In the territory of the Wigry National Park there are 61 protected invertebrate species accounted for. Most of those species are insects Insecta –
dragon-flies, butterflies and hymenopterans, remaining species are molluscs and leeches.
The Park boasts having 40 dragon-fly species (which is over 55% of all the Polish dragon-fly fauna) 4 species of which are legally protected. Those species
are: green club-tailed dragonfly Ophiogomphus cecilia, Eastern white-faced darter Leucorrhinia albifrons, large white-faced darter L. pectoralis, green hawker Aeshna viridis. Except for the latter, all those dragon-flies can be seen in the vicinity of the Park’s water
bodies, in particular the distrophic lakes. The incidence of the green hawker, observed around the Wigry Lake in 1921 has not yet been confirmed and it is
justifiable to deem it extinct in this area.
Coleopterons are the most numerous group of insects. In Poland there are over 6 thousand species, only 300 of them have been observed in the territory of
WNP (about 5% of the domestic coleopteron population). In the Park there are 15 protected species – 10 species of Carabidae, two species of Lucanidae, and one of Dytiscidae, one of Scarabaeidae, and one of Cerambycidae.
The ground beetle
Among Carabidae there are two protected genera in this country: Calosoma, and Carabus. All of the two genera’s species are predatory
insects and belong within the most useful coleopterons in the forest biocoenosis. In the WNP the following Carabus representatives to be observed:Carabus arcensis, C. granulatus, C. coriaceus, C. violaceus, C. nitens, C. menetriesi, C. cancellatus, C. nemoralis, C. hortensis, and C. glabratus.
They all account for about 10 % of all Carabidae species to be seen in the Wigry National Park.
The remaining protected coleopterons from the Park are: the stag beetle (Lucanus cervus), and Dorcus paralellopipedus, Graphoderus bilineatus, Trichius fasciatus, and the Capricorn beetle (Cerambyx cerdo). Both the stag beetle and the Capricorn beetle
are the so-called physiological-technical pests of certain tree species, though owing to their scarcity they have little economic impact. Because those
species are extremely endangered they have been enlisted in the Polish Red Book of Animals.
The Baltic grayling
There are over three thousand butterfly species in the territory of Poland, 220 (7%) of which have been observed in the Park. Of this high number only 34
ones are strictly protected in this country. In the Park there are 7 protected butterflies: the large copper butterfly Lycaena dispar, the violet
copper butterfly Lycaena helle, the bog fritillary Boloria eunomia, the scarce fritillary Euphydryas maturna, the scarce swallowtailIphiclides podalirius, the moorland clouded yellow Colias palaeno, and the Baltic grayling Oeneis jutta. All of those species, except the bog fritillary are enlisted in theList of Dying Out and Endangered Animals in Poland; moreover the scarce swallowtail and the Baltic grayling have also found their place in the Polish Red Book of Animals, and have been indicated as extremely endangered.
The Schrenck’s bumblebee
It is estimated that in this country there are over 8 thousand species of group of insects. In the territory of the WNP there are only about 300 species,
which is less than 4% of the domestic fauna. The hymenopterans have only one species protected – the bumblebee Bombus belonging in the family Apoidea. In Poland there are officially 30 bumblebee species, 24 of which can be seen in the WNP’s territory. Those are: the broken belted bumblebee Bombus soroeensis, the red-tailed bumblebee B. confusus, B. semenoviellus, the buff-tailed bumblebee B. terrestris, the
white-tailed bumblebee B. lucorum, B. cryptarum, B. magnus, B. hypnorum, the heath bumblebee (B. jonellus), the early
bumblebee (B. pratorum), the stone bumblebee B. lapidarius, the garden bumblebee B. hortorum, the knapweed carder bee B. ruderatus, the brown carder bumblebee B. humilis, B. maculidorsis, the large carder bee B. muscorum, the common carder beeB. pascuorum, the red-shanked carder bee B. ruderarius, the Schrenk’s bumblebee B. schrencki, the shrill carder bee B. sylvarum, B. veteranus, the
great yellow bumblebee B. distinguendus, the short-haired bumblebee B. subterraneus and the apple bumblebee B. pomorum.
The heath bumblebee
One of the bumblebees – namely, heath bumblebee, has been included
in the Polish Red Book of Animals, and other 10 species in the Red List of Dying Out and Endangered Animals in Poland.
The protection of all the bumblebee species have been started due to their significant impact they have in the natural environment and a high degree of
endangerment. The main reasons for the existing threat are agricultural chemicalization, air pollution, and disappearance of tree stands and gravel banks
from the agricultural developed areas.
The edible snail
In Poland there are over 270 mollusc species officially, 60 of which are legally protected. In the Wigry National Park 55 species (20% of the domestic
mollusc fauna) have been recently confirmed, including 210 strictly protected species. Those are: the edible snail Helix pomatia, the whorl snail Vertigo moulinsiana, three species
from the family Sphaeriidae - the European fingernail clam Sphaerium corneum, the ubiquitous peaclam Pisidium casertanum, the
short-ended pea mussel Pisidium subtruncatum, the freshwater mussel Unio pictorum, the thick shelled river mussel Unio crassus, the
swollen river mussel Unio tumidus, the swan mussel Anodonta cygnea, the compressed river mussel Anodonta complanata.
The swan mussel
As far as the edible snail is concerned the strict protection is only applied to individuals whose shell’s size does not exceed 30 mm, bigger individuals
are subject to partial protection. Except for the edible snail, the Sphaeriidae and the swollen river mussel, all the other mollusc species are
included in the Red List of Dying Out and Endangered Animals in Poland.
It is not a very numerous animal group consisting of 27 species in Poland, which is about 70% of all the leech fauna in Europe. Up until now in the
territory of the WNP 13 leech species have been confirmed. In this country only one leech species – the medicinal leech Hirudo medicinalis is
subject to legal protection, to be also found in the territory of the Park. The medicinal leech has been included in the Red List of Dying Out and Endangered Animals in Poland, and indicated as extremely endangered from the worldwide standpoint.