DEAR EDITOR,We identified strict monandry in a wandering wolf spider species(Pardosa pseudoannulata) and revealed the underlying mechanisms of this mating structure. Evidence indicated that males damaged the inner wal...DEAR EDITOR,We identified strict monandry in a wandering wolf spider species(Pardosa pseudoannulata) and revealed the underlying mechanisms of this mating structure. Evidence indicated that males damaged the inner walls of the female genital tract with the sharp part of their intromittent organ during insemination. The traumatic mating caused hemolymph hemorrhage, which mixed with seminal fluid and gradually formed an impermeable amorphous mating plug after about15 days, completely blocking the female copulatory opening.展开更多
Although camouflage as an effective antipredator defense strategy is widespread across animals,highly conspicuous color patterning is not uncommon either.Many orb-web spiders adorn their webs with extra bright white s...Although camouflage as an effective antipredator defense strategy is widespread across animals,highly conspicuous color patterning is not uncommon either.Many orb-web spiders adorn their webs with extra bright white silk.These conspicuous decorations are hypothesized to deter predators by warning the presence of sticky webs,camouflaging spiders,acting as a decoy,or intimidating predators by their apparent size.The decorations may also deflect predator attacks from spiders.However,empirical evidence for this deflection function remains limited.Here,we tested this hypothesis using the X-shaped silk cruciform decorations built by females of Argiope minuta.We employed visual modeling to quantify the conspicuousness of spiders and decorations from a perspective of avian predators.Then,we determined actual predation risk on spiders using naïve chicks as predators.Spider bodies and decorations were conspicuous against natural backgrounds to the avian visual systems.Chicks attacked the spider main bodies significantly less frequently on the decorated webs than on the undecorated webs,thus reducing predation risk.When both spiders and decorations were present,chicks also attacked the spider main bodies and their legs or decorations,and not randomly:they attacked the legs or decorations sooner and more frequently than they attacked the main bodies,independent of the ratio of the surface area between the decoration and spider size.Despite the increase in detectability,incorporating a conspicuous cruciform decoration to the web effectively defends the spider by diverting the attack toward the decoration or leg,but not by camouflaging or intimidating,thus,supporting the deflection hypothesis.展开更多
基金supported by the National Natural Science Foundation of China(31801979)State Key Laboratory of Integrated Management of Pest Insects and Rodents,Institute of Zoology,Chinese Academy of Sciences(IPM2208)。
文摘DEAR EDITOR,We identified strict monandry in a wandering wolf spider species(Pardosa pseudoannulata) and revealed the underlying mechanisms of this mating structure. Evidence indicated that males damaged the inner walls of the female genital tract with the sharp part of their intromittent organ during insemination. The traumatic mating caused hemolymph hemorrhage, which mixed with seminal fluid and gradually formed an impermeable amorphous mating plug after about15 days, completely blocking the female copulatory opening.
基金supported by grants from National Natural Science Foundation of China(31801979 and 31872229)from Singapore Ministry of Education(MOE)AcRF Tier 1 grant(R-154-000-B18-114).
文摘Although camouflage as an effective antipredator defense strategy is widespread across animals,highly conspicuous color patterning is not uncommon either.Many orb-web spiders adorn their webs with extra bright white silk.These conspicuous decorations are hypothesized to deter predators by warning the presence of sticky webs,camouflaging spiders,acting as a decoy,or intimidating predators by their apparent size.The decorations may also deflect predator attacks from spiders.However,empirical evidence for this deflection function remains limited.Here,we tested this hypothesis using the X-shaped silk cruciform decorations built by females of Argiope minuta.We employed visual modeling to quantify the conspicuousness of spiders and decorations from a perspective of avian predators.Then,we determined actual predation risk on spiders using naïve chicks as predators.Spider bodies and decorations were conspicuous against natural backgrounds to the avian visual systems.Chicks attacked the spider main bodies significantly less frequently on the decorated webs than on the undecorated webs,thus reducing predation risk.When both spiders and decorations were present,chicks also attacked the spider main bodies and their legs or decorations,and not randomly:they attacked the legs or decorations sooner and more frequently than they attacked the main bodies,independent of the ratio of the surface area between the decoration and spider size.Despite the increase in detectability,incorporating a conspicuous cruciform decoration to the web effectively defends the spider by diverting the attack toward the decoration or leg,but not by camouflaging or intimidating,thus,supporting the deflection hypothesis.
