Funds for this work were provided by an NSF grant to I. Perfecto and J. Vandermeer and by a grant from the Rackham Graduate School of the University of Michigan to H. Hsieh.
Cascading trait-mediated interactions induced by ant pheromones
Article first published online: 27 JUL 2012
© 2012 The Authors. Published by Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Ecology and Evolution
Volume 2, Issue 9, pages 2181–2191, September 2012
How to Cite
Ecology and Evolution 2012; 2(9): 2181–2191
- Issue published online: 11 SEP 2012
- Article first published online: 27 JUL 2012
- Manuscript Accepted: 5 JUN 2012
- Manuscript Revised: 25 MAY 2012
- Manuscript Received: 14 APR 2012
- University of Michigan
- Alarm signaling;
- ant–hemipteran mutualism;
- coffee agroecosystem;
- complex ecological network;
- predator avoidance;
Trait-mediated indirect interactions (TMII) can be as important as density-mediated indirect interactions. Here, we provide evidence for a novel trait-mediated cascade (where one TMII affects another TMII) and demonstrate that the mechanism consists of a predator eavesdropping on chemical signaling. Ants protect scale insects from predation by adult coccinellid beetles – the first TMII. However, parasitic phorid flies reduce ant foraging activity by 50% – the second TMII, providing a window of opportunity for female beetles to oviposit in high-quality microsites. Beetle larvae are protected from ant predation and benefit from living in patches with high scale densities. We demonstrate that female beetles can detect pheromones released by the ant when attacked by phorids, and that only females, and especially gravid females, are attracted to the ant pheromone. As ants reduce their movement when under attack by phorids, we conclude that phorids facilitate beetle oviposition, thus producing the TMII cascade.