How Baskettails Got Their Name

I cannot be everywhere at once, nor witness every amazing behavior that insects do, so I am exceptionally grateful to friends and followers who share their illustrated stories with me. Such was the case when I noticed a post to a Facebook group from Cindy Baranoski. She happened upon a female Prince Baskettail dragonfly, Epitheca princeps, preparing to oviposit.

All photos © Cindy Baranoski

Baskettails are rather generic, non-descript dragonflies in the family Corduliidae, which includes the "emeralds." Both kinds of dragonflies have brilliant green eyes as adults. Otherwise, they can be mistaken for the more abundant "skimmer" dragonflies in the family Libellulidae. Baskettails tend to fly in spring and early summer, with some exceptions like the Prince Baskettail that is at the center of our story here. At first glance, it might be dismissed as a Twelve-spotted Skimmer, but the abdomen is longer, and narrow.

Cindy describes her amazing encounter as follows:

"It was a beautiful day, so my husband and I decided to go for a hike at Blackwell Forest Preserve in Warrenville, Illinois. They have a lovely array of forests, lakes, prairies, and wetlands. I had my camera in my backpack, as usual, waiting to get going into our walk before dragging it out. We had just started out around the first body of water, on a path about twenty feet from the water, and dense with plants. As we walked I saw a dragonfly whizz past us and land on a plant.

All photos © Cindy Baranoski

My first thought was of someone I knew who had shared a photo of a beautiful red dragonfly, and I wondered if this one was like that, or even just different from all the others I'd seen this summer. My husband remained on the path while I slowly and stealthily walked over to see. The dragonfly was in a vertical position on a plant, as usual, but what stuck out immediately was the movement of its tail: A slow and steady rhythmic back and forth movement I had not seen a dragonfly do before. I've seen them do a lot, this was new. I hoped that the dragonfly was ok, or maybe this was some new movement that helps them cool off, like the obelisk position. So I slowly backed away, and frantically pulled out my camera to be sure it was all on the right settings, mentally crossed my fingers, and snuck back over.

By that time I could see a bit of something now on the tail, as it gently waved back and forth. The dragonfly didn't fly away, didn't move, as I kept moving in closer to snap pictures with my camera, which was obnoxiously loud it seemed, and messing up my stealthiness. A bit of time passed and the small spot on the tail grew; and I was pretty sure this dragonfly was laying eggs. The dragonfly became a 'she' now, and she was extruding eggs.

All photos © Cindy Baranoski

I squealed mentally and out loud, and asked my husband to come peek to be sure this was happening. He looked, and said 'yep.' She continued to push out her eggs, and got quite still, and the slow waving of her tail ceased. I kept snapping pictures, praying at least one of them might be clear enough to share with others and document what was happening. Only a matter of minutes passed by, but it seemed forever, and not a thing around me was happening save for this moment. A breeze blew and she did not move. I was nearly on top of her snapping away and she didn't move, intent on what was happening in her own world.

All photos © Cindy Baranoski

Suddenly, in a moment, she took off and was gone. I want to believe that she quickly landed on the water to deposit her eggs. We walked away and I continued to squeal out loud how over absolutely amazing that was to see, and so grateful I was given that moment by her to trust this human observer. When we got home, of course I immediately opened up the pictures to see that many had come out in focus, and I pulled a few I felt were worthy of sharing on Facebook and Instagram. Not as many were as giddy about seeing this as I was, save for Eric and a few others. No worries, it was my special gift she shared with me."

All photos © Cindy Baranoski

Female baskettails quite literally put all their eggs in the one "basket" of her subgenital plate, just prior to laying them. In flight, the tip of the egg-laden abdomen is held aloft in a distinctive posture. They practice what is called exophytic oviposition, meaning that they do not land and insert their eggs singly into aquatic vegetation, bottom sediments, or mud in locations which flood. Instead, they drag the abdomen through the water as they fly, trailing a rope of eggs behind them. They favor tangles of floating and emergent plant stems as locations for their strings of eggs, which may be several feet long. The eggs are suspended in a gelatinous fluid that expands in the water.

All photos © Cindy Baranoski

I want to thank Cindy again for agreeing to let me publish her photos and story. Please consider contacting me if you have something to share that was exciting to you: bugeric247ATgmailDOTcom.

Pigeon Horntail Wasp Ovipositing

I first wrote about the Pigeon Tremex horntail wasp, Tremex columba, back in September, 2012. At that time I had not seen a female of that species here in Colorado. That all changed on the afternoon of August 22 when I witnessed two females of this species laying eggs (ovipositing) in an elm tree at my workplace, a plant nursery here in Colorado Springs.

Horntail wasps belong to the family Siricidae. They are mostly large, cylindrical wasps, the females of which have intimidating spear-like organs protruding from the end of the abdomen. They use this "ovipositor" and its associated appendages to bore into trees and lay their eggs. The larvae that hatch tunnel through the wood, aided by a wood-softening fungus that is deposited by their mother at the time she lays her eggs.

Close-up of ovipositor apparatus

Horntails get their name not from the ovipositor, but from a knob or spur at the tip of the abdomen above the ovipositor in females, but present in both genders. This “cornus” is a feature of the larva, too, aiding the grub in locomotion. The function of the cornus in adult wasps is apparently unknown.

The video below shows the female wasp already engaged in oviposition. Her ovipositor is the black rod perpendicular to her body under her hind leg. The rhythmic movements of her abdomen probably help drive the organ deeper into the wood. The pair of pale appendages extending from the tip of her abdomen function as a sheath that protects the ovipositor when it is not in use.

One reason the mother horntail attempts to lay her eggs deep inside the tree is to keep her offspring out of reach of giant ichneumon wasps and ibaliid wasps that lay their eggs on horntail grubs.

Female giant ichneumon wasp, Megarhyssa sp., from Colorado

Most horntail species are not considered pests because they will lay their eggs in dead, dying, or weakened trees. A handful of species have made their way to the United States from Asia and elsewhere, and those are invasive species that have no known natural enemies here in North America.

The favorite hosts for the Pigeon Tremex are maple and beech, but obviously elm is also acceptable, along with apple, poplar, oak, and other hardwoods. It takes one to two years for a horntail wasp to complete metamorphosis from egg to adult.

Sometimes, the female wasp dies in the act of ovipositing, or is consumed by a predator during this lengthy period of vulnerability. Indeed, on September 4 I found a deceased wasp still embedded in the tree where she was ovipositing; and nearby were the remains of another, just the needle-like ovipositor protruding from the tree trunk.

Deceased female horntail stuck in tree

This is the time of year to be watching for the Pigeon Tremex in your neck of the woods. Watch for their giant ichneumon parasites, too. You might have to spend a lot of time looking up and down dead trees, though.

Source: Eaton, Eric R. 2014. "The Wasp and the Fungus," Northern Woodlands Educators.