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Co-flowering plant species commonly share flower visitors, and thus have the potential to influence each other's pollination. In this study we analysed 750 quantitative plant-pollinator networks from 28 studies representing diverse biomes worldwide. We show that the potential for one plant species to influence another indirectly via shared pollinators was greater for plants whose resources were more abundant (higher floral unit number and nectar sugar content) and more accessible. The potential indirect influence was also stronger between phylogenetically closer plant species and was independent of plant geographic origin (native vs. non-native). The positive effect of nectar sugar content and phylogenetic proximity was much more accentuated for bees than for other groups. Consequently, the impact of these factors depends on the pollination mode of plants, e.g. bee or fly pollinated. Our findings may help predict which plant species have the greatest importance in the functioning of plant-pollination networks.

Co-flowering plant species commonly share flower visitors, and thus have the potential to influence each other's pollination. In this study we analysed 750 quantitative plant–pollinator networks from 28 studies representing diverse biomes worldwide. We show that the potential for one plant species to influence another indirectly via shared pollinators was greater for plants whose resources were more abundant (higher floral unit number and nectar sugar content) and more accessible. The potential indirect influence was also stronger between phylogenetically closer plant species and was independent of plant geographic origin (native vs. non-native). The positive effect of nectar sugar content and phylogenetic proximity was much more accentuated for bees than for other groups. Consequently, the impact of these factors depends on the pollination mode of plants, e.g. bee or fly pollinated. Our findings may help predict which plant species have the greatest importance in the functioning of plant–pollination networks

Few studies on insects and host plant associations have been undertaken in the Galápagos Islands. Since endemism in the Galápagos is high, and those species of endemic plants that are critically endangered will consequently also have an equally endangered insect fauna associated with them, it is important to know the endemic species of insects that have an association with those plants and their degree of dependence. Insect interactions with 19 species of endangered plant were observed and collections made between April 2001 and August 2002. One hundred and eight insect species were found to have some degree of interaction, using plants for refuge and/or as a food source. Eighty two of these could be identified to species. Most of the identified insects (76,8%) are endemic or native and several generalist feeders. They do not appear to have a restricted feeding range or distinct host plant preference., Pocos estudios acerca de insectos asociados a plantas se han realizado en las Islas Galápagos. Tomando en cuenta el alto grado de endemismo en Galápagos, unido al hecho que especies de plantas que están en peligro de extinción consecuentemente también tendrán entomofauna asociada igualmente en peligro, es importante conocer qué especies de insectos usan estas plantas y su grado de dependencia. Durante el periodo comprendido entre abril 2001 y agosto 2002 se observaron y colectaron manualmente insectos que interactúan con 19 especies de plantas en peligro. Ciento ocho especies de insectos fueron observados usando las plantas como refugio y/o fuente de alimento. Ochenta y dos insectos fueron identificados. La mayoría de los insectos identificados observados (76,8%) son endémicos o nativos y de estos varias especies son generalistas ya que aparentemente no tienen un rango restringido de alimentación ni ninguna preferencia por la planta hospedera.