swells's Journal

By the end of June, the mason bees and their predators and parasites on the old spruce stump were pretty much gone. But now it's an active place again. A crabronid wasp (Trypoxylon) is nesting in a drilled hole, as are two species of Megachilid bees. I also noticed a small black bee as it was leaving a tiny beetle(?) hole. And a cuckoo wasp was exploring the nesting sites of the new occupants. Since they were all moving a bit too fast to photograph, I captured them in vials, cooled them down, took some pictures, and released them. Hope they find their way back to the stump.

I spent a few minutes yesterday afternoon (July 4) watching Pemphredon wasps come and go to their nests in the rotting log. I suspect that by now all of the wasps have emerged from the nest where they spent the winter as prepupae. Females have mated with the waiting males, and the former are busy with their nests while the latter have gone off to die -- after the lucky ones have performed their only real function in life.

I noticed that the females seem to be returning with small prey, but they moved too fast to get a picture of them before they entered the nest. So I thought I'd try to capture one in a vial, then cool her down to take some pictures. I suspect the prey is an aphid, but I'm not sure -- so, as usual, I sent a photo into BugGuide for an ID.

20 June 18: I've been watching aphid wasp [Pemphredon (?)] nests in an old rotting log off and on for the last few days. There is one particular entrance which nearly always has a male (at least I think it's a male) standing nearby. He stands there waving his antennae, staring at the tunnel entrance. Occasionally another (male?) wasp comes by and, after a brief altercation, he (or the other male) returns to stand watch above the hole. This series of events continued, as long as the weather permitted, for the last few days.
But yesterday the watching male got lucky. Finally one (a female, I assume) came out and the waiting wasp immediately pounced on it, with both tumbling to the ground, mating for a minute or two.

20 June 18: The nest site was even more active today, with several males hangin around fighting to be the one waiting at the hole entrance. By the late afternoon, there was less activity. I suspect all the wasps in the nest had emerged. I saw one (female?) enter the nest. I suspect the nest is being re-used by a new female.

21 June 18: Guess I was wrong about the nest being emptied. I went out around noon after the morning rain stopped to check on the Pemphredon nest. As soon as I arrived a male was watching the hole and a female was emerging. When the female came out, the male pounced on her. They remained attached for several minutes until the male flew off with the female under him, landing on my leg. Got lots of good pictures this time. Sent to BugGuide and IDed as Pempredon.

As I mentioned in the previous post, we left a stump standing when removing spruce trees after one fell in our backyard about five years ago. The stump has since become a very active place, with lots of bees, wasps, ants, beetles, and other insects making their homes there. At that time, being a bit lazy, I also left some spruce trunks and branches in a brush pile, rather than disposing of all of the debris. And that brush pile has since also become a great place for watching and photographing insects.

I first noticed small wasps (10 -12 mm) flitting about on the larger branches of the brush pile a couple of summers ago. They seemed to be nesting in the log, since I noticed some holes with what appeared to be sawdust piled beneath them. I managed to get a couple poor photos that I posted on iNat, which were subsequently identified by John Ascher as aphid wasps in the genus Pemphredon.

Well, they are back again this year. And I now that I know what they are, I'm able to spend some time observing them -- rather than just trying to get a picture to identify them. Previously when I saw them they were hard to observe or photograph, since they were constantly flying around and never seemed to sit still for more than a second or two. But yesterday they were much more cooperative.

There was one in particular that stood next to a hole in the log. It stood there nearly motionless for several hours -- at least it was there every time I came out to check on it. A couple times when I was watching, another Pemphredon would poke its head out of the hole, at which time the guy (I'm thinking it's a male) appeared to get all excited, tapping his antennae and moving about near the hole. The other wasp would generally go back into the tunnel and then completely emerge a few minutes later. As soon as the wasp left the hole, the waiting wasp would pounce on it for a split second, before the other wasp flew away. I don't think any mating occurred the two times that I observed this behavior. Perhaps the other wasps were males, rather than a female that waiting wasp was waiting for. I never saw a mating event, but I'll keep checking and maybe I (and the waiting male) will get lucky on another day. (It was rainy today so there was no activity.)

While watching the aphid wasps, I noticed some other small ichneumonid wasps (~ 13 mm) flying around the the spruce log. I managed to get a few pictures of them, which I posted to iNat. BugGuide identified them as Perithous scurra subspecies neomexicanus, saying, "The host is an aphid wasp in the genus Pemphredon.

So these little ichneumons are hanging out around the spruce log trying to parasitize the aphids wasp nests! Tomorrow I'll be hanging out there as well, if the weather improves a bit.

About five years ago, an old spruce tree fell down in our yard. Luckily it didn't hit a pedestrian, fall toward the house, or smash a car on the street. It cost a bit to remove, but at least it didn't hurt anyone or anything.

We decided to take out another old spruce at the same time, leaving an eight-foot stump for whatever wildlife might find it useful. I didn't notice much in the first few years, but starting this spring the stump is the most active place in my yard, at least as far as insects are concerned.

The first to show up was a mason bee (Osmia) on April 22. A few days later, I drilled a some holes in the stump, hoping that some bees would use them as nests. And by April 26, some of the holes were already being used by bees.

Here's a list of other visitors to the stump that I've seen so far this spring and the date of first sighting:

April 26: Temnoscheila
A bark-gnawing beetle (Trogossitidae)
These colorful beetles apparently eat the larvae of other beetles. (And, at least on my stump, invade Osmia nests.)
Myrmecos - Friday Beetle Blogging: Temnoscheila Bark-Gnawing Beetle

April 26: Western Carpenter Ant (Camponotus modoc)
I'm not sure of the ID on this, since my observation hasn't yet been confirmed on iNat.
These large ants often hang out on the stump, occasionally entering holes that are occupied bee nests

April 27: Club-horned wasps (Sapygidae)
These wasps land next to an occupied hole and wait until the mother bee leaves to get more pollen. Then the sapygid wasp enters the hole and deposits her eggs. When her eggs hatch, the larvae feed on either the pollen that the bee provided for her larvae or the bee larvae themselves (or both).
(I've often seen them enter the holes, but I couldn't, of course, see what they do when they get inside.)
Here's a post by Bug Eric on them: More Drama at the Bee Block

May 1: Xorides (Ichneumonidae)
These wasps have been present nearly every day for the last six weeks. Often there are two females on the stump at the same time, and occasionally males are present as well. The females slowly move around on the stump while tapping their antennae on the surface of the trunk. Apparently this is the way that they detect beetle larvae in the wood. I've seen females ovipositing, and once observed the entire process, which took about 90 minutes.

May 3: Orussus
Parasitic Wood Wasps (Orussidae)
Females flit about on the spruce stump, stopping occasionally to deposit eggs. It takes a few minutes, during which time it is easy to get up-close pictures. While they search for a place to oviposit, they tap their antennae tips on the stump in much the same way as the Xorides wasps.
(The ovipositor is up to twice as long as her body and is coiled internally in the thoracic and abdominal cavities. - Bug Eric's post)
On May 20, a male showed up and interacted with a female, flicking the tip of his abdomen as they did a little dance while circling around each other. The male of this species (which I suspect is occidentalis) has a black abdomen, while the female's abdomen is red.
I have videos of the female ovipositing and the male/female dance, which I'll post if I ever can figure out how.
Bug Eric - Wasp Wednesday: Orussid Wasps
Olympic Natural History: Parasitic Wood Wasps - Orussus sp.

May 15: Chrysura
Cuckoo Wasps (Chrysididae)
These beautiful little wasps also parasitize Magachilid bees, especially Osmia. They're hard to photograph, though, since they are small and move around fast. The adults have thick armor on their head and thorax to defend against stings from angry mother bees. They also have the ability to roll up into a ball like a pill bug when being attacked. The larvae are also tough little guys, who don't bother with the nectar and pollen provided for the bee larvae; they eat the bee larvae themselves (after eating any siblings that might have hatched from the eggs deposited by the mother wasp).
BugGuide

May 16: Osmia lignaria propinqua
Blue Orchard Bee (Mgachilidae)
Wikipedia
There were other mason bees nesting in the holes in the stump, but so far I've been unable to identify them.

May 20: Zebra Jumper (Salticus scenicus)

May 25: Western Eyed Click Beetle (Alaus melanops)
Larvae are predators of wood-boring beetles
BugGuide
Bug Eric: Eyed Elaters

May 25: Goldenrod Crab Spider (Misumena vatia)

June 11: Potter wasp (Subfamily Eumeninae)
Saw one enter hole in stump. Several others also observed in the vicinity.

June 15 Gasteruption
Small (~13 mm) wasp was patrolling the stump this afternoon. Caught it in tube, cooled, photographed and released.

June 19 Bald-faced Hornet (Dolichovespula maculata)

It's been cold and cloudy today, so I didn't get out much. But every once in a while I wandered around the yard a bit, and on one of my wanderings I saw an insect on the wall of the garage from an order that I've not yet seen in my yard. It was a stonefly (order Plecoptera).

Stoneflies are cool insects. They spend most of their lives as aquatic larvae, living on the bottom of fast-moving streams. They tend not to tolerate streams with poor water quality. Since adults don't live long or fly far after emerging, it makes me wonder where my stonefly spent its youth. The closest stream to my house (Paradise Creek) is at least a kilometer away and it is not known for its great water quality.

The little guy/gal (?) (body length 10 mm, 13 mm from head to wing tip) was easy to catch in a vial. It didn't try to fly away and wasn't bothered by cold weather. It was about 5 degrees C when I captured it in a vial, and it only took a few minutes for it to revive after being stored in the freezer for a couple hours. After taking some pictures I let it go look for someone to mate with.

I'm not sure yet, but I think it's a winter stonefly (famliy Taeniopterygidae), maybe in the genus Strophopteryx. I've submitted it to BugGuide to find out.

It's hard to make iNat observations here in Idaho with two feet of snow on the ground. Yesterday, however, I did manage to get a couple of poor photos of birds (Bohemian Waxwings and a Varied Thrush) that were iNat firsts for me. But I was most excited about a 3 mm insect that I found crawling around on the inside of the window through which I photographed the birds.

It was a dark-winged fungus gnat (Diptera: Sciaridae), a new taxon for me. Although they are quite common, they are rarely noticed and difficult to identify, even to genus. They have a world-wide distribution with 1700 known species and many more undiscovered and unidentified.

My little gnat probably hatched from an egg deposited in one of our flower pots; spent its larval days beneath the surface eating soil fungi and organic debris; remained in the soil to pupate; and recently emerged to breed - only to be caught by me on the window pane.

In the last few days, whenever I walk past my wife's vegetable garden I have to drop whatever I'm doing and go get the camera. The parsley plants have gone to flower and they are covered with nectaring insects.

I observed more than a dozen taxa, some of which I've identified - with the help of iNat and BugGuide.

There were lots of flies: hoverflies - thick-legged (Syritta pipiens) and Villa sp.; thick-headed flies (Theocophora sp.); and cool little tachinids (Gymnosoma sp.) as well as ugly unidentified ones.

Among the Hymenoptera were masked bees (Hylaeus sp.), spider wasps (Calopompilus pyrrhomelas), vespids, and Ichneumonids (Ichneumon sp.).

Several of these taxa were new to me: Theocophora sp., Hylaeus sp. , Calopompilus pyrrhomelas, and Ichneumon sp..

I just wish I could have a few more hours of good Parsley-watching weather. But it's getting cold and rainy now, so I expect the show is over.

I wonder what I'll find next year.

I recently created two new iNat places that are close to my home in Moscow, Idaho: Idler's Rest and Spring Valley Reservoir.

I've visited each a few times, adding several new taxa to my lists. Among them were oblique-lined tiger beetles, a new long-legged fly genus (Dolichopus), and some really bad-ass robber flies. It was nice to see some non-insects, too - a Red Squirrel, Yellow Pine Chipmunk, and Wild Turkey; some new plant taxa - Western Red Cedar, White Pine, and Larch; and some fungi - Turkey Tail and Red-banded Polypore.

Yesterday I visited the arboretum at the University of Idaho. It is a very buggy place.

I took hundreds of photos, ending up with 29 iNat observations from 24 taxa with 11 life list firsts. (New Taxa List Total: 711)

I was especially pleased to find my first member of the Conopidae familiy, Physocephala texana -- or at least that's what I think it is. (I'm waiting for confirmation on this) When I first looked at its photos I thought it was a wasp of some kind, but I couldn't find one that looked like it. Finally I realized that I had been fooled by a fly's disguise. Evolution makes some damned good costumes!

Another one that almost fooled me was Cylindromyia, a tachinid fly that mimics a wasp with a black and red abdomen.

It's a great place to go iNatting, and I'll be back there often in the days ahead.