Skip to main content

#18: Spiracles and Tracheae




Litinsects #18: Spiracles and Tracheae


Take a breath in... and out. Have you ever wondered how insects breathe? They don’t have lungs like we do. In fact they use a completely different respiratory system than vertebrates.


  • Insects breathe through SPIRACLES, which are small holes in the exoskeleton along the thorax and abdomen. A tiny “door” to the spiracle can be opened and closed to reduce water loss

  • Connected to the spiracles is a network of TRACHEAL TUBES that extend throughout the body. Gas exchange occurs by DIFFUSION across the walls of the smallest tubes.

  • In insects, the respiratory system is SEPARATE from the cardiovascular system. Their “blood” does not carry oxygen to cells (technically they don’t have blood but a future post will go into that more)

  • Some insects have collapsible internal sacs to store air for when their spiracles are closed. Aquatic insects use these air reserves while under water and can regulate buoyancy with the air sacs

The coolest thing is, although tracheae extend internally, they are actually invaginations of the exoskeleton so they are still covered by hardened cuticle. When the individual molts, these tubes are also shed. This photo shows these long thin tracheal tubes still connected to a shed exoskeleton (EXUVIA) of an assassin bug. 

 Photo: © Brandon Thorpe

Labels:

Comments

Post a Comment

Popular posts from this blog

#13: Insect Legs

Litinsects #13: Insect Legs Insect legs can be as diverse as the animals themselves. Some are long and slender like a crane fly’s, some are short and hefty like a mole cricket’s. But what all insects share is the number and layout of those legs. Hexapods have 6 LEGS, a pair each of fore, mid, and hind legs that are made up of the same basic units. Starting closest to the body, they are:  (1) the coxa, which attaches the leg to the thorax  (2) the trochanter (3) the femur, which is oft en the thickest segment  (4) the tibia, often covered in tiny hairs (5) the tarsus, which contains 5 “pseudo-segments”  (6) the pretarsal claws, of which most insects have 2 on each leg The basic units of the leg always occur in this order but may be reduced or highly modified in some species to fit certain tasks such as running, digging, swimming, grasping, or jumping. This photo sums it up perfectly: from < https://wiki.bugwood.org/File:Insect...
Post a Comment
Read more

#22: Caterpillars

Litinsects #22: Caterpillars Since you are freshly familiar with metamorphosis from my last posts, I will today be talking about caterpillars 🐛 and some structures that change drastically in appearance from before to after metamorphosis: legs. Caterpillars are the worm-shaped larval stage of butterflies and moths. They have huge appetites; they mainly feed to grow and gain energy for their transformation into adulthood. In order to do this they need to get around, for which they use le gs because only adult stages have wings.  But insects only 3 pairs of legs, right? So where do all these extra legs come from all down the sides of their bodies?  Caterpillars have 3 pairs of TRUE LEGS, attached to their thorax, which are jointed and have little claws on the end. These legs are still present after metamorphosis, though they will have changed substantially Additionally, they usually have 2 to 5 pairs of PROLEGS, which are protrusions fr...
Post a Comment
Read more

WELCOME: Social Distancing Entomology Course

All week I’ve been seeing videos and posts of the creative stuff people have been doing while social distancing, all the while thinking, what could I contribute to all the people sitting at home on social media all day?? Well this morning it hit me. I will do what I do best! And that is... drop some nerd knowledge on you all 🤓 Welcome to my social distancing ENTOMOLOGY COURSE!  Every day I will post an insect photo, most of which I’ve taken through my microscope, and explain about the insect group or the feature pictured. My hope is that you might learn something new about insects and maybe, just mayyyyybe, be a bit more fascinated and a bit less grossed out by the most diverse and arguably most successful group of animals to ever live... thanks for reading, stay tuned 🦋 🦟 🦗 🐞 🐜 🐛
Post a Comment
Read more