A moonlight compass helps ants find their way in the dark

Embargoed until: Publicly released: 2025-11-12 11:01

NSW

Observation by stephvg · no rights reserved - iNaturalist

Ants can use the faint pattern of polarised moonlight in the sky to navigate back to the nest at night, even if they lack the special low-light visual adaptations of nocturnal ants, according to Australian research. The researchers studied two species of bull ant, Myrmecia tarsata, which is active during the day, and Myrmecia midas, which is active at night. They found that both species use solar and lunar polarised light patterns to navigate, but the daytime species, Myrmecia tarsata, was only able to navigate under bright, near-full moons, while the nocturnal species, Myrmecia midas, was able to use polarised moonlight patterns throughout the lunar month.

Media release

From: The Royal Society

Comparative Use of a Polarised Light Compass for Twilight and Moonlight Navigation in Diurnal and Nocturnal Bull Ants

Royal Society Open Science

How do ants find their way in the dark? Many insects use patterns of polarised light in the sky as a built-in compass. We studied two Australian bull ant species: the nocturnal Myrmecia midas and the daytime Myrmecia tarsata. By rotating the sky’s polarised-light pattern with a special filter, we tested whether ants would in turn adjust their headings. The night-active M. midas followed the moon’s pattern even under a thin crescent moon, while M. tarsata detected it only under bright, near-full moons. These results reveal how nocturnal ant’s dim-light eye adaptations allow nighttime navigation using a moonlight compass.

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Research The Royal Society, Web page Please link to the article in online versions of your report (the URL will go live after the embargo ends).

Journal/
conference: Royal Society Open Science

Research:Paper

Organisation/s: Macquarie University

Funder: This project was funded by a Macquarie University Research Fellowship (MQRF0001094) and by an Australian Research Counsel Discoevry Grant (DP200102337).

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