Micaria lenzi and Clubiona juvenis (Araneae: Gnaphosidae, Clubionidae), two spider species new to the dune fauna of Finland

During the last ten years, the two rare spider species Micaria lenzi Bösenberg, 1899 (Gnaphosidae) and Clubiona juvenis Simon, 1878 (Clubionidae) have been found on coastal sand dunes and inland dunes near the coast in Finland. The findings are the northernmost ones in Europe, extending the known range of M. lenzi from southernmost Sweden northwards by almost 1000 kilometers

The synatropic Oecobius navus (Araneae: Oecobiidae) established indoors in southern Finland

Oecobius navus Blackwall has since 2003 been found in basements in Helsinki and other places in southern Finland. This tiny cosmopolitan spider species or any other member of its family hasn’t previously been recorded in Finland or Fennoscandia

A note on multispecies aggregative webs due to spiders (Araneae) escaping floods in Finland

Multispecies aggregative spider webs consisting mainly of linyphiids are reported from the municipality of Vörå in Finland. The dominant species were Erigone atra Blackwall, 1833 and Savignia frontata Blackwall, 1833 and most of these represented by males. The spider assemblage consisted of at least 13 species altogether. The reason for the aggregations was habitat disturbance caused by flooded cultivated fields

The cave spider Meta menardi (Araneae, Tetragnathidae) – occurrence in Finland and notes on its biology

Fifteen years ago the cave spider Meta menardi (Latreille, 1804) was known in Finland in two locations only. Partly due to extensive search it is to date known from 20 sites, all however located in the south-westernmost parts of the country. M. menardi is known to prefer stable and relatively warm subterranean habitats. Our temperature data from a cave on the Åland Islands in Finland indicates that the populations of M. menardi on the northern limit of its distribution could be more cold tolerant than the previously studied populations in Central Europe. In this paper all known locations in Finland are mapped and presented in a table with habitat data. A note on the strategy for catching mosquitoes with the orb web is given and the possible importance of the prey-catching function of the orb web is briefly discussed

On the distribution of Hyptiotes paradoxus (Araneae: Uloboridae) in Estonia and Finland

In Estonia the spider Hyptiotes paradoxus has hitherto only been found in Saaremaa and no individuals have been found since 1934. In this paper several new findings in Saaremaa and the first finding on mainland Estonia is reported. The first finding of this species in Finland was on the Åland Islands in 2001. Four new localities on the Åland Island are reported on here

Mangora acalypha new to Finland, with notes on other araneid species spreading northwards (Araneae, Araneidae)

Two specimens of Mangora acalypha (Walckenaer, 1802) were found in a rich pine fen in Hammarland on the Åland Islands in 2015. The possible connection of global climate change with five recently (within the last 15 years) recorded araneid species as new to Finland is discussed. These are, in addition to M. acalypha, Agalenatea redii (Scopoli, 1763), Argiope bruennichi (Scopoli, 1772), Larinioides sclopetarius (Clerck, 1757), Neoscona adianta (Walckenaer, 1802)

Increased number of observations and notes of offspring production in the invasive orb-web spider Argiope bruennichi (Scopoli, 1772) (Araneae; Araneidae) in Finland

Prior to 2005, the orb-web spider Argiope bruennichi (Scopoli, 1772) was unknown in the Finnish spider fauna. In 2005–2010, four specimens in three localities were found by laymen. In 2011, 13 specimens were observed in various parts of southern Finland. The sample sites are separated by long distances suggesting that A .bruennichi specimens are spread by anemochory, i.e. by ballooning. All the individuals were females. Two cocoons (egg sacks) constructed by one of the two females reared in captivity and one cocoon constructed outdoors by another female yielded live offspring. Whether young A. bruennichi passed the winter in cocoons in Finland or arrived from abroad in spring 2011 prior to reaching maturity during summer of the same year is unknown. Here we compile the records of A. bruennichi gathered in Finland in 2005–2011. We document the arrival and reproduction of this alien spider at the northernmost edge of its range and discuss its dispersal in Northwest Europe and factors related to the establishment of permanent populations in general

Pholcus phalangioides in Finland (Araneae, Pholcidae)

The geographical range of the synanthropic spider Pholcus phalangioides is increasing. During the 15 years since its first documented occurrence in Finland, observations have accumulated substantially. Notably, a public inquiry in 2014 almost doubled the amount. Presently the total number of observations is 62, most of them from the southwestern parts of the country, the northernmost being from Pietarsaari (63°40’ N)

Platybunus pinetorum (Arachnida, Opiliones) new to Sweden

In 2013 and 2015 several specimens of the opilionid Platybunus pinetorum (C.L. Koch, 1839) were found in Sweden in two different places almost 500 kilometers from each other. The species was not previously known in the country. The discovery initiated a survey of specimens reported as Rilaena triangularis (Herbst, 1799) on two Swedish web pages, in search for misidentified P. pinetorum. A further three specimens of the new species were found, indicating that it is already rather widespread in southern Sweden