tracheal gill

These tracheal gills are multifunctional and key to many biological processes.

Some Asian species have tracheal gills and live underwater.

They breathe by means of tracheal gills.

And there is no doubt that the tracheal gills of the mayfly nymph in many species look like wings.

The larvae have paired plumose tracheal gills on each of the first eight abdominal segments.

The tracheal gills are equipped with little winglets that perpetually vibrate and have their own tiny straight muscles.

However, the second and third instars carry seven pairs of jointed, movable tracheal gills beneath their plump abdomen.

The first eight abdominal segments have lateral tactile filaments and the first seven have tracheal gills in tufts.

This peripheral tracheal division may also lie within the tracheal gills where gaseous exchange may also take place.

The moth is notable as its larva, like most members of the crambid subfamily Acentropinae, is aquatic and has tracheal gills.

This proves that abdominal legs have been totally reduced in Recent Ephemerida except for the claspers (gonopods) and that tracheal gills are not flattened legs.

Then comes the fact that insect (larva and nymph) gills are actually a part of a modified, closed trachea system specially adapted for water, called tracheal gills.

According to this theory these tracheal gills, which started their way as exits of the respiratory system and over time were modified into locomotive purposes, eventually developed into wings.

Other smaller numbers of aquatic insects have a closed tracheal system, for example, Odonata, Tricoptera, Ephemeroptera, which have tracheal gills and no functional spiracles.

Apart from the larvae of the demoiselles are difficult to distinguish from each other, the apparent differences lie mainly in the bristles and the severity of the tracheal gills on their abdomen.

The Carboniferous nymphs bear three pairs of almost homonomous thoracic wings and, on the abdomen, nine pairs of legs and nine pairs of tracheal gills (wing homologues).

They are unusual in that although they are generally aquatic, taking in dissolved oxygen through abdominal lateral filaments and tracheal gills, they also have spiracles that allow them to take in air directly when above water.

And finally when looking at the three most primitive insects with aquatic nymphs (called naiads: Ephemeroptera, Odonata and Plecoptera), each order has its own kind of tracheal gills that are so different from one another that they must have separate origins.