The Myrmecophilidae are a little-known family of crickets that make their living by stealing food from ants. The approximately 200 species of ant cricket are distributed worldwide but their habits are obscure because they lurk inside ant colonies, making them difficult to track and observe.
In the March issue of the journal Zootaxa, Brazilian scientists report that they have rediscovered Myrmecophilus americanus following a 120-year absence from the entomological record in their country. The species was first documented in 1904 and 1905 in the state of Pará, but has not been seen in Brazil since.
Two of the paper’s authors found them hopping around their own houses in the state of Paraíba, suggesting that these insects have been hiding in plain sight for over a century.
It is easy to see how it might have been missed – the crickets are tiny at 2–4 millimetres long. And they associate with a single species of ant, the longhorn crazy ant (Paratrechina longicornis), named for its strangely random patterns of movement.
The longhorn crazy ant is considered one of the most widely distributed species of ant in the world. It may have originated in Africa or Asia.
“During our research on the ant’s origin, we found that the most likely hypothesis is that it originated in the Indian subcontinent,” says lead author Alessandre Pereira Colavite.
M. americanus was first identified in Colombia in 1877 – but probably trailed its ant hosts from their original environment.
“We believe the relationship between these two groups is historical, in a process we refer to as coevolution,” Pereira Colavite says. “The crickets likely traveled with the ants to different regions of the world – though of course, that doesn’t mean all colonies are parasitised by them.”
Indeed, the kleptoparasitic ant crickets don’t seem to have managed to trail the species everywhere. The reasons may be climatic – the longhorn crazy ant is present in Florida, for example, but the crickets only appear in ant nests in the southern region of the state.
“In more unstable or extreme environments, ants may adopt more aggressive or selective behaviours, limiting the presence of associated organisms,” Pereira Colavite suggests.
The crickets can be seen following the ants as they escape from their nest during an army ant (Neivamyrmex sp.) raid in a video posted by the scientists.
“I noticed a group of small crickets – about five individuals – standing still along the ants’ pheromone trail. At first, I thought they were early-instar nymphs of common crickets,” recalls Pereira Colavite, a biologist who serves as an adjunct professor at the Federal University of Paraíba.
A series of additional citizen science reports on the platform iNaturalist indicate that the crickets have likely been flourishing, according to the paper.
These crickets are the antithesis of Disney’s Jiminy Cricket: they have no conscience at all.
They are thought to escape detection by scraping cuticular hydrocarbons from both living and dead ants and applying them to their own bodies – thus leading the ants to mistake them for nestmates.
They use their hindlegs to imitate grooming behaviour and thus elicit feeding behaviour from the ants – which regurgitate food for them. However, sometimes their olfactory camouflage fails them and the ants tear them limb from limb.
Main image: Myrmecophilus americanus. Credit: Alessandre Pereira Colavite et al.
More wildlife stories from around the world
- Dusty old moth found in London museum leads taxonomists to remarkable discovery
- The deadliest parasites in the world: 10 terrifying creatures you will want to avoid
- Ancient creatures found encased in amber in remote forests of Myanmar
- Asian hornet guts contain more than 1,400 different species, new study finds