MOTH OF THE DAY - Thursday: Pond moths

Did you know that we have pond moths? People monitoring freshwater health often look at the array of insects surviving in streams and lakes as an indicator of healthy freshwater habitats. Such monitoring people know pond moth Hygraula nitens quite well. It is New Zealand’s only moth with a caterpillar that lives in water. It is also one of our most widespread moths as it lives nationwide, including the Chatham Islands. Caterpillars are peculiar as they are covered in gill structures. Caterpillars eat a range of native and introduced aquatic plants while hiding in a retreat made from plant pieces. Much less frequently noticed, but certainly more attractive, are adults. Partly this is because adults are not all that big (25mm wingspan) and are attracted to lights at night.

Because there are ponded waters everywhere and many of us live near slow moving streams, then almost certainly the pond moth lives near you. They are hardy animals that cope reasonably well with nutrient pollution in waterways, as nutrient enrichment often results in dense aquatic plant growth in slow flowing soft bottom habitats. Because these little moths thrive on the invaded aquatic plants as well as the native, then they are an example of nature adapting and persisting in our own urban and rural back yards.

Posted by morganemerien morganemerien, July 21, 2021 23:40

Comments

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Fantastic. I just looked and we have lots of observations (286) of this species on iNaturalist NZ but nobody's yet uploaded a photo of the caterpillar. All the photos are of adult moths. It would be great to get photos of caterpillars of different instars.

Posted by jon_sullivan 15 days ago (Flag)
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That's cool! I'll look a bit closer at pond pond life. Are the larvae usually underwater, or also above water on aquatic plants?

Posted by jacqui-nz 14 days ago (Flag)

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