Search results for "Systematics"
showing 10 items of 6702 documents
Costs of courtship and mating in a sexually cannibalistic orb-web spider: female mating strategies and their consequences for males
2002
The costs of courtship and mating may include increased risks of predation, the transmission of pathogens, and a loss of foraging opportunities. Thus, a female's decision to tolerate a courting male will depend upon how these costs offset the benefits of mating, which will depend on her reproductive and nutritional status. While these costs may be similar for mated and unmated females, the benefits of mating will be less for mated than virgin females. However, the cost of lost foraging opportunities may be higher for females with fewer nutritional reserves necessary for forming eggs. We examined how these costs and benefits influence the courtship and mating behaviour of male and female orb…
Knowing the Risk: Crickets Distinguish between Spider Predators of Different Size and Commonness
2013
Predators unintentionally release chemical and other cues into their environment that can be used by prey to assess predator presence. Prey organisms can therefore perform specific antipredator behavior to reduce predation risk, which can strongly shape the outcome of trophic interactions. In contrast to aquatic systems, studies on cue-driven antipredator behavior in terrestrial arthropods cover only few species to date. Here, we investigated occurrence and strength of antipredator behavior of the wood cricket Nemobius sylvestris toward cues of 14 syntopic spider species that are potential predators of wood crickets. We used two different behavioral arena experiments to investigate the infl…
Sparassidae of Japan. I. New Species of Olios, Heteropoda, and Sinopoda, with Notes on Some Known Species (Araneae: Sparassidae: Sparassinae and Hete…
2000
Four new species of the spider family Sparassidae are described from Japan under the names Olios japonicus sp. nov., Heteropoda simplex sp. nov., Sinopoda okinawana sp. nov. and S. tanikawai sp. nov. The genus Olios is recorded for the first time from Japan. Taxonomical notes and new records of some known species and comments on diagnostic characters of the subfamilies and genera of the Japanese Sparassidae are presented.
Overwintering survival in relation to body mass in a field population of the wolf spider ( Hygrolycosa rubrofasciata )
1999
Body size is often considered to be an important trait affecting individual fitness. In arthropods, females commonly benefit from larger size directly through increased fecundity (Roff, 1992), and males through increased mating success (Andersson, 1994). It has also been suggested that larger individuals may in general have a better survival than smaller individuals (Calder, 1983; Peters, 1983). From this suggestion it may be predicted that during stressful environmental conditions larger individuals should do better than smaller individuals.
First records of the genera Pseudopoda, Sinopoda, and Olios from Taiwan with descriptions of four new species (Araneae: Sparassidae)
2001
Four new species of the spider family Sparassidae are described from Taiwan: Pseudopoda serrata sp. nov. (male and females), Pseudopoda recta sp. nov. (female), Sinopoda exspectata sp. nov. (male), and Olios scalptor sp. nov. (male). These represent first records of the three genera for Taiwan. A record of Heteropoda venatoria (Linne 1767) is also reported.
Survival strategies of the crab spider Thomisus onustus Walckenaer 1806 (Chelicerata, Arachnida, Thomisidae).
1989
The initial energy supply of emerging spiderlings is relatively meagre, so survival without feeding on insects during a spell of bad weather is limited to a period of a few days or weeks. During our investigations, spiderlings of Thomisus onustus (Arachnida, Thomisidae) were kept on different diets. There was a significant difference in survival rate between spiderlings that were starved or fed on pollen, “nectar”, or Drosophila. The results showed that pollen and nectar can be a source of energy for spiders for an extensive period. This demonstrates another way in which spiders may survive starvation when insect prey is lacking and thus ensure the survival of a whole population.
Sorbus busambarensis (Rosaceae), a new endemic species of Sicily
2012
Abstract In this study, Sorbus busambarensis, a new species from Rocca Busambra (Palermo, NW Sicily) has been described and named. On the basis of the critical features of its flowers, fruits and leaves, it is noted to be a member of S. sect. Aria and is related to the other taxa that form the polymorphic group of S. aria, which in Sicily is represented by S. aria s. str., S. graeca and S. umbellata.
Determining the potential impacts of fire and different land uses on splash erosion in the margins of drylands
2021
Abstract This research aimed to estimate the splash erosion and its evolution during the first months in specific land uses after a forest fire. The study area was located in Congosto (North-West Spain), in the margins of Spanish drylands, after a wildfire occurred in May 2012, which burned 15.56 ha of scrubland and Pinus reforestation. Two different burned land uses were selected and compared to control areas: i) burned pine forest; and, scrublands. Rainfall intensity and the number, sizes and speed of raindrops were measured by an optical disdrometer and soil loss by funnels. Moreover, infiltration, soil moisture content, aggregate stability, water repellence, pH and organic matter were a…
Paracrobeles psammophilus sp. nov. (Nematoda: Cephalobidae) from El Saler, Valencia (Spain)
1999
Paracrobeles psammophilus sp. nov. (Nematoda: Cephalobidae) is described from soil of the Dehesa de El Saler (province of Valencia, Spain). This is the second record of a species of the genus Paracrobeles Heyns, 1968. The new species is characterized by rounded cheilorhabdions and the large spicules and gubernaculum of males.
Pathogenicity of intrathoracically administrated Bacillus thuringiensis spores in Blatta orientalis.
2006
Abstract The ability of Bacillus thuringiensis to produce septicaemia in Periplaneta americana and Blatta orientalis has been investigated. Spores and crystals from several wild-type strains as well as spores of a B. thuringiensis crystal-deficient mutant, were first orally administrated at high doses, and no significant mortality was recorded. Intrathoracic injection of spore suspensions in P. americana revealed that this species is not very susceptible to B. thuringiensis spores. B. orientalis , by contrast, was found to be very susceptible to B. thuringiensis , with a LD 50 of about 35,000 spores, that is similar to that reported on Lepidoptera challenged with parenterally injected B. th…