Dead Logs are a Wasp's Aphrodisiac

I set out on a hike today in search of anything neat I missed during yesterday's hike, which I started too late to take full advantage of the daylight. I made it through the entire trail today, and had quite the detour along the way. I stopped by a dead Sycamore tree to look for beetles, since I found a neat species of Osmoderma beetle in it last year, but no dice this time. I trudged on, arriving at a small area with some fallen trees, and decided to stay a while.

I quickly noticed that there were wasps flying around EVERYWHERE. Thankfully, these were Ichneumonid wasps in the genus Megarhyssa, which are harmless to humans.

A male Megarhyssa sp. wasp.

There were dozens of males like the one above flying around and landing on the fallen tree I was examining. Some were larger with vaguely different markings, indicating that I had at least two different species around, which seems to be normal for the genus, I usually see groups of more than species. The males were gathered to find females, which lay their eggs in dead logs. I was surprised at their sheer numbers this time--if I had a phobia of wasps I might have passed out!

When it comes down to it, you're looking for the same thing the males are: a female, which surpasses the males in the coolness department...

Female Megarhyssa macrurus, drilling into the wood.

The female has a four inch long ovipositor that looks intimidating, but is thankfully not used to sting humans. Instead, it's made up of three filaments that together drill into dead wood, and upon finding a wasp larva of a horntail wasp, sting and paralyze it. The wasp then throws in an egg, which hatches and eats the other wasp larva. It's breathtaking to see the drilling process in action and the raw power of the wasp's actions is surprising.

Female Megarhyssa atrata ovipositing in dead wood.

There was also another female of a different species nearby! This is Megarhyssa atrata, immediately recognizable by its jet-black body and yellow head and front legs. I've never seen this species before today and was in awe upon finding it. I actually almost missed it because it was on the same log as the female Megarhyssa macrurus, which had all my attention! It was fascinating to watch both these wasps go about their business, and I sat there for almost an hour watching them.

Male Megarhyssa sp. wasps hanging out and making friends.

The males were quite funny in their antics. They would scatter if I moved around too suddenly, but then return to the log within minutes. Some of them would dive bomb other males and attempt to mate with them, thinking they were females. They realized their folly after a few seconds and jumped off. Apparently it was more important for them to take every chance they had instead of dealing with unimportant things like making sure they were humping the correct gender.

 Male Megarhyssa sp.

When a female finally did visit, a few males would switch to dive bombing her in attempts to mate, but they were unsuccessful. She either flew away or shrugged them off: she had other business to attend to.

Apparently, sometimes the ovipositor can break off inside of the hole, as the above photo shows. I didn't witness it, but I found two holes like this one in the log. It probably didn't feel too great for the wasp.

Pinned Megarhyssa atratra.

You can see the disassembled ovipositor itself in the above photo with its three parts: two that work together to drill into the wood, and a long thin tube that deposits the egg. All in all, it's a stunning wasp and a beauty to find. This one is going into my collection that I bring with me whenever I give a presentation about insects, so it's sure to garner a lot of attention.

I learned a very important lesson today while watching these wasps. Well, a few important lessons. 1. Knowledge is power, especially when it's knowing that the swarm of wasps flying around are harmless and there's no reason to freak out. 2. I shouldn't tell someone an estimated time when I will be back after a hike, because I always get distracted by something cool.

Mushroom & Millipede Hunting

Yesterday was a nice day outside, and I figured it would probably be one of the last before the snow started falling. I decided to take advantage of this, and set off to find some mushrooms. (Also, it was snowing when I woke up this morning, so I was correct in my assumption. Maybe I should take up weather forecasting.)

I packed some collecting supplies and set off for the nature trail near my old elementary school. It has a nice array of habitat types and gratuitous amounts of decaying logs, so I was optimistic that I would find some nice mushrooms. However, almost immediately after I stepped onto the trail, my trip turned into millipede hunting. It's just too difficult to resist turning over every decaying log I find in hopes of getting some millipedes out of it.

My habit ended up paying off: I found many millipedes and collected 7 specimens from 4 separate species. It's astounding how many little critters live in decaying wood and the surrounding leaf litter. It's a miniature rain forest in there, but is often overlooked. It's really quite easy to collect arthropods using leaf litter: take a few fistfuls of leaf litter and maybe a little dirt, stuff it into a plastic bag, and later transfer it into a funnel. Put a light bulb above the funnel and a jar with some alcohol underneath the funnel, and give it a few days. All the arthropods will dig down through the leaves and fall into the jar. Put your catch underneath the microscope and you'll see all kinds of spiders, pseudoscorpions, harvestmen, millipedes, insects, mites, and so much more.

Though my excursion focused on millipedes, I did eventually incorporate fungi as well.

Another mysterious fungus, along with a millipede.

I rooted through the leaf litter near a dead log and turned over this old piece of bark. The fungus caught my eye long enough to distract me from the millipede (which I did catch later). It reminded me of another fungus I saw a few summers ago and blogged about here. I'm still at a loss for what they could be and need to find a good resource on fungi to research it more. I poked one of the drops and it ran onto the wood, into which it was readily absorbed.

The millipede ran surprisingly quickly, as they're usually slow. It didn't try to curl into a spiral when I picked it up, but rather thrashed around a bit instead. This is atypical for millipedes, which was intriguing. I think it's a Chordeumatid in the genus Cleidona, but I'll need to get it under a microscope and look at a few features before I can be sure.

The other millipedes I found were much more millipede-like in their habits. The most abundant millipede I found was a Polydesmid that I've found a few other times, but have yet to identify. 

Crawling around its new home, a nice plastic container I prepared.

It looks similar to another millipede I've seen before, Pseudopolydesmus serratus, though it doesn't fluoresce under UV light. I grabbed three specimens, and one is a male, so I should be able to figure it out.

After turning over enough decaying logs, I've learned which millipedes I can expect to see more often than not. And like usual, the beautiful Euryurus leachii, showed up under the logs I looked at.

This millipede is a little over an inch long and is easy to recognize. It has a blunt epiproct (its "tail"), separating it from other Polydesmids. The orange spots along its back and at the edges of its paranota, combined with the purplish hue of its body, readily identify this native millipede. It's certainly in the running for most beautiful millipede in Ohio. Once you cross into the central US, however, be careful: Auturus evides is a lookalike. I haven't seen a specimen of A. evides for myself, so I'm not yet sure how to differentiate them.

Another reason for E. leachii's beauty: its fluorescence under UV light.

Not to be outdone by all these amazing millipedes, the fungi made a comeback somewhere around the Soggy Bottom Trail.

It's usually much soggier. 

Decaying wood isn't only for millipedes, it's also great habitat for moss and mushrooms!

Those little brown mushrooms made a cute little home in a hole in the log, flanked by moss. If you look closely at the stalks coming up from the moss, you can see the calyptra (the green sheath) around the spore capsule. Think of the calyptra as a protective blanket keeping the capsule safe until it's time to let the spores go. If you look in the background, you'll also see a polypore coming out of the log...

The Soggy Bottom Trail did not disappoint!

"It looks like an uncooked sausage"

One of my mantras when I go out to look for bugs and other critters is "Turn over that decaying log." You always have a great chance of finding neat stuff when you look through decaying wood, including creatures such as centipedes, millipedes, spiders, slugs, and of course, insects.

Today was no exception.

"O hai!"

After rolling over a particularly good log, I looked into a hole bored into the wood and found what one girl described as "an uncooked sausage" before she backed away to find some prettier biology. Despite its leathery appearance a bird or small mammal would look upon this beetle grub with much more glee. Then it would gobble this sucker down in a heartbeat.

A grub in the hand is worth...two in the log?

Judging by the size of this grub, I'm guessing that it's a grub of the Eastern Hercules Beetle (Dynastes tityus), though I'm not completely sure. I've uploaded it to BugGuide and hope to hear back about it soon. 

While decaying logs may not be the prettiest addition to wooded areas, they're still quite useful to the ecology of the forest. Without them, beetle grubs like this one would lose their only habitat, thus denying us their impressive beauty as adult beetles.