Oct 112019

Ruddy Streak. Not the greatest image but sufficient for identification and the only image of the first Irish Tachystola acroxantha.

I work in The King’s Hospital, a co-educational secondary school with a parkland campus between Lucan and Palmerstown — the school grounds extend down through wooded hillsides to the banks of the Liffey.

Two initiatives within the school led me to undertake three years (2016-2018) of weekly moth trapping as part of the Garden Moth Scheme. The first was the introduction of a tree trail of 100 notable trees of numerous species in the school grounds. The next step was (and is) to undertake research for a broader trail of flora and fauna. These nature trails are intended for the use of classes in subjects such as Art and Science as well as by visitors. The other initiative was the school’s environment committee’s pursuit of the Green Flag for biodiversity.

The campus includes two houses which had gardens prior to the school’s relocation from the city centre in 1971. I chose one of them as the site for trapping. I placed the Robinson Trap (60W Actinic) at the back of the garden between the house (Avondale) and the woods. Although it did not yield large numbers of moths, it did occasionally indicate interesting aspects of biodiversity on the campus. Some of the more unusual species were Oak Nycteoline, Orange Sallow, Pine Shoot Moth and Thistle Ermine.

During the summer of 2017, I had become aware of tiny moths associated with birds’ nests and similar indoor habitats (for example, Tinea trinotella, which I saw in my mother’s garden near Mullingar that May). There was a swallow’s nest in the outhouse where I stored the trap and I wondered if that might be relevant.

When I went to the trap on the morning of 5 August 2017, I could easily have overlooked a small moth in the trap. Likewise, I could have written it down as a strange-looking Brown House Moth and nothing more. I had, however, as I said, recently had my eyes opened to moths associated with nests, so I was interested and took what turned out to be a poor photograph just in case.

When I started looking at the picture in the office and comparing it with online information (I didn’t have the Sterling and Parsons field guide to hand), I began to wonder whether it could be a Ruddy Streak. I contacted my Garden Moth Scheme mentor Don Hodgers.

Here’s the conversation:

AW: Tentatively, Don, I have a Ruddy Streak (Tachystola acroxantha) sighting in the trap in Dublin last night. I’ve a poor photograph but it is clearly a Brown House Moth size and style of moth with orange termen. Is it common in Ireland?

DH: I don’t think it’s on the Irish list as yet so a photo would be very important.  But it would have to be good enough to rule out other species.  It’s always possible — 4 new additions to the list in the last fortnight or so!

AW: Here are the images from that trapping, Don.

DH: Yes, a Ruddy Streak, congratulations!  I don’t know if any others have been found, as the latest records available are for the end of 2015 and someone might have it on their list — but I don’t think so.  They are spreading through Britain and it was only a matter of time.  They are originally from Australia… feeding on leaf litter with a number of generations a year, they could be the next Light Brown Apple Moth! 

Although the image was poor, he was completely satisfied that it could be nothing else.

The first-ever sighting of Ruddy Streak in Ireland might be explained in the same way as its introduction to Britain as an adventive. A possible connection to the Bloom event in the Phoenix Park cannot be ruled out.

Andrew Whiteside.

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