A dragonfly pictured at Cabragh Wetlands
The whole story of seed dispersal is the essence of autumn but a stroll outside soon brings another natural wonder to light.
The meteorolgists tell us that July and August have been the dullest on record-tell me about it!
Yet, on the very early mornings in September, as I sat in the Cabragh Wetlands Centre gazing on the wild meadow still full of colour but inevitably going to seed, a charm of goldfinch alighted on the flower heads and the darting black, gold red and white lit up the scene in the morning sunshine-the seed eaters were back with a vengeance.
Throughout the autumn you will be able to admire them in a close up manner from the hide. The whole story of seed dispersal is the essence of autumn but a stroll outside soon brings another natural wonder to light.
As summer begins to shade into autumn, hedges and banks become festooned with vertical, spirally patterned webs made by spiders. Each is intricately woven and at this time of the year these web spiders reach full size and maturity making ever larger webs throughout the summer as they themselves increase in size. The webs seem to appear overnight on almost every bush, bank and hedge. The dew spangled webs are very visible in the early morning. They can stretch to two feet or more across and the webs built by young spiders are just as intricate as those of adults. The spider waits in the centre of the web or sometimes under a leaf nearby for small insects to blunder in and get caught by the sticky threads.
All orb spiders begin their web with a horizontal bridge line. A thread is secured at one end while the other is allowed to float across space until it adheres to a twig or leaf. The spider strengthens this bridge by passing over it several times, laying down more silk. Next, it passes from one end of the bridge to the other dragging a loose thread and fixing it at both ends. It then forms a closed letter Y with the centre of the Y forming the centre of the web. Soon the spider adds more frame lines and radii by a series of climbing and dropping manoeuvres.
Finally, it goes over the main spirals again, destroying them as it goes and replacing them with gum-coated lines that will secure its prey. Oil on the spider’s feet prevent it being caught in its own web.
The web is commonly positioned about 1-2 feet above the ground at vantage points instinctively chosen to secure a steady stream of prey. In gardens they take a heavy toll of insects especially crane flies, daddy long legs, whose low flight renders them prone to entrapment.
We often see crane flies with one leg missing having survived a near miss with destiny. Only the larger outer spirals of the web are sticky and it is in this region that insects are trapped. If the spider is lurking in its lair, notice of the victim’s arrival is given by means of a line of silk connected to the web which the spider holds in its forelegs. It dashes across the web to bite its prey, injecting it with venom which breaks down the insects’ tissues into liquid which the spider drinks. At the same time, the spider swathes its captive in silk so that it becomes powerless and can be stored for future use.
The spider’s silk is remarkably strong-produced by six spinnerets which exude silk in multiple strands that coalesce and solidify as they leave the body.
With a little time and patience you can watch this wonderful story unfold all around Cabragh Wetlands. Of course spiders are a part of the cycle of life and while their impact on controlling the insect population is significant, they themselves also have enemies. Birds take their toll as do hunting wasps and other spiders.
This week we host our A.G.M. for the first time on Zoom. Cabragh Wetlands faces an exciting future as it becomes more established as the nerve centre of environmental Tipperary. The present impasse of Covid 19 will pass and the array of activities will resume. Climate change, biodiversity and environment will return to centre stage and many have a contribution to make to ensure a better world for this and future generations. We need you to be part of this growing movement.
Our A.G.M. takes place on Tuesday September 15 at 20:00 on line.
If you wish to be involved ring Cabragh Wetlands at 0504 43879 for details of participation.Bí linn!
Stay safe-wash your hands.
Slán go fóill.