The breathing in the butterflies is very particular, with important differences compared to respiration in other organisms. Compared with the respiratory system of humans, the respiratory system of butterflies is characterized by the absence of lungs.
Instead of lungs, butterflies have spiracles. These spiracles are holes in the bodies of butterflies that allow the passage of oxygen to the trachea.
The trachea is a system of tubes inside the body of butterflies that allow the transport of oxygen to different parts of the body.
Butterflies do not have a system that pumps oxygen into tissues. In general the respiratory process occurs by means of passive gas diffusion in the throttle body and by self-ventilation.
Self-ventilation consists of modifying the volumes of the tubes of the trachea. Such modification is caused by the movements of the insect body in the air.
These modifications generate air pressure gradients within the tubes and allow their flow into the throttle body.
Some studies indicate that butterflies may experience rapid compressions of tracheas that help transport oxygen during respiration.
These compressions of the trachea can be due to the movement of various muscles of the body like the muscles of the extremities.
Spiracles and trachea
In general, the respiratory system of a butterfly has about nine spiracles located on the sides of its body. These spiracles are external orifices that allow breathing.
Spiracles are not exclusive to butterflies. These holes are also present in various organisms such as fish, cetaceans, arachnids and insects.
The trachea in turn forms a complex network of tubes filled with gas (oxygen-containing air) and branches to various parts of the insect such as wings, legs and body segments.
The exchange of oxygen between the trachea and the tissues occurs through tracheoles. Tracheoles are the smallest tubes in the tracheas that can have about one micrometer in diameter.
Efficiency of the respiratory system of butterflies
The respiratory system of the butterflies is quite simple. This simple system is inefficient compared to other animals, which causes butterflies with large bodies to manage their energy inefficiently.
Given the difference in size and efficiency of their respiratory systems, butterflies are slower than other flying organisms like birds and are easy prey for them.
Other functions of the respiratory system of butterflies
Like many insects, butterflies can regulate the exchange of liquids with the outside by means of the spiracles.
The opening and closing of the spiracles allow to control the evaporation of water from the body of the insect to the environment.
One of the most important characteristics of the respiratory system of butterflies is their role in thermoregulation.
Through an excessive breathing process, butterflies can control their body temperature.
References
- Butterfly, the adult. Available at: science.jrank.org
- Clench H. Behavioral Thermoregulation in Butterflies. Ecology. 1966; 47 (6): 1021-1034
- Kearny E. (2010) The biology of butterflies. Cornell University
- Kristensen N. Respiratory system of the primitive moth Micropterix calthella (Linnaeus) (Lepidoptera: Micropterigidae). International Journal of Insect Morphology and Embryology. 1984; 13 (2): 137-156
- Westneat M. et al. Tracheal Respiration in Insects Visualized with Synchrotron X-ray Imaging. Science, New Series. 2003; 299 (5606): 558-560