A Damsel in Distress

The other day I was surprised to see one of my damselfly larva wandering about the tank during daylight hours. Normally, the only time I see them is when they crawl on the rocks late at night. Since it was so easy to see, I decided to ID this guy, which was quite easy.

You'll notice the fan-like projections at the end of its tail, these are actually its gills. These caudal gills are thick and triquetral in shape, most other damselfly larvae have thin, long caudal gills. It also has a thicker body compared to other damselflies. All of these characteristics indicate it is a member of the family Coenagrionidae and the genus Argia. I lack a key to bring it to species, but I also lack a scope to closely examine it.

These larvae are cold intolerant, and usually mature when the weather begins to warm up in order to take advantage of the summer months. Due to the fluctuations in temperature in the tank, I'm sure its juvenile hormone levels have been ebbing and flowing, both encouraging and deterring its maturation.

In my mind, I thought that perhaps it was hunting in preparation for the energy depleting molt leading to adulthood. I felt guilty that I hadn't sampled in awhile (the weather has been incredibly dry and hot) and as a result had few mayflies for it to hunt. So, I dug up a caddisfly and pushed it towards it in the hopes that it would feed.

Instead, it walked over the undulating caddisfly larva, and walked into the hole I created digging it up. It was frustrating to see this odd behavior. I was worried that perhaps something was seriously wrong with the pH or chemical levels in the tank.

My nervousness increased when I noticed the larva pawing at the corner of the tank, and swimming up the corner then floating down. Although it was capable of a burst of speed, it was unable to reach the water's surface.

I was compelled to push it toward the divider at the center of the tank, all the mayfly larvae had used it during their adult molts (most anyway), but I assumed it would prolong the molting until it felt air.

After taking a few more pictures, I left it alone in the hopes that it would climb the divider and emerge in the appropriate fashion.

I was disappointed when I returned to check on it after a few hours.

It had begun to molt still in the water, and probably drowned after a certain point. Due to this catastrophe, I decided to redesign the tank to create more "ladders" to the surface of the water.

I feel it's more fung shui now

I still have one damselfly larva left, I'm planning on doing better for this one whenever it decides to molt.