The different stages of development of Rhionaeshna californica the California Darner for making comparisons
 |
| An adult male California Darner (Rhionaeshna californica). |
 |
| An example of the pieces of a California Darner naiad from a Western Pond Turtle stomach. |
During an earlier post I mentioned how significant it is to know what the organism looks like prior to being eaten. Knowing what its role in the ecosystem as an adult and naiad is even more helpful.
 |
| The sample to the left is a free-swimming naiad and to the right is an exuvia, the last stage before it becomes the adult Anisoptera. |
When I see all the stages then even something that looks like an amorphous piece of animal tissue is identifiable.
 |
| This is a freshly consumed naiad from the stomach of a Western Pond Turtle. Can you see some familiar body parts? |
Lastly, yesterday I saw the adult male dragonfly grabbing small flying insects from the air and looking for a mate. The naiad stage can be several years, whereas the adult stage lasts just a few weeks.
 |
| This naiad was in a sample of filamentous algae I collected yesterday and kept in my refrigerator overnight to examine this morning. As it warmed up, it went after a water strider that was also ensnared in the algae sample. |
Prementum and palpal lobes
The prementum is a powerful tool the naiad uses to hunt prey that includes insects, immature crayfish, and even small fish! The next time I will have some nice photographs showing where they are and how they work. It's my project for tomorrow. For now take a look at the prementum and try to figure out how it works.
 |
The number one indicates the location of the mouth and number two indicates the prementum that is folded up in the picture above. When the naiad is feeding it extends this arm-like organ forward to grab prey and while doing so it exposes the palpal lobes that help draw food upward to the mouth.
|
Next time ... a closer look at the prementum and palpal lobes!
No comments:
Post a Comment