According to Rewild, the elusive Fagilde Trapdoor Spider (Nemesia berlandi) had been hiding underground for 92 years just outside Fagilde, Portugal. It was rediscovered recently near the village it was named after. The female Fagilde Trapdoor spiders are tiny, growing up to 2.2 cm long. They blend well with the background because of their deep-brown bodies. Also, from the outside, predators would rarely be able to recognize their burrows because the opening is built using the surrounding materials, providing camouflage. Plus, they build round doors to their burrows that can be locked from the inside. It’s a miracle that they were rediscovered recently.

Getting to Know Fagilde’s Trapdoor Spider

The tap-dancing Fagilde Trapdoor Spider is the 12th of Rewild’s 25 most wanted lost species. So far, only 3 females have been found by scientists. It’s easier to find females because they stay inside their burrows most of the time. The males have not been seen in the wild because they move around a lot. Though they’re nocturnal, it’s not enough that darkness hides them. At night they move from one hiding spot to the next – from under a rock to under a log, and so on, searching for female mates.

They were last seen in 1931 when  Amélia Bacelar, a female entomologist, found two female spiders outside Fagilde, which is situated in north-central Portugal. The town has a very small area and a population of less than 400 people as of 2011. Bacelar described the spiders’ bodies’ deep brown hue, which helps them blend into the background. They measure 2.2 centimeters at most, and they’re the only spiders living in horizontal underground burrows. All others of this species inhabit vertical underground homes.

The females build trapdoors at the entrance to their burrows, which they lock from the inside. Their home averages 4 inches in length. The doors are circular, with an opening that measures one inch. Inside, they have a protective wall behind which they hide.

The spiders build at night, preferably after rainfall, which makes the soil moist. These homes are made from the natural material around them such as soil and leaves, and are undergirded with silk that emanates from their bodies. Scientists have studied silk released by other spider species and are awed by their strength, comparable to high-grade steel. It would be tough to find the burrow of this spider because it’s made to blend so much with the environment that one could never guess that a trapdoor spider lives there. Dr. Sergio Henriques of the Global Center for Species Survival, Indianapolis Zoo, calls the homes of trapdoor spiders “a masterpiece of engineering.”

Mating occurs in the autumn season. The males roam about, searching for a mate. Once they find one, they perform a tap dance to attract the female. The female is safe in her burrow and knows more about the outside than one would imagine. She stays indoors because her spider senses and the silk she used on her door let her know what’s going on outside, and whether other creatures are around her home. The female senses this through the vibrations that these outside creatures make. The female’s keen sense lets her know if a species traveling near her home is a predator or a prey.

Like other species, Fagilde Trapdoor Spiders can lose one of its legs if, for example, a predator latches onto it. By losing its leg, the spider can escape from the predator with only the loss of a leg that will regenerate over time.

What leg could this spider afford to lose with the least inconvenience? The Fagilde Trapdoor Spider needs its upper limbs to move about and dig tunnels. The back legs hold onto the tunnel it’s building. So for them, it’s easier to lose a back limb than an upper limb.

Other threats to this spider include agriculture, urban development, and wildfires. This may be why it was rediscovered just outside Fagilde. The tiny village has a small population of 397 humans as of 2011, and its area of 1.181 km² is tiny.

Searching for the Tap-dancing  Fagilde Trapdoor Spider

 In 2011 Dr. Henriques et. al. of the Global Center for Species Survival, Indianapolis Zoo discovered several horizontal burrows in a forested area in Fagilde, suggesting that trapdoor spiders lived inside of them. But upon searching further, all they found were the remains of dead Trapdoor Spiders.  Henriques took samples and sent them to undergo DNA analysis. The test confirmed the Fagilde Trapdoor Species still exists in the area. Scientists believe that locals may have seen this spider in their homes or the wild without realizing the value of this rare, endangered creature.

In 2021, Dr. Henriques returned to Fagilde to search for the trapdoor spider. In August 2021, from late summer to early fall, they looked for this spider which grows to a maximum size of 1.2 to 2.2 centimeters. These spiders are masters at hiding and know their home space well. The scientists focused on natural habitats knowing that Fagilde Trapdoor Spiders like to stay in the same space throughout their lives, from generation to generation. If they found one Fagilde Trapdoor in a space, they could safely assume that they would find another Fagilde Spider in the same area on a separate day.

With the help of locals, they combed the forest grounds. The team bowed down on their hands and knees. They pushed aside fallen leaves, lifted moss and litter, and checked under tree trunks. They did this from the year 2021 to November 2023. They hoped, in particular, to find a male Fagilde trapdoor spider which was tricky. Although the males roamed around at night, they did it by moving from one hiding space to another. For example, first, they’d hide under a rock, then move to hiding under a log. They went from one hiding place to another toward the direction of a female spider’s burrow. So far, no scientist has seen a male Fagilde trapdoor spider, much less studied one.

Henriques’s Findings

Another time, the team found a silk-covered burrow, a clear indicator of the presence of trapdoor spiders. The measurement of the burrow and the size and presence of circular doors further evidenced that the spider they were looking for was there.

Henriques slowly and carefully unearthed the burrow on one side, and inside, he found an adult female mother staunchly guarding her 10 baby spiders. They occupied the only area in the forest where Fagilde’s trapdoor spider had been previously recorded. Physically they matched the description written in 1931 by Bacelar, the female pioneering entomologist mentioned earlier.

Finally, Dr. Henriques found one trapdoor spider, but he wasn’t sure if it was a Fagilde Trapdoor Spider. The only way to prove it would be through a DNA test. He decided to remove the mother’s third leg, which is the least helpful leg to the spider. Then he returned the mother to her babies.

The test showed that the DNA failed to match other known trapdoor spiders in the area. The evidence was conclusive.  This meant that Henriques could safely conclude that they found Fagilde’s Trapdoor Spider.  However, until today, no scientist has seen a male Fagilde Trapdoor Spider yet.

A Single Habitat

As earlier said, this spider likes to stay within a single habitat and will rarely stray far. That is not good, because the forest area in which the Fagilde Trapdoor stays is becoming prone to wildfires due to climate change.

Hopefully, the local community can understand how special the Fagilde Trapdoor Spider is, and this will be their driving force to protect these spiders.

Now, one may think, what’s so important about a bug? The answer is that spiders, insects, crabs, crab louse, and similar creatures are part of a group of critters called invertebrates, and they comprise  97% of all living things on our earth.

If we understand that the tiniest of creatures can save us, we will know that preserving the tap-dancing Fajilde Trapdoor Spider is vital to our lives, as are all critically endangered species in the world.