How Do Moths Navigate by Moonlight?

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How do moths navigate by moonlight? The most direct evidence here comes from a field study of male privet hawk moths. Its authors state that “moths use the moon for orientation and reach females significantly faster with increasing moon elevation” [1]. A second study, of a migratory moth under skyglow, found that “moths consistently flew toward darker parts of the sky” [2]. Together, the two studies show that sky light shapes moth orientation, though neither one maps the full sensory mechanism.

Quick answer

• The moon works as an orientation cue for moths. The authors write that “Our results confirm that moths use the moon as an orientation cue” [1].
• The moon’s position mattered in the trial. “the choice of flight direction depended on the cardinal position of the moon” [1].
• Artificial horizon light did not explain that choice. The same study reports “but not on the illumination of the horizon caused by artificial light” [1].
• The sensory route is not settled. The authors name polarized light as a topic for further work, and say the moon’s role may be explained there [1].

What the privet hawk moth study tested

The study used one species. “Privet hawk moth males ( Sphinx ligustri L., Lepidoptera, Sphingidae) were released individually and equidistantly” at a set distance from caged females [1]. The caged females were the attractant: “Each trap consisted of three virgin females kept individually in gauze cages attached to a wooden stick” [1]. The males were “reliably attracted by caged virgin females” [1], which let the authors measure how long each male took to reach a trap.

The design set up a choice. “one trap was located in the North, the other one in the South of the release site” [1]. Because each male could fly toward either trap, the direction it picked became the measured outcome. The field work ran “from 19 July 2019 to 31 July 2019 on a meadow” [1], and the experiment followed the moon through its phases: “The experiment was performed during the lunar phases from the full moon” to the new moon [1].

The authors also set conditions for the flights. “Experiments were only performed during warm summer nights without rain or strong wind” [1]. That control matters for the moon results, because cloud and wind could change what the moths see and how they fly.

Why the moon’s position and height matter

The main finding is about position. The authors tested the moon’s cardinal position against the trap choice. They note that the moon was visible “as it was almost exclusively visible in the southern hemisphere of the sky” [1], which made the moon’s position a variable that could be compared with the choice of trap [1].

The height of the moon also changed flight. “Since flight duration decreased as a function of lunar elevation, we conclude that the moon contributes to mating success, especially when it can be easily perceived” [1]. The abstract puts the result this way: “The experimental release of male moths show that moon presence, location, and elevation affect their finding of mates” [1]. The outcome measured was mate finding, so the results describe how the moon helped moths reach females rather than how they travel across a landscape.

The authors connect this to the general idea that moths need more than one cue. “Our results confirm that moths use the moon as an orientation cue, supporting the notion of Vickers & Baker 34 that pheromones alone are not sufficient for successful (and fast) orientation” [1]. In their reading, the moon is one part of a set of cues, and the pheromone signal from the females is not enough by itself.

Sky light and orientation in a second species

The skyglow study looked at a different question: how artificial light changes the direction of flight. It starts from the premise that “Artificial light at night (ALAN) is altering nocturnal ecosystems” [2]. The species studied was “a globally invasive nocturnal migrant” [2], the fall armyworm.

The authors explain why orientation cues matter for migrants: insects make long-distance flight decisions “relying on cues such as celestial information, wind fields” [2], and celestial cues are “one of the most extensively studied orientation mechanisms in migratory insects” [2]. Their field trials were run on nights without a moon. “Under natural sky luminance gradients, moths exhibited a consistent northeastward orientation on moonless nights” [2].

The key result for this question is that the moths followed darkness, not light. “moths consistently flew toward darker parts of the sky, even when this conflicted with their natural migratory direction” [2]. The authors read this as a warning about light pollution: “This suggests that skyglow can mislead insects, drawing them away from their normal orientation and trapping them in unsuitable habitats” [2]. The moon-based study and the skyglow study therefore point in the same direction. Sky brightness and its pattern carry information that moths use.

A related explainer on how dung beetles use the night sky is how dung beetles navigate using the night sky. For how moths locate flowers after dark, see how moths find night-blooming flowers.

How we chose these sources

Both sources were picked for their direct measurements of moths and light. The first is a field study that “combined behavioral experiments performed with free-flying male moths” with a sky-brightness camera, which is the kind of data needed to link moonlight to flight. The second combines field observations with indoor flight-simulator tests. Both pages were fetched directly with curl, returned HTTP 200 on 2026-10-28, and contain full article text.

What we could not verify

What the sources do not say

The sources do not identify the sensory system a moth uses to read the moon’s direction. The first study names a gap: “investigate the relevance of polarized light” [1], and it suggests that polarization “could provide an explanation for the occasional fast flights at times of low lunar elevations” [1]. That is a proposal for future work, not a result.

The two studies also use different species. The moon study concerns “Privet hawk moth males ( Sphinx ligustri L., Lepidoptera, Sphingidae)” [1], and the skyglow study concerns the fall armyworm [2]. Neither source tests the other species, so a claim about all moths would go beyond the evidence. The moon study covered a single set of summer nights in one meadow [1].

Frequently asked questions

Do moths use moonlight to find their way?

The first study says they use the moon as a cue: “moths use the moon for orientation and reach females significantly faster with increasing moon elevation” [1]. The study measured mate finding in a specific trap setup, so the result is about that task.

Can artificial light override the moon for moths?

In that trial, it did not. The choice “depended on the cardinal position of the moon but not on the illumination of the horizon caused by artificial light” [1]. This applies to the conditions tested, and the authors did not test every light source.

Why would the moon’s height matter to a moth?

The authors found that flight duration changed with elevation: “Since flight duration decreased as a function of lunar elevation” [1]. They link this to success: “the moon contributes to mating success, especially when it can be easily perceived” [1].

Does skyglow confuse moths?

The migratory moth study says it can. “This suggests that skyglow can mislead insects, drawing them away from their normal orientation and trapping them in unsuitable habitats” [2]. The study was done on one migratory species, so the effect may vary by species.

Is the moon the only cue moths use?

No. The first study notes that pheromones alone are “not sufficient for successful (and fast) orientation” [1]. The second study lists other cues migrants use, including “relying on cues such as celestial information, wind fields” [2].

Sources

• [1] “The rising moon promotes mate finding in moths”, PMC9051113, https://pmc.ncbi.nlm.nih.gov/articles/PMC9051113/ (HTTP 200, opened 2026-10-28)
• [2] “Skyglow-Induced Luminance Gradients Influence Orientation in a Migratory Moth”, PMC12734188, https://pmc.ncbi.nlm.nih.gov/articles/PMC12734188/ (HTTP 200, opened 2026-10-28)