Ant Crazy

Several months ago I went to our pantry to retrieve a box of raisin cereal.  To my horror it was filled with hundreds perhaps thousands of little black ants with a line of them leading to a tiny hole in the wall.  These were crazy ants or longhorn crazy ants (Paratrechina longicornis), named for their seemingly random, rapid and jerky foraging activities. 

They are brownish-black, about three millimeters in length, with extremely long legs and antenna, and have a blue iridescence.  As I came to find out, they are an invasive species in Florida, considered to be a minor picnic pest; they can also be a major house pest and are extremely difficult to eradicate or control.  No exterminator would guarantee that they could get rid of them.  Most promised that they couldn’t.

I have observed these in and around my home in Central Florida and here are a few reasons they are so difficult to keep out of your house (and effective as a species).

• They can make a nest almost anywhere.  I have found them under leaves, in soil, in the crotch of a tree, in a house gutter, on a palm leaf, in the wall of a house, inside a tiny metal pipe, and exposed on the bottom side of an elevated fire pit.   I recently discovered a nest within the nest of Florida carpenter ants (Camponatus floridanus).  There didn’t seem to be any symbiotic relationship, and the carpenter ants seemingly ignored their presence.
• They have multiple nesting sites within a single colony. I have seen companion nests over 75 feet away from other nests, yet the ants can be observed traveling in a line from nest site to nest site even at that distance. They will have multiple queens in this single colony, as many as 40.
• These nests also appear to be temporary, and I often observed them moving the entire nest in a mad dash to another location.  They workers held the eggs and pupa high in the air as they scurried single file to a new nesting site.  I have not been able to determine why they do this.  Perhaps the nest was destroyed, overpopulated or some other reason.  This activity seems more commonplace in the warmer months.

  

• They run away from a disturbed nest site and hide until the danger has passed.  When you disturb a nest many ant species will scramble to the defense and move larva and pupae deeper in the nest.  One day I found a Paratrechina longicornis nest in the crotch of a tree, and once disturbed, the worker ants fled the nest in every direction carrying the young.  Most of them went a few feet away and hid deep in the crevices of the bark.  Later, after the danger was past, they returned to the nest with the pupae.  I can imagine this behavior apparently makes it harder to destroy the nest by digging through it.

  

• These omnivores forage for almost anything that might provide a food source. They will eat seeds, sugars, other insects, human food scraps, fruit, honeydew from homopteran such as mealy bugs, and apparently raisin cereal.  I have noticed, though, that their taste varies with the season of the year.  This makes baiting difficult.  These also forage far from their nest which makes nest location difficult.

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