Rod: Micaria

Arachnologický průzkum na Mostecku a Chomutovsku byl doposud soustředěn zejména na Krušné hory (BUCHAR a HAJER 1999, 2005, 2010. ROUŠAR 2011. RŮŽIČKA a HAJER 2002, 2003), jednotlivé sběry z okolí jsou také zahrnuty v katalogu pavouků ČR (BUCHAR a RŮŽIČKA 2002), na Chomutovsku je známo také několik publikovaných sběrů Antonína Roušara (ROUŠAR 2009, 2015, 2016). Přesto údaje o výskytu pavouků z mnoha lokalit scházejí. Proto od 1. do 4. června 2017 uspořádalo Oblastní muzeum v Mostě arachnologické exkurze do nejbližšího okolí Mostu a Chomutova, kterých se zúčastnili členové České arachnologické společnosti. Jako cílové byly zvoleny lokality, na kterých se systematicky pavoukovci dosud nesbírali, ale i lokality, které by vzhledem ke svým přírodním hodnotám mohly být v budoucnu zařazeny mezi zvláště chráněná území. Tento článek předkládá seznam všech druhů pavouků, kteří byli během akce zjištěni.

Results of the exploration of the araneofauna and the entomofauna in West Bohemian heathlands are presented. Spiders and carabid beetles were collected during the vegetation seasons in 2011 and 2012 by the method of pitfall trapping. In total, 3188 specimens of 171 Araneae species and 2168 specimens of 93 Carabid species were determined. The most frequent spiders were Xerolycosa nemoralis (Westring, 1861), a common forest species. The following identified species are listed among the endangered spiders in the Czech Republic in the category „endangered“: Alopecosa schmidti (Hahn, 1835), Micaria dives (Lucas, 1846),  Peponocranium orbiculatum (O. P.-Cambridge, 1882), in the category „vulnerable“: Centromerus incilium (L. Koch, 1881), Evansia merens O. P.-Cambridge, 1900, Metopobactrus prominulus (O. P.-Cambridge, 1872), Arctosa figurata (Simon, 1876), Arctosa lutetiana (Simon, 1876), Pardosa nigriceps (Thorell, 1872), Gnaphosa bicolor (Hahn, 1833), Xysticus striatipes L. Koch, 1870, Evarcha laetabunda (C. L. Koch, 1846) and Trichopterna cito (Blackwall, 1841). The most remarkable species of the Carabids were the Amara equestris equestris (Duftschmid, 1812), Amara pulpani Kult, 1949, Bradycellus ruficollis (Stephens, 1828), Carabus arcensis arcensis Herbst, 1784, Carabus problematicus harcyniae Sturm, 1815, Cymindis axillaris axillaris (Fabricius, 1794), Cymindis vaporariorum (Linné, 1758), Masoreus wetterhallii wetterhallii (Gyllenhal, 1813), Olisthopus rotundatus rotundatus (Paykull, 1790). Studied material was reposited at the Department of Zoology of the West Bohemian Museum in Pilsen.

Open interior sands represent a highly threatened habitat in Europe. In recent times, their associated organisms have often found secondary refuges outside their natural habitats, mainly in sand pits. We investigated the effects of different restoration approaches, i.e. spontaneous succession without additional disturbances, spontaneous succession with additional disturbances caused by recreational activities, and forestry reclamation, on the diversity and conservation values of spiders, beetles, flies, bees and wasps, orthopterans and vascular plants in a large sand pit in the Czech Republic, Central Europe. Out of 406 species recorded in total, 112 were classified as open sand specialists and 71 as threatened. The sites restored through spontaneous succession with additional disturbances hosted the largest proportion of open sand specialists and threatened species. The forestry reclamations, in contrast, hosted few such species. The sites with spontaneous succession without disturbances represent a transition between these two approaches. While restoration through spontaneous succession favours biodiversity in contrast to forestry reclamation, additional disturbances are necessary to maintain early successional habitats essential for threatened species and open sand specialists.  Therefore, recreational activities seem to be an economically efficient restoration tool that will also benefit biodiversity in sand pits.

Background: Sperm competition imposes a strong selective pressure on males, leading to the evolution of various physiological, morphological and behavioral traits. Sperm competition can be prevented by blocking or impeding the access to female genitalia by means of a mating plug. We investigated the factors responsible for plug production and function in the promiscuous female-cannibalistic spider Micaria sociabilis (Gnaphosidae).

Results: We performed mating trials using females with and without a plug that consists of an amorphous mass. The mating trials demonstrated that the probability of male plugging increased non-linearly with the duration of copulation. Copulation duration and plug production seem to be controlled by the female. We found that females terminated matings later if males were fast at genital coupling. Whereas incomplete plugs had disappeared on the day following copulation, complete plugs persisted (40%). In matings with females with complete plugs, only a small proportion of males (7%) were able to remove the plug, indicating the high effectiveness of plugging. Moreover, males ceased attempts to copulate with plugged females with higher probability. 3D X-ray microscopy of the female and male genitalia showed that the plug material can extend far into the female genital tract and that the plug material is produced by a massive gland inside the palpal organ of the modified male pedipalps.

Conclusions: Our study demonstrates that the mating plug in Micaria sociabilis constitutes an effective male strategy to avoid sperm competition that seems to be under female control.

Keywords: Secretory plugs, Sperm competition, Cryptic female choice, Multiple mating, X-ray microscopy