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Carrière Y, Tabashnik BE. Negative association between host plant suitability and the fitness cost of resistance to Bacillus thuringiensis (Bacillales: Bacillaceae). JOURNAL OF ECONOMIC ENTOMOLOGY 2024; 117:1106-1112. [PMID: 38603568 DOI: 10.1093/jee/toae077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/18/2024] [Accepted: 04/02/2024] [Indexed: 04/13/2024]
Abstract
Transgenic crops producing Bacillus thuringiensis (Bt) toxins are commonly used for controlling insect pests. Nearby refuges of non-Bt host plants play a central role in delaying the evolution of resistance to Bt toxins by pests. Pervasive fitness costs associated with resistance, which entail lower fitness of resistant than susceptible individuals in refuges, can increase the ability of refuges to delay resistance. Moreover, these costs are affected by environmental factors such as host plant suitability, implying that manipulating refuge plant suitability could improve the success of the refuge strategy. Based on results from a previous study of Trichoplusia ni resistant to Bt sprays, it was proposed that low-suitability host plants could magnify costs. To test this hypothesis, we investigated the association between host plant suitability and fitness costs for 80 observations from 30 cases reported in 18 studies of 8 pest species from 5 countries. Consistent with the hypothesis, the association between plant suitability and fitness cost was negative. With plant suitability scaled to range from 0 (low) to 1 (high), the expected cost was 20.7% with a suitability of 1 and the fitness cost increased 2.5% for each 0.1 decrease in suitability. The most common type of resistance to Bt toxins involves mutations affecting a few types of midgut proteins to which Bt toxins bind to kill insects. A better understanding of how such mutations interact with host plant suitability to generate fitness costs could be useful for enhancing the refuge strategy and sustaining the efficacy of Bt crops.
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2
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Deschodt PS, Cory JS. Resource limitation has a limited impact on the outcome of virus-fungus co-infection in an insect host. Ecol Evol 2022; 12:e8707. [PMID: 35342581 PMCID: PMC8928876 DOI: 10.1002/ece3.8707] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 11/10/2022] Open
Abstract
Infection by pathogens is strongly affected by the diet or condition of the prospective host. Studies that examine the impact of diet have mainly focused on single pathogens; however, co-infections within a single host are thought to be common. Different pathogen groups might respond differently to resource availability and diverse infections could increase the costs of host defense, meaning the outcome of mixed infections under varying dietary regimes is likely to be hard to predict. We used the generalist cabbage looper, Trichoplusia ni and two of its pathogens, the DNA virus T. ni nucleopolyhedrovirus (TniSNPV) and the entomopathogenic fungus, Beauveria bassiana to examine how nutrient reduction affected the outcome of mixed pathogen infection. We challenged insects with a low or high effective dose of virus, alone or combined with a single dose of fungus. We manipulated food availability after pathogen challenge by diluting artificial diet with cellulose, a non-nutritious bulking agent, and examined its impact on host and pathogen fitness. Reducing diet quantity did not alter overall or pathogen-specific mortality. In all cases, TniSNPV-induced mortality was negatively affected by fungus challenge. Similarly, B. bassiana-induced mortality was negatively affected by TniSNPV challenge, but only at the higher virus dose. Dietary dilution mainly affected B. bassiana speed of kill when mixed with a high dose of TniSNPV, with an increase in the duration of fungal infection when cellulose was low (high quantity). One pathogen dominated the production of transmission stages in the cadavers and co-infection did not affect the yield of either pathogen. There was no evidence that co-infections were more costly to the survivors of pathogen challenge. In conclusion, dietary dilution did not determine the outcome of mixed pathogen infection, but it had more subtle effects, that differed between the two pathogens and could potentially alter pathogen recycling and host-pathogen dynamics.
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Affiliation(s)
- Pauline S Deschodt
- Department of Biological Sciences Simon Fraser University Burnaby British Columbia Canada
| | - Jenny S Cory
- Department of Biological Sciences Simon Fraser University Burnaby British Columbia Canada
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3
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Nawrot-Esposito MP, Babin A, Pasco M, Poirié M, Gatti JL, Gallet A. Bacillus thuringiensis Bioinsecticides Induce Developmental Defects in Non-Target Drosophila melanogaster Larvae. INSECTS 2020; 11:E697. [PMID: 33066180 PMCID: PMC7601982 DOI: 10.3390/insects11100697] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022]
Abstract
Bioinsecticides made from the bacterium Bacillus thuringiensis (Bt) are the bestselling bioinsecticide worldwide. Among Bt bioinsecticides, those based on the strain Bt subsp. kurstaki (Btk) are widely used in farming to specifically control pest lepidopteran larvae. Although there is much evidence of the lack of acute lethality of Btk products for non-target animals, only scarce data are available on their potential non-lethal developmental adverse effects. Using a concentration that could be reached in the field upon sprayings, we show that Btk products impair growth and developmental time of the non-target dipteran Drosophila melanogaster. We demonstrate that these effects are mediated by the synergy between Btk bacteria and Btk insecticidal toxins. We further show that Btk bioinsecticides trigger intestinal cell death and alter protein digestion without modifying the food intake and feeding behavior of the larvae. Interestingly, these harmful effects can be mitigated by a protein-rich diet or by adding the probiotic bacterium Lactobacillus plantarum into the food. Finally, we unravel two new cellular mechanisms allowing the larval midgut to maintain its integrity upon Btk aggression: First the flattening of surviving enterocytes and second, the generation of new immature cells arising from the adult midgut precursor cells. Together, these mechanisms participate to quickly fill in the holes left by the dying enterocytes.
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Affiliation(s)
| | | | | | | | | | - Armel Gallet
- Université Côte d’Azur, CNRS, INRAE, ISA, UMR CNRS 7254/INRAE 1355/UCA, 400 route des Chappes, BP 167, 06903 Sophia Antipolis CEDEX, France; (M.-P.N.-E.); (A.B.); (M.P.); (M.P.); (J.-L.G.)
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4
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Herbivore-Induced Defenses in Tomato Plants Enhance the Lethality of the Entomopathogenic Bacterium, Bacillus thuringiensis var. kurstaki. J Chem Ecol 2018; 44:947-956. [PMID: 29980959 DOI: 10.1007/s10886-018-0987-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/22/2018] [Accepted: 07/03/2018] [Indexed: 10/28/2022]
Abstract
Plants can influence the effectiveness of microbial insecticides through numerous mechanisms. One of these mechanisms is the oxidation of plant phenolics by plant enzymes, such as polyphenol oxidases (PPO) and peroxidases (POD). These reactions generate a variety of products and intermediates that play important roles in resistance against herbivores. Oxidation of the catecholic phenolic compound chlorogenic acid by PPO enhances the lethality of the insect-killing bacterial pathogen, Bacillus thuringiensis var. kurstaki (Bt) to the polyphagous caterpillar, Helicoverpa zea. Since herbivore feeding damage often triggers the induction of higher activities of oxidative enzymes in plant tissues, here we hypothesized that the induction of plant defenses would enhance the lethality of Bt on those plants. We found that the lethality of a commercial formulation of Bt (Dipel® PRO DF) on tomato plants was higher if it was applied to plants that were induced by H. zea feeding or induced by the phytohormone jasmonic acid. Higher proportions of H. zea larvae killed by Bt were strongly correlated with higher levels of PPO activity in the leaflet tissue. Higher POD activity was only weakly associated with higher levels of Bt-induced mortality. While plant-mediated variation in entomopathogen lethality is well known, our findings demonstrate that plants can induce defensive responses that work in concert with a microbial insecticide/entomopathogen to protect against insect herbivores.
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5
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Pennington MJ, Rothman JA, Dudley SL, Jones MB, McFrederick QS, Gan J, Trumble JT. Contaminants of emerging concern affect Trichoplusia ni growth and development on artificial diets and a key host plant. Proc Natl Acad Sci U S A 2017; 114:E9923-E9931. [PMID: 29087336 PMCID: PMC5699077 DOI: 10.1073/pnas.1713385114] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Many countries are utilizing reclaimed wastewater for agriculture because drought, rising temperatures, and expanding human populations are increasing water demands. Unfortunately, wastewater often contains biologically active, pseudopersistent pharmaceuticals, even after treatment. Runoff from farms and output from wastewater treatment plants also contribute high concentrations of pharmaceuticals to the environment. This study assessed the effects of common pharmaceuticals on an agricultural pest, Trichoplusia ni (Lepidoptera: Noctuidae). Larvae were reared on artificial diets spiked with contaminants of emerging concern (CECs) at environmentally relevant concentrations. Trichoplusia ni showed increased developmental time and mortality when reared on artificial diets containing antibiotics, hormones, or a mixture of contaminants. Mortality was also increased when T. ni were reared on tomatoes grown hydroponically with the same concentrations of antibiotics. The antibiotic-treated plants translocated ciprofloxacin through their tissues to roots, shoots, and leaves. Microbial communities of T. ni changed substantially between developmental stages and when exposed to CECs in their diets. Our results suggest that use of reclaimed wastewater for irrigation of crops can affect the developmental biology and microbial communities of an insect of agricultural importance.
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Affiliation(s)
- Marcus J Pennington
- Department of Entomology, University of California, Riverside, CA 92521
- Graduate Program in Environmental Toxicology, University of California, Riverside, CA 92521
| | - Jason A Rothman
- Department of Entomology, University of California, Riverside, CA 92521
- Graduate Program in Microbiology, University of California, Riverside, CA 92521
| | - Stacia L Dudley
- Graduate Program in Environmental Toxicology, University of California, Riverside, CA 92521
- Department of Environmental Science, University of California, Riverside, CA 92521
| | - Michael B Jones
- Department of Entomology, University of California, Riverside, CA 92521
| | - Quinn S McFrederick
- Department of Entomology, University of California, Riverside, CA 92521
- Graduate Program in Microbiology, University of California, Riverside, CA 92521
| | - Jay Gan
- Graduate Program in Environmental Toxicology, University of California, Riverside, CA 92521
- Department of Environmental Science, University of California, Riverside, CA 92521
| | - John T Trumble
- Department of Entomology, University of California, Riverside, CA 92521;
- Graduate Program in Environmental Toxicology, University of California, Riverside, CA 92521
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6
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Shikano I. Evolutionary Ecology of Multitrophic Interactions between Plants, Insect Herbivores and Entomopathogens. J Chem Ecol 2017; 43:586-598. [DOI: 10.1007/s10886-017-0850-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/06/2017] [Accepted: 05/15/2017] [Indexed: 02/07/2023]
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7
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Deans CA, Behmer ST, Tessnow AE, Tamez-Guerra P, Pusztai-Carey M, Sword GA. Nutrition affects insect susceptibility to Bt toxins. Sci Rep 2017; 7:39705. [PMID: 28045087 PMCID: PMC5206677 DOI: 10.1038/srep39705] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/25/2016] [Indexed: 11/09/2022] Open
Abstract
Pesticide resistance represents a major challenge to global food production. The spread of resistance alleles is the primary explanation for observations of reduced pesticide efficacy over time, but the potential for gene-by-environment interactions (plasticity) to mediate susceptibility has largely been overlooked. Here we show that nutrition is an environmental factor that affects susceptibility to Bt toxins. Protein and carbohydrates are two key macronutrients for insect herbivores, and the polyphagous pest Helicoverpa zea self-selects and performs best on diets that are protein-biased relative to carbohydrates. Despite this, most Bt bioassays employ carbohydrate-biased rearing diets. This study explored the effect of diet protein-carbohydrate content on H. zea susceptibility to Cry1Ac, a common Bt endotoxin. We detected a 100-fold increase in LC50 for larvae on optimal versus carbohydrate-biased diets, and significant diet-mediated variation in survival and performance when challenged with Cry1Ac. Our results suggest that Bt resistance bioassays that use ecologically- and physiologically-mismatched diets over-estimate susceptibility and under-estimate resistance.
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Affiliation(s)
- Carrie A. Deans
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
- Department of Entomology, University of Minnesota, St. Paul, MN 55108, USA
| | - Spencer T. Behmer
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
- Ecology & Evolutionary Biology Graduate Program, Texas A&M University, College Station, TX 77843, USA
| | - Ashley E. Tessnow
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
| | - Patricia Tamez-Guerra
- LIV-DEMI, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, N.L. 66455, México
| | | | - Gregory A. Sword
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
- Ecology & Evolutionary Biology Graduate Program, Texas A&M University, College Station, TX 77843, USA
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8
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Shikano I, Cory JS. Altered nutrient intake by baculovirus-challenged insects: Self-medication or compensatory feeding? J Invertebr Pathol 2016; 139:25-33. [DOI: 10.1016/j.jip.2016.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/06/2016] [Accepted: 07/09/2016] [Indexed: 10/21/2022]
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9
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Jensen K, Ko AE, Schal C, Silverman J. Insecticide resistance and nutrition interactively shape life-history parameters in German cockroaches. Sci Rep 2016; 6:28731. [PMID: 27345220 PMCID: PMC4922014 DOI: 10.1038/srep28731] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/08/2016] [Indexed: 11/09/2022] Open
Abstract
Fitness-related costs of evolving insecticide resistance have been reported in a number of insect species, but the interplay between evolutionary adaptation to insecticide pressure and variable environmental conditions has received little attention. We provisioned nymphs from three German cockroach (Blattella germanica L.) populations, which differed in insecticide resistance, with either nutritionally rich or poor (diluted) diet throughout their development. One population was an insecticide-susceptible laboratory strain; the other two populations originated from a field-collected indoxacarb-resistant population, which upon collection was maintained either with or without further selection with indoxacarb. We then measured development time, survival to the adult stage, adult body size, and results of a challenge with indoxacarb. Our results show that indoxacarb resistance and poor nutritional condition increased development time and lowered adult body size, with reinforcing interactions. We also found lower survival to the adult stage in the indoxacarb-selected population, which was exacerbated by poor nutrition. In addition, nutrition imparted a highly significant effect on indoxacarb susceptibility. This study exemplifies how poor nutritional condition can aggravate the life-history costs of resistance and elevate the detrimental effects of insecticide exposure, demonstrating how environmental conditions and resistance may interactively impact individual fitness and insecticide efficacy.
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Affiliation(s)
- Kim Jensen
- Department of Entomology, North Carolina State University, Raleigh, NC 27695, USA.,W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Alexander E Ko
- Department of Entomology, North Carolina State University, Raleigh, NC 27695, USA.,W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Coby Schal
- Department of Entomology, North Carolina State University, Raleigh, NC 27695, USA.,W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Jules Silverman
- Department of Entomology, North Carolina State University, Raleigh, NC 27695, USA
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10
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Bunning H, Bassett L, Clowser C, Rapkin J, Jensen K, House CM, Archer CR, Hunt J. Dietary choice for a balanced nutrient intake increases the mean and reduces the variance in the reproductive performance of male and female cockroaches. Ecol Evol 2016; 6:4711-30. [PMID: 27547307 PMCID: PMC4979701 DOI: 10.1002/ece3.2243] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 05/13/2016] [Accepted: 05/16/2016] [Indexed: 01/20/2023] Open
Abstract
Sexual selection may cause dietary requirements for reproduction to diverge across the sexes and promote the evolution of different foraging strategies in males and females. However, our understanding of how the sexes regulate their nutrition and the effects that this has on sex‐specific fitness is limited. We quantified how protein (P) and carbohydrate (C) intakes affect reproductive traits in male (pheromone expression) and female (clutch size and gestation time) cockroaches (Nauphoeta cinerea). We then determined how the sexes regulate their intake of nutrients when restricted to a single diet and when given dietary choice and how this affected expression of these important reproductive traits. Pheromone levels that improve male attractiveness, female clutch size and gestation time all peaked at a high daily intake of P:C in a 1:8 ratio. This is surprising because female insects typically require more P than males to maximize reproduction. The relatively low P requirement of females may reflect the action of cockroach endosymbionts that help recycle stored nitrogen for protein synthesis. When constrained to a single diet, both sexes prioritized regulating their daily intake of P over C, although this prioritization was stronger in females than males. When given the choice between diets, both sexes actively regulated their intake of nutrients at a 1:4.8 P:C ratio. The P:C ratio did not overlap exactly with the intake of nutrients that optimized reproductive trait expression. Despite this, cockroaches of both sexes that were given dietary choice generally improved the mean and reduced the variance in all reproductive traits we measured relative to animals fed a single diet from the diet choice pair. This pattern was not as strong when compared to the single best diet in our geometric array, suggesting that the relationship between nutrient balancing and reproduction is complex in this species.
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Affiliation(s)
- Harriet Bunning
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Tremough Campus Penryn TR10 9EZ UK
| | - Lee Bassett
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Tremough Campus Penryn TR10 9EZ UK
| | - Christina Clowser
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Tremough Campus Penryn TR10 9EZ UK
| | - James Rapkin
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Tremough Campus Penryn TR10 9EZ UK
| | - Kim Jensen
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Tremough Campus Penryn TR10 9EZ UK; Department of Entomology North Carolina State University Gardner Hall Raleigh North Carolina 27695-7613
| | - Clarissa M House
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Tremough Campus Penryn TR10 9EZ UK
| | - Catharine R Archer
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Tremough Campus Penryn TR10 9EZ UK; MaxNetAging School Max Planck Institute for Demographic Research Konrad-Zuse-Straße 118057 Rostock Germany
| | - John Hunt
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Tremough Campus Penryn TR10 9EZ UK
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Deans CA, Sword GA, Behmer ST. Nutrition as a neglected factor in insect herbivore susceptibility to Bt toxins. CURRENT OPINION IN INSECT SCIENCE 2016; 15:97-103. [PMID: 27436738 DOI: 10.1016/j.cois.2016.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/23/2016] [Accepted: 04/13/2016] [Indexed: 06/06/2023]
Abstract
The widespread global adoption of Bt crops elevates concerns about the evolution of Bt resistance in insect pest species. Current insecticide resistance management (IRM) strategies focus solely on genetic variation as a causal factor in the evolution of resistance, but ignore the role that environmental factors, such as nutrition, may play. In this opinion paper, we discuss the benefits that insect herbivores gain from consuming foods with protein-carbohydrate content that matches their self-selected protein-carbohydrate intake, and show that even within monocultures there is amply opportunity for insect herbivores to regulate their macronutrient intake. Next we review new data that show that dietary protein and carbohydrates can: firstly, have predictably strong effects on the survival and performance of caterpillars challenged with Bt toxins, and secondly, mediate plasticity in susceptibility to Cry1Ac, which can account for large differences in LC50 values. Nutrition-Bt interactions such as these have important implications for IRM, particularly given that diet-incorporated Bt bioassays commonly use artificial diets that vary substantially from their self-selected optimal diets, which likely results in underestimates of resistance in the field. Failing to bioassay larvae on ecologically-relevant diets can seriously confound the results of Bt resistance monitoring bioassays and undermine our ability to detect resistance in the field.
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Affiliation(s)
- C A Deans
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA; Department of Entomology, University of Minnesota, St. Paul, MN 55108, USA.
| | - G A Sword
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA; Ecology & Evolutionary Biology Graduate Program, Texas A&M University, College Station, TX 77843, USA
| | - S T Behmer
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA; Ecology & Evolutionary Biology Graduate Program, Texas A&M University, College Station, TX 77843, USA
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12
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Shikano I, Hua KN, Cory JS. Baculovirus-challenge and poor nutrition inflict within-generation fitness costs without triggering transgenerational immune priming. J Invertebr Pathol 2016; 136:35-42. [DOI: 10.1016/j.jip.2016.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/22/2016] [Accepted: 03/01/2016] [Indexed: 10/22/2022]
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13
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Orpet RJ, Degain BA, Tabashnik BE, Carrière Y. Balancing Bt Toxin Avoidance and Nutrient Intake by Helicoverpa zea (Lepidoptera: Noctuidae) Larvae. JOURNAL OF ECONOMIC ENTOMOLOGY 2015; 108:2581-2588. [PMID: 26470372 DOI: 10.1093/jee/tov226] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 07/07/2015] [Indexed: 06/05/2023]
Abstract
To evaluate how the Cry1Ac Bacillus thuringiensis (Bt) toxin and the ratio of dietary protein to carbohydrate (P:C) independently and jointly affect Helicoverpa zea (Boddie) larval feeding performance and behavior, we conducted no-choice and binary choice experiments using chemically defined diets. We tested two related strains of this polyphagous pest: a strain selected for resistance to Cry1Ac in the laboratory (GA-R), and its field-derived parent strain (GA). In no-choice tests, feeding performance in GA and GA-R was superior on a non-Cry1Ac 80P:20C diet compared to a non-Cry1Ac 35P:65C diet or an 80P:20C diet containing Cry1Ac. Based on consumption and position measurements in binary choice tests, larvae preferred the non-Cry1Ac 80P:20C diet over the other two diets mentioned above. However, the association between preference and performance was weaker when comparing the Cry1Ac 80P:20C diet versus a Cry1Ac 35P:65C diet, and when comparing the Cry1Ac 80P:20C diet versus the non-Cry1Ac 35P:65C diet. In all choice situations, consumption preference occurred mainly by the percentage of larvae that fed almost entirely from one or the other diet, rather than from variation in the extent of diet mixing by individuals. Resistance to Cry1Ac affected the balance between toxin avoidance and nutrient intake: larvae from the more resistant GA-R strain consumed significantly more of the Cry1Ac 80P:20C diet when paired with non-Cry1Ac 35P:65C diet, while GA larvae consumed more of the latter, though not significantly. The results show that dietary P:C ratio, Cry1Ac, and resistance to Cry1Ac affected feeding behavior and performance of H. zea larvae.
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Affiliation(s)
- Robert J Orpet
- Department of Entomology, Tree Fruit Research and Extension Center, Washington State University, 1100 N. Western Ave., Wenatchee, WA 98801.
| | - Benjamin A Degain
- Department of Entomology, University of Arizona, Forbes 410, PO Box 210036, Tucson, AZ 85721
| | - Bruce E Tabashnik
- Department of Entomology, University of Arizona, Forbes 410, PO Box 210036, Tucson, AZ 85721
| | - Yves Carrière
- Department of Entomology, University of Arizona, Forbes 410, PO Box 210036, Tucson, AZ 85721
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14
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Hesketh H, Hails RS. Bacillus thuringiensis impacts on primary and secondary baculovirus transmission dynamics in Lepidoptera. J Invertebr Pathol 2015; 132:171-181. [DOI: 10.1016/j.jip.2015.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/20/2015] [Accepted: 09/22/2015] [Indexed: 12/13/2022]
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15
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Shikano I, Cory JS. Impact Of Environmental Variation On Host Performance Differs With Pathogen Identity: Implications For Host-Pathogen Interactions In A Changing Climate. Sci Rep 2015; 5:15351. [PMID: 26477393 PMCID: PMC4609993 DOI: 10.1038/srep15351] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/23/2015] [Indexed: 01/16/2023] Open
Abstract
Specialist and generalist pathogens may exert different costs on their hosts; thereby altering the way hosts cope with environmental variation. We examined how pathogen-challenge alters the environmental conditions that maximize host performance by simultaneously varying temperature and nutrition (protein to carbohydrate ratio; P:C) after exposure to two baculoviruses; one that is specific to the cabbage looper, Trichoplusia ni (TnSNPV) and another that has a broad host range (AcMNPV). Virus-challenged larvae performed better on more protein-biased diets, primarily due to higher survival, whereas unchallenged larvae performed best on a balanced diet. The environmental conditions that maximized host performance differed with virus identity because TnSNPV-challenge inflicted fitness costs (reduced pupal weight and prolonged development) whereas AcMNPV-challenge did not. The performance of TnSNPV-challenged larvae rose with increasing P:C across all temperatures, whereas temperature modulated the optimal P:C in AcMNPV-challenged larvae (slightly protein-biased at 16 °C to increasingly higher P:C as temperature increased). Increasing temperature reduced pupal size, but only at more balanced P:C ratios, indicating that nutrition moderates the temperature-size rule. Our findings highlight the complex environmental interactions that can alter host performance after exposure to pathogens, which could impact the role of entomopathogens as regulators of insect populations in a changing climate.
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Affiliation(s)
- Ikkei Shikano
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A1S6, Canada
| | - Jenny S. Cory
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A1S6, Canada
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16
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Vijendravarma RK, Narasimha S, Chakrabarti S, Babin A, Kolly S, Lemaitre B, Kawecki TJ. Gut physiology mediates a trade‐off between adaptation to malnutrition and susceptibility to food‐borne pathogens. Ecol Lett 2015; 18:1078-86. [DOI: 10.1111/ele.12490] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/28/2015] [Accepted: 07/12/2015] [Indexed: 12/12/2022]
Affiliation(s)
| | - Sunitha Narasimha
- Department of Ecology and Evolution University of Lausanne CH 1015 Lausanne Switzerland
| | | | - Aurelie Babin
- Department of Ecology and Evolution University of Lausanne CH 1015 Lausanne Switzerland
| | - Sylvain Kolly
- Department of Ecology and Evolution University of Lausanne CH 1015 Lausanne Switzerland
| | - Bruno Lemaitre
- Global Health Institute EPFL CH 1015 Lausanne Switzerland
| | - Tadeusz J. Kawecki
- Department of Ecology and Evolution University of Lausanne CH 1015 Lausanne Switzerland
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17
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Jensen K, Schal C, Silverman J. Adaptive contraction of diet breadth affects sexual maturation and specific nutrient consumption in an extreme generalist omnivore. J Evol Biol 2015; 28:906-16. [DOI: 10.1111/jeb.12617] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/14/2015] [Accepted: 03/09/2015] [Indexed: 01/13/2023]
Affiliation(s)
- K. Jensen
- Department of Entomology; North Carolina State University; Raleigh NC USA
- W. M. Keck Center for Behavioral Biology; North Carolina State University; Raleigh NC USA
| | - C. Schal
- Department of Entomology; North Carolina State University; Raleigh NC USA
- W. M. Keck Center for Behavioral Biology; North Carolina State University; Raleigh NC USA
| | - J. Silverman
- Department of Entomology; North Carolina State University; Raleigh NC USA
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18
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Shikano I, Oak MC, Halpert‐Scanderbeg O, Cory JS. Trade‐offs between transgenerational transfer of nutritional stress tolerance and immune priming. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12422] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Ikkei Shikano
- Department of Biological Sciences Simon Fraser University Burnaby BC V5A1S6 Canada
| | - Miranda C. Oak
- Department of Biological Sciences Simon Fraser University Burnaby BC V5A1S6 Canada
| | | | - Jenny S. Cory
- Department of Biological Sciences Simon Fraser University Burnaby BC V5A1S6 Canada
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