New records of phoretic associations between pseudoscorpions and their hosts in Slovakia (Pseudoscorpiones: Atemnidae, Chernetidae)

Abstract. New cases of phoresy of pseudoscorpions (Pseudoscorpiones: Atemnidae, Chernetidae) are recorded from Slovakia. The phoresy of the species Atemnus politus (Simon, 1878) involving owlet moth (Noctuidae) as a host is documented for the first time not only in Slovakia, but also worldwide. One phoretic female of Lamprochernes chyzeri (Tömösváry, 1883) was attached to the leg of a lance fly (Lonchaeidae). It represents the second known phoresy of the species from Slovakia and the record of a new host.

Phoresy is a non-permanent interaction in which one organism (a phoront) attaches itself to another (the host). Pseudoscorpions attach themselves to mobile animals and subsequently disperse into new habitats (White et al. 2017). Species hide under the elytra, among the feathers or fur or they grasp the extremities, sternites, or other body parts of the hosts (e.g. Jones 1978, Zeh & Zeh 1992, Carl 1994). There exist two hypotheses about the evolution of pseudoscorpion phoresy (summarized in Zeh & Zeh 1992). Some authors regard pseudoscorpion phoresy as a behaviour primarily aimed at dispersal (the dispersal hypothesis; e.g. Beier 1948, Weygoldt 1969, Legg 1975. Others argue that the phoresy is the accidental by-product of unsuccessful predation (the predation hypothesis; e.g. Vachon 1940, 1953, Muchmore 1971. In Europe, the most common phoretic associations are between pseudoscorpions and insects and are mostly known from the families Chernetidae and Cheliferidae (Poinar et al. 1998).
In Slovakia, several phoretic associations were recorded. Mašán & Krištofík (1992) collected two males of Lampro chernes nodosus (Schrank, 1803) on two species of Diptera using the traps baited with decaying meat or faeces. A male of Lamprochernes chyzeri (Tömösváry, 1883) was attached to Diptera (Christophoryová et al. 2011b) and a female of Rha cochelifer euboicus Mahnert, 1977 was found in a Malaise trap phoretic on Lepidoptera , Hernández-Corral et al. 2018. Christophoryová et al. (2017) recorded several phoretic associations of females of Allochernes pere grinus Lohmander, 1939 and Lamprochernes sp. on Diptera. Multiple phoresies of L. nodosus on Diptera were documented from Slovakia by Christophoryová et al. (2018); one to five females were attached to the hosts. The latest cases of phoresy by chernetids were evidenced by Červená et al. (2019). Pseudoscorpion phoresy involving Heteroptera as a host was recorded for the first time in Slovakia (a female of L. nodosus), as well as a case of phoresy by the species Pselaphochernes scor pioides (Hermann, 1804) (Červená et al. 2019).
Summarizing all above-mentioned published data, five pseudoscorpion species are known to be phoretic on Diptera, Heteroptera and Lepidoptera in Slovakia. In the present study, three new records of phoretic associations between pseudoscorpions and their hosts from Slovakia are documented.

Material and methods
Pseudoscorpions and their hosts were collected using Malaise traps at the locality of Virt in Slovakia (leg. J. Kodada, S. Krčmárik, D. Selnekovič). All pseudoscorpions were studied as temporary slide mounts using lactic acid and then rinsed in the water and returned to 70% alcohol. The pseudoscorpion specimens were identified using the key in Christophoryová et al. (2011a). Hosts were identified only to genus level by specialists as mentioned in the Results part. Digital photographs were taken using a Canon EOS 5D Mark II camera attached to a Zeiss Axio Zoom V16 stereomicroscope. Im age stacks were produced manually, combined using the Zerene Stacker software and subsequently edited in Adobe Photoshop CC. The material is deposited in the zoological collection at the Department of Zoology, Comenius University in Bratislava.  1 ( and 1 ) of Atemnus politus on Ta I and Ta II of owlet moth (Lepidoptera, Noctuidae, Euxoa; det. J. Šumpich; Fig. 3).

Discussion
To the best of our knowledge, the phoresy of Atemnus politus is documented here for the first time not only in Slovakia but worldwide. Records of pseudoscorpions on moths are exceedingly rare, and this applies also to atemnids. Only Beier (1930) recorded adults of Diplotemnus balcanicus (Redikorzev, 1928) taken from moths attracted to light in Algeria [as Atemnus piger (Simon, 1878)]. For atemnids, the majority of phoresies are known on hosts from Coleoptera, Hemiptera or Hymenoptera (e.g. Beier 1932, 1948, Muchmore 1971, 1972, Aguiar & Bührnheim 1998, Poinar et al. 1998. A phoresy of a male of Lamprochernes chyzeri was observed in Slovakia on Diptera, Muscidae (Christophoryová et al. 2011b). From Europe, only a few phoresy cases of this species were recorded. Vachon (1954) found the species attached to Lepidoptera and Meinertz (1964) on Diptera, Muscidae. Jones (1978) published an attachment to Diptera, Lonchaeidae. Legg & Jones (1988) mentioned that the species is phoretic on flies and Drogla & Lippold (2004) recorded seven phoretic specimens without specific hosts.