Regular readers of our website will know that we find moths fascinating. Well, OK, we find all insects fascinating but getting to know the local moths is very high on our naturalist agenda. For several reasons.
Moths are mysterious. We rarely get a glimpse into the world of moths. As adults, moths don’t generally live very long. Some, such as the ghost moth below, last just a day or two. Most remain hidden or camouflaged during daylight and usually choose the darkest of nights to fly.
Moths are under-loved. Moths spend most of their lives as caterpillars and play critical roles in the forest ecosystem. They are food for all kinds of insects, birds and other animals. Just as important is their role in recycling leaf litter. There is a large family of moths that feed on dead leaves on the forest floor. They make a major contribution to reducing fire intensity. Ironically, regular ‘hazard-reduction’ burning can wipe out these very same species.
Moth identification is a challenge. There are so very many species. For every butterfly species in Australia there are 50 species of moth!
It’s not just the sheer numbers that make moth identification such a challenge. The features used to distinguish one group of moths from another are typically microscopic and hidden. Fortunately, wing colours and patterns are useful, so photo-matching can work. If you’re lucky. And if you know where to look.
So our aim is to become familiar with some of the main families of moths. For example, if we can look at a moth and think “oh, an Oecophoridae”, we’ll know what lists of moth photos to start trawling through as we search for a match.
For the past couple of weeks we’ve been devoting ourselves to this task. We have a wonderful dataset to work with – hundreds of photos of hundreds of insects, all seen here on one night in early April this year.
Surveying local moths with the help of a visiting friend
Moths are famous for their tendency to fly to light. Indeed, many of our ad hoc moth sightings at home are of moths drawn to the house lights. However, to really see who’s out there at night we needed a special kind of light, set up in the right way, and under the best environmental conditions.
Glenn Cocking is a moth expert. He spends many hours each week at the Australian National Insect Collection in Canberra, cataloguing and identifying moths. He also undertakes regular surveys in the bush around the ACT and here on the far south coast. And we were delighted when he agreed to visit and help us get to know the insect night life in our patch of forest.
The 3rd April 2019 was a perfect night for a light sheet survey. No moon, very little breeze, mild temperatures, and good humidity due to recent rain. Starting just after dark, we checked the sheet at regular intervals until dawn.
And what we found amazed us all. There were so very many different moths, and the species mix changed throughout the night.
We are now sorting through our photos, learning how to recognise the main moth families, and then seeking to put species names to individual sightings. It’s a challenge, and we’re loving every minute of it. Soon we’ll send our homework to Glenn.
The gallery below gives an indication of the diversity of moths on the wing, in this one patch of forest, on just one night in April. Biodiversity writ large!
I’ve tried not to include a species twice, and this is just a sample. At least 150 different species of moth visited the light sheet. No text - just images - as identifications remain a work in progress.
Oh, and it’s not just moths that were attracted to the bright light in the dark of a forest on 3rd April.
Wasps, flies, mantids, bugs, beetles, grasshoppers, ants, lacewings, spiders … and even butterflies. An invertebrate festival.
We’ve nearly gone as far as we can with our identifications. Next, we’ll add the photos to the Atlas of Life database. The survey results will then be publicly available, records for scientists and others to access and analyse. Not a bad hobby, we think.