A New Damselfly

On Saturday (25 June 2016) I spent part of the day at the Mt. Pleasant Discovery Museum looking collecting and identifying aquatic invertebrates as part of their Backyard Summer Series.  I found a lot of different organisms; I think the final number ended up being seventeen different types.  My favorite moment though was having this damselfly emerge from its final larval exoskeleton as a brand new adult.

Welcome to a great, big, brand-new world.

Woodworking for bees

Over the weekend I built a pair of nesting blocks for native bees.  Many species of  native bees (such as leafcutter bees, mason bees, and small carpenter bees) are solitary cavity nesters.  Individual female bees will seek out abandoned beetle tunnels in wood, hollow plant stems, and other cavities in which to deposit their eggs.  It is easy to help these species by providing nesting sites in the garden.  Our home garden has a nest site that has been used for several years and I have recently begun placing nesting sites in school gardens.

Nesting blocks for bees can be incredibly simple.  The ones that I constructed over the weekend consist of a block of untreated lumber with holes drilled in it, a backboard for attacking to a post or other structure, and an overhanging roof.  The blocks of wood that I used are more than six inchhes deep - many species of bees will not nest in short tunnels.

I'm not sure where these nest blocks will go as of yet, but I plan to build several more before spring.  With luck, next winter the drilled holes will be filled with overwintering bee larvae and pupae.  The picture below shows several leafcutter bee larvae in a bamboo stem that I recently pulled from from the nest site in our garden.

Next up on my woodworking projects list is nesting box for bumble bees.

"I find you galling", said the goldenrod to the fly.

Winter weather has hit Mid-Michigan.  The roadsides and meadows look brown and devoid of life, but if you look closer you can find signs that life, for some species, continues on through the winter.

At first glance, a patch of goldenrod looks dead and devoid of life.  Closer inspection reveals signs that life is present, if not visible.  Goldenrod is the host plant for many species of insects including midges, wasps, and flies.  The larva of some of those species cause galls to form on the plant.  Looking at the photographs below several of those galls are visible.

Goldenrod patch - look closely and you can see at least two types of goldenrod galls

The first type of gall is formed on the tip of the plant by the larva of several species of midges.  This type of gall is known as a bunch gall, rosette gall, or flower gall.  The gall is caused by chemicals released by the midge larva which cause the plant to grow abnormally.  The gall serves as both food and protection for the developing midge.

Goldenrod bunch gall

A second common goldenrod gall is the goldenrod ball gall.  This gall is cause by the larva of the Goldenrod Gall Fly (Eurost solidaginis).  This gall is created as a reaction to chemicals is the saliva of the feeding fly larva.  The larva will remain in the gall all winter long.  The larva produces chemical that act as an antifreeze - allowing it to freeze without damaging its cells.  The larva remain a state of suspended animation all winter long.  When the weather warms in the spring, the larva will "come back to life" and pupate for a period of time before emerging as an adult fly.

Goldenrod Ball Gall - caused by the larva of the Goldenrod Gall Fly

   
As a kid I remember collecting dozens of these galls to use the larva as bait for ice-fishing.   

Several goldenrod ball galls

Each of these galls is approximately 1 inch across.

Goldenrod ball gall - approximately 1 inch diameter

If you cut open the gall, the larva can be found curled up in the center.  Before the winter, the larva will chew an exit tunnel to just beneath the surface of the gall.  This allows the adult midge to easily emerge in the spring.

Goldenrod ball gall - cut open to reveal the larva in the center and its exit tunnel

 

Goldenrod Ball Gall with larva removed to show chamber in the center of the gall and the exit tunnel.

Just for fun, I took several pictures of the larva through a digital microscope at 2X magnification.

As the larva warmed up it started to become active, squirming around on the microscope. Here is a short video of it squirming around.