Honey Bees Avoiding Ant Harassment at Flowers Using Scent Cues.

Area of Science:

• Ecology
• Entomology
• Urban Ecology

Background:

• Pollinators need year-round floral resources for population health.
• Urban-natural interfaces face limited floral availability, especially during drought and fire threats.
• Succulents like Aloe spp. are used in landscaping for drought and fire resistance, potentially aiding pollinators.

Purpose of the Study:

• To investigate honey bee foraging behavior on Aloe flowers in the presence of Argentine ants.
• To determine if honey bees avoid ant-occupied flowers and if ant chemical cues mediate this avoidance.
• To assess the impact of invasive Argentine ants on pollinator resource acquisition.

Main Methods:

• Measured honey bee (Apis mellifera) visitation rates and durations to aloe flowers with and without Argentine ants (Linepithema humile).
• Conducted experiments comparing bee visitation to ant-occupied versus ant-excluded flowers.
• Assessed bee visitation to flowers treated with ant pheromone versus unmanipulated flowers.

Main Results:

• Honey bees actively avoided foraging on aloe flowers occupied by Argentine ants.
• Bees accepted ant-free flowers at a higher rate and increased visitation duration on ant-excluded flowers.
• Honey bees avoided flowers with Argentine ant pheromone and preferentially visited unmanipulated flowers.

Conclusions:

• Honey bees avoid floral resources occupied by invasive Argentine ants.
• Ant chemical cues (pheromones) are used by honey bees to identify and avoid ant-infested flowers.
• Invasive ants can limit crucial floral resource access for pollinators, impacting their populations at the urban-natural interface.