Nettlecombe 2007

Caddis fly larvae in freshwater use silk to build protective cases from gravel, twigs, needles, or sand. Different species build distinct cases, but they often lose them when removed from a stream. Caddis flies are invertebrates that emerge to mate as winged adults. Caddis fly larvae make a living in a variety of ways: some capture food in nets, others scrape algae or shred leaf litter. Free-living caddis fly larvae do not build cases; many are predators and need to move quickly to capture other animals for food. Some caddis flies are very sensitive to human disturbance; others are more tolerant.

This one just wasn't quick enough. 

Stonefly nymphs are typically found on or near stones in slow-flowing water in streams. They are rather primitive and are thought to have been among the first insects to develop flight. Adult males and females emerge from the water to mate and locate each other by drumming with their abdomens. Stoneflies move like turtles. Many are predators, hiding and stalking their prey between stones and cobble. Stoneflies look similar to mayflies but are stockier.  

The weather was getting chilly as we searched for grubs and all this talk of food was making some of us hungry

and so the long trek back to base camp began.

What had started as a lovely sunny day was fast becoming a cold, grey afternoon on Exmoor.