Size-dependent foraging gene expression and behavioral caste differentiation in Bombus ignitus

Area of Science:

• Insect behavior
• Molecular biology
• Evolutionary genetics

Background:

• Foraging genes, like cGMP-dependent protein kinase, are linked to behavioral castes in eusocial insects.
• Honeybee foraging gene expression contrasts with ants and wasps, suggesting diverse mechanisms for division of labor.
• Bumblebees exhibit size-dependent behavioral castes, offering a novel system to study foraging genes.

Purpose of the Study:

• To characterize the foraging gene (Bifor) in bumblebees (Bombus ignitus).
• To investigate the relationship between Bifor expression and size-dependent behavioral caste differentiation in bumblebees.

Main Methods:

• Gene characterization of Bifor in Bombus ignitus.
• Analysis of Bifor expression levels in different behavioral castes (nurses vs. foragers).
• Statistical analysis of Bifor expression correlation with individual body size.

Main Results:

• The bumblebee Bifor gene is 2004 bp long, encoding 668 amino acids with high identity to orthologs.
• Bifor expression was higher in nurses than in foragers, consistent with ants and wasps.
• Bifor expression showed a negative correlation with body size within behavioral castes.

Conclusions:

• Bifor expression in bumblebees is dependent on body size.
• These findings support the role of Bifor in behavioral caste differentiation in bumblebees.
• The study identified a conserved relationship between foraging gene expression and division of labor across different insect societies.