A Trip to Texas Provides a Long Sought Photographic Opportunity - Observation of the Week, 6/21/20

Our Observation of the Week is this Long-tailed Giant Ichneumonid Wasp (Megarhyssa macrurus), seen in the United States by @cholmesphoto!

“I became interested in Megarhyssa a number of years ago when I stumbled across a congregation of males of M. macrurus and M. greenei on a log waiting to mate with emerging females,” recalls New York based photographer Clarence Holmes. “I was able to capture photos of the males, but one of my macro targets since then has been to capture photos of a female (particularly M. macrurus ovipositing). I have had limited opportunities until recently.”

That changed, however, on a recent trip to the Dallas-Fort Worth area of Texas this spring. On his first visit to the Lewisville Lake Environmental Learning Area (LLELA) he found an ovipositing female but couldn’t get a good angle on it.  “At the time I added it to my long mental list of missed opportunities and moved on...

The next day I returned to investigate a few different trails, and while walking one of them stopped to take in a view along a creek.  I detected motion to my right and there I saw three female M. macrurus all ovipositing on the same tree!  I took time to observe their behavior and was able to capture my long desired photo of the female ovipositing.

Take a look at Clarence’s photo and you’ll see the remarkable mechanism this insect uses to get her young off to a good start. Megarhyssa wasps, also known as “stump stabbers”, are able to detect their hosts (the wood-boring larvae of Tremex columba sawflies) then drill into the wood using their incredible long ovipositors (this can take 40 minutes!). The translucent blue membrane you see at the base of the ovipositor pushes it into the wood as the tip cuts. Once the host is found, it is stung and paralyzed, then the egg is laid. The wasp larva will consume the paralyzed host then pupate in the burrow before emerging. 

Growing up in the US state of Ohio, Clarence (above) tells me he’s always been interested in nature, and observed the various birds, insects and plants in his backyard and beyond. “I started doing macro photography of insects in my teens and it has been a constant throughout my life,” he says. “I have expanded my observation of nature as a birder, and recently have taken an interest in fungi and lichens. I license many of my photos of the natural world for various uses including print publications and for use on the web.”

He joined iNat in late 2018 and started uploading his photos and making IDs in 2019. He first tries to use resources like field guides and BugGuide, but says iNats help if he’s stumped (no pun intended).

My primary interest is insects and spiders, but I have also posted observations of anything in nature that I have been able to capture photos of. I spend a lot of time out in the field hoping to discover, observe, capture (photos), and learn about insects and any other aspects of nature that I encounter. iNaturalist has added to these activities by helping me see what others are seeing in my area, by helping me identify what I see, and by allowing me to improve my identification skills in many taxons.

- by Tony Iwane

- You can check out Clarence’s photos here, he’s got quite a diverse portfolio.

- This page goes into the Megarhyssa oviposition process in some detail and includes video. Pretty sweet!

- This is not the first Observation of the Week from LLELA - take a trip with us down memory lane back to December of 2015!

Julkaistu kesäkuu 22, 2020 01:16 AP. käyttäjältä tiwane