#72 Scarlet Caterpillar Club Fungi by Mark Wills
Meet Mark Wills, Operations Manager at NEYEDC!
Regular readers of our ‘Natural History of Yorkshire in 100 Species’ blog series will have noticed that we missed our regular bi-weekly slot last week, this was so we could bring you a Hallowe’en Special, celebrating the darker and more macabre side of nature! This week’s blog has been written by our Operations Manager, Mark Wills. Mark has been with NEYEDC for nearly 20 years and has played a key role in the evolution of NEYEDC from the days of 7-day turnarounds for enquiries involving photocopying records and target notes to be sent out by post, through to the current system of online interactive mapping delivering our services within a matter of hours!
Mark’s interest in Biological Science began whilst studying the Human Anatomy & Physiology section of his GCSE in P.E., an interest that was further developed through studying Zoology and Biodiversity & Conservation at Leeds University and time spent working on a conservation project in Zambia, curating the beetle collection.
Scarlet Caterpillar Club Fungi in situ; Dave Conniss
Mark’s chosen species is the Scarlet caterpillar club fungus Cordyceps militaris, his interest having been piqued when he read about it’s particularly dark lifecycle. This brightly coloured species is found mainly in grassland and on woodland edges during late summer and autumn. Although this species is not one of the clubs of the Clavariaceae family that NEYEDC are recording as part of their ‘waxcap’ project, it was found at a recent training event in Rosedale, North York Moors. But similar to the Clavariaceae family, the fruiting bodies of C. militaris are not the classic ‘mushroom’ shape of many fungi, but are slender club-like shoots 2-4mm in diameter and between 0.5 and 4cm long. The Lorn Natural History Group has more great images of this fungi.
On the surface, C. militaris appears to be like many other fungi species, producing fruiting bodies late in the year from which spores are produced, which is how it is able to spread. These spores, however, are its secret weapon. The scarlet caterpillar club is a parasitic fungus, that grows on the larvae and pupae of moths. The unlucky caterpillar comes into contact with the fungus spores, and once infected the caterpillar moves slowly through the ground into a position which is ideal for spore dispersal – just the right depth for the club to push up through the surface.
Once in position the caterpillar then begins to pupate and from there it does not move. The unfortunate host is slowly consumed by the developing fungus as the fungal mycelium begins to grow inside it, replacing the caterpillar's own insides. The host is long dead by the time the fungus sends up its bright orange-red club the following season to release its spores in the hope of finding another host caterpillar to parasitise.
Scarlet Caterpillar Club with pupae remains and mycelium; Dave Conniss
As a sac fungi or ascomycete, C. militaris has a smooth appearance to the bottom of the club (or stipe) but a bobbly-looking upper surface, as seen on Ken’s photo. This bobbly appearance is due to the perithecia which cover the upper surface, each of which is a small fruiting body whose job is to burst open, sending its spores out far and wide. The distances that fungal spores can travel via wind dispersal are quite variable but they can easily travel several kilometres and some studies have reported spores to have travelled thousands of kilometres. Moth caterpillars need to go quite some distance to be safe from the spores of the scarlet caterpillar club!
C. militaris is one of about 400 Cordyceps worldwide and are closely related to the genera Ophiocordyceps and Tolypocladium. Several species from these groups are so called “zombie fungi” because of the way they take over an insects body and alter its behaviour. The most famous example is Ophiocordyceps unilateralis, a parasite of carpenter ants in tropical forests. The ant is infected by spores and is made to travel away from the nest to a plant in a more humid location that is better suited to the fungus’s growth. The ant is then compelled to sink its jaws into a leaf vein on the north side of the plant and wait for death, while the fungus feeds on the victim’s innards. It then sends a fruiting body out of the ants head to release its spores to infect more ants.
It is unclear quite how the fungus can take control of the host’s behaviour, whether by releasing a chemical or altering its’ DNA, but it is thought that fungal cells grow around the brain of the host which hijack the insect’s nervous system to control its muscles.
Returning to our chosen species, if a scarlet caterpillar club is gently removed from the soil, it is sometimes possible to find its host. The fruiting body usually grows out of the head end of the pupae or caterpillar, however by the time the host can be found, indicated by the presence of the bright coloured fruiting body, it is often too digested to identify.
Scarlet Caterpillar Club surface texture; Ken Gartside
There is little documented uses of the fungi in Yorkshire either for nutritional or medicinal uses (North American field guides consider it “inedible” or “probably edible”). It is however well known within the realm of traditional Chinese medicine and its anti-inflammatory, anti-tumour, anti-aging properties have been well documented. It is also used in Asian cooking, the fruiting body being cooked as a mushroom in dishes like chicken soup, pork bone soup and hot pot.
Recording and monitoring
C. militaris would seem to be fairly conspicuous given its brightly coloured fruiting body, however it is infrequently found in Britain and Ireland. It is likely to be more common than records show as it is actually quite difficult to spot because the clubs are usually much shorter than the grass or moss amongst which they are growing.
Jar of Cordyceps fungi for use in cooking
Its known distribution in Yorkshire is, in common with a lot of fungi species, an underrepresentation of its actual distribution, with 622 records nationally on iRecord, and just 19 of these recorded in Yorkshire. Meanwhile, iNaturalistUK has a total of 276 records nationally. The British Mycological Society’s Fungal Records Database of Britain and Ireland (FRDBI) holds 91 records across Yorkshire, 60 of which are within the last 50 years, whilst the oldest record dates back to 1880. These records are scattered across all Vice Counties in Yorkshire and across different Natural Areas.
Any species of fungi can be added to the FRDBI and NEYEDC are particularly interested in CHEGD species across Yorkshire to help support their waxcap project and the identification of long-established and ancient grasslands - a rare and under-recorded habitat that needs protections (https://www.neyedc.org.uk/waxcaps).
Further information and acknowledgements
NEYEDC would like to thank Mark for his time and expertise in helping to create this blog.