In an earlier post I pondered what lay within a silky tent strung between segments of chicken wire. A butterfly larva? Or as one reader opined, perhaps a paralyzed caterpillar, soon to be devoured by a spider?
While I wasn’t looking, the caterpillar — which was very much alive and not on anyone’s menu — continued to spin its magic and metamorphosed into a shiny cocoon.
Because creosote is so common and grows literally everywhere here on the desert, I often tend to overlook it. My mistake.
The other day it surprised me. As I passed by yet another bush of same-old-same-old, I spotted several lumps on two of the branches. I was stumped. They were hard and dry and asymmetrical. What were they?
It took a chance encounter with a docent at the Arizona-Sonoran Desert Museum to find the answer. This was the work of lac insects. (If shellac comes to mind, it’s because this insect is related to the one from which that varnish and sealant is produced.)
The tiny lac insects suck up sugary sap from the creosote, using some for food and eliminating the rest. As the sap hardens it forms a natural protection against predators and the weather.
Although I checked the two branches carefully I couldn’t see any live insects. Nor could I see any ants, who sometimes protect lac colonies from predators, “milking” them like cows, just as they do with aphids.
The lesson for me? Don’t ignore what’s right under my nose. 🙂
The size, colour and speed of the pinacate (pin-uh-KAW-tay) beetle make it easy to spot on the desert.
Unfortunately this one was moving so fast I could hardly keep it in focus. So I placed a twig in its path to slow it down.
It immediately went into a defensive headstand. The first time I saw this I was startled. This time I was pleased — it stopped moving so I could finally focus on it in the dying light.
Like the small milkweed bug, pinacates rely on chemical protection from predators. But they take it one step further. Their bottoms-up stance is a warning. Ignore it and you get a blast of apparently noxious-smelling chemicals. I say apparently because I’ve never tried to provoke one to the point that it let loose with the spray. It has worse enemies than me to look out for.
While the spray deters some predators, the pinacate is no match for the grasshopper mouse. It grabs the beetle with its paws, stuffs the bottom end into the sand and begins dining at the top end, stopping short of the nasty gland at the other end.
Pinacate beetle/Clown beetle/Stink beetle Eleodes spp (probably E. obscurus)
If the adage holds true, then if you eat poison, you are poison.
Small milkweed bugs eat mainly milkweed plants whose sap contains poisons and latex. Decorating yourself with bright colours lets potential “diners” know they best choose another item on the menu if they don’t want to get sick.
The bug’s colours are quite distinctive — the white spots on the black wing tips caught my attention first. Sort of like eye sockets in a skull. Also noticeable is the orangey-red “X” on its back that doesn’t quite meet in the middle.
I found this bug sleeping on a globemallow leaf one cool morning recently. Nearby was a rambling milkweed plant, leafless and flowerless, its numerous thin stems twisted around each other like a rope. Little shelter for a bug overnight so perhaps that’s why it climbed onto something more substantial.
Milkweed bugs are true bugs (not beetles) with piercing/sucking mouthparts. Milkweed sap contains latex (a whitish gum-like goo) and poisons. The bug pierces the “skin” of the plants to reach the poisonous sap. Once it removes its mouthparts, the latex oozes into the hole where it dries, effectively sealing the hole. Such a tidy eater.
I was huddled near the end of a rotting log when I spotted a brightly patterned bug just a few inches away. This was quickly followed by a good-grief-what-the-heck? moment when I realized it was “attached” to a large caterpillar. What followed next was fascinating.
The piercing mouthparts of this immature stink bug had seized hold of one of the caterpillar’s hind “legs” (known as prolegs to bugsters) and it was feeding on the still-living larva.
The caterpillar was strong. It pulled that stink bug several inches across the log face. Despite its best efforts, however, it couldn’t break free.
The stink bug’s grip was stronger. In fact, several times the caterpillar swung loose, dangling in air. The stink bug never lost its hold on the log or the larva.
Although the larva was still alive when I left, the end was inevitable — it was lunch on legs for this young spined soldier bug.
The stink bug’s piercing mouthparts latched on to one of the caterpillar’s hind “legs”.
The caterpillar was strong enough to drag the stink bug across the log face but not strong enough to dislodge the mouthparts.
I spotted the stink bug first and only then realized it was feeding on the caterpillar.
The stink bug will feed well on this caterpillar.
The stink bug’s grip, though slender, was tenacious. Even when the caterpillar swung free in the air, it didn’t dislodge the bug’s grip on either its dinner or the log.
When I first spotted this duo, the caterpillar was clinging to the leaf at the bottom of the log. They travelled quite a distance during this deadly tug-of-war.
The spined soldier bug goes through 5 stages (instars, for the biologically inclined) between egg and adult. Each stage looks quite different than the others. Turns out I found the third instar.
The Tortrix moth infestation that occurred this spring was of almost biblical proportions. Many of the aspen forests were completely denuded by the ravenous caterpillars (aka larvae).
They pupated next, then after a short respite, the adult moths appeared. Thousands of them. And of course, their main goal was mating and egg laying, which they did in grand fashion.
In fact, so intense was the drive to lay eggs, they did so in the most unusual places. We discovered egg cases, like the one above, on the windows of the house, on the siding and on the vehicles.
Many of these eggs never hatched. The ones on the south-facing windows, for example, simply got too hot. But not before some activity occurred.
The egg cases were all about the same size as this one — 1.3 cm or so long (0.5 in). The original egg case was a lime green — some of that is still visible. I’m assuming it was plant material to feed the newly hatched larvae.
The comma-shaped figures are the newly hatched black-headed larvae. Some of the cells are empty — perhaps they survived?
Mother Nature’s Natural History Show is a wonder. Glad I caught this episode.