27 July 2011

Beetle Anatomy

Insects exchange gases through a respiratory system that is made up of spiracles, trachea, and tracheoles. Spiracles are the openings to the atmosphere and they connect to the trachea and eventually tracheoles. The tracheoles are the smallest tubes of the arthropod respiratory system and are the site of gas exchange. The concentration of trachea and tracheoles is highest in those tissues that are most metabolically active like the alimentary canal. The two pictures below show the branching trachea found supplying the alimentary canal of a Tenebrionidae larva.

Trachea supplying the alimentary canal

Coleoptera Trachea

To get these pictures I dissected the larva by first submersing it in insect saline solution which is made by mixing .9 grams of NaCl with 100 ml of distilled water. I then used micro-scissors to slice open the dorsal side of the body and minuten nadelns to hold the sclerites away from the body so that the internal organs could be seen. For my first dissection of a small larva I feel that it went well.

These pictures were taken as part of my goal to build up a collection of photos that I can use in teaching entomology in the future. I used the same Nikon SMZ1500 scope with a Nikon Digital Sight DS-Fi-1 camera to take these photographs that I use for almost everything on this blog. As always I used gimp and combine ZP for the editing process.


  1. Fine post - short but sweet, and an aspect of beetle anatomy rarely seen.

  2. Fantastic photos illustrating these minute structures! Your future students are in for a great class with images such as these!