Litinsects

© Günther Matula Litinsects #28: Odonata Dragonflies and damselflies (both not actually flies) make up the order ODONATA, meaning “toothed ones”, which refers to the insects’ strong and sharp mouthparts. This is one of the most primitive orders of winged insects! Odonates are further categorized into two infraorders, the dragonflies and the damselflies. Dragonflies belong to ANISOPTERA, from the Greek anisos for “unequal” and pteron for “wing” because their front wings are slightly narrower than t heir hindwings (just check out the first picture). Damselflies belong to the infraorder ZYGOPTERA, from the Greek zugos meaning “even” because both wing pairs have the same shape Damselflies are generally daintier looking, while dragonflies appear more robust. An easy way to differentiate between the groups is how they hold their wings at rest: dragonflies hold them open and out to the side while damselflies hold them closed and upright over their backs (see t...

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 a...