New Zealand ghost moths

Hepialidae, commonly known as ghost moths are a family of moths that are considered ‘primitive’ in that they have remained relatively unchanged for a long time. Unlike other groups of Lepidoptera such as the butterflies which have evolved with flowering plants and consume nectar allowing them to live longer, ghost moths are unable to utilise nectar as a food source. This results in ghost moths having very short lifespans – often just one night long. This is just the adult moths I am talking about though, as the caterpillars of some ghost moths can be very long lived. A great example of this is the puriri moth caterpillar which spends several years feeding. Initially on the forest floor on dead wood and lichens before boring into the trunks of trees such as the puriri tree and beech trees from which it emerges at night to feed on callus tissue (tissue produced by the plant in response to injury) growing around the tunnel entrance. The adult moths however are very short lived – probably just a couple of days if they are lucky. The reason for this is evident when you see them in the field. They seem to have very little control over their flight and are often heard before they are seen due to them crashing into objects on the forest floor. But this seems to work for them as despite the incredibly long time it takes for them to reach adulthood, the adult moths are found every year, often in very large numbers as I am sure some of you have experienced. I was lucky enough to experience this myself over the summer – I say lucky because the Puriri moth, which happens to be New Zealand largest moth is only found in the North Island. While light trapping (if you don’t know what this is – see my first blog) at the base of the Ruahine Range over the summer, over 70 of these elegant moths came in – all with slightly different wing colorations.

Pictures one and two. Two puriri moths I photographed in Hawkes Bay over the Summer.

Heloxycanus patricki is yet another fascinating endemic ghost moth. I was lucky enough to collect a few of these over the weekend when I was in Southland. This moth feeds on sphagnum moss and its habitat is now severely fragmented due to the drainage of its wetland habitat which is also under threat from fire and activities such as sphagnum mining. A lot less is known about this species then the puriri moth but we do know it spends a minimum of two years as a caterpillar. We know this because the adult moths are only seen on odd numbered years (2009,2011,2013 and so on) which might be why it was discovered as recently as 1979. Like a few other New Zealand ghost moths Heloxycanus patricki flies late, from April to June. These strategies may be useful for avoiding predators, parasites, parasitoids and disease. Due to the beautiful colouration and appeal of moths such as Heloxycanus patricki they are good advocacy tools to help preserve the beautiful southern wetlands which they need to survive – and are also home to other nice insects such as flightless crane-flies and ground weta which I saw in the weekend.

Pictures three and four. Heloxycanus patricki male (top) and female (bottom) photographed on sphagnum moss

Picture five. Heloxycanus patricki habitat.

Despite their ‘primitive’ appearance, ghost moths are a successful group and have remained relatively unchanged for a reason – their strategy works. A testament to this is the large numbers that are often seen in the field as well as the fact that several ghost moth species in the genus Wiseana are some of only a few native-insect agricultural pests.

If you wish to learn more about New Zealand ghost moths I recommend the Hepailidae fauna of New Zealand.  And if you wish to read more about the Puriri moth lifecycle then I recommend the paper below

Grehan J.R. 1987. Life cycle of a wood-borer Aenetus virescens (Lepidoptera: Hepialidae). New Zealand Journal of Zoology, 14, 209-217.

In case you didn’t know, the second moth in my first blog was also a ghost moth. We have an awsome ghost moth fauna here in New Zealand!

A potential new species of New Zealand butterfly

New Zealand has three named species of tussock butterfly, all of which are endemic to the South Island. They have this name because the adult butterflies are found around the tussock plant which they ate as caterpillars. Around ten years ago, when I was catching insects with my father in the mountains of Otago I came across tussock butterflies that looked similar to one of the named species but were distinctly different in both morphology (how they look) and behaviour.

Picture One. The three named species of tussock butterfly and my potential new one. Top left: Argyrophenga antipodum. Top right: the potential new species I am studying. Bottom left : Argyrophenga harrisi. Bottom right: Argyrophenga janitae.

This semester I was lucky enough to be eligible to do a research placement, so I choose this project since I have wanted to sort it out for such a long time. I applied to the Miss E. L. Hellaby Indigenous Grasslands Research Trust for money for the project as I needed money for sequencing two genes in the butterflies as well as a trip to Wellington to see NZ butterfly expert George Gibbs who has offered to help teach me how to dissect butterfly genitalia (sexual organs – the sexual organs of insects are often used to differentiate between species). I applied to the Hellaby trust because this potential new species appears to only feed on an endemic tussock species (tussocks are grasses).

Picture two. Alpine tussock butterfly habitat: the natural habitat of a butterfly hunter

So far with this project I have collected specimens of this potential new species as well as specimens of two of the other tussock butterfly species (a great excuse to get into the beautiful Otago and Canterbury mountains). I already had a large collection of these butterflies but I wanted to have fresh ones for DNA extraction as it is harder to extract DNA from old specimens. I have also started to look through all of the literature relating to this group of butterflies. These days I am working in a lab in the burns building doing genetic work. I am planning to sequence two genes in these butterflies, one from mitochondrial DNA and one from nuclear DNA. It is a big process to get sequences from a butterfly. First I extract DNA from butterfly tissue (I use part of a butterfly leg), then PCR (polymerase chain reaction) is used to make many copies of the gene I am hoping to sequence as well as to see if there was contamination. The PCR products are run through a gel to see if the gene was amplified because the next step, sequencing, costs around $12 per sample. Once I have all my sequences I will be able to generate trees that show how these two gene regions differ across the butterflies sequenced. The tree that I make on the computer does not directly tell me if it is a new species or not but it will give evidence that can be used in conjunction with other methods to elucidate the species status of this potential new species.

Picture three. A Gel picture. Numbers 1-8 are the 8 samples (from butterflies). The black band below the number indicates that DNA was amplified. The position of the bands in relation to the molecular weight ladder (MW) were used to figure out if the correct sequence of DNA was amplified. + and – are positive and negative controls used to help figure out what the problem is when something goes wrong (e.g. contamination). 

It will be very interesting to see what results I get from the lab as well as from other areas. Hopefully I will get good results as I am going to give a talk on this work at the upcoming Australia and NZ shared entomological conference that will be held here at Lincoln in August. I also plan on producing a paper on this work.

This research placement has been a good opportunity to see what it is like being a post-grad student as well as to learn many techniques that will benefit me in the future. I couldn’t recommend a research placement more highly.

Anyway…. I better get back into the lab. Will hopefully have some interesting results to tell you about soon!

Picture four.  Part of my tussock butterfly collection the specimens of the potential new species are in the top right corner.

Moths with flightless females: two New Zealand examples.

New Zealand is unique in the world, having a large number of endemic moth species with flightless females. During the midterm break I was lucky enough to see one of these when I went down to Riverton in Southland for a family reunion. After arriving in Southland with my father, step mum and new baby brother, we decided to go out to Tiwai Point to do some serious moth collecting before settling into our rental accommodation. After arriving at a coastal spot with low native vegetation, we proceeded to put out a light trap. This consisted of a Mercury Vapour light positioned on a white sheet and powered by a portable generator. While we were hoping for some moth species to come into light, me and my father walked down to the strip of grassland beside the beach and looked for a very unique moth species. The moth we were looking for was Asaphodes frivola and only known from a handful of localities in costal Southland. One male of this species was caught by Alfred Philpot, a New Zealand entomologist, around 100 years ago. It was then described in the UK by Edward Merick where the original specimen is now thought to be. Subsequent New Zealand entomologists such as George Hudson (famous for inventing day light savings) mentioned this species in one of his books, but because he didn’t have access to a specimen was not able to provide an illustration. Without an illustration and much information on its ecology, Asaphodes frivola remained un-collected for around 70 years, until in 1981, when it was rediscovered at Otatara by Brian Patrick (my Dad). Unlike the male which looks like a fairly typical moth, he found that the female had thin, scrunched up wings that can’t be used to fly with. Anyway, back at Tiwai point I was able to; with the help of my father find several males of Asaphodes frivola at the bases of native tussocks. These flew up once I had disturbed them and settled on the ground a few meters from where they had been disturbed. After a long search, I eventually located several of the well camouflaged females sitting in the tips of the native tussocks. When we arrived back at the light trap, we found that no moths had come into light. Only two flies were present. This demonstrates how some knowledge of an insect’s ecology can greatly increase the chance of finding it in the field.

Photograph 1: A female of Asaphodes frivola sitting on the lawn of our rental house in Riverton.

Other New Zealand moth species with flightless females include ghost moth and tiger moth species. The reason for the evolution of flightlessness is thought to be due to females maximising their egg laying potential as when you fly you need to worry about having a large, heavy egg-fulled body. The downside to flightlessness is that it can be harder to find mates. Females of the New Zealand ghost moths overcome this by releasing pheromones; these are picked up by male antennae (feelers) and followed to the highest concentration, to the female. It is thought that this species also used pheromones to attract males. One of the New Zealand ghost moths with a flightless female is Aoraia macropis. I was lucky enough to find this species in March of this year up the Old Man Range in Central Otago. At 1300m above sea level on a roadside wetland, a male of this species was observed. After several hours of searching, I was able to locate five females that were moving over the wetland depositing eggs every few seconds as they were walking. These females where then placed into a container with no lid. After a short time, many of the usually fast and hard to catch males flew close to the container and started to fly around it before eventually entering the container and trying to mate with the females located inside. As well as making the males more catchable, this demonstrated how the female uses pheromones to attract males. In the course half an hour, around 30 males came in showing the effectiveness of this strategy. 

Photograph 2: Two males (upper and lower left) and two females (upper and lower right) of Aoraia macropis collected up the Old Man Range.

Because these moths have flightless females, they are not as fast as species with flighted females at invading new habitats and reinvading ones that they have become locally extinct at. It is therefore of the upmost importance that the habitat of these moths is preserved.

You can find further information on the two moth species mentioned in the flowing references;
Asaphodes frivila: Patrick B. 1981. Notes on an interesting moth Asaphodes oraria at otatara near Invercargill. Weta 4, page 23. Asaphodes frivola is mentioned at the end of this paper where it was referred to as Asaphodes sp. Only after the publication of this paper was it figured out that it was a species that had already been named.

Aoraia macropis: Dugdale J.S. 1994. Hepialidae (Insecta: Lepidoptera). Fauna of New Zealand 30, 164 pages. I also recommend taking a look at any of books written by George V. Hudson. Despite working in a post office he was a prolific entomologist and produced books on a large variety of New Zealand insects. These books contain magnificent plates.