Sunday, May 31, 2015

Sawfly Refuge

While spending a pleasant afternoon in the backyard garden, the kids and I discovered a few of these "caterpillars" on a chrysanthemum plant. They are not caterpillars, but sawfly larva. The most obvious visual difference between caterpillars (which remember are butterfly and moth larva) and sawfly larva are the number of prolegs. Caterpillars have five or fewer, sawflies have six or more.
Sawflies are in the Hymenoptera, the bees, wasps, and ants. The adults most resemble wasps. Not all the larva resemble caterpillars, some species have larva with a definite grub-like look.
Since we found these initially on a chrysanthemum, I thought that must be what they were feeding on. But there was no evidence, no larva bite marks. Then I thought maybe they were eating plum tree leaves, and onto the mums from overhanging branches. But again no evidence of feeding, and no larva on the tree. The next day I did a bit of research, and found out that we had found European Pine Sawfly larva, Neodiprion sertifer While reading that they feed on the older needles of a variety of pines a light bulb went off in my head; a small Mugo Pine shrub in our yard had an distinctive pattern of defoliation; all the lower needles were missing. They had eaten the needles except the new growth, found at top. I had attributed this to rabbits feeding over the winter, though they had never touched it before - and I hadn't noticed any missing needles all winter. After a quick look over the Mugo Pine, I found another larva, some likely molts, and a lot of frass on the ground.
I think we found them away from the Mugo Pine because they had eaten all the old needles and needed to find a new pine to feed on. My kids took quite an interest in them. After trying to design a sawfly larva carnival(?), they placed any that they found under the swing set slide where we leave patch of grass unmowed as a bug refuge.
May 2, 2017 update I didn't notice any last spring, but they are back in full force this year.  I have to admit I've taken steps to remove them this time, but not before a got a decent photograph of an earlier instar

Saturday, May 30, 2015

Illustrated Life List: Tennessee Warbler

an excerpt from "The Birds of Minnesota" by Thomas S. Roberts (a really cool, old school bird guide in two volumes):

He says exactly what I want to say about the Tennessee Warbler, and much more eloquently than I could.
The picture was inspired by a grey morning earlier in May. Walking by a stand of large Cottonwood trees I could hear numerous Tennessee Warblers calling from the tree tops. They were so loud, but invisible among the leaves. I considered grabbing a pair of binoculars, but figured more enjoyment could be had by just listening to their staccato song; if I tried to search for them I'd be straining my neck to look straight up into the trees and would probably only catch a glimpse or two. The overcast conditions would have made them mostly silhouettes anyway.
Tennessee Warblers certainly aren't one of the most colorful of the wood warblers, nor are they typically one of the more sought after by birders. But they are one of my favorites. I appreciate their volume and their dependability. I look forward to the day when their song seems to be everywhere. Later in the day the flock had moved on (replaced by an equally loud flock of American Goldfinches), but I felt satisfied in witnessing this annual tick of the phenological clock.


Tuesday, May 19, 2015

Common Baskettail Emergence

Over the weekend the annual mass emergence of Common Baskettail dragonflies, Epitheca cynosure occurred at Westwood Hills Nature Center. This event usually happens within days of a large midge emergence, which happened earlier in the week.

It poured rain later in the afternoon, and then the next day was cold and windy, which undoubtly made the transition from aquatic, nymphal life to terrestrial/ aerial adulthood difficult. I wonder if there will be noticeable fewer Baskettails flying about this spring.
I didn't get a good photo of one actually splitting out of its nymphal skin, but wedding parties kept filling the dock up photos - of themselves, not the dragonflies.







Monday, May 18, 2015

Don't Step On The Mushrooms Shirt

Warning! This post contains crass commercialism and shameless self promotion.


Don't Be the Last Kid in the Woods

without a "Don't Step on the Mushrooms" t-shirt from the Distracted Naturalist RedBubble store. Order yours today!

And while you're there, check out the other available art work!




Tuesday, May 5, 2015

Small Green Caterpillar on Silver Maple

Lesser Maple Spanworm, Speranza pustularia. A few of these caterpillars, along with the leaves they were on, were blown out of our front yard's Silver Maple tree during yesterday evening's thunderstorm. They are members of the Geometridae, the inchworm family.

The eggs overwinter on the branches of a tree, typically a maple. In May the caterpillars hatch and begin feeding on leaves. The adult moths can be found throughout the summer.

It's not a very distinctive caterpillar. The most distinctive identifying features are the light colored stripes running along the upper sides of the caterpillar's body (the sub dorsal stripe).