Dominance hierarchies are ubiquitous in invertebrates and vertebrates, but little is known on how genes influence dominance rank. Our gaps in knowledge are specifically significant con-cerning female hierarchies, particularly in insects. To start filling these gaps, we studied the social bumble bee Bombus terrestris, in which social hierarchies among females are common and functionally significant. Dominance rank in this bee is influenced by multiple factors, including juvenile hormone (JH) that is a major gonadotropin in this species. We tested the hypothesis that the JH responsive transcription factor Krüppel homologue 1 (Kr-h1) mediates hormonal influences on dominance behavior. We first developed and validated a perfluorocarbon nanoparticles-based RNA interference protocol for knocking down Kr-h1 expression. We then used this procedure to show that Kr-h1 mediates the influence of JH, not only on oogenesis and wax production, but also on aggression and dominance rank. To the best of our knowledge, this is the first study causally linking a gene to dominance rank in social insects, and one of only a few such studies on insects or on female hierarchies. These findings are important for determining whether there are general molecular principles governing dominance rank across gender and taxa.
Bibliographical noteFunding Information:
Acknowledgments: This research was supported by grants from the US-Israel Binational Agricultural Research and Development Fund (BARD, grant No. IS-4418-11, and IS-5077-18, to G.B.), ISF-NSFC joint research program (grant No. 3391/20 to G.B.), the United States-Israel Binational Science Foundation (BSF grant No. 2017188 to G.B.), and The Planning and Budgeting Committee (PBC) Fellowship Program for Outstanding Chinese and Indian Post-Doctoral Fellows (to A.P).
Funding: This research was funded by grants from the US-Israel Binational Agricultural Research and Development Fund (BARD, grant No. IS-4418-11, and IS-5077-18), ISF-NSFC joint research program (grant No. 3391/20), the United States-Israel Binational Science Foundation (BSF grant No. 2017188).
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
- Juvenile hormone
- Krüppel-homologue 1
- RNA interference