Re-emerging into the Warm Sunshine

On Monday, I took advantage of very pleasant weather to visit one of our Platte River Prairies I hadn’t seen for a while. The warm sunny day felt great to me, but apparently also invigorated a lot of other creatures. Wild turkeys were in full display mode, with males showing off to each other and to nearby females, and I flushed a prairie chicken from near where it and others had been lekking earlier in the day.

More interestingly, I saw all kinds of insect activity. Big green darner dragonflies were zipping around wetlands adjacent to the river, and nearby patches of bare sand were full of small hordes of brightly colored tiger beetles chasing after flies and other tiny insects.  I wondered whether the adult insects I was seeing had spent the winter as adults, and if so, how.  Green darner dragonflies are migratory, so the ones I saw might have moved back north from wherever they go during the winter.  I’m pretty sure the tiger beetles I saw had spent the winter as adults, sheltered in their burrows.

I’m pretty sure this is the bronze tiger beetle (Cicindela repanda) because it fits both the visual description and the habitat (bare moist sand near the river). This was the most common tiger beetle I saw.

There many fewer festive tiger beetles (Cicindela scutellaria), but they were certainly the most colorful.

As I was crawling through the sand on my belly, trying to get close enough to photograph tiger beetles, I occasionally flushed band-winged grasshoppers that were hanging around on the same patches of bare ground.  I managed to photograph both green and brown ones, which I assumed were different species until I got home and looked more closely at the photographs.  Despite the different colors, the patterns and textures of the grasshoppers looked identical to each other, so I sent the photos to a couple friends who have shown themselves willing to put up with my grasshopper questions in the past.

The brown form of the greenstriped grasshopper was much more common (and harder to see against the mostly still brown grass) in the prairies this week.

Both Ellen Welti and Angela Laws responded and let me know that both the green and brown grasshoppers were greenstriped grasshoppers (Chortophaga viridifasciata).  Greenstriped grasshoppers are band-winged grasshoppers, which are known for their colorful wings and their habitat of crepitation (loud snapping noise) as they are flushed and fly away.  Band-wings also tend to hang out in areas of bare ground, which matches where I found them this week.

The greenstripped grasshopper is very common and abundant in the eastern United States, but it is found in much more scattered populations out here in the west where it tends to be tied to areas of moist soil. The grasshoppers hatch from eggs in mid-summer and then overwinter as late stage nymphs.  Once they emerge in the spring, they molt into their adult form. During the winter they are in diapause (a kind of dormant state) that is apparently broken in the spring, not by temperature, but by increased photoperiod (daylength).  All of this means that greenstriped grasshoppers have to be extremely cold tolerant.  They have to survive the winter, of course, but even after they emerge in the spring they still have to face the kinds of spring cold snaps we’ve been dealing with this year.  During those cold periods, the grasshoppers find a place where they can nestle into some prairie thatch until temperatures rise again.  Then they bask in the sun until they’re warm enough to resume their regular activities.

In its green form, the greenstriped grasshopper is sure handsome, isn’t it?

Ellen shared a great anecdote about how cold tolerant the greenstriped grasshopper can be.  While doing grasshopper research at Konza Prairie (near Manhattan, KS), she put a batch of caught grasshoppers in the freezer – a standard way to kill insects before sorting, identifying, and pinning them.  Three days later, when she brought the bag of frozen insects out to work through them, a greenstriped grasshopper started kicking its legs!  Ellen said she felt bad for the grasshopper and ended up taking it back out to the prairie, where it seemed to be completely unphased by the whole experience and hopped back into the grass.

Seeing how quickly insect activity resumes after cold snaps during the spring is a great reminder of how resilient and well-adapted those creatures are.  We complain about having to put up with wild temperature swings, but we’ve got cozy homes and appropriate clothing to help us cope.  Birds, insects, and other animals don’t have the advantages we have – they’re just tougher than we are.  While not all of them can stand being frozen solid like the greenstriped grasshopper (though many of them can), they have been dealing with crazy weather events for many thousands of years, and will likely continue to do so in the distant future.  I bet they whine a lot less about it too.

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.