Diving bell spiders, also known as water spiders (scientific name: Argyroneta aquatica), exhibit peculiar behavior in their mating rituals, with instances of males occasionally consuming females in a phenomenon known as reverse sexual cannibalism.
The diving bell spider is the sole aquatic arachnid known to construct a web underwater as its habitat.
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| Diving bell spiders utilize their body hairs to transport air from the surface to their underwater webs. (Image credit: Minden Pictures / Alamy Stock Photo) |
What makes the diving bell spider truly remarkable is its unique lifestyle—living predominantly underwater, it is the only spider known to do so. Despite this, it still requires oxygen to survive. To meet this need, the spider ingeniously constructs a diving bell by weaving a web between underwater plants. It then transports air from the water's surface down to its web using its hairy body.
Craig Macadam, conservation director of the U.K.-based invertebrate charity Buglife, explains this remarkable adaptation: "The spider has numerous water-repellent hairs over its body which trap air from the water surface. The spider then spins a silk structure where it forms an air bubble, which it uses in the same way as a diving bell."
The spider expands the bubble until it can fit inside. Female spiders construct larger chambers compared to males, as they require space for nursing their young. The air in the diving bell is regularly replenished, and the spider carries a bubble of water around itself, giving it a silvery appearance.
In an unusual twist for spiders, male diving bell spiders are larger and heavier than females. A study published in the journal Evolutionary Ecology Research in 2003 examined this phenomenon and concluded that larger size, along with longer front legs, allows males to move more efficiently underwater. Conversely, the size of females is limited by the necessity to build larger air bells for nurturing their offspring and the energy costs associated with frequently replenishing the air supply.
