Horizontal and vertical distribution of spiders (Araneae) in sunflowers stano Pekár

Дата канвертавання25.04.2016
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Fauna and Zoogeography of Spiders (Araneae) in Bulgaria

Christo Deltshev: Institute of Zoology, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Bld., 1000 Sofia, Bulgaria. E-mail: cdeltshev@zoology.bas.bg
Abstract. Bulgaria is home to 975 species of spiders in 41 families. This number was established after a critical review of the existing literature and taxonomic review of the available collections. The spiders are distributed in all districts of Bulgaria, occurring in lowlands, forests, mountains, caves and urban territories. According to their current distribution the established 975 species can be split into 27 zoogeographical categories, grouped into five major chorotypes (Cosmopolitan, Holarctic, European, Mediterranean, Endemics). The largest number of species belongs to the widely distributed species in the Holarctic, but the most characteristic are the endemics. Their established number (76 species) is high and reflects the local character of the fauna. This phenomenon can be attributed to the relative isolation of the mountains compared with the lowlands in the context of paleo-enviromental changes since the Pliocene.
Geographical context of Speciation in a radiation of Hawaiian Tetragnatha Spiders (ARANEAE, TETRAGNATHIDAE)

Rosemary G. Gillespie: Division of Insect Biology, University of California Berkeley, 137 Mulford Hall, Berkeley, California 94720-3114, U.S.A.

Abstract. Adaptive radiation involves the diversification of species each adapted to exploit different ecological roles. I have studied a radiation of spiders in the genus Tetragnatha (Tetragnathidae) in the Hawaiian Islands to elucidate processes involved in such diversification. The temporal framework of the Hawaiian Islands allows examination of the changing pattern of adaptive radiation over time, as lineages have generally progressed down the island chain from older to younger islands. Species of Tetragnatha in the spiny-leg clade on any one island are typically most closely related to others on the same island, and the same set of ecological forms (ecomorphs) has evolved repeatedly on different islands. These results indicate that adaptive radiation frequently involves ecological divergence between sister taxa to allow multiple close relatives to co-occur in the same habitat. The current study examines the geographical context within which these species arose. I focus on a clade of 5 species that occur on the volcano of East Maui; at any given site 3 species can co-occur, one of each of 3 different ecomorphs. Mitochondrial DNA sequences from populations of these 5 species from throughout their distribution (Maui, Lanai and Molokai) were used to infer the geographic history of the species on East Maui and to determine whether diversification likely occurred in situ, or alternatively whether diversification occurred in allopatry on different volcanoes. Although ecological differentiation between taxa is evident, allopatry is clearly implicated in the initial divergence of taxa. Further study is required to understand the nature of the interplay between allopatry and ecological divergence in species formation.

Diversity of arboreal spiders in primary and disturbed tropical forests

Andreas Floren: Dept. of Animal Ecology and Tropical Biology, University Wuerzburg, Biozentrum Am Hubland, D-97074 Wuerzburg, Germany. E-mail: floren@biozentrum.uni-wuerzburg.de

Christa Deeleman-Reinhold: Sparrenlaan 8, 4641 GA Ossendrecht, The Netherlands

ABSTRACT. This study investigates how arboreal spider communities in SE-Asian primary lowland rain forests change after anthropogenic disturbance. Two types of secondary forests were distinguished: 1) forests adjacent to each other, which finally merged into primary forest and 2) forests that were isolated by at least 10 km from the primary forest. Three forests of different age were investigated from each type and compared with undisturbed primary forest. All disturbed forests had been used some years for agriculture and were then left between 5 and 50 years to regenerate naturally. Spiders from at least seven trees per forest type were collected using insecticidal knockdown fogging and sorted to species or morphospecies level. Spiders represented between 5--10% of all canopy arthropods. A similar number of spiders were collected per square meter from all trees. However, communities in the primary forest differed greatly in their alpha- and beta-diversity and in community structure from those in the disturbed forest types. Diversity was high in the regenerating forests connected to the primary forest and approximated the conditions of the primary forest during the course of forest succession. In contrast, the isolated forests were of low diversity and communities showed little change during forest regeneration. These results indicate the importance of a species-source from which disturbed forests can be recolonized. However, even under optimal conditions this process needed decades before spider communities became similar to those of the primary forest. With no species-source available, spider diversity changed little during 50 years of forest regeneration. In the isolated forest we observed a drastic turnover from forest species towards species characteristic of open vegetation and shrubs. Our results give an indication of how large a loss in diversity can be expected in isolated forest fragments.


Volker W. Framenau1: Department of Zoology, The University of Melbourne, Parkville, Victoria, 3010, Australia. E-mail: volker.framenau@museum.wa.gov.au
ABSTRACT. Sexual dimorphism of locomotory organs appears to be common in a variety of arthropods, however, the underlying evolutionary mechanisms remain poorly understood and may be the consequence of natural or sexual selection, or a combination of both. I analyzed the activity pattern of seven cohorts of a wolf spider, Venatrix lapidosa, over four consecutive years. Males appear to be the more active sex in search for a mate as they show temporarily higher activity prior to the periods of female brood care. Morphometric data on leg length showed comparatively longer legs for males than females. Allometric leg elongation in all four legs of males arises only after the final molt suggesting its significance in reproductive behavior such as mate search. A comparative analysis of two Australasian wolf spider genera with different activity profile of females, Venatrix (sedentary females) and Artoria (vagrant females) provides further evidence that limb elongation in males mainly arises due to indirect male mate competition.

Gail E. Stratton: Department of Biology, University of Mississippi, University, Mississippi 38677, U.S.A. E-mail: Byges@olemiss.edu
ABSTRACT. A phylogenetic analysis for the North American Schizocosa species was undertaken by scoring 49 morphological characters for 31 taxa representing all of the Nearctic species of Schizocosa plus individuals that are hybrids between S. ocreata and S. rovneri. Rabidosa rabida, Allocosa georgicola and Gladicosa pulchra were used as outgroups. Three clades are recognized: a large clade from eastern North America (Clade A) within which is nested the S. ocreata clade; Clade B, which includes the widespread S. avida and the western S. mccooki, and a smaller, third clade, Clade C. Sexual ornamentation occurs on the first legs of mature males of several species within the Schizocosa and takes the form of pigmentation and or bristles primarily on the tibia of leg I; there is at least one species with bristles in each of the three main clades. Mapping the occurrence of male ornamentation on the preferred phylogeny suggests that ornamentation evolved 5 or 6 separate times and was subsequently lost 2 or 3 times. The ornamentation is concentrated in the S. ocreata clade, a clade defined by a finger like projection on the paleal process of the male pedipalp. Courtship behavior is known for 20 of the 31 taxa. All species studied utilize chemical communication and seismic signals for communication; some species also have distinct visual signals. Seismic signals are produced by palpal drumming (as is seen in several species within Clade B), or by stridulation (seen in Clade A). Visual signals consisting of movements of the first pair of legs are common in species that are distinctly ornamented. This study provides the first phylogenetic study of a North American genus of wolf spider and provides morphometric comparisons of the North American species in Schizocosa.
Factors affecting cannibalism among newly hatched wolf spiders (Lycosidae, Pardosa amentata)

Aino Hvam1, David Mayntz1, 2, 3 and Rikke Kruse Nielsen1

1Department of Ecology and Genetics, University of Aarhus, Bldg. 540, DK-8000 Århus C, Denmark.

2Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK

3Corresponding author.
ABSTRACT. Cannibalism is a common phenomenon among young wolf spiders (Lycosidae). The purpose of this study was to investigate how various factors influence cannibalistic tendencies in hatchlings of Pardosa amentata (Clerk 1757). The basic experimental approach was to place pairs of unfed hatchlings of similar body mass in small containers without prey and to measure if and when cannibalism happened. From the data, we identified three different cannibalistic strategies. One large group of hatchlings never cannibalized and thus died from starvation. Another group cannibalized shortly before the time at which they were predicted to die from starvation. In these spiders, there was a strong positive relationship between average body mass of the contestants and their latency to cannibalize. A third group cannibalized quickly and the latency to cannibalize in these spiders was independent of body mass. We also tested if cannibalistic tendencies were higher among unrelated pairs than among pairs of siblings, but we did not find any support for this hypothesis. In another experiment we tested if maternal effects influenced cannibalism, i.e. if siblings from certain mothers were more cannibalistic than siblings from others. We did not find any evidence that maternal effects influenced whether or not cannibalism occurred. However, when cannibalism did occur, the latency to cannibalize varied significantly among siblings from different mothers beyond what would have been predicted solely from hatchling body mass.
Data on the biology of Alopecosa psammophila Buchar 2001

(Araneae, Lycosidae)
Csaba Szinetár & János Eichardt: Department of Zoology, Berzsenyi College, Károlyi Gáspár tér 4. Szombathely, H-9700 Hungary. E-mail: szcsaba@bdtf.hu

Roland Horváth: Department of Evolutionary Zoology and Human Biology, University of Debrecen, POB. 3, Debrecen, H-4010 Hungary
ABSTRACT. This paper presents electron micrographs of the genitalia of Alopecosa psammophila, describes the morphological characteristics of the species and also gives information on its habitat preference, the co-occurring ground-dwelling spiders, and the phenological characteristics of the species. Barber pitfall trappings have been carried out since 2000 in dry sandy grasslands in three regions of Hungary: the Kiskunság area (Kiskunság National Park); the Nyírség area (Hortobágy National Park); and since 2004 the Kisalföld area (Fertő-Hanság National Park). Specimens of the species, hitherto unknown in Hungary, have been collected from 17 localities in all three areas. We collected specimens in calciferous open sand steppes and in acidic open sand steppes. In the females, two activity periods were apparent (from April to end July and in October). A few males were collected in April and in October--November they had an extreme activity peak. We assume that the species has adult specimens throughout the winter. Alopecosa psammophila is most similar to Xysticus ninni Thorell 1872 and Zelotes longipes (L. Koch 1866) in terms of its environmental needs.

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