Effects of the parasitism of Struthanthus flexicaulis (Mart.) Mart. (Loranthaceae) on the fitness of Mimosa calodendron Mart. (Fabaceae), an endemic shrub from rupestrian fields over ironstone outcrops, Minas Gerais State, Brazil

Abstract

Effects of the parasitism of (Fabaceae) is a legume abundant in rupestrian fields on ironstone outcrops, frequently attacked by the hemiparasite Struthanthus flexicaulis (Loranthaceae). The objective of this study was to evaluate the consequences of parasitism by S. flexicaulis on the fitness of M. calodendron. The intensity of parasitism and mortality on hosts of different sizes was evaluated, and foliage cover, fruit and seed set in parasitized and non-parasitized individuals were compared. More than 65% of a population of 1820 individuals was attacked. Host density positively influenced parasitism. The mortality and number of attacked hosts increased with their crown diameter. Heavily parasitized individuals showed 75 to 95% reduction of leaf cover and fruit production of 25% of those non-parasitized. Although no statistical difference was detected between the number of seeds per fruit, seed weight was lower in attacked plants. Parasitism by S. flexicaulis on M. calodendron may alter its population structure and dynamics, by reducing survival and fecundity rates.

Host specificity and experimental assessment of the early establishment of the mistletoe Phoradendron crassifolium (Pohl ex DC.) Eichler (Santalaceae) in a fragment of Atlantic Forest in southeast Brazil

“…These plants grow on twigs and branches of host plants (usually trees) using a specialized system of roots, called haustoria, that penetrate into the vascular tissue of the host and extract essential minerals and water (Kuijt 2003). Mistletoes may alter host growth, reproduction and physiology, decreasing its fitness (Mourão et al 2009;Bell & Adams 2011). Thin twigs (< 1 cm in diameter) often die when infected by mistletoes (Sargent 1995), as can highly infected hosts (Teodoro et al 2013).…”

Two mistletoes are too many?: Interspecific occurrence of mistletoes on the same host tree

“…Although this is not the norm in the fi eld, there is a lack of data on this subject in the literature and our knowledge of the particularities of mistletoe-host interactions is therefore limited. Mistletoe can have a major impact on the development of host plants (Press & Phoenix 2005, Arruda et al 2009Mourão et al 2009, Arruda et al 2012. Because mistletoe draws nutrition from its host-either by intercepting the xylem, as is the case for Struthanthus spp.…”

Ecology of neotropical mistletoes: an important canopy-dwelling component of Brazilian ecosystems

“…When mistletoes infest the host vascular system, they can alter growth, reproduction and physiology of the host, significantly reducing their performance (Medel 2000;Aukema 2003;Mourão et al 2009;Cameron et al 2009;Bell & Adams 2011). Th is eff ect on host growth and architecture may reduce host photosynthetic effi ciency and alter the respiration rates of the plants (Watling & Press 2001;Cameron et al 2008).…”