive chemicals, which can cause minor skin irritations. Their only real defense against predation for the Florida ivory millipede is to curl up into a ball, exposing their hardened outer shell and protecting their soft underside.
Upon your first encounter with this formidable looking insect, your initial reaction might be to run. Grandpus bugs look altogether too similar to scorpions and the long whip appears ready to strike at any moment. The strange thing is that the whip is harmless and grandpa bugs are non-venomous. Their appearance is far more frightening that their bite, or complete lack thereof.
Grandpus bugs are a form of spider, though more closely related to true scorpions than your typical spider. They have a unique defensive mechanism that sprays a foul smelling odor made up of acetic acid when attacked. That is the main ingredient in vinegar, hence the nickname vinegaroon. The best place to find a grandpa bug is under old rotting logs, rocks or inside of water meter boxes. They do look scary and despite the fact that they really cannot hurt you, I doubt anyone who finds one would be willing to put it in their hand.
They feed on millipedes, caterpillars, cockroaches and crickets. They are fed upon by armadillos, opossums, rats, mice and snakes. They are considered a beneficial species in that they help to keep the cockroach and millipede population in balance.
This is an excerpt from Living Sanibel – A Nature Guide to Sanibel & Captiva Islands by Charles Sobczak. The book is available at all the Island bookstores, Baileys, Jerry’s and your favorite online sites.