The beginning of interest in the terrestrial fauna of Polish caves dates back to the first years of the 20^th century when Kazimierz Demel conducted his pioneer research in 1914. Unfortunately, the First World War prevented him from processing and issuing the results, which were actually published in 1918. Demel presented the fauna inhabiting eight caves of the Ojców area (southern part of Kraków-Częstochowa Upland), i.e. Jaskinia Koziarnia, Jaskinia Pustelnia, Jaskinia Biała, Jaskinia Złodziejska, Jaskinia Zbójecka, Jaskinia Łokietka, Jaskinia Ciemna and Jaskinia Jerzmanowska. Despite the period devoted to the research being relatively short (two and a half months), Demel collected a vast number of invertebrates, and in the presented results listed 30 species of invertebrates, 11 of which were described as cave forms, although they could be observed outside of caves (contemporarily named as troglophiles). In his works, Demel compared his results to the ones already presented by the cave fauna researchers from Germany, Belgium, France and Austria, giving attention to faunal similarities with other caves. In the papers of the above-mentioned author, one can find both: a list of species and data concerning cave environment observations, i.e. temperature, humidity, light coverage and access to degrading organic matter, which enabled the author to perform ecological analyses.

Based on the material compiled by Demel, Stach (1919) proved the presence of five species of springtails, including description of one species new to science, i.e. Mesachorutes ojcovensis. The author also compared the Polish springtail fauna to that of other European countries and confirmed Demel’s assumptions that troglobionts are scarce in Polish caves. Furthermore, the data concerning springtail species found in Polish caves were summarised by Stach (1947–1963).

In the 1920s, Arndt (1921, 1923) published two papers based on his research in a few caves and mines (e.g. Złota Sztolnia) in Sudety Mountains. Nowadays most of these mines are located in the Czech Republic, while others, i.e. Niedźwiedzia Jama or Solna Jama, in Poland. Despite the research was conducted only from March to October 1920, Arndt proved the presence of 42 invertebrate species (including stygobiotic ones) and recognised the Schaefferia emucronata springtail as a troglobiont species. He noticed that the fauna of the Sudety Mountains lacks the species typical to the caves of Harz Mountains, Central Alps and Urals, i.e. blind beetles (Coleoptera), Orthoptera and Acari. In the second paper, Arndt (1923) supplemented the information on ecological groups and faunal genesis in the examined subterranean sites.

Other papers devoted to the cave-dwelling fauna of the Sudety Mountains were published by Pax and Maschke (1935) and Pax (1937). The object of the research was both terrestrial and aquatic fauna in the Rogóżka Cave. The research, which began in 1933, was focused not only on the cave fauna but also on the environmental conditions, i.e. the physical and chemical properties of the lake water, and the air temperature. Nowadays the Rogóżka Cave is the non-existed cave, in 1962 it was partly destroyed by mining in the crystalline limestones quarry, and next the entrance was covered by stones (Bieroński et al. 2009).

The Second World War delayed the faunal research in Polish caves for a few years. The first post-war researcher who was interested in cave-dwelling invertebrate fauna was Kazimierz Kowalski, who presented the results of his biological observations and the research project on the Tatra Mountains caves for the years 1951–1952 in the “Wierchy” annual. In 1955, he published a paper with the results of the above-mentioned research. During his research, he visited all known Tatra caves, but his main research interest was in six caves, i.e. Jaskinia Dziura Wyżnia, Jaskinia Zimna, Jaskinia Groby, Jaskinia Magurska, Jaskinia Lodowa and Jaskinia Dziura. His methodology included not only the faunal collection by means of Barber traps or direct search methods, but also microclimate analyses, i.e. light influence and air movement. Kowalski did not limit his research to the invertebrate fauna, as it included also bats. In his work, the characteristics of the research area and detailed descriptions of microclimate conditions can be found.

In the following decades, i.e. in the 60s and 70s of the 20^th century, Skalski presented exceptional research activity in the field of cave-dwelling fauna. He published his first work together with Wójcik (Skalski and Wójcik 1968), where they presented faunal genesis and microclimate characteristics of selected caves of the Częstochowa area. They proved the presence of six troglobiont species i.e. Mesachorutes ojcoviensis, Catops tristis infernus, Choleva lederiana gracilenta, Porrhomma egeria, Arrhopalites pygmeus, Onychiurus alborufescens and also determined the geographical distribution of these species.

The subsequent works by Skalski (1967, 1969) were dedicated to invertebrate fauna in the Tatra Mountains. In addition to the presented list of species, he also considered the relationship between the age of the cave and the number of troglobionts as an important factor influencing the species variety. Furthermore, he presented detailed information about the occurrence of Onychiurus armatus springtails in the Mylna and Czarna caves, Hypena obsitalis butterflies in the Mylna cave and Exephanes ischioxanthus hymenoptera in Szczelina Chochołowska.

In 1973, Skalski published an extensive paper on the research and observations conducted in the years 1957–1970 in 19 caves of the Częstochowa Upland. Using a wide range of entomological methods (Barber traps, Tullgren funnels, entomological sieves and direct searches), he detected 83 species belonging to a few arthropod and molluscan orders. He extensively discussed ecological issues, also concerning trogloxenes, for example he paid special attention to describing the associations of arthropods living or resting on cave walls. The paper includes valuable data on reproduction, position and spread of individual species in the caves like characteristics of massive occurrence of Choleva lederiana gracilenta if there is high availability of food.

Apart from the above mentioned research published in the form of papers, presentations at Speleological Conferences, which have been taking place since 1965, give an update on the invertebrate cave fauna research. The first information can be found in the materials form 3^rd/4^th Speleological Conference (1971), where Skalski (1971) presented overview of terrestrial and aquatic fauna, named all the known species and compared the knowledge from various Polish cave regions.

In his subsequent paper, Skalski (1981) focused on known data of invertebrate fauna again. However, he put particular emphasis on dominant groups and tried to determine the reasons for underground sites colonisation. He emphasised the primary dominance of not only insects and springtails in the caves but also spiders, and analysed the conditions favourable to cave organisms, i.e. food accessibility and cave habitat as a shelter for fauna during the winter.

In 1975, Baranek and Powichrowski published an article about the cave fauna in Dolina Wodącej. Three caves of the valley, Jaskinia Źródlana (Psia), Jasknia Zegarowa and Jaskinia Mroczna, were discussed in the paper. The authors observed the associations of arthropods trogloxenes like numerous fly community, spiders (particularly Meta sp.) and other arachnids on the cave walls. Springtails and beetles of families Staphylinidae and Catopidae (Leiodidae) were recognised among the regular cave-dwelling species. The only troglobiont species recorded was Porhomma moravicum (currently P. egeria), which was observed in Jaskinia Mroczna.

Sanocka-Wołoszynowa (1981) on Kraków – Częstochowa Upland arachnids study added great value to the state of knowledge of invertebrate fauna exploration. The author examined 184 caves and shelters; 40 of them were examined in all four seasons. Samples were collected by means of Barber traps or direct search. As a result, 13000 specimens representing 186 species of spiders, arachnids and pseudoscorpions were collected. Two species of spiders recorded deserve special attention: troglobiontic Porhomma egeria (in the paper P. moravicum) and troglophilic Meta menardi. Among arachnids also harvestman Ischyropsalis helwigii, known earlier from the Sudety Mountains area, the observation of which in Kraków – Częstochowa Upland widened the range of its occurrence. The author in addition to the detailed list of species, carried out an ecological and zoocoenological analysis, for example, she distinguished communities of arachnids living in the litter, associations of wall arachnids and a deep-cave group of species with dominant species Porrhomma egeria.

At the 15^th Speleological Conference, Sobiepanek (1985) described the results of the research conducted during Tatra Mountains caves inventory. During the research, the samples were collected by direct search or by means of Barber traps. As a result, many taxa belonging to dipterans, beetles, trichopterans, millipedes, spiders, gastropods, springtails and earthworms were observed. During the 30^th Speleological Conference, Gubała (1996) presented his paper about the results of an inventory of 131 caves and shelters in świętokrzyskie region.

The end of the 20^th century provided new data to particular systematic groups. Pomorski (1992) focused on the springtail fauna in the Sudety Mountains caves and mines. In his study, Pomorski detected 34 species, seven of which were classified as troglobionts i.e. Bonetogastrura cavicola, Schaefferia emucronata, Oligaphorura schoetti, Onychiurus ambulans, Onychiurus cebennarius, Oncopodura reyersdorfensis, Arrhopalites bifidus and 10 as troglophiles. Skalski (1994) noted the successful introduction of Speonomus hydrophilus to Jaskinia Dzwonnica in Wyżyna Częstochowska.

Further papers were published after the year 2000. The studies by Maślak and Barczyk (2011) and Barczyk and Madej (2014) were devoted to cave mites. The first article refers to Oribatida dwelling in five Jurassic caves, i.e. Jaskinia Nietoperzowa, Jaskinia Wierna, Jaskinia Studnisko, Jaskinia Błotna and Jaskinia Pod Porzeczką, and their immediate surroundings. The study presented an analysis of faunistic similarities between the species and caves. Altogether 65 Orbatida species, including one typically cave dwelling species, were recorded. It was proven that the faunal composition of larger caves significantly differs from smaller ones. Communities of small caves, such as Jaskinia Błotna, Jaskinia Pod Porzeczką were similar to soil fauna communities. The species composition was mainly influenced by the accessibility of particular food sources (leaves, guano, wood) (Maślak and Barczyk 2011). The second paper refers to eight caves of the Kraków – Częstochowa Upland (Jaskinia Lodowa, Jaskinia poniżej Lodowej, Jaskinia Pod Porzeczką, Jaskinia Studnisko, Jaskinia Pod Sokołą, Jaskinia Jasna, Jaskinia Błotna and Jaskinia Schronisko koło Jaskini Lodowej), where 316 samples were collected. There were 270 samples collected from the immediate surroundings of the caves. As a result, the author identified 106 species from 13 families, including four species new in Polish fauna i.e. Paragamasus arcuatus, Parasitus hortivagus, Pachylaelaps sublongisetis, Pachyglobolaelaps hallidayi and troglobiont species recognised earlier in other caves. Significant differences in species composition between Acari communities inhabiting caves and cave surroundings were described.

Among the contemporary studies devoted to invertebrate fauna, Dumnicka and Płotek (2013) discussed the differences in invertebrate fauna between the caves Jaskinia Towarna and Jaskinia Dzwonnica, with regards to microclimate conditions, organic matter content in the cave deposits and tourism intensity.

During the 49^th Speleological Conference, Kocot – Zalewska (2015) presented the preliminary results of the research on Jaskinia Kroczycka fauna. The presentation included general data however indicated seven orders: butterflies, dipterans, spiders, beetles, trichopterans, mites and springtails. At the next Speleological Conference, Kocot – Zalewska (2016) presented the results of the observation of Jaskinia Towarna colonisation by Speonomus normandi hydrophilus of Leiodidae family. The beetle was introduced in the caves in 1982 and its natural place of occurrence is Arize Massif in Pyrenees.

In a contemporary paper, Kur et al. (2016) characterised the fauna of Jaskinia Szeptunów (Szmaragdowa). Based on the samples collected in the years 2005, 2006, 2010, 2014, 2015, 5 species of springtails, 2 species of Myriapoda, 1 spider species, 2 species of butterflies and mites were observed. The cave was opened in 1990 and the colonisation rate by living organisms was monitored.

At the 51^st Speleological Conference, Kocot – Zalewska and Słupińska (2017) presented the discovery of a great population of Choleva lederiana gracilenta, which is endemic to Sokole Mountain caves, and presented detailed information about its quantity, sex ratio and cave positioning. During the same Speleological Conference, Dumnicka (2017) discussed the state of knowledge of invertebrate cave fauna of Polish Tatra Mountains based on literature data, mainly the works by Stach (1934, 1954) and Kowalski (1955).

Several short articles were devoted to interesting discoveries of invertebrate species found in caves (Dylewska and Błoszyk 2006, Kocot-Zalewska and Rozwałka 2018, Kasprzak 1973, Weiner 1990), however, several synthetic articles were also written, summarizing the state of knowledge and valorization of a valuable studied area (Błoszyk and Rozwałka 2008, Ochman 2004, Wołoszyn and Wójcik 1964).

Based on published literature, 593 species of terrestrial invertebrate are recorded in Polish caves.

Insects are represented by 146 species. Respectively: Coleoptera 50 species, Diptera 60 species, Hymenoptera 18 species, Lepidoptera 10 species, Trichoptera 4 species, Siphonaptera 3 species, Thysanoptera 1 species. Detailed list of recorded species is presented in Table 1.

Arachnids are the most often represented group of terrestrial invertebrate with 317 recorded species. Among the arachnids the mites (Acari) are represented by 189 species, spiders (Araneae) by 103 species. Remaining orders of Arachnids (Opiliones and Pseudoscorpionida) are represented by 20 and 5 species respectively. Detailed list of arachnids recorded in Polish caves is presented in Table 2.

The remaining Arthropoda groups are represented as follows: Collembola 79 species, Diplura 1 species, Chilopoda 1 species, Diplopoda 8 species, Symphyla 1 species, Isopoda 9 species. Among other invertebrates recorded in Polish caves 11 species are represented by Oligochaeta and 20 species by Mollusca. Detailed list of species is presented in Table 3.