# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DcY_apQgM56
- **Gondola URL:** https://gondola.cc/posts/69727807-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/f4a9ff74f7.jpg
- **Posted:** 2026-08-23T17:12:01.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

Drop an ant into water and it struggles. Give a colony water, a food reward and a pile of sand, and it builds infrastructure.

In 2020, Aiming Zhou at Huazhong Agricultural University and Jian Chen of the USDA published one of the cleanest tests of invertebrate problem-solving on record. The subject was the black imported fire ant, Solenopsis richteri. The apparatus was deliberately crude: a shallow container of 15% sugar water, and loose sand grains scattered nearby.

Baseline behaviour was unremarkable. A fire ant’s cuticle is hydrophobic, so workers simply walked out onto the liquid surface and fed. No drowning, no tools required.

Then the team changed exactly one variable. Adding TWEEN 80, a non-toxic surfactant, cut the surface tension and turned a walkable film into a lethal one. The behaviour flipped:

- Workers stopped entering the container entirely
- They began ferrying sand grains to the rim, depositing them inside and outside the wall
- The two deposits met to form a continuous porous path
- Capillary action drew sugar water up through the packed grains and over the edge
- Around half the liquid was wicked out within five minutes

The crucial result is not that ants use objects. It is that they graded the response. As drowning risk rose with surfactant concentration, workers shifted sand from inside the container to outside it, and adjusted their preferred grain size accordingly. Feeding rose while losses fell. That is not a fixed reflex firing on a trigger; it is a decision rule sampling an environmental variable and returning a proportional answer.

No individual ant understands capillary rise. The colony does not need it to. Local rules, applied thousands of times against a shared surface, converge on a structure that a hydraulics engineer would recognise.

Competence does not require comprehension.

#stemantics #entomology #collectivebehaviour #biomimetics #swarmintelligence

## Stats

- **Views:** 29,886
- **Likes:** 257
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## Tags

biomimetics, collectivebehaviour, entomology, swarmintelligence, stemantics

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