caa a22 4500 606164707 CHVBK 20210128100650.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s10144-014-0451-4 doi (NATIONALLICENCE)springer-10.1007/s10144-014-0451-4 Allee effects and population regulation: a test for biotic resistance against an invasive leafroller by resident parasitoids [Elektronische Daten] [Linda Bürgi, William Roltsch, Nicholas Mills] Resident natural enemies can impact invasive species by causing Allee effects, leading to a reduction in establishment success of small founder populations, or by regulating or merely suppressing the abundance of established populations. Epiphyas postvittana, the Light Brown Apple Moth, an invasive leafroller in California, has been found to be attacked by a large assemblage of resident parasitoids that cause relatively high rates of parasitism. Over a 4-year period, we measured the abundance and per capita growth rates of four E. postvittana populations in California and determined parasitism rates. We found that at two of the sites, parasitism caused a component Allee effect, a reduction in individual survivorship at lower E. postvittana population densities, although it did not translate into a demographic Allee effect, an impact on per capita population growth rates at low densities. Instead, E. postvittana populations at all four sites exhibited strong compensatory density feedback throughout the entire range of densities observed at each site. As we found no evidence for a negative relationship between per capita population growth rates and parasitism rates, we concluded that resident parasitoids were unable to regulate E. postvittana populations in California. Despite a lack of evidence for regulation or a demographic Allee effect, the impact of resident parasitoids on E. postvittana populations is substantial and demonstrates significant biotic resistance against this new invader. The Society of Population Ecology and Springer Japan, 2014 Density feedback nationallicence Epiphyas postvittana nationallicence Meteorus ictericus nationallicence Population growth rates nationallicence Bürgi Linda Department of Environmental Science, Policy and Management, University of California, Berkeley, USA aut Roltsch William Biological Control Program, California Department of Food and Agriculture, 3288 Meadowview Rd, Sacramento, CA, USA aut Mills Nicholas Department of Environmental Science, Policy and Management, University of California, Berkeley, USA aut Population Ecology Springer Japan 57/1(2015-01-01), 215-225 1438-3896 57:1<215 2015 57 10144 https://doi.org/10.1007/s10144-014-0451-4 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10144-014-0451-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bürgi Linda Department of Environmental Science, Policy and Management, University of California, Berkeley, USA aut NATIONALLICENCE 700 1- Roltsch William Biological Control Program, California Department of Food and Agriculture, 3288 Meadowview Rd, Sacramento, CA, USA aut NATIONALLICENCE 700 1- Mills Nicholas Department of Environmental Science, Policy and Management, University of California, Berkeley, USA aut NATIONALLICENCE 773 0- Population Ecology Springer Japan 57/1(2015-01-01), 215-225 1438-3896 57:1<215 2015 57 10144