Mycophagists can influence fungal diversity within their home ranges by ensuring the continued and effective dispersal of spores from one site to another. However, the passage of spores through the digestive tract of ...Mycophagists can influence fungal diversity within their home ranges by ensuring the continued and effective dispersal of spores from one site to another. However, the passage of spores through the digestive tract of vertebrates can affect the activity and viability of the spores ingested. This phenomenon has been rarely documented in opportunistic mycophagists consuming epigeous fungi. Using laboratory experiments, we investigated the activity and viability of spores of two epigeous ectomycorrhizal fungal species （Laccaria trichodermophora and SuiUus tomentosus） after passage through the digestive tract of two opportunistic mycophagous small rodents, the volcano mouse Peromyscus alstoni and the deer mouse P maniculatus. We found that passage through the gut of either species of rodent had a significant effect on spore activity and viability for both fungal species. The proportion of active spores （0.37-0.40） of L. trichodermophora in the feces of both species of rodents was less than that recorded for the control （0.82）. However, the proportion of active spores （0.644）.73） of S. tomentosus in the feces of each species of rodent was higher than in the control （0.40）. On the other hand, the viability of spores was lower （0.26-0.30 in L. trichodermophora and 0.604）.69 in S. tomentosus） for both fungi when consumed by either rodent relative to the controls （0.90 in L. trichodermophora and 0.82 in S. tomentosus）. These findings suggest that these rodent species may be effective dispersers of both epigeous fungi [Current Zoology 57 （3）： 293-299, 2011].展开更多
Intra and in terspecific competiti on for n ectar play an imports nt role in hummingbird communities. Larger sized species usually exclude smaller species from the rich floral resources. However, it has been recently ...Intra and in terspecific competiti on for n ectar play an imports nt role in hummingbird communities. Larger sized species usually exclude smaller species from the rich floral resources. However, it has been recently postulated that the competitive advantages of a large body size decline as the evolutionary distance between the contending species in creases. In this study, we analyzed dominance hierarchy dynamics in a hummingbird assemblage in central Mexico. By monitoring hummingbird territories established in three plant species through 1 year, we assessed the effects of energy within territories and the territory owners identity in the frequency of inter and intraspecific encounters. We also evaluated if these factors affect the dominance of larger species when they compete against smaller distantly related contenders. Our results show that their frequency of intraspecific encounters was related with the identity of the territory's owner. On the contrary, the frequency of interspecific encounters was related with both the territory and the identity of the territory's owner. We did not find a significant difference between the number of encounters dominated by larger and smaller species and their conte nders. However, the in crease in genetic dista nee between contenders was positively associated with a higher frequency of encounters dominated by small hummingbirds.Our results showed that the ecological factors and evolutionary relationships among contenders play important roles in the dominance hierarchy dynamics.展开更多
文摘Mycophagists can influence fungal diversity within their home ranges by ensuring the continued and effective dispersal of spores from one site to another. However, the passage of spores through the digestive tract of vertebrates can affect the activity and viability of the spores ingested. This phenomenon has been rarely documented in opportunistic mycophagists consuming epigeous fungi. Using laboratory experiments, we investigated the activity and viability of spores of two epigeous ectomycorrhizal fungal species （Laccaria trichodermophora and SuiUus tomentosus） after passage through the digestive tract of two opportunistic mycophagous small rodents, the volcano mouse Peromyscus alstoni and the deer mouse P maniculatus. We found that passage through the gut of either species of rodent had a significant effect on spore activity and viability for both fungal species. The proportion of active spores （0.37-0.40） of L. trichodermophora in the feces of both species of rodents was less than that recorded for the control （0.82）. However, the proportion of active spores （0.644）.73） of S. tomentosus in the feces of each species of rodent was higher than in the control （0.40）. On the other hand, the viability of spores was lower （0.26-0.30 in L. trichodermophora and 0.604）.69 in S. tomentosus） for both fungi when consumed by either rodent relative to the controls （0.90 in L. trichodermophora and 0.82 in S. tomentosus）. These findings suggest that these rodent species may be effective dispersers of both epigeous fungi [Current Zoology 57 （3）： 293-299, 2011].
文摘Intra and in terspecific competiti on for n ectar play an imports nt role in hummingbird communities. Larger sized species usually exclude smaller species from the rich floral resources. However, it has been recently postulated that the competitive advantages of a large body size decline as the evolutionary distance between the contending species in creases. In this study, we analyzed dominance hierarchy dynamics in a hummingbird assemblage in central Mexico. By monitoring hummingbird territories established in three plant species through 1 year, we assessed the effects of energy within territories and the territory owners identity in the frequency of inter and intraspecific encounters. We also evaluated if these factors affect the dominance of larger species when they compete against smaller distantly related contenders. Our results show that their frequency of intraspecific encounters was related with the identity of the territory's owner. On the contrary, the frequency of interspecific encounters was related with both the territory and the identity of the territory's owner. We did not find a significant difference between the number of encounters dominated by larger and smaller species and their conte nders. However, the in crease in genetic dista nee between contenders was positively associated with a higher frequency of encounters dominated by small hummingbirds.Our results showed that the ecological factors and evolutionary relationships among contenders play important roles in the dominance hierarchy dynamics.
