Caddisflies

views updated May 17 2018

Caddisflies

North Americas streams, rivers, and lakes are home to more than 1,200 different species of caddisflies, which are aquatic insects in the order Trichoptera. Adaptations to different water conditions and food types allow this group of insects to populate a variety of habitats in Americas waters.

Caddisflies are best known and most easily identified in their larval stages. Most caddisfly larvae either spin shelters of silk or build tubular cases. The type of shelter can be used to assign caddisflies to their different families. Some species make shelters from the hollow stems of grasses. Others inhabit shelters constructed from rock fragments, pieces of bark, or other available materials. Some species of caddisfly carry their shelters with them as they graze on the algae on rocks; others remain anchored to a rock. Caddisflies that spin silk shelters also spin nets that filter out food particles from the flowing water.

Immature caddisflies are aquatic and must obtain oxygen from the water. Mobile caddisfly larvae move water through their gills. Sedentary caddisfly larvae make undulating movements to move water across their gills. The larval cases of sedentary caddiflies restrict or direct flow in some essential way, for if the cases are removed, the larvae usually die.

Like many other insects, caddisflies undergo complete metamorphosis, from egg to larva to pupa to adult. The aquatic larvae eventually spin a cocoon or pupal case and become dormant. At the end of the pupation period, adult caddisflies break free of their cocoons and swim to the surface. There, the new adults dry their wings and begin their short adult lives as active, sexually mature air-breathing insects.

Most adult caddisflies live less than a month. During that time, they are inactive during the day, and active at night. Adult caddisflies feed on plant nectar, or other plant liquids. After the females have mated, they lay their eggs. Where they lay their eggs depends on their species. The female of one caddisfly species remains underwater for more than 15 minutes as she lays her eggs. A female of another species deposits her eggs on plants above water, while another lays her eggs on the water surfacethe mass of eggs

then absorbs water, sinks, and adheres to an underwater rock or other surface.

As an order, caddisflies are associated with a variety of aquatic habitats: rushing mountain streams, ephemeral spring seeps, slow-moving rivers and tranquil lakes. A single habitat, such as a stream, can support several different species of caddisflies as part of a complex aquatic food web. The larvae of a species grazes on algae on rocks, another feeds on leaves and other plant parts that fall into the water, shredding the material into fine particles. Another species filters food from the fast-moving rapids, while another species catches of food items that flow by in slower-moving waters.

Caddisflies specialize in how they acquire food rather than in the type of food they ingest. These specializations make caddisflies one of the most varied and abundant species of aquatic insects in North America.

Caddisflies

views updated Jun 11 2018

Caddisflies

North America's streams, rivers , and lakes are home to more than 1,200 different species of caddisflies, which are aquatic insects in the order Trichoptera. Adaptations to different water conditions and food types allow this group of insects to populate a variety of habitats in America's waters.

Caddisflies are best known and most easily identified in their larval stages. Most caddisfly larvae either spin shelters of silk or build tubular cases. The type of shelter can be used to assign caddisflies to their different families. Some species make shelters from the hollow stems of grasses . Others inhabit shelters constructed from rock fragments, pieces of bark , or other available materials. Some species of caddisfly carry their shelters with them as they graze on the algae on rocks ; others remain anchored to a rock. Caddisflies that spin silk shelters also spin nets that filter out food particles from the flowing water.

Immature caddisflies are aquatic and must obtain oxygen from the water. Mobile caddisfly larvae move water through their gills. Sedentary caddisfly larvae make undulating movements to move water across their gills. The larval cases of sedentary caddiflies restrict or direct flow in some essential way, for if the cases are removed, the larvae usually die.

Like many other insects, caddisflies undergo complete metamorphosis , from egg to larva to pupa to adult. The aquatic larvae eventually spin a cocoon or pupal case and become dormant. At the end of the pupation period, adult caddisflies break free of their cocoons and swim to the surface. There, the new adults dry their wings and begin their short adult lives as active, sexually mature air-breathing insects.

Most adult caddisflies live less than a month. During that time, they are inactive during the day, and active at night. Adult caddisflies feed on plant nectar , or other plant liquids. After the females have mated they lay their eggs. Where they lay their eggs depends on their species: One species of caddisfly remains underwater for more than 15 minutes as she lays her eggs. Another species deposits her eggs on plants above water, while another species lays her eggs on the water surface—the mass of eggs then absorbs water, sinks, and adheres to an underwater rock or other surface.

As an order, caddisflies are associated with a variety of aquatic habitats: rushing mountain streams, ephemeral spring seeps, slow moving rivers and tranquil lakes. A single habitat such as a stream, can support several different species of caddisflies as part of a complex aquatic food web. The larvae of a species grazes on algae on rocks, another feeds on leaves and other plant parts that fall into the water, shredding the material into fine particles. Another species filters food from the fast moving rapids, while another species catches of food items that flow by in slower-moving waters.

Caddisflies specialize in how they acquire food rather than in the type of food they ingest. These specializations make caddisflies one of the most varied and abundant species of aquatic insects in North America .

Caddisflies

views updated Jun 08 2018

Caddisflies

Adult caddisflies are very active. After hatching they can live for about 3 weeks. At low light they dance on the rivers surface. Perhaps they are either drinking or laying eggs. Whether they are drinking or laying eggs, they skitter the surface in erratic flight patterns. Fish love them.

I fish them in an active skating retrieve combined with an assortment of presentations. The classic upstream, Youngs method, and the downstream presentations are effective. I prefer to fish 2 flies. One is an exact size and the other is one size larger than the naturals. I fish the smaller pattern on the dropper which is about 2-3 feet away from the larger fly. My favorite patterns are the elk hair caddis ones treated with fly floatant. (Gink etc.)

This skating method is explained in the retrieves chapter. I exaggerate the motions so that the dropper fly lifts off of the water a few inches and splashes back down. The larger fly actively disturbs the surface. This presentation and retrieve elicits aggressive surface rises. I have found it to be effective even when the caddisflies are not active such as in bright sunlight. This method, fished next to bank side shadows, can entice inactive fish into feeding. When used in low light conditions when lots of caddisflies are active, it can be extremely effective.

I prefer the Youngs method for this skating technique. I allow the flies to be active and then float freely for a short distance. This activity attracts fish to your flies.

Caddisflies

views updated May 29 2018

Caddisflies

Order: Trichoptera

Number of species: over 1200

Life Cycle: complete metamorphosis

Four Life Stages: egg, larva, pupa, adult

Larva

Body Description

Abdomen: 9 segments

Thorax: 3 segments

Legs: 6

Worm-like appearance, fragile

Size: 6-22, up to 1 1/2 in length

Most are case builders (case made of bottom debris which protects fragile larvae)

Activity: some are free roaming but move at a slow crawl

Pupa

Body Description

Wings: Distinguished by folding wings in a downward position under the bodys sides

Activity: may capture an air bubble to float to the surface

Adult

Body Description

Antenna: long (2x body)

Wings: tent like wings fold over body

Tails: none

Colors: mottled shades: olives, browns, tans, grays, yellows

Activity: fast & erratic

Hook Size: 6-22, 14-16 most common

There are five groups of caddisflies which are determined by the larvas behavior: free-living caddis, saddle-case caddis, net-spinning caddis, tube-case caddis, and purse-case caddis.

Caddisflies are typically found in cold, oxygen-rich water such as mountain streams where there are riffles and runs.

caddis fly

views updated Jun 08 2018

caddis fly Any of several moth-like insects of the order Trichoptera. Adults have long, many-jointed antennae, hold their wings tent-like over the body, and usually grow to about 25mm (1in) long.

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