Enemy escape: A general phenomenon in a fragmented literature?
Julia J. Mlynarek,
Chandra E. Moffat,
Sara Edwards,
Anthony L. Einfeldt,
Allyson Heustis,
Rob Johns,
Mallory MacDonnell,
Deepa S. Pureswaran,
Dan T. Quiring,
Zoryana Shibel,
Stephen B. Heard
Affiliations
Julia J. Mlynarek
Department of Biology, University of New Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada; Present address: Harrow Research and Development Centre, Agriculture and Agri-Food Canada, 2585 County Road 20, Harrow, ON N0R 1G0, Canada; These authors contributed equally to this work.
Chandra E. Moffat
Department of Biology, University of New Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada; Present address: Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, 850 Lincoln Road, Post Office Box 20280, Fredericton, NB E3B 4Z7, Canada; These authors contributed equally to this work.
Sara Edwards
Population Ecology Group, Faculty of Forestry & Environmental Management, University of New Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada
Anthony L. Einfeldt
Department of Biology, University of New Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada
Allyson Heustis
Department of Biology, University of New Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada; Forest Insect Ecology, Atlantic Forestry Centre, 1350 Regent Street, P.O. Box 4000, Fredericton, NB E3B 5P7, Canada
Rob Johns
Forest Insect Ecology, Atlantic Forestry Centre, 1350 Regent Street, P.O. Box 4000, Fredericton, NB E3B 5P7, Canada
Mallory MacDonnell
Department of Biology, University of New Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada
Deepa S. Pureswaran
Forest Insect Ecology, Laurentian Forestry Centre, 1055 Du PEPS Street, P.O. Box 10380, Québec, QC G1V 4C7, Canada
Dan T. Quiring
Population Ecology Group, Faculty of Forestry & Environmental Management, University of New Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada
Zoryana Shibel
Department of Biology, University of New Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada
Stephen B. Heard
Department of Biology, University of New Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada
Many populations are thought to be regulated, in part, by their natural enemies. If so, disruption of this regulation should allow rapid population growth. Such “enemy escape” may occur in a variety of circumstances, including invasion, natural range expansion, range edges, suppression of enemy populations, host shifting, phenological changes, and defensive innovation. Periods of relaxed enemy pressure also occur in, and may drive, population oscillations and outbreaks. We draw attention to similarities among circumstances of enemy escape and build a general conceptual framework for the phenomenon. Although these circumstances share common mechanisms and depend on common assumptions, enemy escape can involve dynamics operating on very different temporal and spatial scales. In particular, the duration of enemy escape is rarely considered but will likely vary among circumstances. Enemy escape can have important evolutionary consequences including increasing competitive ability, spurring diversification, or triggering enemy counteradaptation. These evolutionary consequences have been considered for plant–herbivore interactions and invasions but largely neglected for other circumstances of enemy escape. We aim to unite the fragmented literature, which we argue has impeded progress in building a broader understanding of the eco-evolutionary dynamics of enemy escape.
