Tuesday, 14 July 2015

Day 253 - Life Cycle of Dragonflies and Damselflies

Hey Everyone, Day 253 today and I firstly have to apologise for there not being a post yesterday, but there's a good reason, I was at my graduation!  Yes it`s the end of my time at primary school and our leaver's evening assembly was a graduation ceremony.  We had mortar board hats and were given a scroll award certificate and had to give a presentation.  Everyone had an award relating to their skills or character. My award was for "Services to Birdwatching and all things Nature"!  This was because I'd been the founder of the school bird club and because of this blog. It was a great evening. I also got to do some really good drumming too!

By the way - what great news about the fox hunting debate being postponed - hurray!

What's that on that rock?
Anyway on to this post.  When I was at Nosterfield Nature Reserve at this weekend I was by the dipping pond and I happened to notice something on a rock near to the water.  I got down really close to it to inspect it and called Mum and Dad over.  We couldn't work it out at first but then realised it was a dragonfly emerging from its larvae skin.  It was fascinating, and that made me want to find out more about its life cycle. I know I've mentioned this in previous dragonfly and damselfly blogs but today I will be going into much more detail.  So here are the facts:

  • There are three stages of the life cycle. They each last for significantly varying lengths of time, one as long as a year or more, another for maybe only a week.
    It's a dragonfly emerging from its larval form
    - it looks so much bigger than the skin its coming from
  • Mating is a spectacular sight as the male gets hold of the female "by the scruff of her neck" and during mating can form an endearing heart shape!
  • Some species can complete in a few seconds, others take up to 6 hours...
  • The male will often stay attached to the female afterwards to guard her and they can even fly around like that.
  • After a short while the female lays hundreds of eggs in batches over a number of days or weeks.  The eggs are either laid on plant material or straight into water.
  • If they are laid on plants the eggs are elongated, and if they are in water they will be surrounded by a jelly-like substance to protect them.
  • There are various ways of depositing eggs depending on the species of dragonfly or damselfly.  For example all damselflies and hawker dragonflies have "ovipositors" which are scythe-like implements that inject eggs into plant leaves or stems, or into rotten wood or mud.  Some damselflies go completely under the water to lay their eggs and may need their mates to help pull them out. Golden-ringed Dragonflies hover vertically and stab their bodies down into the water to lay their eggs, but the majority of species including many of the emerald dragonflies, skimmers, chasers and darters will repeatedly dip their bodies into the water releasing one egg at a time just below the surface.
  • After about 2-5 weeks the eggs will hatch.  What comes out of the egg is a tiny larvae which looks a bit like a tadpole.  It will moult away its skin several times as it grows, sometimes up to 14 times until it is fully grown.
    A very alien looking sight.
  • This whole process usually takes a couple of years, but can be as quick as 2-3 months for emerald damselflies or up to 5 years for golden-ringed dragonflies.
  • During this stage the larvae can catch its own prey and has wing sheaths, legs and a hinged jaw. It will eat anything that is small and gets close enough from insect larvae to worms, leeches, tadpoles etc.  They prefer unshaded, unpolluted water in ponds that are not moving. They are also at risk to predators.  If any limbs are bitten off, they can regrow them during the next moult.
  • Dragon and damselflies don't have a pupae stage like most winged insects.  Instead they go straight into their final moult dependant on weather, temperature etc, They climb out of the water, start to breathe air and crawl away to a safe place.  There they push their heads, legs and wings out of the skin, wait for a bit to let their legs harden for a while, then push out their long abdomen which also needs to harden. This process can take up to 3 hours.
  • The new dragon or damselfly then takes its maiden voyage.  It can be a shaky start as it gets used to its wings. Sometimes it can fall prey to a predator such as a bird and even rain can have a harmful effect on its new wings.
    A fully emerged Broad-bodied Chaser
  • The new adults spend around a week adapting to their new form and feeding where they can, and develop their colouring during this time until they reach maturity. 
  • They then need to search for a mate, and the whole process starts over again.
  • The lifespan of the adult is short, usually only a week or two if they are lucky enough not to get caught by predators, but in some circumstances they have been known to live for up to 7 or 8 weeks.
So what we saw at Nosterfield I now know was a dragonfly in the third stage of emergence. You can find out more at lots of cool sites including www.british-dragonflies.org.uk.

Hope you enjoyed,


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