The yearly Swedish entomology meeting 2017 was organized by the local entomology

society of Gotland, on the northern part of the Baltic island Gotland near Bunge, 4-6 August.

One thematic excursion was focused on aquatic insects, especiallly aquatic beetles,

bugs and dragonflies. A shallow pond, Äskåkersvät, with Characeae in an open grazed

landscape with high natural values was studied. Äskåkersvät lies just adjacent to the larger

area around lake Bästeträsk which is the focus of a pilot study evaluating its potential as

a future national park. The pilot study is undertaken by Gotland County Administrative

Board, the Swedish Environmental Protection Agency, Region Gotland and the Swedish

Agency for Marine and Water Management. Here we give an annotated report of the 103

species found: 69 species of water beetles (out of which 34 were Dytiscidae), 20 species

of aquatic or semiaquatic bugs (out of which 10 were Corixidae), and 14 species of dragonflies.

These include Hydrophilus piceus and H. aterrimus redlisted in Sweden (both as

NT), and Dytiscus latissimus, globally redlisted (VU). We also noted the noble crayfish,

Astacus astacus (redlisted as CR in Sweden) and the European medicinal leech Hirudo

medicinalis (redlisted as NT globally). The blue emperor dragonfly (Anax imperator) was

noted, a species first recorded from Gotland in 2002 and we present a graph on its increase

and spreading on the island since. The number of species found in spite of a relatively

modest collecting effort at a suboptimal time when many species may be in pupal stage out

of water as witnessed by many teneral individuals, indicates a species rich locality with

high natural value. The stoneworts (Characeae) vegetation certainly contributes to this, for

instance vouched for by the occurrence of specialists as Haliplus confinis and H. obliquus

whose larvae feed on stoneworts.