Caddisfly

Caddisflies are a broad order of insects that can be spotted in all kinds of wetlands. The larvae are recognized for making cases to pupate in, collecting pebbles, sand and leaves, fragments of wood, and covering them with silk. The silk is produced by the larvae with a particular gland called the 'labium'.

Caddisfly House is an aquatic insect that lives most of its life underwater and part of it as a winged adult (quick note, all insects undergo transformation). These bugs sustain as a nymph underwater in rivers, streams, and lakes for up to two years. Then when they gearup, they pupate into an adult inside of their case and fragment the case. Later after, they swim to the surface of the water where they appear from the water and fly off.  They must do this very fast since fish and other animals are looking to eat them!

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Did you know?

One species of caddisfly named 'land caddis' (Enoicyla pusilla), differs from all the others consisting of a larva that lives, not under the water, but amidst leaf litter in woods in the West Midlands. This also provides its common name, the 'land caddis'.

Incredible Facts about Caddisfly

• There are over 1,000 species of caddisflies in North America and more than 7,000 around the world.

• Caddisflies are closely linked to butterflies and moths.

• Caddisflies construct protective covering around their bodies.

• These tiny insects play a crucial role in river ecosystems. They are a significant food source for fish (adults as well as nymphs).

• The nymphs of caddisfly larvae are the most unique about these insects. They utilize silk from their body to construct protective cases around their soft bodies in order to shield them from outside threats. These cases are made of stones, sand, and plant material.

• The nymphs of caddisfly larvae are also eaten by a special bird – the American dipper, which moves underwater in the base of rivers and streams. The adult caddisflies are a food source for birds, reptiles, and amphibians.

• An artist named Hubert Dubrat incorporated caddisflies to construct unique sculptural forms. He eliminates caddisfly larvae from their existing cases and then puts them into an environment having materials such as gold flakes, precious pearls, gemstones, and leaves to make cases out of these materials.

• When the female Caddisfly house goes underwater to lay eggs, she can stay under for up to 30 minutes while she sticks her eggs to submerged rocks and vegetation. The female does this by using air that is trapped on her little hairs for oxygen.

• Ahead of him starting to experiment in the 1980s, other companies have used this technique to create jewelry that can be sold.

Caddisfly House Scientific Name

The scientific name of caddisfly is Trichoptera.

Caddisfly Species

Caddisflies are one of the massive groups of aquatic insects with approximately 7,100 explained species worldwide. There are about 1,340 species in North America. Caddisfly larvae have adapted well to a wide range of different microhabitats.

Caddisfly Statistics

Caddisflies Characteristics

Caddisflies are associated with Lepidoptera and bear a resemblance to small hairy moths, but their wings are wrapped in dense hairs instead of scales and they lack the customary curled proboscis of most moths and butterflies. Besides this, a caddisfly is recognizable by the following characteristics as below:-

• They are usually dull-colored

• In terms of body length, range in size from 2-40 millimeters. 

• Have an elongated body

• Wings are covered in fine hairs. When at rest, wings form a roof over the abdomen

• Consist of two pairs of membranous wings which are of differing size

• Long tapering, filiform antennae, and Reduced mouthparts

Caddisfly Distribution and Habitat

The species is widespread. Caddisfly larvae are commonly found in freshwater, wetlands, gardens, and towns. That being said, caddisflies are majorly diverse in cool, moving water, but have intruded on a broad range of habitats. They are known to build cases out of silk and different other materials, for shelter.

Most caddisflies can be seen in benthic habitats, both cool and warm, in temperate rivers, lakes, marshes, and ponds. They can bear with low oxygen concentrations.

Each species of caddisfly contains larvae that are successfully adapted to specific water speeds and temperatures, mineral and pollutant concentrations, and sun exposure.

Adult caddisflies are terrestrial and they are predisposed to be most active at night, hiding in cool, moist habitats (like riparian vegetation) during daytime.

Caddisfly Diet and Feeding

The larval stage of caddisflies consists of highly diverse diets and feeding methodologies, covering a range of trophic levels and functional feeding flocks from filter feeders and predators.

Caddisfly Larvae are principally herbivorous scavengers, feeding primarily on living vegetation, fragments of plant substances, and other living and dead organisms.

Caddisflies can be characterized as gatherers, shredders, scrapers, and predators; feeding techniques may differ seasonally as the food supply alters throughout the year, or as the caddisfly larvae grow and get larger.

The larvae can graze on the seized food in the net. They may act as selective feeders, consuming the more nutritious foods.

Adult caddisflies also tend to feed on liquids, as they do not have well-developed mouthparts. They consume only plant fluids, such as nectar, or may not just feed at all

Caddisfly Mate

A Caddisfly is usually nocturnal (active during the night). Upon inception from the papal stage, adults are ready to mate. They may mate on nearby vegetation or on the ground and can also mate while in flight.

Mating practices may involve the use of chemicals to captivate females (known as pheromones), while males of other species collect in huge swarms and exhibit mating dances to bewitch females. Some may also throw across species-specific sounds to attract the other.

Sperm is transmitted directly from the male to the reproductive organs of the female. At the time of mating, the two partners may live together for only a few minutes, or for several hours. Both male and female caddisflies may mate multiple times with several different partners.

Most species have a life cycle that spans about 1 year. In colder climates, several bigger species may require more than a year to develop.

Caddisfly Life Cycle

Like all flies, they experience complete transformation, meaning that they cross four complete life stages i.e. the egg, larval, pupal, and adult stages. Let’s take a look through these 4 stages of caddisfly metamorphosis. 

1. Egg: 

Caddisflies mate during flight and one female lays up to several hundred eggs. Eggs are wrapped in a gelatinous mass on or near the water. The caddisfly larvae are aquatic in nature and have a sclerotized head, thorax, and full growth legs. They have a very soft body, which they encapsulate in a case made from silk that they cover in different materials such as sand, stone, or plant debris to render protection and camouflage from predators.

2. Larvae: 

Caddisfly larvae generally grow through 6-7 instars and as they materialize more material to the front of the protective casing. Upon hatching, the first instar of the larvae remains in the gelatinous mass for a certain span of time, after which they break out of the matrix and starts building a case or silk net. When climatic conditions are favorable, the larvae continue to develop through instars. However, When conditions are not preferable, the development process is delayed until it gets better.

During winters, larvae living in shallow water may be encapsulated embedded in ice, occasionally for a period of up to 6 months, bearing temperatures as low as -10dC.

The fifth instar of larval development lasts the longest. In this stage, the larvae do the most feeding in order to prepare to pupate.

During the final instar, the larvae grow a pupal case, either by sealing off their existing case or building a new one.

3. Pupae: 

Pupation occurs underwater within the larval case or in a pupal case. composed of silk.  After concealing the case, the final instar of the caddisfly larvae gets shorter, stiff, and wider, while lacking flexibility in the head and abdomen. The pupal stage generally lasts about 2 to 3 weeks, and the process occurs underwater but some species may overwinter as pupae.

When the pupae have grown into an adult and are ready to spring up from the case, it uses specialized appendages, referred to as mandibles, to chew its way out of the case and swim to the water surface.

4. Adults: 

Nearly all of the caddisflies' life cycle is spent in the larval stage and the adults are usually short-lived. The lifespan depends on the species and other environmental factors

Lifespan of a Caddisfly

An adult caddisfly is not a long-lived insect and thus does not live very long. The nymphs of caddisfly house live underwater for up to 2 years, but the winged adults only live for some weeks to months at maximum. The adults do not have developed mouthparts and are only capable of sipping liquids for their food, such as nectar.  Their main motive is to reproduce.

Some species of caddisflies utilize the silk from their body in order to create nets.  These nets step out from their cases into the moving water. The water flow gathers food particles into the net, which gets grasped and are eaten.