Susceptibility of native and non-native common reed to the non-native mealy plum aphid (Homoptera: Aphididae) in North America.
An aggressive, non-native haplotype (distinct genetic lineage within a species) of Phragmites australis is invading brackish and freshwater systems in the eastern United States, potentially displacing native haplotypes. We studied the differential susceptibility of native and non-native populations collected from sites throughout North America to the non-native aphid, Hyalopterus pruni. In a greenhouse study, we found significantly higher aphid populations on native haplotypes than on the non-native haplotype 2 mo after infestation. Aphid feeding caused chlorosis and death of native stems, and in some cases, killed whole native genets. The non-native plants remained relatively undamaged. In a field study, non-native plants had significantly lower aphid densities than native plants or remained aphid free. There was an interactive effect in which aphid populations increased on the native plants over the 1-mo study period but remained low on non-native plants over the same period. The susceptibility of native North American populations of P. australis to non-native aphid infestation may indirectly affect the ability of these native plants to compete with non-native plant populations, ultimately contributing to the decline of native haplotypes.
Lambert
Adam M
AM
Department of Plant Sciences, University of Rhode Island, Kingston, Rhode Island 02881, USA. lambert@msi.ucsb.edu
Casagrande
Richard A
RA
D000818:Animals; D001042:Aphids / Q000254:growth & development*; D017753:Ecosystem; D005260:Female; D006239:Haplotypes; D008297:Male; D009656:North America; D010572:Pest Control, Biological / Q000379:methods*; D006109:Poaceae / Q000235:genetics* / Q000469:parasitology*; D011156:Population Density; D011157:Population Dynamics; D013045:Species Specificity