I am writing this article with all the excitement of our first few weeks of successful lake dipping at the National Botanic Garden of Wales.
We have found some weird and wonderful creatures in abundance, many of which can only be found in places with excellent water quality. One of these creatures is even a record-breaking find!
The water stick insect (Ranatra linearis) is the largest water insect in Europe, measuring 4cm along its body or, including its rear-end breathing tube, 7cm. It preys on tadpoles and small fish in ponds and in lakes with good vegetation.
As you’d expect from a stick insect, its main strategy for avoiding predation is to tuck its legs in and remain rigid, camouflaging itself to appear as an old piece of reed. Though it may seem unassuming, this is our record-breaking find.
Water stick insects are mostly found in and around the central part of the UK. This sighting is one of the farthest west a water stick insect has been recorded since the 1970s.
Since 1970, more than 50 per cent of freshwater and wetland species have declined in number, with 132 species now categorised as threatened. This is a result of water pollution (e.g. leached fertilisers from farming) damaging the quality of these habitats.
Water stick insects rely on good-quality water because their prey, small fish and tadpoles, cannot tolerate high levels of pollution. This is why it is critical that leaders in conservation, like our National Botanic Garden, have areas like their lakes and ensure they are wildlife-friendly places.
The presence of these creatures can be used as an indication of clean water and a healthy ecosystem, in which we found some other fascinating creatures.
The three-spined stickleback is a fish that prefers slow-flowing water with plenty of vegetation. It can live in freshwater, brackish water or saltwater. It hunts tadpoles and small fish and is a key part in the diet of herons and kingfishers. It has the ability to raise its dorsal spines when threatened, making it uncomfortable for predators to have in their mouths.
A few of our lake dippers caught a juvenile newt. This prompted an interesting discussion – in the picture you will notice the newt has feathery gills on either side of its head. On maturation in late summer, newts lose these gills in favour of breathing air through their lungs and with some oxygen exchange through their moist skin too.
In abundance, we’ve found water scorpions – not actually a type of scorpion, this leaf-shaped insect hides in underwater plants and grabs passing insects, tadpoles and small fish with its pincer-like front legs. Like the water stick insect, it has a long tail that acts as a breathing tube, like a snorkel.
Here is a list of other species we found present in the lakes: water hoglouse, flatworm, freshwater shrimp, damselfly nymph, mayfly nymph, leech, midge larva, caddisfly larva, pond snail, ramshorn snail, pond skater, greater water boatman, lesser water boatman, diving beetle, whirligig beetle.
Tara Crank
Family Engagement officer at Tadorna
Look out for more brilliant Wildlife Hub activities run by our friends at Tadorna Tours. These include a Winter Bird Walk on Saturday 25 September and half-term activities, from October 23-31. If you know a budding bird-watcher (6-16 years old), why not sign up for our Young Birders’ Day on Sunday, September 26. For more info, visit https://tadornatours.co.uk/wildlifehubevents/