The top predator on Philip Island is a 12 inch long centipede with armored plating and a venomous bite. This monstrous creature preys upon sea bird nestlings, lizards (skinks and geckos), and crickets. It also eats the vomited fish and squid parent birds regurgitated to feed their chicks. About half of its diet consists of vertebrates, an unusual ratio for a terrestrial invertebrate. Scientists estimate 11%-19% of black-winged petrel chicks are lost to centipede predation every year. However, centipedes don’t prey upon white winged petrel nestlings because they are larger and can defend themselves against the centipedes.
Scientists think centipedes may be able to help restore the ecology of Philip Island. Originally, the island was covered with white oaks, Norfolk pines, and red legged grass; but sailors introduced goats, pigs, and rabbits as a food source, and the feral animals denuded much of the island of vegetation. People eradicated the animals about 40 years ago to save the island ecosystem. Centipedes eat the sea birds and transfer marine nutrients to the rest of the island in their feces. This added nutrition may help the trees and grass grow back faster.
The largest species of centipede in Georgia grows to about 3 inches long–1/4th the size of the Philip Island centipede. This species is known as the red bark centipede (Scolocryptis sexspinosus), and I have seen this species in my yard. They have a venomous bite that is painful to humans but not fatal. It can live up to 5 years and will molt its exoskeleton as it grows. They are predatory but not often seen because they are usually nocturnal and fossorial. Worldwide, there are 8000 species of centipedes. Though their name means 100-legged, their number of legs can vary from 54-354, depending upon the species. Centipedes don’t mate. Instead, the male drops off its sperm, and the female later comes along and engulfs it. Females defend their eggs, and some species even defend their young.
Reference:
Halpin, L; et. al.
“Arthropod Predation of Vertebrate Structures Trophic Dynamics in an Island Ecosystem”
The American Naturalist 198 (3) September 2021
Tags: black winged petrel, Philip Island centipede, red bark centipede
GeorgiaBeforePeople 
September 10, 2021 at 2:44 pm |
Thank you for the interesting article. I’m curious to know how did centipedes manage to colonize remote islands such as Philip Island? Was it by rafting?
From a more broad biogeographical point of view, what is the secret that centipedes have to achieve world-wide distribution? Most insects can fly (at least in adult phase) and arachnids such as spiders can colonize remote islands by ballooning. So do centipedes have a secret way to propagate themselves around the world over millennia?
September 11, 2021 at 12:36 pm |
Rafting is 1 way. Also, centipedes are such an old group of animals that they already existed before continents and islands drifted apart.