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A MIXED DIET IMPROVES PERFORMANCE AND HERBIVORE RESISTANCE OF A PARASITIC PLANT
Author(s) -
Marvier Michelle
Publication year - 1998
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/0012-9658(1998)079[1272:amdipa]2.0.co;2
Subject(s) - biology , aphid , scrophulariaceae , generalist and specialist species , herbivore , host (biology) , fabaceae , parasitic plant , lupinus , botany , acyrthosiphon pisum , ecology , aphididae , habitat , homoptera , pest analysis
I examined how the performance of Castilleja wightii (Scrophulariaceae), a generalist root parasite, is affected by the availability of different combinations of host species. In this greenhouse study, I focused on pairs of hosts consisting of either two leguminous host individuals ( Lupinus arboreus ; Fabaceae), two non‐nitrogen‐fixing hosts ( Eriophyllum stachaedifolium ; Asteraceae), or one individual of each of these species. Castilleja growth and reproductive performance were greatly improved by the simultaneous attack of two distinct host species, even though Castilleja grown with two Lupinus hosts had significantly higher nitrogen content. Different combinations of host species also strongly affected the growth of aphid colonies feeding on the Castilleja used in this experiment. Across all treatments, the growth of aphid colonies was positively correlated with the nitrogen content of the parasitic plants, which, in turn depended on the combination of hosts attacked. Aphid colonies feeding on parasites attacking a mixture of host species grew more slowly than those on parasites attacking two Lupinus individuals. Therefore, simultaneous attack of a mixture of host species may lead to improved parasite performance in two ways—via a direct benefit on parasite growth and flowering as well as a possible indirect benefit because of the relatively poor performance of herbivores feeding on these parasites.