When I was about 7 or 8 years old, my biology-professor dad brought me a present home from work: a jar of sticks. Or at least that’s what I thought it was. When some of them started moving he explained that they were stick insects. I kept them for a while and found them fascinating. They weren’t cute and cuddly but they had something else: they were cool.

Seems I was ahead of my time. Last month, two Belgian teenagers were released from jail in Kenya after paying a fine for wildlife piracy. Their crime, to which they pleaded guilty, was attempting to smuggle 5000 ants out of the country. Smuggled ants often turn up in what reports describe as a “booming” global trade in exotic invertebrate pets. Their haul included giant African harvester ants (Messor cephalotes). A colony of these highly prized mini-beasts sells for around £170 in the UK.

Ants are by no means the only invertebrate group being traded and kept as pets. The menagerie also includes spiders, scorpions, mantises, beetles, cockroaches, grasshoppers, snails, slugs and, of course, stick insects.

A recent review found that almost 1000 invertebrate species are being traded on the exotic pet market. Some are traded legally, but others are contraband. Giant African harvester ants, for example, are a protected species in Kenya.

Keeping invertebrates as pets may seem like a harmless hobby, but it can have serious consequences for biodiversity. Putting firm numbers on any of this is difficult, but an estimated two-thirds of the arachnids on the market are poached from the wild. In Mexico, overharvesting of Brachypelma tarantulas has caused significant population declines. In the limestone karsts under the Dinaric Alps of south-eastern Europe, poachers of troglobionts – animals adapted to living in caves – have helped to push several already-endangered insects closer to extinction.

Unsustainable harvesting also damages the wider ecosystem. Invertebrates are an important food source for many vertebrates, and they supply vital ecosystem services such as decomposition and nutrient cycling.

Poaching destroys habitats directly. Many prized tarantulas live in vase-shaped plants called bromeliads, which also provide a home to frogs and other animals. According to Caroline Sayuri Fukushima at Tarantupedia, an online taxonomic database of large spiders, the poachers just chop the plants down, killing them and their captive ecosystems. In the Balkans, the poachers set pitfall traps that kill thousands of non-target species.

Exotic invertebrates are also a threat to the locations where they end up. Indeed, 57 ant species known to be traded are classed as invasive by the International Union for Conservation of Nature (IUCN), and 13 of them are among the top 20 worst global ant invaders.

Stopping the trade will be very difficult. The Kenyan judges – who sentenced the Belgians to either a fine of 1 million Kenyan shillings (£5700) or a year in jail – reportedly said they wanted to send a strong message that trafficking of all protected wildlife is unacceptable. But people must be getting away with it. I found several websites advertising giant African harvester ants, which live only in East Africa.

The Belgian teenagers were caught red-ant-handed, but according to the authors of a 2022 survey of the global arachnid trade, smuggling invertebrates is relatively straightforward, at least compared with smuggling vertebrates. They are small and easily concealed, and aren’t picked up by X-ray machines or thermal cameras at airports. Protected species can also be laundered as legally tradeable ones, as customs officers lack the taxonomic expertise to tell them apart.

It’s the same old story of greed, exploitation and destruction. But it doesn’t have to be like this. According to biologists who study it, the trade in invertebrates can be a force for good. Sustainable harvesting of wild species can support the livelihoods of some of the world’s poorest people, while also diverting them away from more harmful acts such as illegal logging. Increased recognition of the trade is stimulating much-needed research on wild populations of target species and their conservation status. It is also getting organisations such as the IUCN to pay attention to a group of animals they have historically neglected.

As for the collectors themselves, they are obviously interested in the amazing variety of life on this planet, and could also be recruited into the fight to save it. I think they should be allowed to indulge their hobby, albeit within a well-regulated system of sustainably harvested or captive-bred, non-invasive invertebrates. I won’t be getting any more stick insects, but they certainly helped to stimulate my interest in the natural world.

What I’m reading

Many Things Under a Rock: The mysteries of octopuses by David Scheel.

What I’m watching

The Survivors on Netflix.

What I’m working on

The York Festival of Ideas is on this week, so I’ve been going to talks and events looking for… er… ideas.

Graham Lawton is a staff writer at New Scientist and author of Mustn’t Grumble: The surprising science of everyday ailments. You can follow him @grahamlawton