Thursday, November 1, 2012

Winter Sanctuary for Yellow Jackets

     Here in the Pacific Northwest, we have had a prolonged Indian summer period which ended abruptly two weeks ago when the Pineapple Express starting funneling in huge tropical rainstorms from Hawaii.  Out in the world of nature, everything went from crackling dry, ready for a major forest fire to sodden:  the bright leaves ripped out of the trees and now stuck to the walkways, the mushrooms logs awaiting that rain now starting to sprout oyster and shitakes, the people (like me) slogging out to the car with wet socks and pant hems.  It has been a very abrupt finish to a halcyon summer that seemed as if it would never end...

     It’s been a precipitous turnaround for the insects, as well.  Lately I’ve been watching several fat Yellow Jacket queen wasps, hovering at the walls of our house, seeking out a place to find sanctuary from the coming winter.  Days are getting shorter, colder and wetter and soon they must find a safe place, or die.

     Here at our house, these queens often crawl in our mason bee tube colonies, tucking down into the dry spaces between the wooden tubes.  Once safely stowed away, they go dormant, reducing their metabolism and feeding off their stored fat.  Here is a picture from one of our mason bee houses; you can see two different queens deeply asleep and well protected between the tubes.

     They often find piles of woodland duff or conifer needles to overwinter in.  One memory from childhood is when I climbed up in our juniper trees and found a fat, cold, sleeping queen buried in a pile of needles in the crotch of the tree.  I was both terrified and fascinated to see how quiet she was, though as I prodded her she began to waken and within a few minutes was more than capable of defending herself.  I fled that tree forthwith. 

     Yellow jackets often overwinter in cold outbuildings.  I remember going into an unused cabin in mid-February:  we turned on the heat and the lights and within half an hour we had awoken a dozy queen; she was at the ceiling light, grumbling away with that low, steady, ominous buuuzzzzz that can still freak me out. 

     Yellow jacket is the common name for predatory wasps of the Vespula and Dolichovespula genera.  Most of us know these wasps as the uninvited guests at the summer picnic.  Most humans give little respect to these wasps, but in fact the Yellow Jackets play an important part in the natural world:  they are key predators of insects such as caterpillars, grubs, crickets and any other bugs too slow to get away.   Were it not for predators such as these, keeping populations in check , our world would soon be over run by insects. 

     Yellow jackets have select food preferences and they are voracious about these preferences.  The adults like sweet-tasting liquids, such as nectar in flowers.  They also like rotting fruit, and can be found swarming over fall fruit on the ground, especially juicy ones.  They like tree sap, which explains why our drippy Norway Spruce always has lots of yellow jackets around it in the summer.  All of these natural sweet items are mimicked in our sodas and fruit drinks, which is one big reason why Yellow Jackets visit the picnic table.
     The other reason is meat.  The young larvae growing in the hive require animal protein to grow.  This is why the adults hunt for burgers.  But they will also forage for dead insect carcasses, the yellow jacket version of road kill.

     The adults also happily settle for any other available protein.  Glen had a friend who brought home some salmon bone carcasses, which she planned to use in an art project.  She hung the carcasses out in the carport to dry; Glen watched over several weeks as the yellow jackets came and went, efficiently stripping off the fish to take home to the nest to feed their young.  He watched in fascination as some worker wasps carved off huge hunks of salmon, some of which were so large the wasp could barely fly.  Over time the yellow jackets completely cleaned the bones.  Their growing larvae were well-fed and Glen’s artist friend got some spanking clean bones out of the process.
     Yellow jackets have their predators as well.  A related black and white wasp commonly called a Bald-faced Hornet specializes in catching and eating bees and wasps.  I have seen this first hand.  
    One late summer day I was sitting outside near our plum tree.  It had produced masses of fruit that year , so a lot of it was on the ground, slowly fermenting in the sun.  There were yellow jackets all over these plums, sucking up a quick energy snack before foraging for the hive.  
     I was watching a yellow jacket crawling over the surface of a plum, looking for the best place to dig in, when a Bald-faced hornet appeared.  I expected to see a skirmish over the plum and was curious about who would win.  I was wrong: the Bald-faced hornet was hunting meat.  There was an epic battle where the two wasps duked it out, loud buzzing , frantic manueverings and stinging like crazy.  The Bald-faced hornet won.  I watched the yellow jacket die, and then the Bald-faced hornet efficiently began to carve it up and carry away pieces back to her hive.  It took a couple of trips.   That predatory Yellow Jacket was the building block for more Bald-faced hornet workers.  And so the cycle continues...

     Today the Pineapple Express has finally changed tracks.  The clouds are breaking open and sun is pouring through my window.  The temperature gauge reads 56 degrees, which is warm enough for wasps.  I expect to see more queens hovering at our wooden siding, looking for a safe place to make it through the cold days approaching.  Soon they will be completely gone for the season. 

     Come next March, when the temperatures rise once more into the low 50’s and the sun makes a serious appearance, these queens will shake off their sleep and find the nearest nectar to recharge their energy.  Here is a photo I took in late March, at a crocus flower bed in our nearby park.  This was a queen who had found a good winter sanctuary and made it through.  Here are the wasp queens, coming out of dormancy and back into the active hive life for the new year ahead. 

Janet Partlow
Resources:  hive photo by wise acres gardens.  All other photos by BBB naturalists.

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