Functional trait mismatch between native and introduced bee pollinators servicing a global fruit crop

Area of Science:

• Ecology
• Evolutionary Biology
• Conservation Biology

Background:

• Ecosystem services, like pollination, are increasingly understood through functional traits and phylogenetic methods, moving beyond simple species richness.
• Orchards surrounded by natural versus disturbed landscapes in Australia were studied to compare hymenopteran pollinator communities.
• The research assessed functional traits and phylogenetic patterns of pollinators to understand their roles in apple pollination.

Purpose of the Study:

• To investigate the functional ecology and phylogenetic diversity of hymenopteran pollinators in apple orchards.
• To determine if functional traits exhibit non-random phylogenetic patterns.
• To explore the functional entities (FEs) of bees and assess functional redundancy in different landscape types.

Main Methods:

• Phylogenetic analysis using ultraconserved elements (UCEs) to build a maximum likelihood phylogeny for 48 hymenopteran morphospecies.
• Assessment of morphological and behavioral traits (hairiness, body size, glossa length, pollen load purity, loose pollen) for phylogenetic signal.
• Calculation of phylogenetic diversity and functional richness, evenness, and diversion using functional entities (FEs) for each landscape.

Main Results:

• Pollinator communities in natural landscapes showed higher phylogenetic complexity and functional divergence than in disturbed landscapes.
• Bee hairiness was the only trait with a significant phylogenetic signal; other traits showed weaker or no phylogenetic association.
• Despite landscape differences, both supported equal numbers of bee functional entities (FEs), with the introduced honey bee occupying a unique FE.

Conclusions:

• Bee hairiness is a key functional trait with phylogenetic signal, influencing pollination services.
• While both landscape types had similar numbers of bee FEs, native bees did not fully functionally replace honey bees.
• Threats to honey bee populations pose a significant risk to pollination-dependent crops due to low functional redundancy in pollinator assemblages.