Do Ants Kill Spiders?
WouterWhether or not ants kill spiders depends on the species of spiders. There are some that prefer ants, while others are detritivores. Ants are omnivores, eating a variety of food including spiders. They can also break down spider protein to help build other proteins, such as enzymes.
There are also some spiders that are “myrmecophagous” – they eat only ants. These spiders are part of a group of free-living solitary predators. They are characterized by a distinctive pheromone – a chemical signal that enables spiders to entice other predators.
Scientists have not studied spider myrmecophiles as extensively as spider myrmecomorphs. Some spider myrmecophiles, such as Zodarion alacre, have weak similarities to ants. Others, such as Zodarion rubidium, eat only the front ends of ants.
Researchers placed banded sugar ants near spiders and recorded interactions with high-speed video cameras. They also studied chemical traces left by the ants. Some ants, such as European fire ants, are particularly aggressive.
Ants and spiders often live in the same habitat. However, spiders have evolved in ways to avoid aggressive ants. Some spiders use Batesian mimicry to deceive predators. They pretend to be dead ants or carry them as shields. These mimics have been found to be particularly effective in preventing predators that dislike ants from attacking.
In order to determine whether or not ants kill spiders, Fischer and colleagues gave young female spiders a series of different ant types. They used small, medium, and large whole ants, as well as gasters. They also gave them a protein-rich diet. They found that spiders that were given only whole ants did not develop as quickly as those that were given gasters. However, spiders given a front-end ant part had a longer lifespan.
