caa a22 4500 388035838 CHVBK 20180307125004.0 cr unu---uuuuu 161130e199812 xx s 000 0 eng 10.1017/S0007485300054286 doi S0007485300054286 pii (NATIONALLICENCE)cambridge-10.1017/S0007485300054286 Impact and oviposition behaviour of Ageniaspis fuscicollis (Hymenoptera: Encyrtidae), a polyembryonic parasitoid of the apple ermine moth, Yponomeuta malinellus (Lepidoptera: Yponomeutidae) [Elektronische Daten] The distribution and extent of parasitism of the apple ermine moth Yponomeuta malinellus Zeller by the polyembyronic encyrtid parasitoid Ageniaspis fuscicollis (Dalman) were examined in a three year field study and related to oviposition behaviour in the laboratory. Ageniaspis fuscicollis attacks egg batches of its host and kills the final instar larvae, which feed gregariously from within tents. Host population densities in the field were low, from 1.5 to 2.2 tents per 100 leaf clusters, and parasitism increased from 7.8% to 18% over the three year period. Parasitism was independent of host density at the whole tree scale, but at the individual tent scale, the probability of a tent containing parasitized host larvae increased and percent parasitism decreased with the number of host larvae per tent. Observations on the oviposition behaviour of A. fuscicollis in the laboratory revealed that parasitoids distributed their eggs randomly within host egg batches. On average, they spent almost two hours on an egg batch and laid 44% of their egg load of 132 eggs into the first egg batch visited, leading to a mean of 1.4 eggs laid per host egg through frequent self-superparasitism of hosts. The percentage of eggs receiving one or more ovipositions was independent of the size of an egg batch, contradicting our field observations of inverse density dependence. Factors that might account for the differences in rates of parasitism and attack distributions between laboratory and field data are discussed. Copyright © Cambridge University Press 1998 Kuhlmann U. CABI Bioscience Centre, 1 Rue des Grillons, CH-2800 Delémont, Switzerland Babendreier D. CABI Bioscience Centre, 1 Rue des Grillons, CH-2800 Delémont, Switzerland Hoffmeister T.S. Zoologisches Institut der Universität Kiel - Ökologie, Germany Mills N.J. Center for Biological Control, University of California at Berkeley, USA Bulletin of Entomological Research Cambridge University Press 88/6(1998-12), 617-625 0007-4853 88:6<617 1998 88 BER https://doi.org/10.1017/S0007485300054286 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0007485300054286 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kuhlmann U. CABI Bioscience Centre, 1 Rue des Grillons, CH-2800 Delémont, Switzerland NATIONALLICENCE 700 1- Babendreier D. CABI Bioscience Centre, 1 Rue des Grillons, CH-2800 Delémont, Switzerland NATIONALLICENCE 700 1- Hoffmeister T.S. Zoologisches Institut der Universität Kiel - Ökologie, Germany NATIONALLICENCE 700 1- Mills N.J. Center for Biological Control, University of California at Berkeley, USA NATIONALLICENCE 773 0- Bulletin of Entomological Research Cambridge University Press 88/6(1998-12), 617-625 0007-4853 88:6<617 1998 88 BER CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge