That Predator Just Killed My Predator!

I spent last week in the Nebraska Sandhills, possibly the greatest grassland in the world.  Last week’s trip was one of several I’ve gotten to make around that landscape this summer.  It’s been great to see a much wider swath of the Sandhills than I have in previous years, and my appreciation for the area has grown even stronger than before.

The big sand tiger beetle (Cicindela formosa) has been eluding me this summer, but I finally get a good set of photos of one eating a recently captured ant.
The big sand tiger beetle (Cicindela formosa) has been eluding me most of this summer, but I finally got a good set of photos of one eating an ant.  Clicking on this and other photos from this post will give you a larger and more clear image to look at.  It’s worth it.

In a previous post, I wrote about the importance of Sandhills blowouts as habitat for species that thrive in bare sand.  I’ve been trying to document and photograph as many of those creatures as I can this summer.  Some of the most difficult to photograph have been tiger beetles.  These incredible predators run very quickly along the sand in search of small insect prey, but can also fly easily when they see me or other scary things approaching.  It’s been fun to chase them around, but the vast majority of attempts to photograph them end in them flying away just before I’m close enough.

One of the species I’ve been unable to photograph so far is a beautiful metallic blue tiger beetle called the sandy tiger beetle, aka Cicindela limbata.  You can read more about this critter in a great blog post by Ted MacRae.  I had seen and admired the beetle, but was running out of time to photograph it before my trip ended.  Finally, I spotted it again, and started stalking it.  (I should mention that I was doing this while 7 other people were watching and waiting for me, semi-patiently, so we could move to another location.)

I edged close to the beetle, but (as usual) just as I got almost within photo range, it took off and flew about 15 feet away.  I let out a small sigh and starting creeping toward its new location.  This time, it took off when I was still five feet away.  However, just as the tiger beetle left the earth, a big gray robber fly streaked up from the ground nearby and knocked the beetle right out of the air.  It was like a ground-to-air missile attack, but much faster.  The two tumbled back to the sand together, the tiger beetle firmly in the clutches of the robber fly.

The robber fly and tiger beetle landed upside down right after the initial attack.
The robber fly and tiger beetle landed upside down after the initial attack.  For scale, the tiger beetle is about 1/2 inch long.

As I watched, the robber fly got back to its feet and struggled to keep a hold on the beetle.  Though I couldn’t see it happening, I knew the fly was also injecting the beetle with toxic saliva to immobilize it.  Eventually, the saliva would also liquefy the innards of the beetle so fly could consume the resulting beetle soup.

Upright again, the robber fly tried to hang on to the beetle while injecting it with toxic saliva.
Upright again, the robber fly tried to hang on to the beetle while injecting it with toxic saliva.
The robber fly had to periodically readjust its grip as the tiger beetle struggled to escape.
The robber fly had to periodically readjust its grip as the tiger beetle struggled to escape.

Within a few minutes, the beetle seemed to stop moving.  Having taken approximately 10,000 photos of the scene (from the perspective of my waiting colleagues), I grudgingly got up off the sand and backed slowly away to move on to our next site.  I still don’t have a stand alone photo of C. limbata, but I’ll get one someday.  In the meantime, I feel like I had a front row seat for a miniature version of the kind of predator/prey attack usually seen in nature documentaries from the Serengeti.  I can live with that.  As I’ve said numerous times before, I’ve got a pretty good job…

A final look at these two magnificent predators.
A final look at these two magnificent and beautiful predators.

Photo of the Week – August 11, 2016

I made a quick trip up to the Niobrara Valley Preserve this week.  As always, there was a treasure trove of unexpected finds.  Here are some of them.

Bison calves are growing fast. Their coats have darkened to match the adults, and their horns are starting to look like more than just little bumps.
Bison calves are growing fast. Their coats have darkened to match the adults, and their horns are starting to look like more than just little bumps.
Bison tend not to hang around wooded areas for shade, but they also like to rub on trees aggressively enough to keep them stunted or even kill them. This bull was one of several bison that had evidence of recent rubbing on eastern red cedar trees.
Bison tend not to hang around wooded areas for shade, but they also like to rub on trees aggressively enough to keep them stunted or even kill them. This bull was one of several bison I saw this week that had apparently been recently rubbing on eastern red cedar trees.  Good for them.
Robber flies are amazing predators and always fun to photograph, but this might be my favorite of all time. This gorgeous robber fly landed in a sand blowout and was consuming a leaf hopper.
Robber flies are amazing predators and always fun to photograph, but this might be my favorite of all time. This gorgeous robber fly landed in a sand blowout and was consuming a leaf hopper.
Sand bluestem (Andropogon hallii) is sometimes lumped with big bluestem (Andropogon gerardii) and sometimes considered a separate species. I'm not entering that argument. However, sand bluestem (shown here) does tend to have much hairier flowers.
Sand bluestem (Andropogon hallii) is sometimes lumped with big bluestem (Andropogon gerardii) and sometimes considered a separate species. I’m not entering that argument. However, sand bluestem (shown here) does tend to have much hairier flowers.

How many of you noticed the small larva in the above photo?  I didn’t, until I was going through the photos on the computer the day after taking them.  Look below for a more close-up view of the larva.  You can see it at its original scale just to the left of the bottom left of the inset image.

Fly larva? Whatever it is, it sure is small. Wouldn't you love to know what it's doing there?
Fly larva? Whatever it is, it sure is small. Wouldn’t you love to know what it’s doing there?
This tumbleweed (Russian thistle, aka Salsola iberica) was lodged up against a fence in a big sand blowout.
This tumbleweed (Russian thistle, aka Salsola iberica) was lodged up against a fence in a big sand blowout.
This tiny pale bee (Perdita perpallida) is a specialist in prairie clovers (Dalea species) but I've only seen it on one species - Silky prairie clover (Dalea villosa)
This tiny pale bee (Perdita perpallida) is a specialist in prairie clovers but I’ve only seen it on one species – Silky prairie clover (Dalea villosa).  Its pale color helps it blend in very well. Thanks to Mike Arduser for ID and information.
What is more evocative of the Great Plains than bison grazing in a prairie dog town as the sun goes down over an expansive grassy landscape?
What is more evocative of the Great Plains than bison grazing in a prairie dog town as the sun goes down over an expansive grassy landscape?