title: Apparent competition drives community-wide parasitism rates and changes in host abundance across ecosystem boundaries.
abstract: Species have strong indirect effects on others, and predicting these effects is a central challenge in ecology. Prey species sharing an enemy (predator or parasitoid) can be linked by apparent competition, but it is unknown whether this process is strong enough to be a community-wide structuring mechanism that could be used to predict future states of diverse food webs. Whether species abundances are spatially coupled by enemy movement across different habitats is also untested. Here, using a field experiment, we show that predicted apparent competitive effects between species, mediated via shared parasitoids, can significantly explain future parasitism rates and herbivore abundances. These predictions are successful even across edges between natural and managed forests, following experimental reduction of herbivore densities by aerial spraying of insecticide over 20 hectares. This result shows that trophic indirect effects propagate across networks and habitats in important, predictable ways, with implications for landscape planning, invasion biology and biological control.
authors: Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
authors: Carol M
authors: 0000-0003-3805-5528
authors: CM
authors: Frost
authors: Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
authors: Guadalupe
authors: G
authors: Peralta
authors: USDA-ARS Northern Plains Agricultural Research Laboratory, Sidney, Montana 59270, USA.
authors: Tatyana A
authors: TA
authors: Rand
authors: School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley Western Australia 6009, Australia.|CSIRO Land &Water, Centre for Environment and Life Sciences, Underwood Ave, Floreat Western Australia 6014, Australia.
authors: Raphael K
authors: RK
authors: Didham
authors: Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.|Biomolecular Interaction Centre, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.|Structural Biology Research Unit, Department of Clinical Laboratory Sciences, University of Cape Town, Observatory, Cape Town 7700, South Africa.|Department of Plant Pathology and Emerging Pathogens Institute, University of Florida, Gainesville, Florida 32611, USA.
authors: Arvind
authors: A
authors: Varsani
authors: Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.|Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK.
authors: Jason M
authors: 0000-0001-7402-5620
authors: JM
authors: Tylianakis
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000472:pathogenicity; D061046:Biological Control Agents / Q000008:administration & dosage; D005260:Female; D020387:Food Chain; D005544:Forecasting / Q000379:methods; D065928:Forests; D060434:Herbivory / Q000502:physiology*; D006790:Host-Parasite Interactions; D007448:Invertebrates / Q000382:microbiology / Q000502:physiology*; D007814:Larva / Q000382:microbiology / Q000502:physiology; D008297:Male; D009520:New Zealand; D011157:Population Dynamics / Q000639:trends; D014197:Trees / Q000469:parasitology / Q000502:physiology*; D014863:Wasps
chemical_list: D061046:Biological Control Agents