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Nuptial gifts may serve to increase male mating success, copulation duration, and fertilization success, as is known for the nuptial feeding spider Pisaura mirabilis Clerck, 1757. In this species, strong sexual selection for the gift-giving trait may lead to male strategies, such as gift enlargement or thanatosis behaviour (death feigning), which ultimately maximize male fitness. In laboratory trials, we observed male gift enlargement by inclusion of an autosomal (self-amputated) limb, female consumption of male soma during copulation, and high-injury risk thanatosis in which a male feigned death while still in copula and only attached to the female with his pedipalp, instead of hanging onto the gift with the chelicerae as is performed in a typical thanatosis. Although the observations are anecdotal, we propose functional hypotheses for these traits in the context of extreme male mating effort and cannibalism avoidance, which are characteristics of the mating system of this species. Sexual selection and sexual conflict are major evolutionary forces that shape a variety of morphological, behavioural, and physiological traits (Parker 1979). Males must compete intra-sexually over access to females or inter-sexually to attract females, and have evolved traits that serve to increase their reproductive success (Andersson 1994).
Allocosa brasiliensis is a sand-dwelling wolf spider that constructs burrows along the coasts of rivers, lakes, and the Atlantic Ocean in Argentina, Brazil, and Uruguay. This species shows a reversal in typical sex roles in spiders: females wander searching for males and initiate courtship, while both females and males are selective when taking mating decisions. Females prefer to mate with males that show long burrows. As burrow digging in the sand seems to be an energetically expensive activity, we would expect differences in burrow characteristics according to developmental stage and selection pressures. Our aim was to describe female and juvenile digging behaviour in A. brasiliensis and report burrow dimensions, comparing the results with data available for males of this species. We placed each individual (n = 30 of each category) in a glass cage with sand as substrate and recorded burrow construction under laboratory conditions. Only five females and nine juveniles constructed burrows after 72 hours. Burrow dimensions did not show significant differences between females or juveniles, but burrow length was markedly lower than reports for males of this species. Burrow digging was stereotyped both in females and juveniles, following a sequence of behavioural units repeated in a cycle. Digging behaviour would be highly conserved in A. brasiliensis. However, variations in burrow digging behaviour and final burrow dimensions would reflect differences in strategies according to sex and stage.
In male spiders, genitalia, sexual behaviour and secondary sex morphology tend to diverge rapidly across species, presumably as a result of sexual selection. In the three Leucauge species for which pre- and copulatory courtship behaviour is known, females clamp the male chelicerae prior to and during copulation. This brings the basal segment of the male's chelicerae into contact with the anterior surface of the female's chelicerae. The basal segment of male's chelicerae has also morphological features such as sturdy, abundant setae which are thought to have evolved to stimulate females, as well as other morphological features whose specific function is yet unknown. We show here that in a fourth species, Leucauge sp., the female does not clamp the male's chelicerae; as expected, this absence is associated with a lack of secondary sexual differences in the male chelicerae.
The Torneträsk area, including the Abisko National Park, Sweden, is arachnologically one of the best explored sites of Fennoscandia. Here, we report the results of pitfall trapping at Abisko Scientific Research Station during the summers of 2004 and 2005, recording 791 individuals of 62 species of spiders. As expected, at the species level, samples were dominated by members of the Linyphiidae, while at the level of individuals Pardosa hyperborea and other lycosids were dominant. Two subsites, on heath and bog, differed substantially in their species profile: seven species were statistically overrepresented on the drier heath site, while two showed a strong preference for the wetter bog site. The samples also contained the first reported lateral gynandromorph of Archaeodictyna consecuta (Dictynidae). This study, from 195 km north of the Arctic Circle, provides important reference data for continued studies on the long-term effects of climate change on Arctic ecosystems.
Collecting trapdoor spiders (Idiopidae) for research is difficult due to their deep, convoluted burrows and almost entirely fossorial life history. Digging idiopids out of their burrows is laborious, disturbs the environment, and can only be undertaken in open areas with soft soil. Here we describe “beetling”: a quicker, easier method of capturing idiopids, using tethered beetles to lure the spiders from their burrows. Beetling was used to capture 123 individual Cantuaria spp. (Idiopidae) out of a total of 130 successfully throughout New Zealand during March–June, September, November, and December. We conclude that beetling is an effective method for the live capture of idiopids, despite some limitations such as the need to work at night, and to culture live beetles, but they are outweighed by the advantages of having a reliable, efficient method of capturing live spiders. Beetling could also be used to catch other fossorial invertebrates, such as lycosids and carabid larvae.
Phoneyusa elephantiasisBerland, 1917 is illustrated, redescribed and, along with Phoneyusa celerieraeSmith, 1990 and Phoneyusa efuliensisSmith, 1990, transferred to the genus HysterocratesSimon, 1892. Type material of HysterocratesgigasPocock, 1897 and topotypes of Phoneyusa lesserti Dresco, 1973 are illustrated for comparison. Phoneyusa nigroventris (Marx, 1893) is treated as nomen dubium.