DOI: 10.5061/dryad.m2763r3
title: Data from: Infrapopulation size and mate availability influence reproductive success of a parasitic plant

description: 1. Aggregated distributions of parasite individuals across host
 individuals are nearly ubiquitous among parasitic taxa. The size and sex
 ratio of the population of one parasite species infecting a single host
 (hereafter “infrapopulation”) can influence parasite fitness through
 intraspecific competition, mate availability, and the ability to attract
 vectors for transmission of parasite propagules. Competition for both
 resources and for pollen and seed vector services may limit reproductive
 success (pollen receipt, fruit production, and seed dispersal) in large
 infrapopulations of parasitic plants, while mate limitation or reduced
 ability to attract vectors may limit this success in small
 infrapopulations. 2. Using a dioecious parasitic plant, desert mistletoe
 (Phoradendron californicum), we experimentally removed reproductive tissue
 from male parasites in whole infrapopulations to test for independent
 effects of infrapopulation size and within-host mate availability on
 female fitness. As desert mistletoe requires both pollen and seed vectors
 for successful reproduction, the species provides the opportunity to test
 how infrapopulation characteristics affect multiple components of parasite
 fitness. 3. We found that insect-mediated pollen receipt decreased for
 parasites on treated hosts, consistent with within-host mate limitation.
 Additionally, the relationship between mate availability and fruit
 production per flower ranged from neutral to positive depending on year of
 the experiment. 4. As expected if competition for host resources limits
 reproductive success more than mate availability in larger
 infrapopulations, the greater pollen receipt to females in large
 infrapopulations did not generally translate into increased mistletoe
 fruit production. Relationships between mistletoe fruit production per
 flower and infrapopulation size ranged from negative to neutral. 5. Both
 pollen receipt and pollinator visitation increased with infrapopulation
 size, indicating that larger populations can be more attractive to pollen
 vectors independent of mate availability. However, we found no
 relationship between infrapopulation size and fruit removal by dispersers
 and, thus, no evidence that attraction of seed dispersal vectors increases
 with infrapopulation size. 6. Synthesis: These results highlight the
 interactive roles of within-host processes (resource competition, mate
 availability, and vector attraction) in determining the fitness of
 biotically-transmitted parasite individuals.
description: Experimental Data on
 Phoradendron californicum infrapopulation experimentAll data from the
 associated manuscript are provided. Natural_infrapopulations sheet
 provides observational data on infrapopulations assessed in the field.
 Pollinator_visitation sheet provides data on observation of pollinator
 visitation to infrapopulations of different characteristics.
 Pollen_deposition sheet provides data on pollen receipt to flowers of
 female parasitic plants on control and treated host plants.
 Fruit_success_removal provides data on fruit set and fruit removal for
 female parasitic plants on control and treated host plants. Please see the
 metadata sheet for definitions of all column names provided in the data
 sheets.InfrapopulationExperiment_DryadData.xlsx