TY - JOUR

T1 - Natural enemy diversity reduces temporal variability in wasp but not bee parasitism

AU - Veddeler, Dorte

AU - Tylianakis, Jason M.

AU - Tscharntke, Teja

AU - Klein, Alexandra-Maria

N1 - Funding Information: Acknowledgments We would like to thank Dr Giovanni Onore for the use of the bee and wasp collection at the Universidad Catolica in Quito for further identification, Free de Koning, Roland Olschewski, and Betty Pico Díaz of the BIO-SYS project (Evaluation of biological diversity of land-use systems in a mega-diverse region of Ecuador) for their support and help, and Tannya Lozada for help with tree data collection. We are thankful to Gricel Sacoto, Jubian Casquete, Jose Pico, Cesar Calderon, Angel Chóez, and Jesus Lino for field and laboratory assistance, and to all Ecuadorian smallholders in and around Jipijapa for their permission to work in their ‘‘cafetales’’. We also greatly acknowledge helpful comments provided by Bernard Schmidt and one anonymous referee on a previous draft of the manuscript. Finally, we would like to thank the Deutsche Gesellschaft für technische Zusammenarbeit (GTZ) for their cooperation and the German Ministry of Education and Research (BMBF) for the financial support. The experiments described here comply with the current laws of the country in which they were performed.

PY - 2010/3

Y1 - 2010/3

N2 - Biodiversity may enhance and stabilise ecosystem functioning, but little evidence exists for diversity–function relationships involving multitrophic interactions in real landscapes. In multitrophic communities diversity may vary at different trophic levels, with either synergistic or antagonistic effects on ecosystem functioning. Intensification of land-use systems is often found to reduce diversity, which in turn may lead to reduced associated ecological functions in natural food webs, such as hostparasite interactions. In this study we investigated therelationship between the number of natural enemy and host species and the mean rate and temporal variability of parasitism (inverse of stability), along an intensification gradient of coffee agroforests in Ecuador. We used standardised trap nests for bees and wasps and their natural enemies in 14 agroforests, and evaluated these monthly over a period of 17 months. We found that parasitism rates of wasps and bees increased with increasing number of enemy species and decreased with increasing number of host species. Temporal variability in parasitism rates decreased with increasing number of enemy species and increased with temporal variability in enemy species richness; however, these effects were restricted to wasp hosts. Intensification of agroforests did not significantly affect species richness of hosts or enemies or their relationto parasitism and its temporal variability. We conclude that high enemy diversity may enhance parasitism rates and that high host diversity may provide resistance against consumption. Furthermore, we show that a diverse and stableenemy community may also have a stabilizing effect on parasitism rates. However, these effects may be host-guild specific, as these relations were restricted to wasps.

AB - Biodiversity may enhance and stabilise ecosystem functioning, but little evidence exists for diversity–function relationships involving multitrophic interactions in real landscapes. In multitrophic communities diversity may vary at different trophic levels, with either synergistic or antagonistic effects on ecosystem functioning. Intensification of land-use systems is often found to reduce diversity, which in turn may lead to reduced associated ecological functions in natural food webs, such as hostparasite interactions. In this study we investigated therelationship between the number of natural enemy and host species and the mean rate and temporal variability of parasitism (inverse of stability), along an intensification gradient of coffee agroforests in Ecuador. We used standardised trap nests for bees and wasps and their natural enemies in 14 agroforests, and evaluated these monthly over a period of 17 months. We found that parasitism rates of wasps and bees increased with increasing number of enemy species and decreased with increasing number of host species. Temporal variability in parasitism rates decreased with increasing number of enemy species and increased with temporal variability in enemy species richness; however, these effects were restricted to wasp hosts. Intensification of agroforests did not significantly affect species richness of hosts or enemies or their relationto parasitism and its temporal variability. We conclude that high enemy diversity may enhance parasitism rates and that high host diversity may provide resistance against consumption. Furthermore, we show that a diverse and stableenemy community may also have a stabilizing effect on parasitism rates. However, these effects may be host-guild specific, as these relations were restricted to wasps.

KW - Ecosystems Research

KW - Didactics of sciences education

KW - Biology

KW - Land use

KW - Biodiversity

KW - Management

KW - Pollinator

KW - Predator

UR - http://www.scopus.com/inward/record.url?scp=77949275183&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/2c5e50a0-a97f-30cd-98bd-b32cd8d591db/

U2 - 10.1007/s00442-009-1491-x

DO - 10.1007/s00442-009-1491-x

M3 - Journal articles

C2 - 19924447

VL - 162

SP - 755

EP - 762

JO - Oecologia

JF - Oecologia

SN - 0029-8549

IS - 3

ER -