Survival and development of parasitic and autoparasitic Phoradendron californicum (desert mistletoe) and their Acacia greggii (catclaw) hosts were quantitatively investigated during the 1997 drought in southern Nevada. Phoradendron californicum was parasitic on other individuals of the same species (autoparasitic), and these in turn were parasitic on A. greggii hosts. An extensive drought from February 1995 to mid-July 1997 was characterized by extremely low seasonal rainfall and high summer air temperatures. Extensively mistletoe-infested hosts had significantly less canopy volume and produced significantly fewer leaves, flowers, and fruits than uninfested (control) or lightly infested hosts. Mistletoe plants on A. greggii hosts with fewer infections produced significantly more leaves and fruits and survived better than mistletoe plants on A. greggii hosts with extensive infestations. Autoparasites had significantly less canopy volume and fruit production than their parasitic hosts and parasites on hosts with fewer infections. Severity of infestation was significantly negatively correlated with A. greggii and P. californicum survival, as it was with leaf, flower, and fruit development of A. greggii and parasitic and autoparasitic P. californicum during the 1997 drought in southern Nevada.
Lei, Simon A.
"Survival and development of Phoradendron californicum and Acacia greggii during a drought,"
Western North American Naturalist: Vol. 61
, Article 10.
Available at: http://scholarsarchive.byu.edu/wnan/vol61/iss1/10