Rickia wasmannii everywhere

Thanks to John Pontin for pointing out the Rickia infested ant in one of this years Wildlife Photographer of the Year competition. I had the portfolio at home, but hadn't noticed the fungus on the ant. It's a bit hard to tell from the online image, but is really quite clear when it's a bit bigger.

I'm thinking that the ant is probably Myrmica rubra. As far as I know, R. wasmannii has not been recorded on this species before. Perhaps the photographer, András Mészáros, would be able to help establish whether I'm right?

I'm starting to think that R. wasmannii is actually quite common in Europe, but just under-recorded. Has anyone else made Rickia sightings?

Entomophthora muscae

The largest part of the autumn fungus fruiting season may have passed in the UK, or at least where I live, but there are still a few things around, if you're prepared to look closely for them.

Yes, it's a fly (I don't know which species), but it is a fly with a fungal parasite, Entomophthora muscae. The fungus grows inside the fly, eventually reaching the fly's brain and influencing its behaviour. The fungus needs to get as high as possible to ensure reproductive success, so it forces the fly to climb to the top of a flower, twig or, as in this case, blade of grass and then makes it hold tight. In some cases I've even seen fungal hyphae around the flies proboscis and legs where the fungus has apparently anchored its host (though I suppose this could be a secondary infection in older specimens). The fungus then kills the fly and bursts through its abdomen to shed its spores. These spores are picked up by the wind to infect the next generation of flies.

E. muscae isn't rare by any means, but it does seem to be overlooked. It also seems to be most abundant as it starts to get wetter in autumn, so I find it most years at about this time. Nevertheless, I have very rarely found as perfect a specimen as this.

I know there won't be many others who share this opinion, but I do think that E. muscae is rather awesome.

Hygrocybe intermedia

One of the few things that the UK seems to do really well is waxcaps (Hygrocybe sp.). They are one of the more spectacular groups of fungi, coming in a range of very vivid colours. In Europe they are associated with grasslands, though elsewhere in the world they tend to occur in woodlands.

The first time I encountered Hygrocybe intermedia was in 2000, on the sand dunes just a few metres from Sizewell nuclear power station in Suffolk. At the time, the species was listed on the provisional UK red data list for fungi. Although it has since been removed, it's evidently not that common, with only 410 records on the Fungal Records Database of Britain and Ireland.

This specimen was found at Brown Robin, a Cumbria Wildlife Trust reserve near Grange over Sands, where H. intermedia was the most abundant fruiting fungus present. As fungi go, it is an unmistakable waxcap, in the Northern Europe at least, due to it's colour, squamulose pileus (cap) and fibrillose stipe (stem).

Ustilago maydis

Always on the look out for something really weird, in 2006 I found this grotesque thing. The general impression is of a set of giant rotting teeth.

It didn't take much tracking down. Many fungi are host specific, so if you can tell what the fungus is growing on you stand a chance of identifying it. This rises to a good chance when the fungus is as distinctive as this. In this case the host was maize Zea mays and the fungus is maize smut Ustilago maydis. The fungus was growing on the cobs.

Though U. maydis is common in North America, it's very rare in the UK. This was only the ninth time that it had been recorded. It's unlikely to be overlooked, so it's probably genuinely rare. The field it was found in had Z. mays growing with other exotic grasses that had obviously been sown for game cover. As a result, I suspect that the field had not been sprayed with fungicides that would ordinarily prevent U. maydis from growing.

Apparently, in North America U. maydis has traditionally been, and is still considered by some, to be a good edible fungus. In fact I read that some cultures prize the fungus more than the sweetcorn. Would you eat this?

Rickia wasmannii

Fairly regularly something comes along and completely stumps me, but it doesn't normally happen with European ants.

I thought I knew Myrmica well, especially M. scabrinodis, which is one of the species I most regularly encounter. This Bavarian specimen really has caused me to do a disproportionate amount of work to resolve it's identity.

First of all I wasn't even 100% certain that it was a Myrmica. It has unusually large mandibles and, particularly, it appears to be covered with rather strange clavate hairs. I had to get my BIG eyepieces out to check the tibial spurs on the middle and hind legs (which were dubiously pectinate) and then count the palp segments, which always takes a lot of effort to get the position and lighting good enough to see anything. The result was that it is definitely a Myrmica.

By this stage I had already decided that it had the antennal scape and overall shape of M. scabrinodis, but those hairs were peculiar. I worked my mounted specimen through Seifert (1988) and his new book (2007), both of which suggested clearly that the specimen is M. scabrinodis¹.

I then really started asking questions about those hairs and, once I had thought of fungi as a possibility, I quickly found was seems to be the most likely answer: Rickia wasmannii. This was described from Germany, though I've no idea how common recorded it is. It was only recently collected from Hungary and Romania (Tartally, et al, 2007), and does not appear to be known from the UK. All five specimens in this collection are covered in these little growths on almost every part of their bodies.

I haven't actually confirmed this, but I suspect that species of Rickia are host specific and that R. wasmannii is the only one that is known from Myrmica sp. However, if anyone has any additional information on Rickia sp. I'd be very grateful to hear about it. In the meantime I will spend a lot more time looking at British Myrmica in the hope that I can get the first UK record of R. wasmannii!

I sure know how to have fun on a Friday evening.

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¹ For those who are interested in such things, the standard measurements and indices used to make the identification were as follows:
     Head length (HL) = 996 µm
     Head width (HW) = 952 µm
          HL/HW = 1.047
     Scape length (SL) = 763 µm
          SL/HL = 0.767
     Minimum distance between frontal carinae (FR) = 310 µm
          HW/FR = 3.071
     Maximum distance between frontal lobes (FL) = 443 µm
          FL/FR = 1.428
     Length of propodeal spines (SP) = 310 µm
          SP/HW = 0.311
     Petiole width (PE) = 266 µm
          PE/HW = 0.279
     Postpetiole width (PP) = 376 µm
          PP/HW = 0.395

Fungal attack - Cordyceps gracilis

In a few months I'm going to let my online gallery close, so I'm taking the opportunity to post some of the more unusual photographs here.

This is Cordyceps gracilis. Cordyceps fungi are parasitic on insects, some of which are quite extraordinary looking.

The common species of Cordyceps within the UK is C. militaris, which can occasionally be found growing out of buried Lepidoptera.

C. gracilis is much rarer and very different in appearance, but also infects Lepidoptera. It was collected during a heathland survey training event at Poors Allotment, nr. Chepstow and was only the second record for Gloucestershire (though there are now four). It was growing in Pteridium aquilinum litter, which meant that I only had to reach down to pick it up and the whole thing came out easily, caterpillar as well. In case you don't believe that it is a caterpillar, I pulled the mycelium away from the caterpillar's head and took the close up photograph below.


Here is a short clip about tropical Cordyceps and ants: