Original Citation:A global synthesis of the effects of diversified farming systems on arthropod diversity within fields and across agricultural landscapes Published version:DOI:10.1111/gcb.13714 Terms of use:Open Access (Article begins on next page) Anyone can freely access the full text of works made available as "Open Access". Works made available under a Creative Commons license can be used according to the terms and conditions of said license. Use of all other works requires consent of the right holder (author or publisher) if not exempted from copyright protection by the applicable law. Agricultural intensification is a leading cause of global biodiversity loss, which can reduce the provisioning of ecosystem services in managed ecosystems. Organic farming and plant diversification are farm management schemes that may mitigate potential ecological harm by increasing species richness and boosting related ecosystem services to agroecosystems. What remains unclear is the extent to which farm management schemes affect biodiversity components other than species richness, and whether impacts differ across spatial scales and landscape contexts. Using a global meta-dataset, we quantified the effects of organic farming and plant diversification on abundance, local diversity (communities within fields), and regional diversity (communities across fields) of arthropod pollinators, predators, herbivores, and detritivores. Both organic farming and higher in-field plant diversity enhanced arthropod abundance, particularly for rare taxa. This resulted in increased richness but decreased evenness. While these responses were stronger at local relative to regional scales, richness and abundance increased at both scales, and richness on farms embedded in complex relative to simple landscapes. Overall, both organic farming and in-field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations. Our results suggest that organic farming and plant diversification promote diverse arthropod metacommunities that may provide temporal and spatial stability of ecosystem service provisioning. Conserving diverse plant and arthropod communities in farming systems therefore requires sustainable practices that operate both within fields and across landscapes. Availability: This is the author's manuscript

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Food web ecologists have long sought to characterize the trophic niches of animals using stable isotopic analysis. However, distilling trophic position from isotopic composition has been difficult, largely because of the variability associated with trophic discrimination factors (inter-trophic isotopic fractionation and routing). We circumvented much of this variability using compound-specific isotopic analysis (CSIA). We examined the 15N signatures of amino acids extracted from organisms reared in pure culture at four discrete trophic levels, across two model communities. We calculated the degree of enrichment at each trophic level and found there was a consistent trophic discrimination factor (~7.6‰). The constancy of the CSIA-derived discrimination factor permitted unprecedented accuracy in the measurement of animal trophic position. Conversely, trophic position estimates generated via bulk-15N analysis significantly underestimated trophic position, particularly among higher-order consumers. We then examined the trophic hierarchy of a free-roaming arthropod community, revealing the highest trophic position (5.07) and longest food chain ever reported using CSIA. High accuracy in trophic position estimation brings trophic function into sharper focus, providing greater resolution to the analysis of food webs.

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The seminal work of Stern and his coauthors on integrated control has had a profound and long-lasting effect on the development of IPM programs in western orchard systems. Management systems based solely on pesticides have proven to be unstable, and the success of IPM systems in western orchards has been driven by conservation of natural enemies to control secondary pests, combined with pesticides and mating disruption to suppress the key lepidopteran pests. However, the legislatively mandated changes in pesticide use patterns prompted by the Food Quality Protection Act of 1996 have resulted in an increased instability of pest populations in orchards because of natural enemy destruction. The management system changes have made it necessary to focus efforts on enhancing biological control not only of secondary pests but also of primary lepidopteran pests to help augment new pesticides and mating disruption tactics. The new management programs envisioned will be information extensive as well as time sensitive and will require redesign of educational and outreach programs to be successful. The developing programs will continue to use the core principles of Stern and his co-authors, but go beyond them to incorporate changes in society, technology and information transfer, as needed.

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A series of studies was conducted to test methods for marking a wide variety of arthropods with inexpensive proteins for mark-capture dispersal research. The markers tested included egg albumin protein in chicken egg whites and casein protein in bovine milk. The first study qualified the effectiveness of the two marks on more than 50 arthropod species inhabiting cotton via two application procedures. The application methods included: (1) a topical plus residue protein application, and (2) a residue-only protein application. Both protein marks, regardless of the method of application, were readily retained on the arthropod assemblage over the duration of the study. The second study determined how rapidly insects acquire chicken egg albumin protein after contact exposure to cotton tissue sprayed with an egg whites solution. Under laboratory conditions, the vast majority of adult Hippodamia convergens Guérin-Méneville (Coleoptera: Coccinellidae) and Lygus hesperus Knight (Heteroptera: Miridae) acquired the mark after 5 min, and immature Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) acquired the marker after 40 min. The third study determined how rapidly H. convergens and L. hesperus acquire bovine casein protein after contact exposure to either alfalfa, Medicago sativa L. (Fabaceae), or lesquerella, Lesquerella fendleri (Watson) (Brassicaceae), plants sprayed with a bovine milk solution. These insects rapidly acquired the casein mark from the plant residue under field conditions. A final study determined how long H. convergens retain casein protein after 24-h exposure to alfalfa and lesquerella plants containing a 7-day-old residue of bovine milk. Approximately 95% of the H. convergens maintained the casein mark for 2 days after removal from each type of plant.

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