Ferromagnetic nanoparticles are ubiquitous across a wide range of bee species

Sunday, November 10, 2024

10:24 AM – 10:36 AM MST

Location: Phoenix Convention Center, 222 B, PCC

Presenting Author(s)

Anne F. Murray

University of Tennessee
Knoxville, Tennessee

Co-Author(s)

CJ

Cameron Jorgensen

University of Tennessee
Knoxville, Tennessee
CB

Charlote Buchanan

University of Tennessee
Knoxville, Tennessee
WL

WLNC Liyanage

University of Tennessee
Knoxville, Tennessee
Laurence Packer (he/him/his)

Distinguished Research Professor
York University
Toronto, Ontario, Canada
MW

Micheal Winklhofer

University of Oldenburg
Oldenburg, Niedersachsen, Germany
Laura Russo

Assistant Professor
University of Tennessee
Knoxville, Tennessee
DG

Dustin Gilbert

University of Tennessee
Knoxville, Tennessee

Magnetoreception, the ability to sense the geomagnetic field, is broadly distributed across animals. The honey bee (Apis mellifera) is well known to be magnetoreceptive, along with two less studied groups: stingless bees and bumble bees (Bombus spp.). All of these are closely related and eusocial, raising questions about the evolutionary origin of magnetoreception in bees and its link to sociality. We measured the magnetic properties of 71 bee species and found 83% exhibited an appreciable magnetic response; 52 newly identified as magnetic. We classified bees as: “non-magnetic” (paramagnetic or diamagnetic), “ferromagnetic”, or “superparamagnetic”. Ferromagnetism corresponds to magnetic polarization associated with iron oxide nanoparticles necessary to distinguish North from South. Superparamagnets are exceedingly small (< 20 nm diameter) ferromagnets, resulting in a loss of thermodynamic stability, reducing agglomeration while maintaining magnetic sensitivity without the ability to distinguish North from South. Magnetic properties were broadly distributed in individuals from Apidae, Halictidae and Megachilidae, and detected in some Colletidae and Andrenidae. We observed heterogeneity among body parts, with the head, including antennae, being least likely to have a magnetic response. Female and male bees of the same species varied in magnetic response and there was a negative trend between magnetic strength and intertegular distance (ITD). Surprisingly, we did not see any consistent patterns between magnetism and sociality or nesting behavior. Magnetism is broadly present across bee taxa, but not uniform. Future efforts are focused on whether these magnetic properties correspond to magnetoreception in live bees, which we will assess through field behavior experiments.