Michael J. Aikins

Kansas State University, Kansas, United States

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Publications (16)15.69 Total impact

  • Michael J. Aikins, Thomas Phillips
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    ABSTRACT: The red flour beetle, Tribolium castaneum, is a serious pest of stored products world-wide. Feeding males release an aggregation pheromone, 4,8-dimethyldecanal, DMD, that is attractive to both sexes. Previous studies quantified the amount of DMD produced over a given amount of time, but there was substantial variation among these studies in the quantities of DMD reported. In the work discussed here we used a consistent and reliable method to collect volatiles from individual feeding males on the solid-phase absorbent Poropak-Q, followed by quantitative analysis of DMD with gas chromatography-mass spectrometry. The amount of DMD produced by individual males from 10 geographically separate populations of T. castaneum was determined. We found that amounts of DMD released varied from less than 30.0 ng/male/day in beetles from Manitoba and Georgia, to over 150 ng/male/day in beetles from Kansas, Alabama, and California. Males within the same population showed slight variations in the amount of DMD produced. Within the Winnipeg and Georgia populations DMD production ranged from 13.2 to 52.5 ng/male/day and from 0 to 58.4 ng/male/day respectively. The Kansas, Alabama, and California populations had ranges of DMD production that were 62.4 to 347.5 ng/male/day, 3.3 to 316.9 ng/male/day, and 31.4 to 379.9 ng/male/day respectively. Our results suggest that pheromone production in T. castaneum varies significantly among geographically separate populations. Controlled mating with high-producing and low producing males suggest that pheromone production and release is probably controlled by multiple genes.
    Entomological Society of America Annual Meeting 2014; 11/2014
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    ABSTRACT: The bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), has resurged recently as a domestic pest in North America with very limited options for decisive control. We report efficacy studies with sulfuryl fluoride (SF) toward use as a structural fumigant to control bed bugs. Laboratory studies were conducted in which eggs, adults, and nymphs from a pesticide susceptible laboratory population were fumigated for 24 h using SF at 99.8% purity in airtight, 3.8-liter glass containers under two temperatures, 25°C and 15°C. Bed bugs were placed in separate ventilated glass vials and wrapped in mattress padding before fumigation. The gas concentration within each jar was determined using quantitative gas chromatography‐mass spectrometry. Dose‐response trials using eggs of known age (48‐96 h) were conducted at five or six target concentrations measured as concentration × time accumulated dosages (g-h/m3) and one untreated control at each temperature. Each target dose was replicated in four different fumigation containers (replicates), with at least 32 eggs per replicate. The number of hatched and unhatched eggs postfumigation, and number of live and dead nymphs that resulted from hatched eggs, were evaluated daily for at least 1 wk after egg hatch. The lethal accumulated dosage (LAD99) for bed bug eggs was 69.1 (95% fiducial limits [FLs] of 62.9‐79.5) g-h/m3 at 25°C and 149.3 (95% FLs of 134.4‐177.9) g-h/m3 at 15°C. Confirmatory trials with dosages of 1.5× the LAD99 were conducted at 25°C and 1.5× the threshold mortality dose at 15°C with at least 15 adults, 13 late-instar nymphs and 79 eggs of known age per replicate. At 25°C, a target dosage of 103.7 g-h/m3 resulted in 100% mortality of adults and late-instar nymphs. Nymphs emerged and survived from two of 439 eggs treated with SF dosages that were 6‐7 g-h/m3 less than the target dosage. No nymphs emerged from eggs fumigated with dosages >97.9 g-h/m3 in the validation study. Therefore, the threshold dosage for complete egg mortality (97.9 g-h/m3) was used, rather than the LAD99, to calculate the monitored field dosage rate of 148.2 g-h/m3 (= 1.5 × 97.9 g-h/m3) for control of all life stages of bed bugs at 25°C. Based on these results, at 15°C, 1.5× the threshold dosage for complete egg control (189.7 g-h/m3) was used to calculate a target dosage of 285 g-h/m3 for the confirmatory trial, which resulted in 100% mortality of adults, late-instar nymphs, and eggs.
    Journal of Economic Entomology 08/2014; 107(4). · 1.60 Impact Factor
  • Entomological Society of America Annual Meeting 2013; 11/2013
  • Entomological Society of America Annual Meeting 2013; 11/2013
  • Michael J. Aikins, Ozgur Saglam, Thomas Phillips
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    ABSTRACT: Fumigation is one of the best ways to stop infestation of stored products with pest arthropods. Methyl bromide and phosphine are two of the most effective fumigants used. However, methyl bromide will be phased out by 2015 as an ozone-depletor under the US Clean Air Act, and there are many reports of arthropods developing resistance to phosphine. In this study we look at the toxicity of the gas methyl isothiocyanate (C2H3NS), MITC, to various pest arthropods. Various life stages of the pest arthropods were exposed to different levels of methyl isothiocyanate and mortality was assessed. Interestingly, when comparing the susceptibility of the life stages to methyl isothiocyanate, the egg stage appeared to succumb at lower gas concentrations than the other life stages, which his opposite to the case with other fumigants for which eggs area very tolerant life stage. MITC shows good potential as a new fumigant for stored products.
    Entomological Society of America Annual Meeting 2013; 11/2013
  • Michael Jamison Aikins, Hongbo Jiang, Yoonseong Park, Thomas W. Phillips
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    ABSTRACT: The red flour beetle, Tribolium castaneum (Herbst) is one of the most serious stored product insect pests world-wide. Adult males of T. castaneum are known to produce the aggregation pheromone 4,8,-dimethyldecenal when they are feeding, while females and starved males do not produce the pheromone. Here we report the identification of candidate genes potentially involved in the biosynthetic pathway of this pheromone by using Illumina sequencing. Four different samples, fed and unfed males, as well as fed and unfed females had their abdominal epidermal tissue gene expression patterns compared. In the analysis of genes up-regulated in fed-males, we identified a number of candidate genes that may function in the biosynthesis and/or release of this aggregation pheromone. We are currently performing RNA interference on the candidate genes to investigate the roles of each gene in pheromone metabolism.
    Entomological Society of America Annual Meeting 2012; 11/2012
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    ABSTRACT: Phosphine gas, or hydrogen phosphide (PH3), is the most common insecticide applied to durable stored products worldwide and is routinely used in the United States for treatment of bulk-stored cereal grains and other durable stored products. Research from the late 1980s revealed low frequencies of resistance to various residual grain protectant insecticides and to phosphine in grain insect species collected in Oklahoma. The present work, which used the same previously established discriminating dose bioassays for phosphine toxicity as in the earlier study, evaluated adults of nine different populations of red flour beetle, Tribolium castaneum (Herbst), and five populations of lesser grain borer, Rhyzopertha dominica (F.) collected from different geographic locations in Oklahoma. One additional population for each species was a laboratory susceptible strain. Discriminating dose assays determined eight out of the nine T. castaneum populations, and all five populations of R. dominica, contained phosphine-resistant individuals, and highest resistance frequencies were 94 and 98%, respectively. Dose-response bioassays and logit analyses determined that LC99 values were approximately 3 ppm for susceptible and 377 ppm for resistant T. castaneum, and approximately 2 ppm for susceptible and 3,430 ppm for resistant R. dominica. The most resistant T. castaneum population was 119-fold more resistant than the susceptible strain and the most resistant R. dominica population was over 1,500-fold more resistant. Results suggest a substantial increase in phosphine resistance in these major stored-wheat pests in the past 21 yr, and these levels of resistance to phosphine approach those reported for other stored-grain pest species in other countries.
    Journal of Economic Entomology 08/2012; 105(4):1107-14. · 1.60 Impact Factor
  • Journal of Economic Entomology 01/2012; · 1.60 Impact Factor
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    ABSTRACT: We report that the abdominal epidermis and associated tissues are the predominant sources of male-produced pheromones in the red flour beetle, Tribolium castaneum and, for the first time, describe the stereoisomeric composition of the natural blend of isomers of the aggregation pheromone 4,8-dimethyldecanal (DMD) in this important pest species. Quantitative analyses via gas chromatography-mass spectrometry showed that the average amount of DMD released daily by single feeding males of T. castaneum was 878 ± 72 ng (SE). Analysis of different body parts identified the abdominal epidermis as the major source of aggregation pheromone; the thorax was a minor source, while no DMD was detectable in the head. No internal organs or obvious male-specific glands were associated with pheromone deposition. Complete separation of all four stereoisomers of DMD was achieved following oxidation to the corresponding acid, derivatization with (1R, 2R)- and (1S, 2S)-2-(anthracene-2,3-dicarboximido)cyclohexanol to diastereomeric esters, and their separation on reversed-phase high-performance liquid chromatography at -54°C. Analysis of the hexane eluate from Porapak-Q-collected volatiles from feeding males revealed the presence of all four isomers (4R,8R)/(4R,8S)/(4S,8R)/(4S,8S) at a ratio of approximately 4:4:1:1. A walking orientation bioassay in a wind tunnel with various blends of the four synthetic isomers further indicated that the attractive potency of the reconstituted natural blend of 4:4:1:1 was equivalent to that of the natural pheromone and greater than that of the 1:1 blend of (4R,8R)/(4R,8S) used in commercial lures.
    Naturwissenschaften 09/2011; 98(9):755-61. · 2.14 Impact Factor
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    ABSTRACT: In separate experiments, randomized complete block designs with three replications were utilized to evaluate the effects of phosphine (PH(3)) (0, 200 and 1000ppm for 48h) and methyl bromide (MB) (0, 4, 8, 16, and 32mg/L for 48h) fumigation concentration on the volatile flavor compound concentrations in dry cured ham. Minimal differences existed (P>0.05) in the presence and concentration of aroma active compounds in both PH(3) and MB fumigated hams but sulfur and oxidation compounds were more prevalent (P<0.05) in the fumigated treatments when compared to the control. As phosphine fumigation concentration increased, the residual concentration of phosphine also increased in the hams (P<0.05), but all samples contained levels that are lower than the legal limit of phosphine allowed in stored food products (0.01ppm) in the United States. A triangle test (n=56) indicated that consumers could not discriminate (P>0.75) between the control hams and those that were fumigated with PH(3). Minimal aroma/flavor differences existed among MB, PH3 and control hams, and dry cured ham that was fumigated with PH(3) was safe for consumption based on residual phosphine concentrations in the meat tissue.
    Meat Science 10/2010; 86(2):411-7. · 2.75 Impact Factor
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    ABSTRACT: A randomized complete block design with three replications was utilized to evaluate the effects (P<0.05) of various fumigation concentrations of sulfuryl fluoride (SF) (0, 12, 24, 36 and 72 mg/L) on the fluoride, sulfuryl fluoride, and volatile flavor compound concentrations in dry cured ham. Fluoride and SF concentrations increased (P<0.05) in dry cured hams as SF fumigation concentration increased, but all samples contained fluoride and SF concentrations below the legal limits of 20 and 0.01 ppm, respectively. Minimal differences existed (P>0.05) in the presence and concentration of aroma active compounds, but oxidation compounds were slightly more prevalent (P<0.05) in the 72 mg/ml treatment when compared to the control. A triangle test (n=54) indicated that consumers could not discern (P>0.75) between hams that were fumigated with SF at 0 and 36 mg/ml. This study revealed that there were minimal aroma/flavor differences among the ham treatments between 0 and 36 mg/ml, and that dry cured ham that was fumigated with SF was safe and met legal requirements for consumption.
    Meat Science 03/2010; 84(3):505-11. · 2.75 Impact Factor
  • Mahbub Hasan, Thomas W. Phillips, Michael J. Aikins
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    ABSTRACT: Fumigation with methyl bromide (MB) has been a long established and effective method for controlling the pests infesting southern dry-cured ham in the USA. MB has been identified as an ozone-depleting chemical and its use is being restricted in accordance with an international agreement, and a more rapid alternative is desirable. This study compares the efficacy of fumigants including phosphine, sulfuryl fluoride (SF) as an alternative to MB against two major key arthropod pests of dry-cured ham under laboratory conditions. Laboratory bioassay showed that phosphine was more effective for controlling both red-legged ham beetle Necrobia rufipes DeGeer and ham mite Tyrophagus putrescentiae Schrank than MB. Eggs of both species were found to be highly tolerant to phosphine and MB at 48h exposure than other stages. A complete control was achieved for the both species with a dose level 0.85 and 4.0 g/m3 of phosphine and MB respectively. SF yielded 100% control of all the stages of N. rufipes by 8 g/m3 except eggs which required the doses from 20.88 to 24.72 g/m3 for inhibiting 100% hatchability. The ham mite showed high tolerance to SF being able to survive concentration-time products in excess of EPA standard label limit 1500 g.h/m3 over a 48h exposure at 23C.
    Entomological Society of America Annual Meeting 2009; 12/2009
  • Entomological Society of America Annual Meeting 2009; 12/2009
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    ABSTRACT: The insect arginine vasopressin-like (AVPL) peptide is of special interest because of its potential function in the regulation of diuresis. Genome sequences of the red flour beetle Tribolium castaneum yielded the genes encoding AVPL and AVPL receptor, whereas the homologous sequences are absent in the genomes of the fruitfly, malaria mosquito, silkworm, and honeybee, although a recent genome sequence of the jewel wasp revealed an AVPL sequence. The Tribolium receptor for the AVPL, the first such receptor identified in any insect, was expressed in a reporter system, and showed a strong response (EC(50)=1.5 nM) to AVPL F1, the monomeric form having an intramolecular disulfide bond. In addition to identifying the AVPL receptor, we have demonstrated that it has in vivo diuretic activity, but that it has no direct effect on Malpighian tubules. However, when the central nervous system plus corpora cardiaca and corpora allata are incubated along with the peptide and Malpighian tubules, the latter are stimulated by the AVPL peptide, suggesting it acts indirectly. Summing up all the results from this study, we conclude that AVPL functions as a monomer in Tribolium, indirectly stimulating the Malpighian tubules through the central nervous system including the endocrine organs corpora cardiaca and corpora allata. RNA interference in the late larval stages successfully suppressed mRNA levels of avpl and avpl receptor, but with no mortality or abnormal phenotype, implying that the AVPL signaling pathway may have been near-dispensable in the early lineage of holometabolous insects.
    Insect Biochemistry and Molecular Biology 08/2008; 38(7):740-8. · 3.23 Impact Factor
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Publication Stats

29 Citations
15.69 Total Impact Points

Institutions

  • 2008–2014
    • Kansas State University
      • Department of Entomology
      Kansas, United States
  • 2010
    • Mississippi State University
      • Department of Food Science, Nutrition and Health Promotion
      Starkville, MS, United States