Ants. Anybody else being bothered by these little pests? These are no bigger than a full stop and are everywhere lately. For several days we have been tracking a line of them in and out of the house, marching in a line, one lot going one way the other lot going the other, seemingly stopping for a quick chat. What are they doing?

Apparently, they are communicating - touching each other with their antennae when they meet, and these antennae are highly sensitive, containing both touch and smell organs. Each ant colony has a unique smell, so members recognise each other and sniff out intruders. All ants produce pheromones, and they can follow these scent trails back and forth to their nests – and are also able to smell the food others have collected.

The colony that vomits together…

Another thing I found out - ants share vomit to feed each other and communicate within the colony. Feeding through regurgitation is called trophallaxis and is known in many animals, and this seems to also serve an important role in organising the colony, suggesting it helps keep the members of the colony connected. It has been suggested that this behaviour has a few functions, but a major one is to create what is called a ‘social circulatory system’ for the colony. Ants are passing along proteins, hormones, and fragments of genetic material — RNA, a sort of DNA.

In colonies, the exchange of vomit can be seen happening 20 times in a minute. The vomit is usually a clear liquid.

Three stomachs!

Like a lot of other insects, ants have a foregut, midgut and hindgut. The midgut and hindgut are for digested food. The foregut is known as the ‘social gut’ because this is where material is stored before it is vomited into another ant's mouth. (urgh).

There must be a huge colony under my house, because they all seem to be stopping and passing on their disgusting vomit, totally circling the outside of the house, with some veering off to explore the wall and disappearing in the roof. I try to be so careful with crumbs, but they find them, even swarming over a bottle top that escaped our notice.


Called ‘formigas’ in Portuguese, they can become a problem as they furiously dig holes and take food back into their nests, eating just about anything. There are more than 10,000 types of ants, not all here thankfully, and their diet includes sugary nectar, as well as dead insects, seeds, plants, and fungus. Ants also drink water, which they find in sources like dew.

Credits: Unsplash; Author: @miic;

Other critters eat them, including beetles, caterpillars, flies, spiders, snails and snakes. Then come lizards, birds and fish – even some mammals. (Wish some would stop by at the apparent buffet here.) A newly mated queen lays a cluster of about a dozen eggs. When they hatch 7 to 10 days later, the larvae are fed by the queen. Later on, a queen supplied with food by worker ants can lay up to 800 eggs per average day. Ants have a caste system, where responsibilities are divided. The queen is the founder of the colony, and her role is to lay eggs. Worker ants are all female, and this sisterhood is responsible for the harmonious operation of the colony.

Their tasks range from caring for the queen and the young, foraging, policing conflicts in the colony, and waste disposal. Workers will most likely never have their own offspring. The vast majority of eggs develop as workers, but once the colony is ready the queen produces the next generation of reproductives which will go on to start their own colonies. The poor old male ant adults live for only a few days and die after mating with the females.

How long do ants sleep?

A recent study of ants' sleep cycle found that the average worker ant takes approximately 250 naps each day, with each one lasting just over a minute. That adds up to 4 hours and 48 minutes of sleep per day, which means they are pretty much free to invade your home at any time!


Marilyn writes regularly for The Portugal News, and has lived in the Algarve for some years. A dog-lover, she has lived in Ireland, UK, Bermuda and the Isle of Man. 

Marilyn Sheridan