Monthly Archives for September 2017

Friday mystery object #313 answer

Last week I gave you this cheeky chap to have a go at identifying:

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There was some lovely wordplay in the answers, with Chris getting in early with this great one:

I thought I had a shrewed idea until I saw the Bilby in the background which could show this isn’t the elephant in the room. Coot is legs be too Bandi?

This rules out elephant shrews and correctly identifies it as some kind of bandicoot, thanks to its marsupial case companion. Then palfreyman1414 dropped an anagram into the mix with:

Mere ale plus Satan?

which is so nice I wish it was correct, but alas this isn’t a Long-nosed bandicoot Perameles nasuta, although it is in the same genus.

Allen Hazen wondered “How badly does fur fade in preserved specimens?” and that turned out to be the key question, since everyone shied away from the correct identification, because one of the characteristics of this species’ pelage (that’s mammal-fan speak for ‘fur’) is that it’s supposed to have two stripes on its hindquarters or, more accurately, bars. As it turns out, fur fades quite badly in preserved specimens.

This is in fact a Marl or Western barred bandicoot Perameles bougainville Quoy & Gaimard, 1824 (NMINH:1906.301.1).

Marl

These diminutive Australian marsupial insectivores are vulnerable to introduced predators like cats and foxes, so their wild population only remains on some islands after once being widespread across Western Australia.

Even on the islands where they have some protection from placental predators, they face issues with disease, since their population has shrunk by so much it has impacted on their genetic diversity – reducing resistance to disease at the population level. In particular, a virus that causes tumour growth is affecting the animals on some islands, leaving the species increasingly under pressure.

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One island does remain free of the virus, so hopefully with proper management the Marls will be able to hang on in there.

Friday mystery object #312 answer

Last week I gave you this specimen to identify, which came in as an enquiry after being found in someone’s toilet:

There were a variety of great responses, with some fantastic cryptic clues, including an anagram by Claire Miles (great stuff!). Most opted for this being Stegobium paniceum, which is also known by the aliases Drugstore Beetle, Biscuit Beetle or Bread Beetle.

Stegobium paniceum by Sarefo, 2007

Stegobium paniceum by Sarefo, 2007

However, the mystery critter has a subtly different pronotum (that’s the plate over the thorax that extends over the head).

Another suggestion was woodworm or one of the false powderpost beetles, which covers a range of wood-boring beetles, with Liberty Hightower correctly giving the more taxonomically constrained suggestion, of something from the Tribe Anobiini (which includes Stegobium). However, my colleague Olivier sent me an email with a very definitive identification, informed by a past experience with this particular pest – the Furniture Beetle Anobium punctatum De Geer, 1774.

These beetles have a distinctive pronotum that supposedly looks like a monk’s cowl, with a more distinctive hump and slightly pinched looking back section than the more smoothly curving pronotum of the Stegobium. They fall into the broad category of woodworm because their larvae feed on wood, making tunnels hidden from view and only becoming visible when they emerge from small holes in the wood as adults, leaving a little pile of wood dust as they go.

The presence of these beetles in a toilet isn’t related to the water in the bowl or even wood of the seat – it turns out that there was a window above the toilet and the adult beetles, in an attempt to leave the building after emerging, were attracted to the light from the window and flew into the glass only to bounce off and land in the toilet.

This attraction towards light in the dispersing adult stage of the beetle is a handy behaviour if you want to keep track of these pests. If you’re concerned you may have active woodworm it’s worth checking your windowsills in the summer to see if you have any of these adult beetles lying around. Of course, there are other species that would also be worth checking for, since there are plenty of beetles whose larvae would be considered woodworm. Keep your eyes peeled!

Friday mystery object #311 answer

For the last couple of weeks I’ve been offering up what has been affectionately nicknamed ‘cave snot’ for identification:

mystery311a

The initial goop was a bit too difficult to identify from a photo, so I dug in and pulled out the critter responsible:

mystery311c

This proved much more identifiable, with Chris immediately recognising that it’s the larva of a Caddisfly (not really a fly, but a more moth-like insect in the Order Trichoptera – which means ‘hairy wings’ as palfreyman1414 mentioned). Natalia Maas went one better by alluding to the family – the Philopotamidae or Finger-net Caddis, explaining the goop, which is actually made up of little silk nets shaped like fingers (hence the common name for the family). These nets are used to collect organic detritus and diatoms from flowing water, which the larvae then feed on.

I provided a couple of extra images to help narrow down the identification, since there are only five species in three genera of Finger-net Caddis in Ireland (and England for that matter), which are able to be differentiated from the anterior margin of their frontoclypeus (see the diagram below if you’re not sure what that is).

caddis-frontoclypeus

There’s an excellent website looking at Trichoptera in Ireland, descriptively called TrichopteraIreland, where you can find the details of how to tell the larvae of different genera apart, but the short version is to look at the frontoclypeus and if it has a deep U-shaped notch in it you have a Chimarra marginata, if it has a shallow V-shaped notch in it then you have Philopotamus montanus and if it’s a smooth curve then you have a species in the genus Wormaldia (which could be W. subnigra, W. mediana or W. occipitalis).

Unfortunately you can’t readily tell Wormaldia species apart when they’re larvae, so unless I’m missing a well-hidden notch in the frontoclypeus, we can’t identify this to anything better than genus level – but that’s still a substantial improvement on simply calling it cave snot.

I’ll be taking the specimen to the previous Entomology curator of the Museum, since his area of specialist interest is Caddis, so I’m sure he’ll be able to confirm the identification and I expect there may be some interest in where it came from.

More mysteries next week!