Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Nectar exploitation by herbivores and their parasitoids is a function of flower species and relative humidity.
AU - Winkler, Karin
AU - Wäckers, Felix L.
AU - Kaufman, Leyla V.
AU - Larraz, Virginia
AU - van Lenteren, Joop C.
PY - 2009/9
Y1 - 2009/9
N2 - In conservation biological control, diversification of the agro ecosystem with flowering vegetation is seen as an important tool to support the broad range of predators and parasitoids that require nectar and pollen sources to survive and reproduce. In order to identify flowering plants that provide suitable food sources for natural enemies without supporting the pest species, we analyzed the exploitation of 19 flowering plants by two important lepidopteran cabbage pests, Pieris rapae and Plutella xylostella, and their hymenopteran parasitoids, Cotesia glomerata and Diadegma semiclausum. The experiments were conducted at 90% r.h., while Pieris rapae was tested both at 45% r.h. and at 90% r.h. At 45 ± 5% r.h., corresponding with field conditions at which P. rapae is predominantly active, the butterfly was unable to feed on a number of exposed floral nectar sources whose nectar was successfully exploited at 90% r.h. The broader nectar exploitation by P. rapae at the high humidity is presumably explained by the resulting decrease in nectar viscosity. When comparing D. semiclausum and its herbivorous host P. xylostella, the herbivore exploited a broader range of plants. However, those plants that benefited both the parasitoid and the herbivore had a much stronger effect on the longevity of the parasitoid. The results from the accessibility bioassay suggest that flowers where nectar is not accessible can have a negative impact on insect survival presumably by stimulating foraging without providing accessible nectar. Our results underline the importance of considering species-specific environmental conditions when fine-tuning the choice of nectar sources to be used in conservation biological control programs.
AB - In conservation biological control, diversification of the agro ecosystem with flowering vegetation is seen as an important tool to support the broad range of predators and parasitoids that require nectar and pollen sources to survive and reproduce. In order to identify flowering plants that provide suitable food sources for natural enemies without supporting the pest species, we analyzed the exploitation of 19 flowering plants by two important lepidopteran cabbage pests, Pieris rapae and Plutella xylostella, and their hymenopteran parasitoids, Cotesia glomerata and Diadegma semiclausum. The experiments were conducted at 90% r.h., while Pieris rapae was tested both at 45% r.h. and at 90% r.h. At 45 ± 5% r.h., corresponding with field conditions at which P. rapae is predominantly active, the butterfly was unable to feed on a number of exposed floral nectar sources whose nectar was successfully exploited at 90% r.h. The broader nectar exploitation by P. rapae at the high humidity is presumably explained by the resulting decrease in nectar viscosity. When comparing D. semiclausum and its herbivorous host P. xylostella, the herbivore exploited a broader range of plants. However, those plants that benefited both the parasitoid and the herbivore had a much stronger effect on the longevity of the parasitoid. The results from the accessibility bioassay suggest that flowers where nectar is not accessible can have a negative impact on insect survival presumably by stimulating foraging without providing accessible nectar. Our results underline the importance of considering species-specific environmental conditions when fine-tuning the choice of nectar sources to be used in conservation biological control programs.
KW - Conservation biological control
KW - Nectar
KW - Cabbage
KW - Pieris rapae
KW - Plutella xylostella
KW - Cotesia glomerata
KW - Diadegma semiclausum
KW - Herbivore
KW - Parasitoid
KW - Accessibility
KW - Longevity
KW - Selectivity
UR - http://www.scopus.com/inward/record.url?scp=67649494340&partnerID=8YFLogxK
U2 - 10.1016/j.biocontrol.2009.04.009
DO - 10.1016/j.biocontrol.2009.04.009
M3 - Journal article
VL - 50
SP - 299
EP - 306
JO - Biological Control
JF - Biological Control
SN - 1049-9644
IS - 3
ER -