Periodical cicadas(Magicicada spp.)are endemic to deciduous forests in the eastern United States.In successional forests,they must partition resources such as host trees to coexist.We measured tree size,emergence hole...Periodical cicadas(Magicicada spp.)are endemic to deciduous forests in the eastern United States.In successional forests,they must partition resources such as host trees to coexist.We measured tree size,emergence holes,oviposition scar bundles,and chorusing center abundances of Magicicada species on 12 common tree species in a deciduous forest to understand host-tree use.We predicted that the abundance of periodical cicadas and use of specific host-tree species would change depending on the Magicicada species and tree life stage.We considered the size of the tree(diameter at breast height)as a covariate to control for tree size and collected eggs for a greenhouse experiment to assess whether nymphs prefer to feed on Quercus rubra or Acer saccharum.More emergence holes were found below Quercus species than any other tree species.The abundance of periodical cicadas on host trees used for chorusing centers varied depending on the Magicicada species,but were most abundant on Quercus species.Oviposition scar bundles were also more frequent on Quercus.More nymphs were found on Quercus than Acer in the nymph preference study.Though periodical cicadas used Quercus hosts more than other tree species,their abundances on different host tree sizes and species differed significantly.Periodical cicada species may use specific host species and life stages as a way to partition resources and minimize competition among the Magicicada species during emergence years.展开更多
Invasive plants may exhibit priority effects and begin growth before native plants.Priority effects may be an important way that invasive species outcompete native plants.We tested priority effects on the invasive gra...Invasive plants may exhibit priority effects and begin growth before native plants.Priority effects may be an important way that invasive species outcompete native plants.We tested priority effects on the invasive grass Smooth Brome Bromus inermis(cool season C3),the cosmopolitan and invasive Bermuda grass Cynodon dactylon(warm season C4)and a native grass species,Red Fescue Festuca rubra(cool season C3),in the greenhouse.We grew each species alone,with a conspecific neighbor(intraspecific competition),concurrently with one of the two other heterospecifics(interspecific competition),and with a priority effect of one species being present 21 days before the heterospecific neighbor(priority effects).We recorded relative growth rates(RGR),as well as above-and belowground dry biomass.We also used a relative interaction index(RII)to determine the competitive abilities of each of these species.Smooth Brome was significantly heavier than Bermuda and Red Fescue,although Bermuda grass had the highest RGR of the three species.All three species showed stronger effects of intraspecific competition than interspecific competition.Most of the effects were competitive relative to plants grown alone.However,none of these three species exhibited priority effects,unlike a previous study.We conclude that increased competitive ability,particularly of Smooth Brome,may be sufficient to exclude native grasses.展开更多
基金supported by the Herrick Foundation,Kent University。
文摘Periodical cicadas(Magicicada spp.)are endemic to deciduous forests in the eastern United States.In successional forests,they must partition resources such as host trees to coexist.We measured tree size,emergence holes,oviposition scar bundles,and chorusing center abundances of Magicicada species on 12 common tree species in a deciduous forest to understand host-tree use.We predicted that the abundance of periodical cicadas and use of specific host-tree species would change depending on the Magicicada species and tree life stage.We considered the size of the tree(diameter at breast height)as a covariate to control for tree size and collected eggs for a greenhouse experiment to assess whether nymphs prefer to feed on Quercus rubra or Acer saccharum.More emergence holes were found below Quercus species than any other tree species.The abundance of periodical cicadas on host trees used for chorusing centers varied depending on the Magicicada species,but were most abundant on Quercus species.Oviposition scar bundles were also more frequent on Quercus.More nymphs were found on Quercus than Acer in the nymph preference study.Though periodical cicadas used Quercus hosts more than other tree species,their abundances on different host tree sizes and species differed significantly.Periodical cicada species may use specific host species and life stages as a way to partition resources and minimize competition among the Magicicada species during emergence years.
基金funding from the Herrick Trust of Kent State University.
文摘Invasive plants may exhibit priority effects and begin growth before native plants.Priority effects may be an important way that invasive species outcompete native plants.We tested priority effects on the invasive grass Smooth Brome Bromus inermis(cool season C3),the cosmopolitan and invasive Bermuda grass Cynodon dactylon(warm season C4)and a native grass species,Red Fescue Festuca rubra(cool season C3),in the greenhouse.We grew each species alone,with a conspecific neighbor(intraspecific competition),concurrently with one of the two other heterospecifics(interspecific competition),and with a priority effect of one species being present 21 days before the heterospecific neighbor(priority effects).We recorded relative growth rates(RGR),as well as above-and belowground dry biomass.We also used a relative interaction index(RII)to determine the competitive abilities of each of these species.Smooth Brome was significantly heavier than Bermuda and Red Fescue,although Bermuda grass had the highest RGR of the three species.All three species showed stronger effects of intraspecific competition than interspecific competition.Most of the effects were competitive relative to plants grown alone.However,none of these three species exhibited priority effects,unlike a previous study.We conclude that increased competitive ability,particularly of Smooth Brome,may be sufficient to exclude native grasses.
