Defense or Revenge or Both?

Event Reminders:

July 9 field day at the Platte River Prairies. Details here.

Conserving Fragmented Prairies workshop July 25-26. Deadline for registration is July 1 (Friday).

I’m at The Nature Conservancy’s Niobrara Valley Preserve this week. Yesterday morning, I went for a sunrise walk in the prairie. I wasn’t looking for anything in particular to photograph, which almost always leads to fun discoveries.

As the sun rose, I walked toward it and spotted a few adult antlions making short flights in front of me. After a few unsuccessful tries, I found one that let me creep into photo range and captured a few nice images of it backlit against the morning light. For the next few minutes, I found and photographed grasshoppers, bees, and milkweed beetles.

Adult antlion. This creature somewhat resembles a damselfly but has a longer and heavier body and more club-shaped antennae. And a different head shape with smaller eyes, but that’s harder to see from a distance…

My next discovery was a group of ants tending to aphids on the flower head of fourpoint evening primrose (Oenothera rhombipetala). Ants often ‘adopt’ groups of aphids like this, protecting them from predators and harvesting the sweet droplets of honeydew the aphids excrete from their hind ends. I took a few photos and then looked a couple other primrose flowers/buds nearby and was surprised to see ants and aphids on all of them. That’s when the morning suddenly got much more interesting.

Ants tending aphids on fourpoint evening primrose.

As I was looking at some primrose flowers that had just opened up and watching the ants move around their aphid ‘flock’, an antlion flew in to the flower, presumably looking for nectar and/or pollen. It landed on the lip of the flower and scrambled briefly for a foothold.

Antlion landing on the flower to feed.

As soon as it hit the flower, though, it immediately attracted the attention of the ants working with the aphids. Those ants, lightning-quick, swarmed the antlion and attacked it from multiple directions. It was brutal and difficult to watch. The antlion futilely tried to use its legs to dislodge ants but it didn’t stand a chance.

Antlion being swarmed and attacked by ants.

My assumption is that the ants were defending their aphids from danger. Antlion adults feed on nectar and pollen, but at least some are also predators. It makes sense that ants would see this antlion as a threat to the aphids, though I wonder if they knew what it was or just responded to the sudden incursion. Maybe they would have attacked any other creature making a similar approach.

I know it didn’t happen this way, but I also like to imagine the ants might have recognized the antlion as the adult form of the creature that creates the funnel-shaped depressions in sand or other loose soil on the ground. Antlion larvae create those holes and then lie in wait at the bottom of them with only their poison-injecting mandibles exposed. Ants are common victims of antlion larvae because they can slip into the hole if they get too close, sliding inescapably down to the deadly waiting jaws of the larva.

Again, there’s surely no way those ants recognized the antlion adult as the grownup version of that horror-pit-dwelling nightmarish creature. If they did recognize it, though, the attack might have felt that much better as they exacted some measure of revenge upon a creature that likely consumed a number of their kind earlier this year.

As an observer to the event, I felt conflicted. Everyone involved was doing their job and no one was at fault in any way. There was no reason for me to interfere, but that antlion did look awfully pitiful in the jaws of all those ants. After a minute or so, I couldn’t take it any longer, so I took a piece of dried sunflower stem from nearby and lifted the antlion away from the flower. I tried to push some of the ants off of it but their jaws were so tightly clenched, I couldn’t move them. Sadly, I lifted the antlion back to the flower and let the ants finish their work.

This was the third time this year I’ve seen ants farming aphids. Each time, I’ve seen a cluster of ants on a plant and then upon closer inspection spotted the aphids. If you’ve not seen this phenomenon before, just keep your eyes out for multiple ants and take a closer look when you find some. When you find some, you can watch the ants scrambling around, tapping the aphids, and occasionally looking around menacingly for threats.

A couple times, while photographing the ants above, one would stop and turn to face me, lifting its head and torso off the plant toward me. It might have been just trying to get a better look at me, but after seeing what happened to the antlion, I also imagine it might have been issuing a warning. If so, message received!

Photos of the Week – June 24, 2022

Don’t forget to contact us if you’re planning to attend one of the two events we’re hosting at the Platte River Prairies in July. Our public field day on July 9 is free and doesn’t require any registration other than to email Mardell (mjasnowski@tnc.org) so we know how many people are coming and can contact you if plans change. The Conserving Fragmented Prairies workshop (July 25-26) we’re co-hosting with Prairie Plains Resource Institute does require a simple registration, but is also free of charge. Registration deadline is July 1. You can see information about both those events HERE.

Today’s post is a dump of miscellaneous photos from the last couple weeks. I’ve been really busy with data collection and outreach projects, as well as stewardship of our family prairie. Still, I’ve tried to get to the field a little early, or stay a little late, to take advantage of photo-friendly light when it comes around. Most of these images were taken during those periods, which make my days longer, but also more inspiring. If you want a closer look at any of the images, just click on them.

Assassin bug with captured fly on yarrow at the Helzer Family Prairie. Nikon 105mm macro lens. ISO 500, f/16, 1/200 sec.
A tiny katydid nymph with antennae that stretched far beyond the frame of this image. Prairie Plains Resource Institute’s Gjerloff Prairie. Nikon 105mm macro lens. ISO 500, f/18, 1/320 sec.
Spider milkweed, aka antelope horn milkweed, aka green milkweed (Asclepias viridis) at our family prairie. Nikon 105mm macro lens. ISO 500, f/11, 1/500 sec.

It’s been a stormy May and June around here, with some very damaging hail and winds. A couple weeks ago, a storm rolled through in the morning and I scooted out to Lincoln Creek Prairie to catch its backside as it moved to the southeast. This storm was pretty mild but had great lightning.

Lightning from a receding storm. Lincoln Creek Prairie. Tokina 11-20mm lens @11mm. ISO 100, f/22, 3 sec.
Katydid nymph on short-beak sedge. Helzer family prairie. Nikon 105mm macro lens. ISO 500, f/14, 1/500 sec.
Grasshopper nymph. Helzer Family Prairie. Nikon 105mm macro lens. ISO 500, f/14, 1/80 sec.

I keep being drawn to patches of foxtail barley this summer. The texture is just so gorgeous, especially with a low angle sun. As I’ve been photographing the patches, I’m also noticing all the insects that are feeding on the pollen of this grass – and the spiders and predatory insects hunting those pollen-feeders. It’s been a fun community to explore.

Foxtail barley and late day sun. Helzer family prairie. Tokina 11-20mm lens @11mm. ISO 500, f/13, 1/1000 sec.
Foxtail barley and late day sun. Helzer family prairie. Nikon 10.5 fisheye lens. ISO 500, f/22, 1/160 sec.
Damsel bugs are predatory and this one was hunting in a patch of foxtail barley. The Nature Conservancy’s Platte River Prairies. Nikon 105mm macro lens. ISO 250, f/16, 1/80 sec.
Lynx spider. Lincoln Creek Prairie. Nikon 105mm macro lens. ISO 800, f/18, 1/80 sec.
Clay-colored leaf beetle on lead plant. Lincoln Creek Prairie. Nikon 105mm macro lens. ISO 800, f/14, 1/320 sec.
Stilt bug (Berytidae) on velvety gaura (Gaura parviflora). The Nature Conservancy’s Platte River Prairies. Nikon 105mm macro lens. ISO 400, f/16, 1/400 sec.