A Dandy Little Predator

I took my boys to our family’s prairie today.  I was only intending to stay for a little while, but they were having so much fun building forts in the trees and drawing pictures in the mud, we stayed for several hours.  Since they were entertaining themselves, I took a walk to see what was blooming.

Because of the late spring, I only found three wildflower species in bloom.  Ground plum (aka buffalo pea or Astragalus crassicarpus) was going strong, and there were a few pussy toes (Antennaria neglecta) getting started.  But the most abundant flower was the good ol’ dandelion.  While the non-native yard weed is disliked by many people, it was certainly popular with many bees and flies who didn’t have many other options for pollen and nectar sources today.

A sweat bee enjoying a pollen-loaded dandelion at the Helzer prairie south of Aurora, Nebraska.

A sweat bee enjoying a pollen-loaded dandelion at the Helzer prairie south of Aurora, Nebraska.  It’s ALMOST sharp enough to be  a good photo.

I tried a few times to photograph bees and flies visiting dandelions, but most were too wary to let me get very close.  The light was pretty harsh anyway, and the bees certainly weren’t going to let me pull out my diffuser (2 ft diameter thin-cloth-covered circle) before they zipped away.  I did finally manage to find one bee so focused on pollen that I got one nearly decent photo before it noticed me.  Most of the time, however, the pollinators left before I got anywhere close.

As I approached one flower, the small bee on it flew away, but I noticed something else still on the flower.  When I got close enough, I realized it was a spider – apparently hoping to make a meal of the bee I’d inadvertently chased away.  While I felt a little bad about that, I thought maybe the spider would make a more accomodating photo subject, so I got out my diffuser and tripod to see what I could do.  The spider scooted off the top of the dandelion flower when I got close, but it only retreated as far as the stem of the flower, so I did get a few shots of it there.

A spider on a dandelion flower stem.  Moments before it had been stalking a small bee on top of the flower, but a clumsy photographer scared the bee away.

A spider on a dandelion flower stem. Moments before it had been stalking a small bee on top of the flower, but a clumsy photographer scared the bee away.

The spider then (very quickly) scuttled a few inches away from the flower and stopped again.  If I hadn’t seen it move, it would have disappeared completely against the background of the identically-colored prairie thatch.  Beautiful camouflage!

The same spider as above, showing off it's perfect camouflaged coloring against the grass litter.

The same spider as above, showing off it’s perfect camouflage coloring against the grass litter.

I sure wish I’d gotten to see the spider try for that bee.  I’m not sure what kind of spider it was, but it certainly wasn’t a crab spider, which is what I typically see hunting on flowers.  This one looked more like an active hunting spider (similar to a wolf spider) than a nearly blind ambush spider  (such as a crab spider).  I’m guessing prey isn’t overly abundant at this time of year, and its probably hard to turn down an opportunity to hunt in one of the few places you’re pretty sure to find it.

Dandelions might not be everyone’s favorite flower, but I’m sure glad to have them in my prairie in the early spring.  Apparently, so are quite a few bees and flies – and at least one enterprising spider!

Photo of the Week – April 11, 2013

Sometimes, you can see a lot by just sitting down.

I carved out some time in the field last Friday to collect data on poison hemlock in our research plots.  After finishing that, I had about half an hour before I needed to head back to the office, so I took my camera for a walk along the creek running through our Platte River Prairies.  Not having a particular agenda, I stopped to look at a tree that had been recently felled by beavers.

This tree, cut down by our local beavers, had sap seeping from the stump last week.  The Nature Conservancy's Platte River Prairies, Nebraska.

This tree, cut down by our local beavers, had sap seeping from the stump last week. The Nature Conservancy’s Platte River Prairies, Nebraska.

As I was admiring the patterns of tooth marks on the stump, I noticed an interesting-looking little fly hanging around.  As I watched, the fly started to feed on the sap that was oozing out of the tree.  Taking advantage of the fact that the fly was distracted by its meal, I managed to get a couple photos of it.

This fly seemed to be enjoying its meal enough that it didn't mind me sticking my lens in its face.

This fly seemed to be enjoying its meal enough that it didn’t mind me sticking my lens in its face.

Since I had time, I decided to sit and watch the fly for a bit.  Before long, another – different – fly came along.

A second fly joins the meal.

A second fly joins the meal.

One of my favorite statistics is that there are more than 37,000 species of flies in North America.  That seems an almost unfathomable diversity.  Taking that into account, I guess I shouldn’t have been surprised to see a third kind of fly arrive at the stump…

Fly #3.  A big green one.

Fly #3. A big one with blue and green stripes on its abdomen.

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A rear view of fly #3, showing the striped abdomen.

A rear view of fly #3, showing the striped abdomen.

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A tiny wasp (2mm long).

A tiny chalcidoid wasp was on the stump as well, though not feeding on sap (thanks to Mike Arduser for identifying it for me – Mike says they are a group of parasitic and important wasps).  The quality of this image isn’t very good – my excuse is that the wasp was BARELY 2mm LONG and I had to crop it quite a bit so you could even see it…

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A tiny red mite came ambling along...

A tiny red mite came ambling along too…  It was about the same size as the little chalcidoid wasp

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Fly #3 didn't like Fly #1 working over the same puddle of sap and lunged at it

Fly #3 apparently didn’t like Fly #1 working over the same puddle of sap.  This photo captures Fly #1 rearing back as Fly #3 lunged at it.

I wish I’d had more time to stick around; it would have been fun to catalog all the little critters that visited – or were living in – that beaver stump.  I also wish I would have gotten a shot of the little wolf spider hiding in the pile of wood chips at the base of the stump – it darted out and almost caught one of the flies when it landed nearby, but didn’t stick around for a photo.  Too fast for me…

I think my short time watching the beaver stump brings up a number of interesting points that I could focus on as the overall theme of this blog post.  I could focus on the odd side benefits provided by the work beavers do.  I could focus on the crazy diversity of life found on a single tree stump.  I could focus on the way creatures of all different kinds are able to take advantage of unexpected resources (like oozing tree sap) when they appear.

But I think the biggest point is this:  You can see and learn an awful lot by just sitting down and watching.