Tag Archives: sand

That Predator Just Killed My Predator!

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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.

Sand Wasps

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I was introduced to sand wasps (Bembix sp) by Mike Arduser when he came to visit the Platte River Prairies back in 2012.  As we stood together in a sand prairie, a bee-like creature was zipping around us with incredible speed.  Mike explained that it was a sand wasp, and that it wasn’t interested in us, but rather was looking for flies that might be hanging around us.  Since that day, I’ve paid much more attention to sand wasps and have seen them all over the place in sandy places.

Sand wasp (Bembix americana spinolae) burrowing in sand in a blowout. The Nature Conservancy's Niobrara Valley Preserve.

Sand wasp (Bembix americana spinolae) burrowing in sand in a blowout. The Nature Conservancy’s Niobrara Valley Preserve.  This wasp was about 1/2 inch long.

While we were exploring a big sand blowout last week at the Niobrara Valley Preserve, there were lots of sand wasps buzzing around, and we found some of their nest burrows.  I took a little time to sit near a couple nests and photograph the females as they worked to excavate them.  The wind appeared to be blowing just as much sand back into the holes as the bees were digging out…

Here's the same wasp as above as it digs sand out of its burrow.

Here’s the same wasp as above as it digs sand out of its burrow.

The video below shows both the blowing sand and the valiant effort of the wasp to excavate its burrow despite the wind.  If the video doesn’t appear correctly, try clicking on the title of this post to view it through an internet browser.

Mike tells me these sand wasps and their relatives catch and paralyze flies for their young.  They lay eggs in their burrows and provide the flies as food for the larvae.  Females, of course, do all the work to create the burrows, catch the flies and lay the eggs.  The males are just around for mating purposes.  While the wasp larvae eat flies, both the adult males and females feed on nectar and pollen.

Here are a few more images of the sand wasps we saw last week, along with the blowout they were living in.

A big blowout where wind keeps sand moving and open.

A big blowout where wind keeps sand moving and open.

The sand wasp shown earlier takes off and twists its body to zip away.

The sand wasp shown earlier takes off and twists its body to zip away.

This was a little smaller wasp from a different species that was nesting in a different part of the blowout from the first wasp.

This was a smaller wasp from a different Bembix species that was nesting in the same blowout as the first wasp.

...and that wasp was also digging its burrow.

…and that wasp was also digging its burrow.

As often happens with invertebrates, once I’ve been introduced to a creature, I start seeing it everywhere.  Even better, I’ve yet to meet an invertebrate that doesn’t have a fascinating background story.  It’s an awesome world we live in, and we share it with some pretty great neighbors.

Thanks, as always, to Mike Arduser for his help with identification and ecology.