Caddisflies

Caddisflies

In the Order of Trichoptera the caddisfly, of which there are approximately 7000 species, starts life in freshwater habitats and then emerge as an adult.

Caddisfly eggs

The name Trichoptera, derived from the Greek words “trichos” meaning hair and “ptera” meaning wings, refers to the long, silky hairs that cover most of the body and wings.

Caddisflies are moth-like insects with two pairs of hairy wings that are folded roof-like over the abdomen at rest. Antennae are long and many jointed with a large basal segment. Large compound eyes are present. [efn_note] Encyclopedia Britannica [/efn_note]

Life cycle

Eggs numbering around 800 at a time are laid in jelly that swells on contact with water. After a few days the larvae hatch. Depending on the species of caddisfly they may be herbivorous, carnivorous, or a bit of both (omnivorous). 

In this larval stage the young caddisfly will protect itself in many different ways depending on the species. Some will spin protective silky webs around themselves. Some will use that silk to make a web to catch food and some will use it to attach debris to themselves to form a protective layer and camouflage from potential predators (see attached video).

Adult caddisflies

The larvae are important to the aquatic community by controlling plant growth and animal and plant waste. The adult caddisflies are unable to eat solids so imbibe nectar from plants instead. 

Parasitic wasps are known to seek it’s host underwater and lay eggs inside the protective case of the caddisfly. The egg hatches and the larval wasp devours the caddisfly larvae.

When the adults emerge, they behave much like moths, they are strongly attracted to light and can be found swarming around objects on the river banks or shore line.

Hopefully you get to see some of these amazing insets when you go pond dipping or moth trapping.

Tom  

The Ancient Order of Mayflies

Mayfly – unlike its name suggests the Mayfly emerges between spring and autumn and live, on average, 1 day as a full adult. 

Ephemera sp. drying on Equisetum arvense

The Mayfly is part of an ancient order of insects known as Palaeoptera which translates to “Ancient Wings” (from the Latin paleo meaning “old” or “ancient” and Opera meaning “wings”). This order of insects also includes dragonflies and damselflies.

There are over 3000 species of mayfly around the world and they are grouped into 42 families (400 genera). 

As part of this ancient order, mayflies, exhibit some ancestral traits with its long tail and wings that fold back and not over the abdomen like so many other winged insects. 

Life cycle

The Mayfly starts life in water after the female drops between 400 and 1000 eggs onto the surface of the water. Incubation can last anything from a few days to a year. They hatch into larvae and moult as they grow anywhere from 10 to 50 times, as this is dependant on water temperature.

Depending on conditions mayflies can stay as larvae from anything between a few months to several years. They then emerge as adults usually all together when the light (usually at dusk or dawn) and conditions are right. This mass emergence is thought to be a strategy to minimise the chances of being eaten.

Once they become adults, or sub adults, the Mayfly is unique in the fact that it moults one more time to become a fully developed adult. Its surprising that after spending so long under water in the larvae stage they would spend so little time as an adult. Some species are adults for less than five minutes (Dolania americana) and some a couple of days.

Pliny the Elder

The Ancient Roman encyclopaedist Pliny the Elder described the mayfly as the “hemerobius” (from the Greek word hēmerobios meaning living for a day), in his Natural History:

“The River Bug on the Black Sea at midsummer brings down some thin membranes that look like berries out of which burst a four-legged caterpillar in the manner of the creature mentioned above, but it does not live beyond one day, owing to which it is called the hemerobius.”

Pliny the Elder

Mayfly larvae have been chosen by scientists as bio-indicators because they do not tolerate polluted water. Their presence meaning the water is

Mayflies are consumed in several cultures and are estimated to contain the most raw protein content of any edible insect by dry weight. In Malawi, kungu, a paste of mayflies (Caenis kungu) and mosquitoes is made into a cake for eating.

Enjoy

Tom