THE ANIMAL FILES

Diving bell spider

Argyroneta aquatica

An underwater home can still contain breathable air.

The diving bell spider builds silk structures underwater and fills them with air carried from the surface. Dissolved oxygen can diffuse into the bell, yet nitrogen loss gradually shrinks it. The spider remains an air-breather while spending much of life below the surface.[1]

Follow the evidence ↓
Diving bell spider
Image: Norbert Schuller Baupi · Commons · CC BY-SA 3.0
Silver carried underwater
Hydrophobic hairs trap an air layer.[1]
Exchange at the bell
Oxygen diffuses in from water.[1]
A bell that needs maintenance
Nitrogen loss makes the bell shrink.[1]

Silver carried underwater

Air held on the abdomen and legs gives a silvery appearance underwater. The spider transports air to a silk bell anchored among water plants. This is a retained gas space rather than an animal changing to a fish-like water-breathing system.[1]

Exchange at the bell

Respiration consumes oxygen and produces carbon dioxide, maintaining gradients across the bell. Oxygen moves inward and carbon dioxide outward. The bell functions as a physical gill, gaining gas from surrounding water instead of merely exhausting a sealed initial tank.[1]

A bell that needs maintenance

Nitrogen also diffuses outward, reducing bubble volume. The spider periodically adds surface air. Bells are used for feeding and other activities; the female's larger bell also shelters reproduction and young, linking construction with several tasks.[1]

A COMMON MIX-UP

Does living underwater mean it no longer breathes air?

No. Air is retained in body hairs and the silk diving bell.[1]

TRY A LITTLE REASONING

Why replenish a bell even if oxygen can diffuse into it?

Reveal the explanation

Nitrogen escapes and bubble volume decreases, so gas exchange does not keep the bell's size constant.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Diving bell spider (cited revision)
  2. NCBI Taxonomy — Argyroneta aquatica

Last fact check:

One discovery leads to another

Giant huntsman spiderLeg span measures an outline, not the size of the whole solid body.Heteropoda maxima ↗Southern black widowA tangled web is organised around catching and wrapping.Latrodectus mactans ↗Mediterranean black widowThirteen spots are a clue, not a complete identification.Latrodectus tredecimguttatus ↗