Males and females often differ in their susceptibility and exposure to infection. Thus, they may also differ in their ability to avoid infection. The beetle, Tenebrio molitor, risks infection with cysticercoids when i...Males and females often differ in their susceptibility and exposure to infection. Thus, they may also differ in their ability to avoid infection. The beetle, Tenebrio molitor, risks infection with cysticercoids when ingesting rat feces containing eggs of the tapeworm, Hymenolepis diminuta. Previous studies demonstrated that beetles sometimes prefer infective feces suggesting that the tapeworm influences the foraging behavior of beetles. After recording beetle movement in an arena containing infective and uninfective feces for one hour, sex main effects were not significant, but the effect of sex asked in trials was significant for males. Specifically, more male beetles occurred on the uninfective bait than on the infective bait. This observation suggests that male beetles avoid infective feces, which decreases their probability of infection with H. diminuta. If the cost of infection is higher in males, then selection to avoid infective feces may act more strongly on males.展开更多
Toxoplasma gondii is an intracellular parasite involved in the etiology of various behavioral and hormonal alterations in humans and rodents. Various mechanisms, including induction changes of testosterone production,...Toxoplasma gondii is an intracellular parasite involved in the etiology of various behavioral and hormonal alterations in humans and rodents. Various mechanisms, including induction changes of testosterone production, have been proposed in the etiology of behavioral alterations during T. gondii infection. However, controversy remains about the effects of T. gondii infection on testosterone production; in some studies, increased levels of testosterone were reported, whereas other studies reported decreased levels. This is a significant point, because testosterone has been shown to play important roles in various processes, from reproduction to fear and behavior. This contradiction seems to indicate that different factors--primarily parasite strains and host variations--have diverse effects on the intensity of T. gondii infection, which consequently has diverse effects on testosterone production and behavioral alterations. This paper reviews the role of parasite strains, host variations, and intensity of T. gondii infection on behavioral alterations and testosterone production, as well as the role of testosterone in the etiology of these alterations during toxoplasmosis.展开更多
文摘Males and females often differ in their susceptibility and exposure to infection. Thus, they may also differ in their ability to avoid infection. The beetle, Tenebrio molitor, risks infection with cysticercoids when ingesting rat feces containing eggs of the tapeworm, Hymenolepis diminuta. Previous studies demonstrated that beetles sometimes prefer infective feces suggesting that the tapeworm influences the foraging behavior of beetles. After recording beetle movement in an arena containing infective and uninfective feces for one hour, sex main effects were not significant, but the effect of sex asked in trials was significant for males. Specifically, more male beetles occurred on the uninfective bait than on the infective bait. This observation suggests that male beetles avoid infective feces, which decreases their probability of infection with H. diminuta. If the cost of infection is higher in males, then selection to avoid infective feces may act more strongly on males.
文摘Toxoplasma gondii is an intracellular parasite involved in the etiology of various behavioral and hormonal alterations in humans and rodents. Various mechanisms, including induction changes of testosterone production, have been proposed in the etiology of behavioral alterations during T. gondii infection. However, controversy remains about the effects of T. gondii infection on testosterone production; in some studies, increased levels of testosterone were reported, whereas other studies reported decreased levels. This is a significant point, because testosterone has been shown to play important roles in various processes, from reproduction to fear and behavior. This contradiction seems to indicate that different factors--primarily parasite strains and host variations--have diverse effects on the intensity of T. gondii infection, which consequently has diverse effects on testosterone production and behavioral alterations. This paper reviews the role of parasite strains, host variations, and intensity of T. gondii infection on behavioral alterations and testosterone production, as well as the role of testosterone in the etiology of these alterations during toxoplasmosis.
