Static allometry of a threat device that is not a weapon: wing spots in male Heterandrium fallax (Hymenoptera Agaonidae)

Abstract

Males of the agaonid wasp Heterandrium fallax have wing spots that they display during aggressive encounters near the ostioles of syconia of the fig Ficus pertusa, apparently in competition for the opportunity to copulate with emerging females. In accord with predictions of the “functional allometry hypothesis” for the allometry of structures that are under sexual selection as threat devices and that do not function as weapons, larger males tended to have proportionally larger wing spots. Some smaller males lacked spots, and smaller males were less likely to be collected near female emergence sites or to show antennal damage that probably results from male fights.

KEY WORDS:

• fig wasp
• positive allometry
• scaling
• threat signal

ACKNOWLEDGEMENTS

We thank William Ramírez for identifying the fig tree, John Noyes, Eric Grissell and especially Zednek Bouček for help identifying the wasp, Paul Hanson for much good advice, Judith Bronstein for help with references, and one anonymous reviewer for comments.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

SUPPLEMENTAL DATA

Supplemental data for this article can be accessed at https://doi.org/10.1080/03949370.2021.2024269

Additional information

Funding

The authors reported there is no funding associated with the work featured in this article.