Cross-Infection Experiments of Psittacanthus schiedeanus: Effects of Host Provenance, Gut Passage, and Host Fate on Mistletoe Seedling Survival.

Abstract

Host-specific race formation has been suggested for mistletoe species using cross-dispersal experiments. Here, we tested the effects of host provenance, bird gut passage, and host fate on Psittacanthus schiedeanus seed either manually extracted or bird gut-passed on four host species in Veracruz, Mexico: Acacia pennatula, Liquidambar styraciflua, Platanus mexicana, and Quercus germana. Both groups of seed were placed on the branches of host trees in a full factorial design of cross-inoculation. Bird gut passage had no effect on seed germination, and the only factor having a significant effect on seed germination was host provenance. Results of seedling establishment were similar to those of seed germination, where mistletoe seed inoculated on P. mexicana were more likely to germinate and seedlings to establish than seed inoculated on the other hosts. The significant host provenance-fruit treatment interaction was largely due to a lower seedling establishment of gut-passed seed from P. mexicana to P. mexicana and the other hosts. Although host provenance of mistletoe seed was a significant predictor in germination and seedling establishment, the host provenance-host fate interaction was the only significant predictor for seedling survival. The significant host provenance-host fate interaction was largely due to higher survival success of mistletoe seed from L. styraciflua to L. styraciflua and P. mexicana and from P. mexicana to P. mexicana and a lower success from Q. germana to Q. germana and from A. pennatula to A. pennatula.