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For educational purposes:--

Information on the basics of Entomology


Introduction                                                                                                                                                                                                                                                                                                                       Contents


Entomology:  TRICHOPTERA 1

Kingdom:  Animalia, Phylum: Arthropoda

Subphylum: Hexapoda: Class: Insecta: Order: Trichoptera



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Pteragota:  Holometabola

  Order:  Trichoptera (46 Families)

    General Summary

    Morphology & Habits



    Families of Trichoptera

  Sample Examinations

  References      Citations


General Summary of Trichoptera

          Trichoptera -- <Adults> & <Juveniles> --, or caddis flies, are medium-sized insects with bodies and wings with many hairs.  Their mandibles are vestigial or absent; the maxillary and labial palps are well developed, and there are two pairs of similar membranous wings with few cross veins.  These are held in roof-like when at rest.  Metamorphosis complete.


          These drably colored insects are strong fliers and at sexual maturity may producing mating swarms. Oviposition may occur directly into the water or the eggs may be laid on plants above the water where they will await immersion with the winter floods to hatch.


          Larvae live in stagnant and running waters.  While most caddisfly larvae build cases of various materials (sand, small shells and particles of vegetation) in which they live, e.g. Limnophilus, there are others that either wander around without a case, e.g. Hydropsyche, or which move around under stones in running water behind a silken web that they manufacture to catch small animals carried there in the water, e.g. Plectrocncnemius.  The case builders are usually phytophagous, sluggish and wormlike wormlike.  The net-spinners are usually carnivorous, rapid movers and campodeiform.  Eruciform larvae have segmental tufts of tracheal gill filaments on the abdomen.  Campodeiform larvae do not have these. In whatever degree these two larval types differ from each other they all possess the diagnostic feature of a pair of abdominal appendages bearing grappling hooks.



          Pupation takes place in a silken cocoon inside the case where this has been used by the larva. Water circulates through the cocoon making its entrance and exit through the two ends.  The pupa has large mandibles by which it chews its way out of the cocoon and then by strong swimming actions of the mesothoracic legs it passes to the shore, there to emerge as an adult after the final molt. Common examples of case-builders are Phryganea, Odontocerum and Hydroptila and of net-spinners: Plectrocnemius and Polycentropus. Rhyacophila and Hydropsyche, common inhabitants of streams, are wandering carnivores (Borradaile & Potts, 1958).





Morphology & Habits


          Trichoptera adults hold their wings roof-like over the body.  Wing venation is typical but there are no clothing hairs only some very small hairs are present. 



          The larvae prepare cases in which they live.  The cases are constructed of river debris such as sand, leaves, wood, etc.  The cases are enlarged to accommodate the growing insect.  Water flows through spaces in the case and may actually be sucked through.


          The legs of larvae are for grasping prey.  Some larvae do not make cases but rather spin a net.  They have gills on their abdomen.  Pupation occurs on rocks that are located under the water.


          Trichoptera are valuable food sources for fish and other aquatic animals.




Families of Trichoptera


          Seventeen families of Trichoptera are distinguished according to their shapes and habits as follows (see Borror et al. 1989 for details):


          Beraeidae. -- Small group inhabiting the east central United States

          Brachycentridae. -- Immatures feed on algae near the shores of small streams.

          Calamoceratidae. -- Adults are orange or brownish with 5-6 segmented maxillary palps.

          Goeridae. -- Adult males have 3-segmented and females 5-segmented maxillary palps

          Helicopsychidae. -- Snail case caddisflies.

          Hydropsychidae. -- Net spinning caddisflies

          Hydroptilidae. -- Micro caddisflies

          Lepidostomatidae. --Adult males have 1-3 segmented & females 5 segmented maxillary palps.

          Leptoceridae. -- Long horned caddisflies

          Limnephilidae. -- Northern caddisflies

          Molannidae. -- Small sandy stream and lake inhabiting caddisflies

          Odontoceridae. -- Adults average 13 mm long and inhabit swift streams.

          Philopotamidae. -- Fingernet caddisflies

          Phryganeidae. -- Large caddisflies

          Psychomyiidae. -- Tube making and trumpet net caddisflies

          Rhyacophilidae. -- Primitive caddisflies

          Sericostomatidae. -- Only one genus occurs in lakes and streams.




Details of Insect Taxonomic Groups


          Examples of beneficial species occur in almost every insect order, and considerable information on morphology and habits has been assembled.  Therefore, the principal groups of insect parasitoids and predators provide details that refer to the entire class Insecta.  These details are available at <taxnames.htm>.






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