One of my favourite reference books, The Urban Dictionary, finds entomology rather dull and swotty. It comes close to apologising for any guilty pleasure that might be found in creepy crawlies. The entry reads: “Entomology" – noun - The scientific word for the study of insects. It’s bug research pretty much. I enjoy studying entomology. Really.”

This, by the profane standards of the Urban Dictionary, is remarkably demure language (if you don’t know the Urban Dictionary, look it up online – it’s fun, for a while). If I were a swotty entomologist I would expect the Dictionary to be obscenely hostile. But all is not what it seems. Entomologists have hidden qualities.

If you do a little digital digging, you’ll find that amidst the Dictionary’s aggressive smut, the swots and entomologists are an unexpectedly feisty bunch who give as good as they get.

For example, here are a couple of the Dictionary’s more printable definitions of “swot”. The first, appropriately, is written by a swot and it’s a zinger:

1. “Swot" - noun - A word used by morons to insult a person of superior academic abilities.  Morons believe being called a swot is a horrible, undesirable humiliation for the victim. Well, the morons can fuck-off now!

   The morons’ counter-view lacks flair and basic literacy, as our swot would have told us (if only we’d asked):

2. “Swot" - noun - A swot is a person who excels in a subject or lesson, who never gets anythink (sic) wrong and is teachers pet.

Although I rarely did well in exams and was teacher’s pet hate, I like the first definition. I’m sure you’ll agree that a swotty entomologist of the kind who tells the dullards to F-off sounds like good company. And I especially like the added emphasis of the ‘Now!’, an extra flourish added just in case the first 2 words weren’t enough.

So, game on: Saturday night’s all right for fighting – and I’m with the entomologist. BUT, and it’s a big one, fists and fishing don’t always mix well on the bank. So what are these swotty, foul-mouthed fly fetishists for when we’re out there casting a line?

I’m going to declare an interest here. As an intellectually indolent teenager with a serious fly-fishing habit, I didn’t have much truck with entomology. Very early in my slouch through life, I decided that fly presentation was, and still is, everything. I fell into this because it was more fun than learning Latin, flies and all that boring stuff. Adulthood did nothing to change my mind.

Instead, all my effort went into dropping a dry fly of indeterminate type on the nose of a rising trout that I could see. This was a flawed combination of reading the air and the water, and then attempting a perfect cast with my bamboo, now carbon, wand. Being a pretentious little git probably helped me gloss over my shortcomings.

So as you can see, an entomologist might be someone I’d rather rub shoulders with after fishing. Why would I want to be on the bank with a new partner who calls me a moron and tells me to F-off just because my philistine ineptitude is a denial of their faith (and everything)? However, I think I will have to swallow my pride …. While I still won’t pay any attention to fly catalogues, I’m fascinated by entomologists and would like to go fishing with one. Really – and regularly.

Back in the day, my fantasy choice of fishing partner would have been Hunter S Thompson, author of the lost masterpiece Fear and Loathing on a Trout Stream (a frantic tale of sex, drugs and the evening rise). Thompson was a roiling bundle of provocation, and so is our entomologist. Like Thompson, he or she is happy to say F-off to anyone found to be insufferable. In Thompson’s case that was almost everyone he met, especially if the resulting brouhaha made good copy. I like to think my new entomologist friend could do this too, but more selectively. And, fingers crossed, that this would happen with less reliance on the fabulous intake of drink and drugs that kept Thompson in fighting shape. I’m getting a bit long in the tooth to go the full Hunter-S, so absent the great man himself, the entomologist sounds promising.

This is important because every-so-often life washes up people who deserve to be told to F-off now, and I’ll admit I’m not very good at confrontation. So hanging out with an attack entomologist might be useful. Not only can my new friend speak ill unto evil but, most importantly of all, he or she also knows exactly to whom and why it needs saying. And that is why entomology really, really matters. Even to a slouch like me.

It also means that I can be sure that if the entomologist really does do a Thompson and gets us into a fight, then it will be with someone who deserves the beating. And I’m hoping the entomologist will be better with their fists than me, because we’ll be in trouble if they’re not.

But there’s more to entomologists than bare-knuckle jeopardy. They’re a clever and well-educated bunch of people, usually with some paperwork to prove it. So, if you want to know about the impacts of sewage, climate change, industry or farming on a river, just ask an entomologist. And if you also want hard evidence to save your river from any of this, then you know who to ask. I cannot stress enough how important, how essential and wonderful even the foulest-mouthed entomologists are. We should all honk-for-entomology. Hatch Magazine should sell Hug-an-Entomologist t-shirts and Fuck-off Now! coffee mugs (this last item for Christmas presents please).

So forget matching the hatch – I’m never going to do it. But I will dabble in citizen science and count insects to give our pugnacious entomologist the data needed to take down polluters. And if that’s what entomology is for, and it sure looks like it is, then I’m a fan.

I’m also a fan because this is about more than science. Language matters and in this case it’s direct and Anglo-Saxon, the building blocks of good writing. So the Urban Dictionary is right, the morons who wreck rivers really do need to ‘F-off Now’, and they have to do it before it’s too late.

Until about 20 years ago river water quality in my part of the world, Britain and Ireland, was fitfully improving. Now we have a rolling ecological disaster and it’s getting worse. Much worse.

This isn’t a problem peculiar to a small part of northwest Europe. It’s happening just about everywhere people go fishing. So whether it’s raw sewage or farm slurry or some stinking factory or the overheating redds that my new friend the entomologist identifies as the wrecking ball, then I’m with them on the barricades, bandana askew, Che t-shirt rescued from the attic and two fingers aloft.

They can all Fuck-off Now!

Lifelong flyfisher, former BBC TV Environment Correspondent, and filmmaker Richard Wilson writes the monthly newsletter FishRise.