common darter (Sympetrum striolatum) 
Mixed size nymphs
The common darter is a widespread and familiar species of dragonfly native to the UK. Found around ponds, lakes, slow-flowing rivers, and garden water features, it is active from late spring through autumn. Adults are small to medium-sized, with males displaying a bright red abdomen and females typically yellow-brown. They are agile fliers and often seen basking on sunlit stones or perched on vegetation. The larvae (nymphs) live underwater and are important predators of small aquatic invertebrates. As both larvae and adults, common darters play a valuable role in pond ecosystems by helping control insect populations.