* The author is part of the community of readers of La Vanguardia
I have been able to photograph in detail for The Readers’ Photos of La Vanguardia in Altet, in the Urgell region, the blue damselfly (Calopterix virgo), also known as the blue damsel (in Catalan it is also called cavallfust or cavall de serp).
The blue damselfish lives mainly nearby in small and medium-sized streams of water. In this case, I have photographed it in the trail.
They are a little (or quite) selective, since they prefer water with a low temperature and a moderate or fast flow. Additionally, the water should not be rich in nutrients. And even better if they are close to forests.
The curious thing about them being so capricious when it comes to choosing the watercourse where they live is that they end up being, for human beings, good bioindicators of water quality.
Their larvae are much more sensitive to lack of oxygen than the larvae of other zygopterans, which is why they need a sufficient amount of oxygen in the water. And, when it comes to reproducing and laying eggs, they look for cool, shady waters with a more or less strong current with vegetation.
They rest from their flight in trees and bushes, but also stop on top of herbaceous plants such as the large nettle. The males are territorial, they chase other insects, but they always end up returning to the place where they were. Females live far from water, except when they must lay eggs or look for a male.
