The Yellow Crazy Ant

The first time I heard about this ant, I thought that maybe the name was just a nickname…but I soon found out that it was not. The Yellow Crazy ant got its name from the frantic frenzy of movements that it does when foraging, it is also in the 100 most destructive species list. Truly an ant that deserves the name it has!

The Yellow Crazy ant was introduced by accident to Christmas Island in the Indian Ocean and to Australia. It is making a nuisance of himself in both places; scientist really don’t have an exact idea as to where this ant even came from, they think that maybe the place of origin is in Africa, India or maybe even China. These are ants that known how to survive and they also know how to take advantage of their environment; they can make a nest out of anything, they can nest in the ground, in palm trees or even in your potting soil. When they get introduced to a new place, their effect on the ecosystem is devastating.

The exotic Yellow Crazy ant is deadly…about 70 years ago this species of ant got introduced accidentally to Christmas Island - that can be found out in the Indian Ocean – and it quickly got a foothold and started to take over. The Yellow Crazy ants are not hard to see, you can identify them by their light yellow coloring and super long legs and antennae. On Christmas Island, the problem started when the Yellow Crazy ants began to form super colonies.

In a normal ant population, there is one queen with all of her adept followers; these colonies almost always fight with their neighbors and in so doing, they keep each other under control. What the Yellow Crazy ants started to do was to create super colonies; that is a whole bunch of queens and their armies banded together and formed the super colony.

The very first super colony to be discovered on Christmas Island was on a high terrace in 1989, this colony was isolated and eventually died out, but it was not long when they discovered more super colonies that had formed in 1995 and 1997; at least 10 different places were found with super colonies….these colonies were several hectares to a square kilometer.

These super colonies affected some 2500 hectares of the Island or 25% of the forest…when a super colony had established itself, it can double its size in a matter of months, or to put it in other words, it can expand 3 meters a day. Now that is scary!

The devastating effect of the super colonies on the island are readily apparent…these ants can overpower reptiles and coconut crabs, an estimated 20 million red crabs have been killed by these ants, about 30% of the Island’s entire population. The ants succeed in their killing sprees by injecting an acid into the eye of their victim, this acid is poisonous to the red crabs and it blinds them leaving them to starve to death or be killed by predators. If the red Crabs are wiped out completely, the entire ecosystem of the Island will be changed because these crabs live on the forest floor, they eat saplings and turn the soil with their burrows, they also fertilize with their droppings therefore if these crabs disappear, then the effect will be devastating.

The Ants also protect scale insects that harm plant life in general, they harvest the scale insects which suck sap from the trees, the ants take this sap and convert it into honeydew, which they then eat. Because of the little relationship that the two have got going, the scale insect population has greatly increased causing the local plant life to suffer and die.

The native birds have also suffered from this little pest, there is one type of bird named the Christmas Island Frigate Bird that they estimate will decline in population by 80% in the next 20-30 years.

The years 1999 and 2000 were spent with park officials trying to figure out how to make a bait that would kill the ants but be harmless to other animals and people on the Island; it took a while, but there was finally a bait formed that was named Fipronil, it was a fish protein that attracted the ants and a poison that killed them. This form of control has proved successful, but they say that a better one is still needed because the Yellow Crazy and is always three steps ahead.