This summer in Orkney we met up with two friends and fellow enthusiasts for a moth-trapping evening. I loved setting up their ultra-violet light in a big container, littered with egg boxes, and switching it on at night. Less exciting was having to get up at 4am to turn the light off and cover the collection so the moths wouldn’t escape at dawn. Later in the day, as we uncovered the moths from underneath their egg-box hideaways and placed them temporarily in plastic pots, to aid identification, we spotted a Sexton Beetle, Nicrophorus vespillo.
It is years since I’ve seen a Sexton Beetle. As a biology student there were a few compulsory elements of my degree. One was to collect 50 insects and kill them and then pin and mount and label them correctly in a large wooden case. I wonder if that wanton destruction is still a compulsory element today? It seems so shocking now. We were given strict instructions that we had to include insects from many different orders. We couldn’t choose just butterflies and moths, or just true flies, we were warned that people who did that would fail. We had to show we had the skills to catch and kill and mount a full range of different types. The University also sold us the wooden cases to mount them in, each of which had hidden compartments with mothballs in them.
Mothballs were white crystals of naphthalene made from coal tar, a dark fluid made from coal as a by-product of producing coal gas. It’s a process from the time when houses were lit and heated using coal gas. Few people know the smell of coal gas now. I only know the smell of a mushroom which is said to smell of coal gas, the Sulphur Knight, Tricholoma sulphureum. It smells of sulphur. When they stopped using coal gas they had to add smelly substances called mercaptans to the new natural gas so people would still know there was a leak. Mercaptans are the same chemicals which make cabbage smell rank, eggs smell rotten and make asparagus turn your wee smelly.
As with many of the ingredients of coal tar, naphthalene is carcinogenic. That didn’t stop my university giving me vast, stinking quantities of it in a box to keep in my tiny overheated room. Napthalene causes cancer in the same way that room fresheners do; by interfering with the natural process of cell death and replacement. I spent three years inhaling insecticide. Don’t do it. You may poison yourself. Napthalene exposure gives you haemolytic anaemia, where your red blood cells are destroyed faster than they can be made, and cataracts. If you breathe, eat or touch it a lot you get headache, nausea, vomiting, diarrhoea, confusion, anaemia, jaundice, convulsions, and maybe even coma. Never think you can kill insects without having an effect on humans.
I remember going to jumble sales as a child and smelling old fur coats which stank of mothballs. You could smell them from a mile away, metaphorically, not literally. I had a Saturday job in a dry cleaners and remember people bringing in clothes stinking of mothballs. The next Saturday they would come back to collect their items which we had dissolved the dirt stains on, subsequently spreading the dirt all over their clothes in a fine and less visible layer, by using perchloroethylene as the solvent rather than water. This organic solvent, called perc for short, is used for industrial degreasing of metal. Studying people exposed to perc in the workplace shows associations with several types of cancer including bladder cancer, non-Hodgkin lymphoma and multiple myeloma. It can also make you unconscious. If you do collect your dry cleaning, don’t put it in your hot sealed car and drive miles to your home. You may poison yourself.
As well as making mothballs, coal tar was used to make carbolic acid, a key ingredient in coal tar soap. That’s another smell I remember, from children having their mouths washed out with it, as punishment for talking or using bad language. Coal tar is, of course carcinogenic. You can still buy non-prescription coal tar soap, it just doesn’t have any coal tar in it now, it has tea tree oil instead, to make it smell almost the same as it used to. I don’t know whether tea tree oil is carcinogenic, but ingesting it causes drowsiness, confusion, hallucinations, coma, unsteadiness, weakness, vomiting, diarrhoea, stomach upsets, blood cell abnormalities, and severe rashes. But not cancer that I know of, so that’s all right.
I took the instructions to collect 50 insect specimens seriously, even though I hated killing every one. I mainly used jam jars to keep and kill the insects in and filled them with ripped-up laurel leaves. Laurel gives off cyanide gas which kills the insects and relaxes their muscles to make them easier to mount. I used to sniff the top of the jam jar and check that the bitter almond smell was intense enough. Cyanide has a lovely smell. If you do have a laurel hedge don’t flay it, put the trimmings in your hot sealed car and drive miles to your recycling centre. You may poison yourself.
I really wanted to find a theme for my enforced insect collection, even though we weren’t allowed to have one, but I needn’t have worried, because the theme found me. The first to be pinned and mounted was an insect from the order Hemiptera, the true bugs. I found it had piercing mouthparts and sucked blood. I found it in my student house bathroom. Sadly I can’t remember the species. Next to be added was a beetle from the order Coleoptera, a Larder Beetle or Bacon Beetle, Dermestes lardarius, from the kitchen in my student house. Then I added a Carpet Beetle, Anthrenus verbasci, from the living room of my student house. I found a lovely moth on my curtains in my student room, in amongst the holes its caterpillars had made. You can see a theme developing, can’t you?
I decided I couldn’t limit myself to my student house, so went for a walk and found a couple of corpses of poisoned mice with burying beetles on them. These Sexton Beetles have an incredible life, meeting as a pair on a freshly dead corpse, drawn by the smell, sensed by their incredibly sensitive antennae. They then undermine the corpse, bury it and lay eggs near it, which they guard, and then stay to tend and feed the larvae. They can smell a corpse from a mile away, literally, not metaphorically. I added one to my collection. It really was non-stop death and infestation.
I submitted my collection at the end of three years of smelling mothballs in my room and then I got it back again. It had obviously passed. There were no comments and no marks awarded. One of my fellow students had created a collection of just moths from Orkney where his dad was some form of warden. That seemed like cheating to me. However, he didn’t fail, his collection was singled out for special praise, despite not adhering to any of the rules. After all, rules only apply to the little people, don’t they?
It was an emotional moment letting the Sexton Beetle go. I wished it well in finding a corpse.
What happened to my insect collection? I carried it around with me, from dodgy bedsit to shared house, to rented flat to first home, with the scent of mothballs following me as the white crystals turned to gas and slowly disappeared. The wooden box ended up in my loft. One day I got it down and opened it to find each perfectly mounted and labelled specimen had been eaten by Museum Beetles, Anthrenus museorum, or a similar species of Anthrenus. It seemed a fitting end.