TY - JOUR
T1 - Accelerated Development and Toxin Tolerance of the Navel Orangeworm Amyelois transitella (Lepidoptera
T2 - Pyralidae) in the Presence of Aspergillus flavus
AU - Bush, Daniel S.
AU - Siegel, Joel P.
AU - Berenbaum, May R.
N1 - Funding Information:
We thank Mark Demkovich for his advice and assistance. Daniel Raudabaugh advised us on mycology and experimental design, Dr. Rebecca Fuller advised us on graphing in R, and Dr. Themis Michailides provided the AF36 strain. This research was funded by the California Pistachio Research Board and the Almond Board of California. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture or the University of Illinois. USDA is an equal opportunity provider and employer.
Publisher Copyright:
© 2018, Springer Science+Business Media, LLC, part of Springer Nature.
PY - 2018/12/1
Y1 - 2018/12/1
N2 - The navel orangeworm (Amyelois transitella) and the fungus Aspergillus flavus constitute a facultative mutualism and pest complex in tree nut and fruit orchards in California. The possibility exists that the broad detoxification capabilities of A. flavus benefit its insect associate by metabolizing toxicants, including hostplant phytochemicals and pesticides. We examined this hypothesis by conducting laboratory bioassays to assess growth rates and survivorship of pyrethroid-resistant (R347) and susceptible (CPQ) larval strains on potato dextrose agar diet containing almond meal with and without two furanocoumarins, xanthotoxin and bergapten, found in several hostplants, and with and without two insecticides, bifenthrin and spinetoram, used in almond and pistachio orchards. Additionally, fungi were incubated in liquid diets containing the test chemicals, and extracts of these diets were added to almond potato dextrose agar (PDA) diets and fed to larvae to evaluate the ability of the fungus to metabolize these chemicals. Larvae consuming furanocoumarin-containing diet experienced higher mortality than individuals on unamended diets, but adding A. flavus resulted in up to 61.7% greater survival. Aspergillus flavus in the diet increased development rate > two-fold when furanocoumarins were present, demonstrating fungal enhancement of diet quality. Adding extracts of liquid diets containing xanthotoxin and fungus decreased mortality compared to xanthotoxin alone. On diets containing bifenthrin and spinetoram, however, mortality increased. These results support the hypothesis that A. flavus enhances navel orangeworm performance and contributes to detoxification of xenobiotics. Among practical implications of our findings, this mutualistic association should be considered in designing chemical management strategies for these pests.
AB - The navel orangeworm (Amyelois transitella) and the fungus Aspergillus flavus constitute a facultative mutualism and pest complex in tree nut and fruit orchards in California. The possibility exists that the broad detoxification capabilities of A. flavus benefit its insect associate by metabolizing toxicants, including hostplant phytochemicals and pesticides. We examined this hypothesis by conducting laboratory bioassays to assess growth rates and survivorship of pyrethroid-resistant (R347) and susceptible (CPQ) larval strains on potato dextrose agar diet containing almond meal with and without two furanocoumarins, xanthotoxin and bergapten, found in several hostplants, and with and without two insecticides, bifenthrin and spinetoram, used in almond and pistachio orchards. Additionally, fungi were incubated in liquid diets containing the test chemicals, and extracts of these diets were added to almond potato dextrose agar (PDA) diets and fed to larvae to evaluate the ability of the fungus to metabolize these chemicals. Larvae consuming furanocoumarin-containing diet experienced higher mortality than individuals on unamended diets, but adding A. flavus resulted in up to 61.7% greater survival. Aspergillus flavus in the diet increased development rate > two-fold when furanocoumarins were present, demonstrating fungal enhancement of diet quality. Adding extracts of liquid diets containing xanthotoxin and fungus decreased mortality compared to xanthotoxin alone. On diets containing bifenthrin and spinetoram, however, mortality increased. These results support the hypothesis that A. flavus enhances navel orangeworm performance and contributes to detoxification of xenobiotics. Among practical implications of our findings, this mutualistic association should be considered in designing chemical management strategies for these pests.
KW - Detoxification
KW - Fungus
KW - Furanocoumarin
KW - Navel orangeworm
KW - Pyrethroid
KW - Spinosyn
UR - http://www.scopus.com/inward/record.url?scp=85055951332&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85055951332&partnerID=8YFLogxK
U2 - 10.1007/s10886-018-1027-0
DO - 10.1007/s10886-018-1027-0
M3 - Article
C2 - 30370473
AN - SCOPUS:85055951332
SN - 0098-0331
VL - 44
SP - 1170
EP - 1177
JO - Journal of Chemical Ecology
JF - Journal of Chemical Ecology
IS - 12
ER -