Warming, CO2, and nitrogen deposition interactively affect a plant-pollinator mutualism.
Environmental changes threaten plant-pollinator mutualisms and their critical ecosystem service. Drivers such as land use, invasions and climate change can affect pollinator diversity or species encounter rates. However, nitrogen deposition, climate warming and CO(2)  enrichment could interact to disrupt this crucial mutualism by altering plant chemistry in ways that alter floral attractiveness or even nutritional rewards for pollinators. Using a pumpkin model system, we show that these drivers non-additively affect flower morphology, phenology, flower sex ratios and nectar chemistry (sugar and amino acids), thereby altering the attractiveness of nectar to bumble bee pollinators and reducing worker longevity. Alarmingly, bees were attracted to, and consumed more, nectar from a treatment that reduced their survival by 22%. Thus, three of the five major drivers of global environmental change have previously unknown interactive effects on plant-pollinator mutualisms that could not be predicted from studies of individual drivers in isolation.
School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
Shelley E R
SE
Hoover
Jenny J
JJ
Ladley
Anastasia A
AA
Shchepetkina
Maggie
M
Tisch
Steven P
SP
Gieseg
Jason M
JM
Tylianakis
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001516:Bees / Q000502:physiology*; D002245:Carbon Dioxide; D028464:Cucurbita / Q000502:physiology; D017753:Ecosystem; D035264:Flowers / Q000737:chemistry / Q000254:growth & development / Q000502:physiology; D057232:Global Warming; D009584:Nitrogen; D057048:Plant Nectar / Q000737:chemistry*; D018521:Plant Physiological Phenomena; D054817:Pollination; D015996:Survival Rate
D000596:Amino Acids; D057048:Plant Nectar; D002245:Carbon Dioxide; D009584:Nitrogen