Effects of vector behavior and host resistance on mistletoe aggregation
Author
dc.contributor.author
Medel Contreras, Rodrigo
Author
dc.contributor.author
Vergara, Eliseo
Author
dc.contributor.author
Silva, Arturo
Author
dc.contributor.author
Arroyo, Mary T. K.
Admission date
dc.date.accessioned
2018-12-19T20:28:36Z
Available date
dc.date.available
2018-12-19T20:28:36Z
Publication date
dc.date.issued
2004
Cita de ítem
dc.identifier.citation
Ecology, Volumen 85, Issue 1, 2004, Pages 120-126
Identifier
dc.identifier.issn
00129658
Identifier
dc.identifier.other
10.1890/03-0261
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/153558
Abstract
dc.description.abstract
t. Understanding the factors affecting parasite aggregation in natural host pop-
ulations is one of the central questions in parasite ecology. While different biological
mechanisms giving rise to aggregation have been documented in the literature, the role of
established parasites in vector attraction, and its importance in determining clumped parasite
distributions has received less attention. In a two-year field study, we evaluated the im-
portance of a bird vector, Mimus thenca (Mimidae), on the aggregation dynamics of the
holoparasitic mistletoe, Tristerix aphyllus, on its cactus host, Echinopsis chilensis. Removal
of T. aphyllus from cacti decreased the number of visits and the time spent by the bird
vector, which resulted in a 3.5-fold lower seed deposition of the mistletoe on experimental
hosts than on control hosts. Vector preference, however, was not the only factor affecting
aggregation in this system. Spine length of the cactus acted as a first line of defense against
parasitism, by discouraging bird perching on top of host columns. While heavily parasitized
hosts received more seeds than unparasitized hosts, spines counteracted this effect. These
results provide field evidence that parasite aggregation results from the balance between
vector behavior and host resistance traits.