SOCIAL BUT NOT SOLITARY BEES REJECT DANGEROUS FLOWERS WHERE A CONSPECIFIC HAS RECENTLY BEEN ATTACKED

Llandres, A.L., Gonzalvez, F.G., & Rodriguez-Girones, M.A.

Social vs. Solitary Bees

Related bees live together

Infertile females Division of labor A. mellifera, A.

dorsata, A. florea, B. terrestris

Bees are isolated All females fertile Builds own nest N. strigata

Social Solitary

Introduction Animals rely on cues to avoid predators Avoiding flowers with crushed

“conspecifics” Two types of cues produced by prey

By-products of predation Alarm signals

2-heptanone2-methylbutyl

Alarm Signals

2 hypothesized functions: Signals nectar depletion

(Balderrama, 1996) Increases efficiency

Marks dangerous flowers

Both social and solitary bees respond to volatile cues Social bees are less wary

Questions

Do bees mark visited flowers to increase efficiency?

Do solitary bees use alarm signals? No studies for the presence of alarm signals

in solitary bees.

Methods

Inflorescence: a cluster of flowers on one stem

Assigned randomly Experimental Control

Experimental: bees grasped over the thorax

Control: bees visit flower and leave

Methods Record number of bees after that

rejecting or visiting the flower Rejection: Bee hovers, then leaves. Accept: Bee hovers and lands.

All conducted during sunny weather Tested social bees and solitary bees

Methods Experiments in six geographical

locations Baza, Spain Almeria, Spain Vulluercas-Ibores, Spain Cannonvale, Australia MacRitchie Reservoir Park, Singapore Xishuangbanna, China

Trials conducted as far away as possible Experimental: 233, Control: 236

***: Social Bees (P<.0001)NS: Solitary Bees (P>0.25)

Probability of landing vs. Bee species

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Discussion Social bees release alarm signals to warn

of predators Treatment had a strong effect on social

bees relative to solitary bees Solitary bees do not release alarm

signals

Limitations: All tests were not run at the same place, at the same time. Different plant species