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Dryad

Data from: Fitness costs and benefits of a non-native floral resource for subalpine solitary bees

Forrest, Jessica R.K.1; Cahill, Charlotte M.1; CaraDonna, Paul J.2

Research facility: Rocky Mountain Biological Laboratory
Published Jan 23, 2025; Updated Jan 28, 2025 on Dryad. https://doi.org/10.5061/dryad.cc2fqz6g9

Data files

Abstract

Organisms inhabiting seasonal environments must fit their life cycle into a limited time window while also synchronizing periods of resource consumption with timing of resource availability. Introduced non-native species, which often differ in phenology from natives, can alter and expand the seasonal window of resource availability for native consumers, providing potential fitness benefits. However, if these non-native resources are nutritionally unsuitable for native consumers, their presence could elicit foraging behaviour that proves maladaptive—i.e., they could act as an ecological trap. Here, we used multi-year field observations and a laboratory experiment to investigate the impacts of a common non-native plant species on two components of fitness in three solitary bee species (all specialist consumers of pollen from the plant family Asteraceae) native to the Colorado Rocky Mountains. First, we tested whether individual bees that collect pollen from the non-native common dandelion (Taraxacum officinale) produce more offspring than those that do not, thanks to the unusually early flowering phenology of the non-native. Second, we compared survival of bee larvae experimentally reared on Taraxacum pollen to that of larvae reared on native Asteraceae pollen. Bees that used at least some non-native Taraxacum pollen produced more potentially viable offspring, but larval survival was significantly reduced for bee larvae experimentally fed provisions dominated by Taraxacum pollen. Therefore, survival costs may negate the potential fitness benefits of early nesting, indicating that non-native floral resource use may act as an ecological trap for native bees. Using a series of simple simulations informed by our results, we explore the fitness effects of non-native floral resource use, demonstrating that the net cost or benefit depends on how bees respond to resource shortages. Our results highlight the importance of considering organisms’ full life cycles when evaluating the fitness consequences of resource availability and species introductions.