Vera Antonova with the Institute of Biodiversity and Researches of Ecosystems at the Bulgarian Academy of Sciences in an interview with FOCUS News Agency
FOCUS: How do the high temperatures influence the population of ants?
Vera Antonova: The situation with household ants is the same like the situation with cockroaches. The conditions inside houses become very suitable to grow up the offspring of ants, larvae, that’s why their number increases. There are several species of household ants and they breed at a different time. Most of them breed now in July and August and that’s why there are more of them in houses. Winged ants are the mating ants – female and male – and they breed at this time. Worker ants – those we most frequently come across – are considered to be asexual. They are female, but with undeveloped organs. Their number goes up in the summer too, but you can come across mating ants most frequently now.
FOCUS: Does this mean that the warmer the weather is, the more they breed?
Vera Antonova: You can say that the number of mating ants increases, because they need such temperatures and right now they are suitable. I have not heard of a larger number of ants than in previous years.
FOCUS: What attracts ants into houses?
Vera Antonova: There are ants mainly in hotels and restaurants. Only food attracts them to households. There is a large number of ants in graveyards, because people leave food there.
FOCUS: Where are the most frequent shelters of ants in households?
Vera Antonova: In walls. They are not afraid of heights. They creep on sewerage pipes, in hollows. There are cases of houses destroyed by very large nests of ants. The nests become so big and the ants make so many hollows in the walls that the house collapses.
FOCUS: Are there little known facts about ants?
Vera Antonova: There are queen ants which enter the nests of another species of ants, kill their queens and take their place. The new queen in the nest lays eggs, but its smell changes in such a way that the ants in the nest do not take it as an alien entity.
FOCUS: How many species of ants are there in Bulgaria?
Vera Antonova: About 110.
FOCUS: How big is this number in comparison with other countries?
Vera Antonova: Ants increase as you move to the south. In the Scandinavian countries there are about 20 species.
FOCUS: Where is their number the highest?
Vera Antonova: In the tropics. There are hundreds of species there. Not all ants in the tropics have been studied. It is impossible to study them, because there they nest in the trees and it is very difficult to reach them. In our latitudes they dig in the ground.
In Bulgaria there are two species of ants that have come from the tropics. They were brought here and manage to live in houses, hotels, restaurants. There are two or three species which live in external and internal conditions.
FOCUS: What is the difference between these 100 species in Bulgaria?
Vera Antonova: They differ mainly in their outer appearance. Their distinguishing marks are their external features. There are species that are very similar and then DNA analyses are necessary.
FOCUS: How long do they live?
Vera Antonova: A queen lives about 20 years, while a worker between a year and 5-6 years at the longest. Males leave their sperm in females and die. Females eat their wings. Most of them fall victims to birds, because they are an easy prey; they are heavy and fat ants and are eaten up. About 5-6% of them dig themselves in the ground, find a suitable shelter under a stone, in a hole, in a crack and start laying eggs. They take care of the first eggs on their own and the first workers – 5-6 up to 10, for example – are bred and they start taking care of the queen, start building new chambers and enlarging the nest. This queen does not go out any more. The female that lays the eggs remains inside.
The interview has been abridged.