One of the most striking plants in our prairies this time of year is pitcher sage, also known as blue sage (Salvia azurea). It’s tall, of course, but more importantly, as the surrounding prairie is dominated by green-becoming-gold grasses and big yellow flowers, pitcher sage stands out simply because it is starkly and unabashedly blue.
A few weeks ago, I posted a photo of a bee that specializes on pitcher sage, but there are many more insects commonly seen on the plant. Last week, I spent about 45 minutes in our Platte River Prairies, photographing pitcher sage and as many visitors as I could.
I initially pulled my camera out because there were several monarch butterflies flitting around a patch of pitcher sage. While chasing them around (and, as always, being thankful no one was watching me), I came across quite a few other insects – some of which I managed to photograph.
In addition to being tall, striking, and beautiful, pitcher sage is also pretty good at withstanding drought. During late August of 2012 – a year of extreme drought, pitcher sage stood out against a background of brown dormant grass, blooming just like it does every year. Not only did it provide some welcome color when many other plants were wilting, it gave all the insects pictured above, and many others, something to eat when they needed it most.
Predators play key roles in ecosystems. When they are absent or rare, impacts ripple through landscapes, often in unexpected ways. We all rely on the presence and effectiveness of predators, but usually fail to adequately celebrate their importance.
When thinking about predators, most people probably conjure up images of lions, tigers, bears, and other large vertebrates. However, smaller invertebrate predators play the same kinds of critical roles as those big animals. Here are a few portraits of tiny predators that help keep prairies healthy and vibrant.
A few weeks ago, I wrote a post about seeing insects frozen in ice, and speculated about how they’d gotten there and whether or not they might still be alive. Several of you encouraged me to chip them out of the ice and thaw them out, apparently under the impression that I walk around with an ice axe in my camera bag. Nevertheless, it was a fair point. Why speculate aimlessly about something that’s relatively easy to test – especially since it wasn’t the first time I had speculated on the same topic? (See this post from 2014 and this one from 2011.) For my 2014 post, I actually did pull a beetle out of the ice and watched it thaw. It was dead.
Yesterday afternoon, I went out to our family prairie with two of our boys. Daniel needed to do some video work for a school project, and Calvin wanted to continue working on a project he’d started over the weekend, which seems to involve propping sticks against a tree. Anyway, two boys wanted to go to the prairie – what am I going to do, say no? We went.
It was about 60 degrees when we got to the prairie, and while the wetland was still frozen enough to walk on, the top of the ice was melting. Scattered about the wetland and a nearby livestock watering tank were numerous insects that had been frozen yesterday but today were sitting in shallow puddles of water on top of the ice. Ah ha! No ice axe required today! I grabbed a ziplock bag from my pack (an item even more essential to a naturalist than an ice axe) and starting scooping up cold insects and enough water to keep them in.
When we got home, I dumped the bag of pond water and insects into a shallow bowl. The following is a series of observations as I conducted this important scientific research project.
February 26, 2018
6:05 pm – Dumped 18 insects into a bowl, having collected them from thawing water on top of the ice at our prairie. (No ice axe required, thank you.) Initial observation: the insects appear to be motionless. Some are floating, others are submerged. Water is still very cold.
6:31 pm – Added a little warm water to the bowl. Some of the insects moved as I dumped the water in, but seemed to settle back into stillness as the water calmed. Brief movement considered inconclusive as to the status of insects as living or dead. More data needed.
7:48 pm – Water is about room temperature now. Wondering if the floating are the same that were floating earlier? Probably. A couple stray legs seem to be lying around on the bottom of the bowl. If those insects are soon to be alive and kicking, it appears they’ll have fewer legs to kick than they had last fall.
8:33 pm – Of the 18 insects I collected and put in the bowl, 18 still appear to be motionless. Fighting boredom (me, not the insects). Must remain vigilant in order to complete this project for my readers.
9:07 pm – Nothing to report.
10:15 pm – I’m pretty sure several of these insects are actually flies, and not aquatic insects at all. Wondering if I should remove those from the dataset so as not to bias the overall survival rate.
10:56 pm – So tired. Can’t keep my eyes open much longer. Have decided to call it a night and hope not to lose any insects that reanimate during the night and fly off. Will cover the bowl to be sure. One of the water boatmen has a certain look in its eye – just waiting for me to go to sleep so it can make its escape? Better seal the bowl tightly…
February 27, 2018
6:15 am – Woke up and immediately remembered the insects. Hoped none had eaten each other or escaped. Scurried out to the kitchen and did a quick count. All 18 insects accounted for. None seem to be moving. Sleeping after a busy night of swimming? Swished the water around a little, and got some movement, but didn’t seem to be the result of any self-propelling motion by the insects. Hopes diminishing.
7:10 am – Have decided that maybe the water temperature needs to be higher in order to break diapause. Added hot water to the bowl. Awaiting developments.
7:15 am – Trying to fix breakfast and school lunches. Need counter space. Re-evaluating this entire project.
7:23 am – Adapted Monty Python sketch running through my head… “These bugs are no more! They’ve ceased to be! They’ve expired and gone to meet their maker! They’re stiffs! Bereft of life, they rest in peace!…These are EX-BUGS!”
7:24 am – Ok, I’m calling it. Experiment over. These insects are dead, folks. Of the 18 frozen insects removed from the surface of the ice, 18 died. This evidence strongly supports the suggestion that insects found embedded near the surface of frozen wetlands are, in fact, dead. This follows the findings of Helzer (2014) who similarly found a frozen beetle to be dead upon thawing.
Ok. I’m going to clean out that ziplock bag now and get it back in my camera bag. I don’t want to be left without it when the next scientific opportunity presents itself.
Plains sunflower (Helianthus petiolaris) is an annual plant that responds quickly to bare ground in the Nebraska Sandhills. They pop up after fire, intensive grazing, pocket gopher activity or something else allows light to hit the soil. At times, they can be widespread, as they were the year after the 2012 drought. More often, they are found scattered about the prairie in patches of sparse vegetation. They have started to bloom in earnest over the last couple of weeks, adding beautiful accents to the summer prairie.
Last week, I spent an hour photographing sunflowers and the wide variety of small creatures I found hanging about on them. In just one hour, I spotted a pretty incredible abundance and diversity of invertebrates within an area smaller than my backyard. Sunflowers, especially annual sunflowers, are considered by some to be weeds, but these native wildflowers play really important roles in prairie ecology. Their seeds are extremely valuable as food sources for many wildlife species and their young leaves and flower buds/blossoms are quality forage for other species, including cattle. During this time of year, the abundant and accessible pollen and nectar of the flowers is what seemed to be attracting the invertebrates I saw. Here is a selection of photos displaying some of those sunflower visitors.
A variety of grasshopper, katydid, and tree cricket species are all commonly found feeding on the flower parts and pollen of sunflowers. Weevils, long-horned beetles, and other beetles are also frequently seen.
The abundance of herbivores, pollinators, and other insects on the flowers and vegetation of the sunflowers seemed to attract a number of predators as well, including robber flies, spiders, and assassin bugs.
I hope these photos, all taken from a small area and within a short time period, help illustrate the kind of resource annual sunflowers can be in the Sandhills. I’m sure many other wildflowers host similar numbers of invertebrates, but the height and conspicuous nature of sunflowers make it really easy to see and appreciate their value.
Annual sunflowers aren’t aggressive – they just take advantage of open soil and available root space. As vegetation recovers from whatever event caused it to become sparse, sunflower abundance diminishes…until they get another opportunity to pop back from seeds and make their contribution to the prairie ecosystem.
Wow, this was a hot week. About the time I stopped hiking hills and collecting data at the Niobrara Valley Preserve yesterday, my truck’s thermometer said it was 111 degrees Fahrenheit. Sure, it was really hot, but I figured the truck was probably estimating a little high until Kim said she looked at the official weather report from Valentine (nearby town) and it said the high recorded temperature there was 112 degrees. That’s pretty hot for northern Nebraska.
One of the reasons I was trudging through the hills in the heat was to look for lizards, but I’m pretty sure they were smarter than I was and were hanging out in cool shady places, because I didn’t see any after about 11 am. The insects in the prairie seemed less affected by the heat, however, and I saw lots of them, including quite a few gorgeous red assassin bugs.
Wasps also seemed to be particularly abundant this week, especially on the blossoms of sand milkweed and other wildflowers. I enjoyed looking at the diversity of wasp species, but my enthusiasm diminished very suddenly when one of them (I’m pretty sure) stung me in the back. I think it must have gotten itself wedged between my pack and my back. It wasn’t MY fault it got stuck there, but I now have a large ugly welt anyway. Man, that hurt! A lot.
The day before I got stung, I spotted a wasp (probably not the same one) in a patch of bare sand, and thought about photographing it. I glanced down at my bag just long enough to extract my camera, but when I looked back the wasp had moved a few feet and was now grappling with one of those red assassin bugs.
Actually, grappling is probably a misleading term because it looked like a pretty one-sided battle. After a half minute or so, the assassin bug flipped the wasp over and it was clear who was winning.
I photographed the scene quickly and then got up to leave. I must have moved too suddenly for the assassin bug’s liking, though, because it took off and flew a few yards away, leaving the wasp behind. Even after I kept moving away and left the area alone for a few minutes, the assassin bug didn’t return, so I came back and took one final photo of the dead wasp. I’m hoping maybe the bug returned to finish its meal later. I feel bad…
I think the wasp pictured above is a male, though I’m not confident of that. I don’t see a stinger, anyway. While I was driving home yesterday (with the air conditioner blasting pleasantly), I wondered to myself whether or not assassin bugs can tell male wasps from female wasps. Apparently wasps can tell the difference, so it doesn’t seem completely crazy that other insects could as well. It would sure be handy to know whether you’re about to attack a stinger-wielding female or an unarmed male…
Everyone thinks about this kind of thing while they drive, right?
I’m definitely a generalist, rather than a specialist, when it comes to ecology and natural history. I know a little bit about a lot of species rather than a lot about a selected group. If I had to narrow myself down, though, wasps would be a group of organisms I’d like to study. I mean look how cool the blue one above is! Or maybe I could study assassin bugs. They’re pretty amazing too. Or moths… Or grasshoppers… Or flea beetles?
We are doing an intensive week of data collection at the Niobrara Valley Preserve this week. Yesterday, while I was leaning over to look at something, an insect landed on my clipboard. It looked like this (photographed later):
“Interesting,” I thought, “that’s an odd-looking paper wasp…”
Then I peered more closely at it and immediately decided I needed to capture it so I could take it back to the cabin and photograph it. Unfortunately, I didn’t have any bags or containers to put it in. All I had was my aluminum clipboard, which has a skinny compartment for storing extra data sheets. I very carefully nudged the insect inside and carried it back to the truck, where I transferred it to a nice roomy ziplock bag. When we got back to the cabin, I set the creature on a small sunflower plant and took about 230 (not kidding) photos of it. Here’s a nice one from the side:
Basically, I was looking at a wasp-looking insect with front legs like a praying mantis. I’m no entomologist, but I’d never heard of a wasp-mimic praying mantis in Nebraska, so I was confused. Also, mantids don’t have antennae, and this little critter had two of them, which it waved constantly and rapidly. What in the world…??
Fortunately, the modern naturalist has Google to fall back on, and once I got on the internet, it didn’t take long to figure out what this was. As it happens, it’s neither a wasp or a mantid. It’s actually a wasp mantidfly (Climaciella brunnea) which, by the way, is also not a fly! I’d heard of mantidflies, but I don’t think I’ve ever seen one in our prairies. They are fairly closely related to lacewings, and slightly more distantly related to antlions. Wasp mantidflies can be found throughout much of North America, but either they’re not super abundant on our prairies or I’ve fallen for their mimicry an awful lot.
One of the constant themes of this blog is my sense of wonder at the kinds of discoveries I get to make just by paying close attention to the natural world around. me. Mantidflies are certainly no mystery to entomologists, and I’m sure numerous readers saw the first picture and knew immediately what it was. However, the wasp mantidfly was new to me, and has quickly added itself to the long list of amazing organisms I’ve gotten to know and admire. Perhaps the greatest joy of being an ecologist/photographer is that I keep finding new species to add to my list on a regular basis, despite having been a professional ecologist for 20 years and a nature enthusiast for my whole life.
From time to time, I like to use this blog to provide important public service information. Today, I am attempting to fill an important gap in the bank of available prairie ecology images. I looked and looked online but was unable to find any photos of insects on prairie dog poop.
I stole an hour of photography time this week as a foggy morning worked its way toward a sunny afternoon. The small restored prairie on the edge of town was a great place to explore. A few surprises awaited. Though most flowers were well done with flowering, a few late ones were still in bloom – possibly plants that were injured earlier in the season and were trying to squeeze out a flower on hastily regrown stems. Insects were surprisingly abundant – taking advantage of a day with temperatures in the high 60’s and rising. Here is a selection of images from my prairie walk.
I’m pretty good at spotting insects. When I walk around prairies with a camera, I’m usually looking down, scanning for small creatures. Just as I imagine a building inspector develops search images for signs of mold, fire hazards, and shoddy construction, my search images help me pick out grasshoppers, spiders, caterpillars, and stink bugs. Despite that, I rarely see stick insects (aka walking sticks).
I don’t think stick insects are all that uncommon. In fact, about 12 years or so ago, I was using a pull-behind seed stripper to harvest seed from lemon scurfpea (Psoralidium lanceolatum) in one of our Platte River Prairies. The machine essentially uses a street sweeper brush to strip seeds from plants into a hopper. Of course, the brush often captures insects along with the seed. After maybe 10-15 minutes of running the machine, I stopped to check the harvest and was astonished to see hundreds of stick insects swarming about in the hopper. As the machine was harvesting seeds, I had been constantly scanning ahead of it to be sure there were no seed heads of invasive plants and to pick out the best patches to harvest. Regardless, I didn’t see a single stick insect until they ended up in the hopper. I’ve not seen that phenomenon again, but I often wonder if there are hundreds of stick insects hidden all around me as I walk through prairies. That may be true, but I feel lucky every time I actually see one.
Earlier this year, I was photographing bison and saw a couple stick insects riding on the back of one of those big furry animals. Later in the summer, I found one riding along on my own back. I gently put it on a nearby plant and photographed it for a while, grateful for the unexpected opportunity.
Stick insects are in the order Phasmida, along with leaf insects, and there are about 3,000 species of Phasmids worldwide. There is a lot of general information about stick and leaf insects, but I found it hard to know which details fit the stick insects I see in Nebraska prairies. I’d love to hear from others who know more about the ecology and behavior of these creatures.
Here are a few basic facts:
Stick insects are leaf eaters. In some cases, they can cause widespread defoliation of trees, making them pests to those who like those trees. (Or potential heroes to those of us working to limit the number of trees in our prairies!)
Like praying mantids, stick insects can often be seen swaying back and forth on their legs. Some scientists think this might help with their camouflage, giving the impression that they are moving in the breeze. Others think it’s a strategy to help them pick out objects against their background (they are triangulating).
The other major information presented by most sources is that at least some species of stick insects are known for copulating – or at least staying in that position – for days, weeks, or even months at a time. It may be that the female benefits from having the smaller male on her back to act as a shield from predators, or maybe the two of them are just more cumbersome for a predator to deal with. There are other theories about the behavior as well, but I don’t feel qualified to sort through them for you.
As I’ve said numerous times, I’m not an expert on insects and other small invertebrates – I’m just an enthusiast. If there are experts out there who can tell us about the stick insects of prairies, or the one specifically featured in the above photos, please chime in. I’m sure there are fascinating stories to learn.
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.
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.
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.
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…