Riverfly Invertebrates guide - Number 5 the Stonefly
Something different …
A Job Opportunity!
River Lim Action Recruitment is seeking an experienced species of invertebrate larvae for the Team of Eight Riverfly Team.
Opportunity to collaborate with human monitors once a month.
The Riverfly 8 ….. key invertebrates which indicate the ecological health of the river.
The RLA Riverfly team monitor 7 sites on the river every month to detect and count these species. Then that site gets a score which is then updated onto the national Riverfly Partnership Cartographer
Introducing #5 Stoneflies
Stonefly larva
Later …. at the interview!
Q. Tell us a little about yourself, Stonefly nymph
Stoneflies like me have been around for millions of years and are part of the order of Plecoptera. We have a wealth of experience in freshwater habitats and are keen to indicate the ecological health of river and streams for all.
Q: Could you summarise what makes you suitable for the role?
We call out polluted water.
If we’re not there, it’s not clean enough.
Simples.
Q: Could you elaborate on your strength and weaknesses?
I’m in interview mode …… so I’ll say our weaknesses are our strengths!
Some might describe our gills as under developed but what that means is that to survive we need swift currents with a plentiful supply of oxygen only possible with good management of our rivers. We can also absorb oxygen through our exoskeleton so there is a Plan B to help us survive.
Our mouthparts are well adapted for scraping and gathering anything nutritious from the rocks and stones we cling and crawl over and we are beautifully camouflaged to protect us from predators. Have you seen my profile picture?
Q: Anything else?
OK, full confession:
I’m more of a crawler than a swimmer but if needs must, I’m ready to hurl myself into the fast flowing current and go with the flow.
Sounds hairy but it works.
Q: Where do you see yourself in 5 years time?
Realistically, downstream and dead!
After the nymphs have shed repeated exoskeletons through 10-30 stages, us nymphs will have been in the water for 1-4 years.
So personally, my time is limited.
Q: So it’s a short term contract you’re after? We’d better move on quickly then.
Absolutely.
After the last moult, it’s time to find a mate so we crawl out of the water onto vegetation.
Q: Brave move. I understand you males have a rather unusual way of attracting females by drumming with your abdomen on a rock.
That’s news to me as I’m not at that stage yet but if what you’re saying is true, sounds good and I look forward to that craic. Clearly, those female Stoneflies cannot resist those vibrational signals and often respond! After mating, the females can lay thousands of sticky eggs which drop into the water and attach onto stones and branches with the new nymphs emerging a few weeks later when conditions are right.
Q: Anything else we should know about?
We have two tails unlike the mayflies who boast three and us Stonefly nymphs have good strong legs each ending in two claws excellent for clinging. The name Plecoptera means “braided wings” in Ancient Greek and they look perfect held over our adult backs. Shame that they don’t work too well (something to focus on over the next few million years), so we stay close to the stream and only survive a few weeks.
Q: Sad, but you’re in! We are delighted to offer Stoneflies a position on the team of 8!
Great, when do I start and what are the perks?
