Spiders can smell using their legs
A team of researchers from Lund University in Sweden and the University of Greifswald in Germany found some male spiders use olfactory hairs on their legs to distantly detect sexual pheromones that female spiders release. These olfactory hairs had been overlooked until now. The Conversation wrote an article about the discovery on January 7, 2024.
There are more than 45,000 species of spiders in the world. And these creatures have inhabited Earth for 400 billion years. However, although scientists knew these eight-legged beings could detect odors, they didn’t know how, exactly. The researchers published their study in the journal Proceedings of the National Academy of Sciences on January 6, 2025.
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How did they make the discovery?
Spiders do not have nostrils like mammals. Neither do they have antennae like insects, which have olfactory hairs called wall-pore sensilla on their antennae. Insects use these hairs to smell. Previous studies suggested spiders do not have wall-pore sensilla.
However, the researchers in the new study looked at male wasp spiders (Argiope bruennichi). They found the males do indeed have wall-pore sensilla on their legs. You could say these males smell with their legs.
Also, this is not an ability specific to wasp spiders, but rather it’s a capacity prevalent for all (male) spiders.
What is the sense of smell like in spiders?
Scientists studied both male and female spiders of the Argiope bruennichi species. The team used high-resolution scanning electron microscopy and discovered something fascinating. Male spiders have wall-pore sensilla on all eight legs. What’s more, these sensilla are different from the sensilla found in insects and even other arthropods.
The wall-pore sensilla in males are located on the top of the legs, that is, close to the body. These areas almost never come into contact with a surface when spiders move. And, interestingly, the wall-pore sensilla have only been found in adult males. Neither young males nor females have these hairs.
What about female spiders?
Scientists believe male spiders use wall-pore sensilla to detect airborne sex pheromones released by females. This is supposedly how these males find mates. Female spiders release gaseous pheromones that attract males from a distance.
To prove their theory, the scientists placed male spiders under a microscope and connected electrodes to the wall-pore sensilla. When the male spiders were exposed to a pheromone compound, even in a very small amount, the spiders responded with a burst of activity in neuronal cells from the sensilla.
The scientists observed how their olfactory sensilla are incredibly sensitive, much more so than the most sensitive sex pheromone communication systems in insects.
What’s next?
The scientists analyzed 19 other spider species and found that most have wall-pore sensilla and that they are specific to males.
However, other spider species, such as the basal trapdoor spider, do not have these olfactory hairs. The wall-pore sensilla evolved independently within spiders and were lost in some lineages.
Many questions remain to be answered by future studies: Can female spiders and young males smell in another way? How many other species have these olfactory hairs? Can species that do not have these hairs smell in another way? Can spiders detect other chemicals besides sexual pheromones?
It will be exciting to see what new discoveries can tell us.
Bottom line: Scientists knew spiders could smell, but they didn’t know how, exactly. Until now. Spiders can smell using their legs. But, interestingly, young male spiders and female spiders don’t possess this ability. Find out why, here.
Source: PNAS: Olfaction with legs—Spiders use wall-pore sensilla for pheromone detection
Read more: Here are 3 amazing feats of spiders
Read more: Lifeform of the week: Scorpions
The post Spiders can smell using their legs! The secret uncovered first appeared on EarthSky.
from EarthSky https://ift.tt/whODAcE
Spiders can smell using their legs
A team of researchers from Lund University in Sweden and the University of Greifswald in Germany found some male spiders use olfactory hairs on their legs to distantly detect sexual pheromones that female spiders release. These olfactory hairs had been overlooked until now. The Conversation wrote an article about the discovery on January 7, 2024.
There are more than 45,000 species of spiders in the world. And these creatures have inhabited Earth for 400 billion years. However, although scientists knew these eight-legged beings could detect odors, they didn’t know how, exactly. The researchers published their study in the journal Proceedings of the National Academy of Sciences on January 6, 2025.
The 2025 EarthSky lunar calendar makes a great gift. Get yours today!
How did they make the discovery?
Spiders do not have nostrils like mammals. Neither do they have antennae like insects, which have olfactory hairs called wall-pore sensilla on their antennae. Insects use these hairs to smell. Previous studies suggested spiders do not have wall-pore sensilla.
However, the researchers in the new study looked at male wasp spiders (Argiope bruennichi). They found the males do indeed have wall-pore sensilla on their legs. You could say these males smell with their legs.
Also, this is not an ability specific to wasp spiders, but rather it’s a capacity prevalent for all (male) spiders.
What is the sense of smell like in spiders?
Scientists studied both male and female spiders of the Argiope bruennichi species. The team used high-resolution scanning electron microscopy and discovered something fascinating. Male spiders have wall-pore sensilla on all eight legs. What’s more, these sensilla are different from the sensilla found in insects and even other arthropods.
The wall-pore sensilla in males are located on the top of the legs, that is, close to the body. These areas almost never come into contact with a surface when spiders move. And, interestingly, the wall-pore sensilla have only been found in adult males. Neither young males nor females have these hairs.
What about female spiders?
Scientists believe male spiders use wall-pore sensilla to detect airborne sex pheromones released by females. This is supposedly how these males find mates. Female spiders release gaseous pheromones that attract males from a distance.
To prove their theory, the scientists placed male spiders under a microscope and connected electrodes to the wall-pore sensilla. When the male spiders were exposed to a pheromone compound, even in a very small amount, the spiders responded with a burst of activity in neuronal cells from the sensilla.
The scientists observed how their olfactory sensilla are incredibly sensitive, much more so than the most sensitive sex pheromone communication systems in insects.
What’s next?
The scientists analyzed 19 other spider species and found that most have wall-pore sensilla and that they are specific to males.
However, other spider species, such as the basal trapdoor spider, do not have these olfactory hairs. The wall-pore sensilla evolved independently within spiders and were lost in some lineages.
Many questions remain to be answered by future studies: Can female spiders and young males smell in another way? How many other species have these olfactory hairs? Can species that do not have these hairs smell in another way? Can spiders detect other chemicals besides sexual pheromones?
It will be exciting to see what new discoveries can tell us.
Bottom line: Scientists knew spiders could smell, but they didn’t know how, exactly. Until now. Spiders can smell using their legs. But, interestingly, young male spiders and female spiders don’t possess this ability. Find out why, here.
Source: PNAS: Olfaction with legs—Spiders use wall-pore sensilla for pheromone detection
Read more: Here are 3 amazing feats of spiders
Read more: Lifeform of the week: Scorpions
The post Spiders can smell using their legs! The secret uncovered first appeared on EarthSky.
from EarthSky https://ift.tt/whODAcE
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