Thursday, December 22, 2011

What's afoot in the Winter in the Home Bug Garden?

Young Basement Spider Tegenaria domestica
I've always found the first official day of winter somewhat strange, coming as it does, months after winter actually starts. I guess there must be some rhyme or reason to picking the solstice as the beginning of winter instead of say, Winter Hump Day. In much of the world today would be well on the way to Spring. Not in Edmonton, though, we've still a long way to go if previous years are any indication.
A typical March in the Home Bug Garden
So what is the arthropod addict to do with so many more months of winter in the way? Well, our friend John Acorn has come up with the Arthropod Winter Challenge! How many living arthropods can we find in Alberta in the winter? John thinks we can find more arthropod than bird species. Well, inside our house that certainly is true - first look around found three species of arthropods including the half grown Funnel-web Spider (Agelenidae) at the top. That is not quite fair to the birds - we have none to compete - but outside? Yes, there is a cornucopia of arthropods outside that brave the winter weather - but you need to look very closely for them and for many you need to put your nose to the ground.
Microarthropods from a few handfuls of spruce litter under the deep snows of last winter
All gardeners know that a good blanket of snow protects their plants from winter extremes, but even in very cold climates a good snow cover can also capture enough warmth for the tiny animals (microarthropods, nematodes, tardigrades, etc.) and microbes that live in the soil to go about their business. A few degrees above freezing is all they need; but so far, snow has been relatively scarce in Edmonton this winter and so no layer of relative warmth has been trapped. And, while I've enjoyed the less than usual shovelling, it has put a bit of a damper on my response to John's challenge.
A Fairy Wasp (Mymaridae, Polynema sp.) from under last winter's snow
Well, we Edmontonians know that good weather rarely lasts long and I expect that in the New Year I'll have a chance to see quite a bit more snow. I'll take comfort in knowing that under that snow my plants will be safer and there will be tiny arthropods having a good time, like the Fairy Wasp above. This tiny wasp - 0.6 mm long from head to tip of its ovipositor -  is a parasite of the eggs of leafhoppers. Bad news for baby bugs, but good news for the garden.