After a short review of impotence, the definitions of erectants and aphrodisiacs are presented. The Authors propose division of arthropods according to the places of effect. The description of particular arthropods with their pictures and nomenclature, is followed by certain or probable mechanisms of achieving the aphrodisiac and sometimes toxic effect, that were available in the literature sin...

A 48-year-old woman who worked as a cleaner in a Kashan University of Medical Sciences dormitory received a spider bite while collecting garbage on a summer afternoon. She feltimmediate irritation on her arm. She noticed a spider, which she removed and killed. The irritation, itching, and redness on her arm continued. Her hand became edematous and painful after four days and she suffered from i...

We consider the evolution of black widow pulsars (BWPs). The large majority of these are members of globular clusters. For minimum companion masses < 0.1M ̄, adiabatic evolution and consequent mass loss under gravitational radiation appear to provide a coherent explanation of all observable properties. We suggest that the group of BWPs with minimum companion masses ∼> 0.1M ̄ are systems relaxing ...

The iconic red hourglass of the black widow spiders (genus Latrodectus) is traditionally considered an aposematic signal, yet experimental evidence is lacking. Here, we present data that suggest that black widow coloration may have evolved to be an aposematic signal that is more conspicuous to their vertebrate predators than to their insect prey. In choice experiments with wild birds, we found ...

Black widow spider venom (BWSV) stimulates transmitter release and depletes synaptic vesicles from muscles bathed in a sodium free medium containing 1 mM EGTA. However, frog neuromuscular junctions treated with BWSV in glucosamine Ringer's and post-treated with antivenin recover normal function. This suggests that probably the permanent block of neuromuscular transmission is due to changes in p...

Orb-weaving spiders produce webs using two types of silk that have radically different mechanical properties. The dragline silk used to construct the supporting frame and radii of the web is stiff and as strong as steel, while the capture spiral is much weaker but more than ten times as extensible. This remarkable divergence in mechanical properties has been attributed to the aqueous glue that ...