Queen Recognition Signals in Two Primitively Eusocial Halictid Bees: Evolutionary Conservation and Caste-Specific...

Area of Science:

• Insect social behavior
• Chemical ecology
• Eusociality

Background:

• Queen signals are crucial for reproductive harmony in eusocial insects, yet few have been identified.
• Understanding queen signal function and perception is vital for eusocial colony regulation.

Purpose of the Study:

• Identify queen recognition signals in the halictid bee *Lasioglossum pauxillum*.
• Analyze caste differences in olfactory perception of queen signals in *L. pauxillum* and *L. malachurum*.
• Investigate the mode of action for queen signals and their conservation across species.

Main Methods:

• Chemical analyses to determine caste-specific chemical profiles.
• Bioassays to assess worker behavior in response to queen-specific compounds.
• Electrophysiological analyses to study antennal responses in queens.

Main Results:

• Queens of *L. pauxillum* exhibit higher concentrations of macrocyclic lactones compared to workers.
• Macrocyclic lactones elicit subordinate behavior in workers, confirming their role as queen recognition signals.
• Queens of both *L. pauxillum* and *L. malachurum* show no antennal reaction to specific macrocyclic lactones.

Conclusions:

• Macrocyclic lactones function as conserved queen recognition signals in *Lasioglossum* bees.
• The lack of antennal response in queens suggests a mechanism to prevent reproductive self-inhibition.
• Findings prompt further research into the conservation and action of queen signals in eusocial insects.