While the impact of predator‐induced stress on prey has received considerable attention, there has been far less research into the effect of competitors. Cues from aggressive competitors should be particularly likely to evoke behavioral and/or physiological responses, since they may be indicative of both direct (interference) and indirect (exploitative) threats. The danger posed by such competitors, and the “fear” they evoke, should be reduced at lower competitor densities and by the presence of individual conspecifics specialized for defense. We assessed how Reticulitermes flavipes termite workers and soldiers were affected by cues from conspecific nestmates, conspecific non‐nestmates, and the heterospecific competitor R. virginicus. Competitor cues altered flavipes worker and soldier behavior, decreasing worker growth and increasing their mortality. The presence of flavipes soldiers largely ameliorated these negative impacts: adding even a single soldier (5% of flavipes individuals) decreased worker mortality by 50–80%. Although worker mortality increased with competitor density, increased soldier densities did not increase the benefit to workers. The small number of soldiers required to substantially alter cue‐mediated interactions suggests that this caste, in addition to providing direct defense, also occupies a “keystone role” by providing homeostatic feedback to workers functioning in stressful environments.

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Notes/Citation Information

Published in Ecology, v. 98, no. 4, p. 952-960.

© 2017 by the Ecological Society of America

The copyright holder has granted the permission for posting the article here.

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Funding Information

This study was supported by a Vice President Research Grant (Award Number: 1012579960), and a Hatch fund (Accession Number: 1004654) from the USDA National Institute of Food and Agriculture to XZ.

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The information reported in this paper (No. 17-08- 001) is part of a project of the Kentucky Agricultural Experiment Station and is published with the approval of the Director.

Additional supporting information may be found in the online version of this article at http://onlinelibrary.wiley.com/doi/10.1002/ecy.1746/suppinfo

ecy1746-sup-0001-appendixs1.docx (12 kB)
Appendix S1: Table S1