We have been inspired by books lately. In the last post, our inspiration was an adult-level book about katydids. Today it is the children's picture book Little Black Ant on Park Street by Janet Halfmann and Illustrated by Kathleen Rietz. The book is the next installment in the excellent Smithsonian's Backyard series. I reviewed the book at my Wrapped in Foil blog and putting up related hands on activities for children on my Growing With Science blog, but here I'd like to take a look at the biology of the species.
The little black ant, Monomorium minimum, is a relatively tiny species, native to North America.
The workers are black, uniform in size and only about 1/16th of an inch long (1.5 mm). The petiole has two segments.
Monomorium minimum belongs to the tribe Solenopsdini. The workers have antennae with a three-segmented club. Their fire ant relatives have a two-segmented club.
(Ant head and profile from wikimedia)
Unlike the stereotypical ant colonies with only one queen, colonies of little black ants often contain multiple queens.
Monomorium minimum workers feed on honeydew, and scavenge dead insects and other arthropods, usually during the warmest part of the day. When foragers find a suitable item, they recruit nest mates by releasing a pheromone. Once recruited, groups of workers cut up larger items or cart away smaller ones.
As described in the book, when workers of M. minimum run into other ant species that scavenge dead arthropods, the minimum workers raise their gasters, vibrate and release poison gland secretions to chase away any rival ants. This behavior is called "gaster flagging."
Here's a short video of gaster flagging in another species.
For a little ant, they pack a big punch. Monomorium minimum colonies can invade imported fire ant, Solenopsis invicta, colonies and take over.
Given that these little ants are so interesting and relatively widespread and common, I'm surprised how little information I was able to find on them. Perhaps this new children's book will spark some scientific inquiry by the next generation of myrmecologists.
Eldridge S. Adams and James F. A. Traniello. 1981. Chemical interference competition by Monomorium minimum (Hymenoptera: Formicidae). Oecologia. Volume 51, Number 2 / January, 1981. pdf available
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