Monday, 25 May 2015

Day 203 - Beauty of the Mini-beasts - part 7 - Alderfly

Hey everyone, Day 203 and I thought it was time to come back to some of the little critters I see when out and about. Today's beastie I saw at the fabulous Lake Gormire which is a really beautiful place to visit if you get the chance, it's become one of my Mum's favourite places since we've found a route that doesn't involve going up and down Sutton Bank!

Alderfly (Sialis lutaria)
Whilst we were there eating our sandwiches I saw a bug that looked like it was struggling to get out of the water so I had to investigate! It got to a small stick at the edge of the water and very kindly stayed put while I got a few photos. Today's post is on the Alderfly.

So I did some research and here's what I found:

  • They are a primitive insect and apparently one of the first to have developed a pupal stage to their lifecycle.
  • They are not very good at flying so they are mainly found around the ponds and streams that they emerge from and explains why the one I saw looked like it was struggling.
  • Adults only live for a few days. They emerge to mate and may not eat in this time just existing on reserves from the larval stage.
  • Once mating has taken place, which is often at night, the female will lay up to 200 eggs on vegetation over hanging the water. This isn't always on Alder trees
  • When they hatch the larvae fall into the water where they spend most of their life.
  • They live in the silt of the bottom of lakes or slow flowing rivers where they crawl around feeding on smaller organisms and insects. They hide amongst weed and under stones.
  • After a year or sometimes two they go to the pupal stage. They bury into the silt and pupate and after a couple of weeks emerge as adults.
  • They are part of the order of insects called Megaloptera which also has Dobsonflies and Fishflies in it. This order of insects has some of the largest aquatic insect larvae.
  • As larvae the eat a lot of insects but are themselves eaten by fish. Watching the lake while eating my sandwiches I bet the adults are good Swallow food too!
So, I hope you enjoyed this, here's a few links to more information -

Hope you enjoyed, 


1 comment:

  1. I love them, I saw my first one this April - I had never come across them before and was a little startled as I wasn't sure what it was at first! The one I saw hopped straight out of the stream and onto the pebbles by the riverside. Great post and amazing photos too! - Tasha