These crabs use plastic objects as shells: but why?

plastic pollution It is changing ecosystems to a degree that no one could have imagined years ago. For example, new research reveals unusual behavior hermit crabswho begin to use the remains of this material as shell.

These animals are characterized precisely by the fact that, without having a shell, they use shells left by mollusks. This is the mortality of the seabed, as they can transform into many different animals by hiding their delicate bodies inside different shells. But the scientists studying them didn’t expect that plastic pollution would cause them to end up disguised as a yogurt container or bottle cap.

In fact, this is not something that has just been discovered. In fact, the authors of this new study from several Polish research centers were inspired by the work Sean Miller. This is a photographer who in 2014 published several photographs taken in Okinawa, Japan, in which hermit crabs can be seen taking waste from plastic pollution as shells. He was also not the first to mention this issue, as a case report had already been published in 2009. However, it was he who reported it to the world and, therefore, the person who, without knowing it, made the task easier for the authors of the study, which has just been published in General Environment Science.

Hermit crabs miss population target

The new study consists of two parts. Firstly, its authors conducted review of scientific literature. That is, they analyzed previously published studies that talk about the effects of plastic pollution on the behavior of hermit crabs.

However, in the second part, they took advantage of audiovisual content posted online by people. unscientific. First of all, they used images posted on social networks, especially after this problem became widely known in 2014.

After studying the scientific literature, they discovered a message 10 cases crabs with plastic shells. Moreover, they distinguished two species of terrestrial and three marine hermit crabs.

This time, citizen science went much further, as social networks and other online publications found 386 copiesbelonging to 10 different species. They all chose marine waste from human activity as shells. There were different materials, but plastic definitely stood out the most.

The study authors believe this is a good way to identify new cases because it attracts a lot of attention and encourages the public to publish information.

Is this a dangerous consequence of plastic pollution?

In their study, the scientists analyze what could be the reasons why hermit crabs choose plastic remains over mollusk shells.

The first reason is that they usually large in size but lightweight at the same time. One of the criteria by which women choose a male what to mate with is shell size. Unfortunately, larger projectiles tend to be heavier, so a balance needs to be found. However, with plastic-contaminating waste, this balance is easier, since a large container of this material can be a fluffy but lightweight shell. This way they don’t expend as much energy moving around with him on their back.

But do they know it’s something new, or do they think they’re projectiles? We don’t know what’s going on in his head. What these scientists do know is that hermit crabs often navigate by smell dimethyl sulfide. This is a chemical with a very strong and unpleasant odor coming from algae metabolism. In the sea, it penetrates into other components of the ecosystem, such as some mollusks and crustaceans. Therefore, hermit crabs search for this smell to detect free shells.

The problem is that it has been proven that marine debris, be it plastic debris or other materials, they impregnate with this substance as it is released by surrounding algae. That’s why hermit crabs confuse it.

In fact, this is not the only animal that is confused by this smell. It has been proven that many seabirds They eat plastic, confusing it with fish due to the smell of dimethyl sulfide.

Obviously this is dangerous for birds, but it is unknown whether it is also dangerous for hermit crabs. They seem to find benefits in this, but it is not good news that their ecosystem is changing to the extent that plastic is used as shells. This is the reason why it attracts so much attention from social media users.