How Black Saddlebags Lay their Eggs

by Denise D. Greaves, Ph.D.
All Photographs © Denise D. Greaves, 2009, 2010

 

 

I find it fascinating to watch black saddlebags (Tramea lacerata) lay their eggs, especially since I have not seen any other species of dragonfly distribute its eggs in quite the same way.

Black saddlebags are part of the skimmer family (Libellulidae); a female dragonfly of this family lays her eggs by tapping her abdomen on the water. With some species of skimmer, the female lays her eggs while the male (usually) protectively keeps watch. Note the image below, where a male (blue) western pondhawk (Erythemis collocate) hovers in the upper left as the female (green) in the lower right taps the end of her abdomen on the water to scatter the eggs.

 

 

In other skimmer species, a couple will remain attached after mating (the male continues to grasp the female behind the head), and they distribute their eggs while remaining in this tandem configuration. For example note the variegated meadowhawk (Sympetrum corruptum) couple in the photo below, where the male leads and helps swing the female as she scatters the eggs on the water.

 

 

Black saddlebags (Tramea lacerata) sort of combine these two routines to come up with their own particular modus operandi. The male and female remain in tandem after copulation as they patrol for places to deposit their eggs. When they find a suitable spot, he releases her, she descends and strikes the water with the the tip of her abdomen, she flies back up, and they reattach. This all happens in the blink of an eye and is fascinating to watch.

A more thorough account is perhaps easiest if one begins with the so-called mating wheel. The male has appendages at the end of his abdomen with which he grasps the female behind the head. She then bends upward and attaches her ovipositor to the penis on his second abdominal segment, as below.

 

 

After mating, the wheel shape is broken as the female detaches her ovipositor from the male’s penis, but he continues to grasp her behind the head.

 

 

 

 

The couple remains attached as they fly in search of a suitable location to lay eggs.

 

 

When they find a spot that meets with their approval,  the male releases the female,

 

 

who then quickly descends to tap the end of her abdomen on the surface of the water.

 

 

The female scatters eggs as the male waits above.

 

 

She then darts back up to the male, who again clasps her as they fly to their next spot and repeat the process. Note that the male bends his abdomen forward in preparation to reattach as soon as she finishes tapping the water.

 

 

Another photo of pre-reattachment:

 

 

He is curved almost into a circle as they reattach:

 

 

Sometimes lone males will pursue attached couples. This is a threat to the male that is with the female, since the other male could steal her during the brief moment when they are not attached. In the photo below, I cannot tell which male she was with originally, but they compete to catch her as she arises.

 

 

Occasionally I have seen a female saddlebags depositing eggs solo; I assume that either her mate has been eaten or distracted or else the tandem routine is not the only technique that black saddlebags use.

 

 

I witnessed another variation on the egg-laying procedure on 14 September 2009: a female saddlebags was laying eggs solo with a male avidly patrolling. Each time she arose from tapping her abdomen on the surface of the water, it appeared that the male was trying to snag her, but she would dart away before he could catch her. Perhaps she had an independent streak or maybe she was rejecting the male because he was not her original mate? At any rate, the tandem detach-reattach routine is the most common but not the only egg-laying behavior I have observed in black saddlebags.

The pictures in this account were all taken in San Jose, CA, at the Robert W. Gross Groundwater Recharge Ponds. My husband Sheldon and I lived Rhode Island a few years ago, and while there I observed black saddlebags following the same routine. Unfortunately, I have not yet had the privilege of seeing other saddlebags species mating or laying eggs.