Rearing methods of four insect species intended as feed, food, and food ingredients: a review.

Over the past 2 decades, the potential of insects as food and feed has been recognized globally. Insects as feed ingredients can improve sustainability because of their lower greenhouse gas emissions and their potential to transform organic wastes into high-quality feed rich in nutrients. However, currently, the practical use of insects as food or feed is limited by the high costs of insect production. A great deal of effort is required to improve the rearing technology necessary to establish the principles of insect farming. Several insect species have become industrialized using existing methods of production. The most common industrialized insect species intended as feed and food include the yellow mealworm, Tenebrio molitor L. (Coleoptera: Tenebrionidae); the house cricket, Acheta domesticus L. (Orthoptera: Gryllidae); the black soldier fly, Hermetia illucens L. (Diptera: Stratiomyidae); and the house fly, Musca domestica L. (Diptera: Muscidae). This review focuses on describing the existing rearing methods for these 4 insect species, which may provide a basis for future research to enhance insect production capabilities.

Evaluating Acheta domesticus (Orthoptera: Gryllidae) for the reduction of fumonisin B1 levels in livestock feed.

Mycotoxins that contaminate grain can cause the devaluation of agricultural products and create health risks for the consumer. Fumonisins are one such mycotoxin. Produced primarily by Fusarium verticillioides (Hypocreales: Nectriaceae) (Nirenberg, 1976) on corn, fumonisins' economic impact can be significant by causing various diseases in livestock if contaminated corn is not monitored and removed from animal feed. Finding safe alternatives to the destruction and waste of contaminated grain and restoring its economic value is needed for a sustainable future. Safe reintroduction into the farm food web may be possible through a consumable intermediary such as insects. This study demonstrates the suitability of the house cricket, Acheta domesticus L., as an alternative protein source in domestic animal feed by quantifying fumonisin B1 (FB1) levels in their subsequent insect meal and frass. Small colonies of 2nd instar A. domesticus were reared to 5th instar adults on nutrient-optimized corn-based diets treated with 4 levels of FB1 from 0 to 20 ppm. Increasing levels of FB1 had no adverse effects on the survivorship or growth of A. domesticus. Insect meals prepared from A. domesticus had significantly lower levels of FB1, at 3%-5% of their respective diets, while frass did not differ significantly from their diet. The successful rearing to adulthood of A. domesticus on fumonisin-contaminated diet paired with lower levels of FB1 in their processed insect meal supports the idea that more sustainable agricultural practices can be developed through remediation of low-value mycotoxin-contaminated grain with safer, higher-value insects as livestock feed components.

Insect frass composition and potential use as an organic fertilizer in circular economies.

Insect manure or "frass" has emerged as an alternative nutrient source for alleviating the dependence on fossil fuel-based fertilizers, reducing food waste, and promoting food security. Yet, research on insect frass chemical composition is in its infancy. Here, we assessed the chemical properties of yellow mealworm (Tenebrio molitor L.) frass compared with poultry litter (PL). Insect frass was obtained from the National Biological Control Laboratory (NBCL; IF-L) and an insect-rearing company (IF-C). PL was collected from facilities in Arkansas (PL-AR) and North Carolina (PL-NC). Samples were analyzed for pH, electrical conductivity, macro- and micronutrients, heavy metals, pathogens, and indicator microorganisms. On average, insect frass had 43% and 47% higher C and N than PL, respectively (P < 0.05). Considering a 5 mg/ha application rate, IF-C can supply 159 kg N/ha, twice the N supply of PL-AR (78 kg/ha). IF-L had a 53% higher P supply than PL-NC. Mean K, Ca, S, and micronutrient contents were higher in PL than in frass (P < 0.05), whereas As, Cd, Cr, and Pb were nearly absent in frass. Chemical composition and pathogens in fertilizer sources were largely affected by insect-rearing substrate and supplements used in poultry and insect production. Insect frass utilized in this study had optimum C and N rates relative to PL, suggesting a promising soil amendment for improving soil health and C sequestration, thus contributing to sustainable agricultural intensification and reuse of food waste in circular economies.

Evaluation of Black Soldier Fly Hermetia illucens as Food for Pink-Spotted Lady Beetle Coleomegilla maculata.

The discovery of new and improved factitious and artificial diets is necessary for cost-effective rearing of predatory arthropods. This study evaluated Hermetia illucens black soldier fly (BSF) as a suitable alternative food source for rearing the predatory coccinellid Coleomegilla maculata (Cmac). The hypothesis that BSF larval powder was suitable food to support the growth, development, and reproduction of Cmac was tested in the laboratory. When compared to a standard in-house diet containing brine shrimp egg powder plus Chlorella vulgaris green algae and myristic acid (BSE+CM), the BSF and BSF+CM diets reduced immature growth and development. Immatures successfully reared to teneral adults were smaller when fed BSF or BSF+CM rather than BSE+CM. Combining BSF with a powdered artificial diet (AD), i.e., BSF+AD, did not improve predator growth or development, compared to Cmac reared on BSE+CM. Cmac oviposition responses, i.e., egg clutch production, to BSF vs. BSE+CM or BSF+AD vs. BSE+CM did not differ significantly. In conclusion, BSF has the potential to be food that supports Cmac oviposition behavior. Future research is necessary to discover an ideal mixture of BSF, BSE+CM, or AD that supports Cmac growth, development, and reproduction over multiple generations.

Effects of Taurine as Dietary Supplement on the Biological and Demographic Parameters of Nezara viridula (Heteroptera: Pentatomidae).

The southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae), is a widely distributed pest of many economically important crops. Because of its economic impact, multiple examples of rearing methods and diets for N. viridula have been published. However, rearing this pest year-round consistently in all-vegetable diets has been challenging. Preliminary observations have shown that supplementing N. viridula diet with insect components improves the survival and reproduction of this insect. We hypothesized that taurine could be the nutrient present in insect components that was providing the benefits. Treatments consisting of three different watering regimes: 1) Reverse osmosis (RO) water only (W), 2) 2% taurine solution only (T), and 3) a choice between RO water and 2% taurine solution (T&W) were compared for their effects on life cycle and demographic parameters of N. viridula. Both taurine-containing treatments (T and T&W) resulted in a significant increase in nymphal and premating adult survival and egg viability as compared with treatment 'W'. Taurine supplementation did not have significant effect on fecundity and development time significantly increased in the 'T' treatment compared with W and W&T treatments. However, there were significant improvements in demographic parameters showing an increase in fitness levels after taurine supplementation. These results suggest that taurine is an important nutrient for N. viridula, which has been deficient in traditional diets consisting exclusively of vegetable components. Adoption of this new information will help to improve the survival of N. viridula in culture to facilitate this study to develop new methods for its control.

Inheritance of Two Traits With High Plasticity, Developmental Speed, and Body Size, in Tenebrio molitor (Coleoptera: Tenebrionidae).

The study of inheritance of quantitative traits of high plasticity in insects has been limited. The heritability of larval development time and body weight in Tenebrio molitor L. was determined using the method of parent-offspring regression. The parental group of adults obtained from a cohort from one day of oviposition from a stock colony was divided into 28 class groups according to their larval development time and pupal weight. The progeny resulting from these parental classes was grouped in experimental units and allowed to develop to the pupal stage. Means of larval development time and pupal weight of the progeny were compared with their parental class levels using linear regression. The selection of larval development time and pupal weight in the parental classes had a significant impact on the means of larval development time and pupal weight of the progeny. The regression coefficients for larval development time and pupal weight were 0.626 ±â€…0.02 and 0.408 ±â€…0.02, respectively. These values represent the proportion of genetic determination of these two traits based on the principles of the method of parent-offspring regression. The apparent independence of larval development time and pupal weight based on their poor linear correlation is discussed.

Gross Morphology of Diseased Tissues in Nezara viridula (Hemiptera: Pentatomidae) and Molecular Characterization of an Associated Microsporidian.

Nezara viridula (L.) (Hemiptera: Pentatomidae), commonly known in the U.S. as the southern green stink bug (SGSB), is a cosmopolitan, highly polyphagous feeder that causes severe damage to a wide range of agronomically important crops such as fruit, vegetable, grain, tobacco, and cotton, throughout much of the United States, and is a global pest of considerable ecological, agricultural, and economical interest. During dissection of female Nz. viridula, conspicuous black and brown spots or lesions were observed on various internal organs. To determine the cause of these spots or lesions, tissues of fat body, spermatheca, ovaries, and ovulated eggs were collected from healthy and infected individuals. The gross morphology of the spots was characterized, and the microorganisms associated with the infection were identified by amplicon sequencing of the V4 region of the small subunit rRNA gene. The presence of a microsporidian pathogen Nosema maddoxi, Becnel, Solter, Hajek, Huang, Sanscrainte, & Estep (Microsporidia: Nosematidae) which has been observed on other species of stink bug, was evidenced for the first time. The characterization of the gross morphology of this associated microsporidian may enable more rapid determination of microsporidia infection in stink bug colonies and field populations.

Self-Selection of Agricultural By-Products and Food Ingredients by Tenebrio molitor (Coleoptera: Tenebrionidae) and Impact on Food Utilization and Nutrient Intake.

Nutrient self-selection was used to determine optimal intake ratios of macro-nutrients by Tenebrio molitor L. larvae. Self-selection experiments consisted of 9 combinations (treatments) of 8 ingredients, from a total of 20 choices, radially distributed in a multiple-choice arena presented to groups of 100 T. molitor larvae (12th-13th instar). Larvae freely selected and feed on the pelletized ingredients for a period of 21 days at 27 °C, 75% RH, and dark conditions. Consumption (g) of each ingredient, larval live weight gained (mg), and frass production were recorded and used to calculate food assimilation and efficiency of conversion of ingested food. The macro-nutrient intake ratios were 0.06 ± 0.03, 0.23 ± 0.01, and 0.71 ± 0.03 for lipid, protein, and carbohydrate, respectively on the best performing treatments. The intake of neutral detergent fiber negatively impacted food assimilation, food conversion and biomass gain. Food assimilation, food conversion, and biomass gain were significantly impacted by the intake of carbohydrate in a positive way. Cabbage, potato, wheat bran, rice bran (whole and defatted), corn dry distillers' grain, spent brewery dry grain, canola meal and sunflower meal were considered suitable as T. molitor diets ingredients based on their relative consumption percentages (over 10%) within treatment.

Development of a Physiological Age-Grading System for Nezara viridula (Hemiptera: Pentatomidae).

The southern green stink bug (SGSB), Nezara viridula (L.), is an important agricultural pest in the United States. Limited information is available on the morphology of the female's reproductive system in relation to morphological changes associated with the number of eggs produced and egg masses oviposited. The ability to assess reproductive health and reproductive status based on ovarian morphology (i.e., physiological age-grading) can be an important tool for evaluating field populations and laboratory colonies intended for the application of different management strategies and experimental trials. Thus, the goal of this study was to develop a physiological age-grading system for SGSB. Females aged from 0 to 79 d chronologically randomly selected from laboratory colonies and dissected to assess ovarian morphology. Specific morphological differences in ovarian structures including differentiation of the ovarioles, deposition of yolk in the most proximal follicle, quantity and appearance of follicular relics, expansion of the lateral oviducts, and number of developing follicles per ovariole were related to chronological age, the number of eggs produced and number of egg masses. Based on specific combinations of these morphological characteristics, the continuum of ovarian development was divided into three nulliparous (i.e., 'no eggs'; N1, N2, and N3) and three parous stages (i.e., 'with eggs'; P1, P2, and P3). Direct relationships were noted between number of eggs produced and physiological age with over 7-fold higher number of eggs and 14-fold higher number of egg masses associated with the P2 and P3 stages, respectively.

Self-selection of food ingredients and agricultural by-products by the house cricket, Acheta domesticus (Orthoptera: Gryllidae): A holistic approach to develop optimized diets.

The house cricket, Acheta domesticus L. (Orthoptera: Gryllidae) is one of the most important species of industrialized insects in the United States. Within the past five years the market of cricket powder as a food ingredient has been growing with increasing consumer interest on more sustainable sources of food. However, high labor costs of cricket production and high prices of cricket feed formulations result in cricket powder market prices much higher than other protein-rich food ingredients, making cricket powder only competitive within the novelty food market. In this study new diets formulated using by-products were developed using dietary self-selection followed by regression analysis. Crickets selected among seven different combinations of ingredients. Consumption ratios of food ingredients and by-products were used to determine macro and micro-nutrient intake. Regression analysis was used to determine the individual nutrient intake effect on cricket biomass production. Intake of vitamin C, sterol, manganese, and vitamins B1 and B5 had the most significant impact on live biomass production. Four diets were formulated based on this information and compared with a reference (Patton's 13) and a commercial diet. Although, crickets reared on Patton's diet 13 produced the most dry-weight biomass and developed the fastest, diet 4 (consisting of 92% by-products) generated the most profit (with a cost of $0.39 USD per kg) after an economic analysis that did not include the commercial formulation. Dry-weight biomass production was not significantly different among the four new diets and the commercial diet. This study demonstrated the value of dietary self-selection studies in developing oligidic insect diets and in studies of insect nutrition. This is the first such study involving farmed edible crickets and agricultural by-products. Four new cricket diet formulations contain between 62 and 92% agricultural by-products are included.

Body Mass Increase Induced by Eight Years of Artificial Selection in the Yellow Mealworm (Coleoptera: Tenebrionidae) and Life History Trade-offs.

Efforts to improve rearing conditions of Tenebrio molitor L. (Coleoptera: Tenebrionidae) for insect biomass production included selecting for larger size pupae. The effects of an 8-yr continuous selection of T. molitor pupae for larger size were studied. Data consisting of daily counts and weights of pupae were analyzed using regression to determine the effects of selection over time. A preliminary evaluation of food conversion, growth, fecundity, and larval survival was done to compare ancestral versus selected strains. A significant positive correlation was identified between pupal size and time indicating a significant increase in pupal size over time in the selected T. molitor strain. A preliminary comparison of ancestral and selected strains showed significantly larger pupal size, growth rate, fecundity, and efficiency of conversion of ingested food in the selected strain. However, the selected strain also showed significantly lower larval survival than the ancestral strain. The low larval survival impacted the overall productivity of the selected strain resulting in no significant differences in biomass production when compared with the ancestral strain. The potential of using selection to improve biomass productivity in T. molitor is discussed.

Mortality of Solenopsis invicta Workers (Hymenoptera: Formicidae) After Indirect Exposure to Spores of Three Entomopathogenic Fungi.

Mortality caused by indirect exposure to Metarhizium brunneum and Beauveria bassiana (GHA and NI8) to the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), workers was evaluated. Groups of 50 workers were placed in one side of dual-box arenas. The opposite side of the arenas was lined with filter paper squares previously sprayed with unformulated purified spores (106 spores/ml) suspended in 0.2% Ethal TDA 3, HLB 8 of the three fungal strains, or untreated filter paper squares as the control. Daily observations were done for 1 wk to determine mortality. Dead ants from each treatment and control were collected, surface cleaned, and placed in PDA media and incubated at 27°C, 60% RH for 7 d to detect fungal growth. The presence of fungal growth in the dead ants confirmed that fungal spores infected workers while walking on the treated paper. In the M. brunneum and B. bassiana GHA treatments, 51.35 and 56.68% of the workers died, respectively, during days 1 and 2. However, only 9.47 and 35.96% of the mortality could be explained by fungal infection by M. brunneum and B. bassiana GHA, respectively. Most of the mortality observed in the B. bassiana NI8 treatment (84.48%) occurred later (between days 4-6) and most of this mortality occurring during day 4 (89.06%) could be explained by B. bassiana infection. Overall mortality was significantly higher in the B. bassiana NI8 treatment than the other two fungi tested and control. Potential application of these fungal strains for fire ant control are discussed.

Temperature-Dependent Biological and Demographic Parameters of Coleomegilla maculata (Coleoptera: Coccinellidae).

Knowledge of the most suitable environmental conditions for an organism growth and development is a prerequisite for developing mass rearing technology. The temperature requirements for development and the optimal range of temperatures for growth and reproduction of Coleomegilla maculata De Geer were studied. The development time of individual C. maculata larvae was determined at 18, 21, 24, 27, 30, 33, and 36 °C. Development times were converted to development rates and fitted to a nonlinear temperature-dependent model and to the linear day-degree model. Life and fertility table analysis was used to determine the optimal temperature for population growth within a range of favorable temperatures including 24, 25, 26, 27, and 28 °C. Nonlinear estimates of thermal maximum (TM) for the postembryonic development of C. maculata was 35.09 ± 10.35 °C. Estimation of TM based on pupal development was much lower at 27.23 ± 1.52 °C. Linear and nonlinear estimates of low temperature development threshold were 13.13 ± and 4.77 ± 3.03 °C for the whole postembryonic development and 10.95 and 9.18 ± 1.36 °C for the pupal stage alone, respectively. The most favorable temperature for population growth was 25 °C, where C. maculata showed significantly higher intrinsic rate of increase (rm = 0.066) and significantly lower doubling time (10.57 d) than the other favorable temperatures tested. A negative value of rm was obtained at 28 °C, indicating population decline occurring at this temperature making it unfavorable for C. maculata.

A New Report of Nezara viridula f. aurantiaca (Heteroptera: Pentatomidae) from a Cultured Population in Washington County, Mississippi.

Nezara viridula adult coloration can vary, including a rare orange-colored type (i.e., N. viridula f. aurantiaca). In November 2015, three Nezara viridula males displaying orange coloration were found in an established colony in Stoneville, MS. The objectives of this study were to determine if alleles of these orange types conformed to the allele characteristics previously reported for N. viridula f. aurantiaca and to determine if there were any differences in reproductive output compared with the green-colored type. The three orange-type males were crossed with green-type females to produce a hybrid F1 The F1 progeny was allowed us to cross to produce an F2. The F2 progeny consisted of 672 green females, 351 green males, 298 orange males, and 0 orange females. These ratios did not differ significantly from the expected 50:25:25:0 ratios for a single recessive sex linked allele for color phenotype. The F2 cross of green females and orange males produced an F3 consisting of 345 green females, 346 green males, 100 orange females, and 85 orange males. These ratios also conformed to the expected ratios (0.375:0.375:0.125:0.125) with the exception of orange males, which numbers were slightly lower than expected. The pure orange type N. viridula produced significantly less egg masses (0.71 ± 0.15) per day than green types (2.09 ± 0.16) and their reproductive output, measured as net reproductive rate (Ro), was lower in orange (13.71) compared with green (20.67) types.

In Vivo Production of Entomopathogenic Nematodes.

In nature, entomopathogenic nematodes in the genera Heterorhabditis and Steinernema are obligate parasites of insects. The nematodes are used widely as biopesticides for suppression of insect pests. More than a dozen entomopathogenic nematode species have been commercialized for use in biological control. Most nematodes intended for commercial application are produced in artificial media via solid or liquid fermentation. However, for laboratory research and small greenhouse or field trials, in vivo production of entomopathogenic nematodes is the common method of propagation. Additionally, small companies continue to produce nematodes using in vivo methods for application in niche markets. Advances in mechanization and alternative production routes (e.g., production geared toward application of nematodes in infected host cadavers) can improve efficiency and economy of scale. The objective of this chapter is to describe basic and advanced procedures for in vivo production of entomopathogenic nematodes.

Nutritional Value of Pupae Versus Larvae of Tenebrio molitor (Coleoptera: Tenebrionidae) as Food for Rearing Podisus maculiventris (Heteroptera: Pentatomidae).

Life-table analysis yielded demographic parameter values that indicate that Tenebrio molitor (L.) pupae are potentially more suitable factitious prey to mass-produce the predator Podisus maculiventris (Say) and are more suitable prey than the larvae. P. maculiventris developed faster (23.2 vs. 25.5 d), weighed more (females 80.9 vs. 66.6 mg and males 64.7 vs. 53.7 mg), and had a higher survival rate (0.88 vs. 0.7), fecundity, and reproductive output (87.1 vs. 22.8 eggs/female) when reared on pupae compared with larvae of T. molitor. The total protein content and soluble protein content were significantly higher in pupae (60.2 and 23%, respectively) than larvae (53.1 and 14.4%, respectively). Lipid content was significantly lower in pupae (32.1%) than larvae (35.9%), and larvae had more polyunsaturated fatty acids (83.6 vs. 56.6 mg/g) and less oleic (0.1 mg/g) and steric (6.1 mg/g) acids than pupae (37.3 and 12.3 mg/g, respectively). The total sugar content was not significantly different between pupae and larvae. However, larvae had significantly more fructose than pupae, but pupae had more galactose, glucosamine, glucose, mannose, and trehalose than larvae. Differences in nutritional composition and its impact on predator demographic parameters are potential factors that make the pupal stage a better food source.

Effect of Larval Density on Food Utilization Efficiency of Tenebrio molitor (Coleoptera: Tenebrionidae).

Crowding conditions of larvae may have a significant impact on commercial production efficiency of some insects, such as Tenebrio molitor L. (Coleoptera: Tenebrionidae). Although larval densities are known to affect developmental time and growth in T. molitor, no reports were found on the effects of crowding on food utilization. The effect of larval density on food utilization efficiency of T. molitor larvae was studied by measuring efficiency of ingested food conversion (ECI), efficiency of digested food conversion (EDC), and mg of larval weight gain per gram of food consumed (LWGpFC) at increasing larval densities (12, 24, 36, 48, 50, 62, 74, and 96 larvae per dm(2)) over four consecutive 3-wk periods. Individual larval weight gain and food consumption were negatively impacted by larval density. Similarly, ECI, ECD, and LWGpFC were negatively impacted by larval density. Larval ageing, measured as four consecutive 3-wk periods, significantly and independently impacted ECI, ECD, and LWGpFC in a negative way. General linear model analysis showed that age had a higher impact than density on food utilization parameters of T. molitor larvae. Larval growth was determined to be responsible for the age effects, as measurements of larval mass density (in grams of larvae per dm(2)) had a significant impact on food utilization parameters across ages and density treatments (in number of larvae per dm(2)). The importance of mass versus numbers per unit of area as measurements of larval density and the implications of negative effects of density on food utilization for insect biomass production are discussed.

Optimization of a Host Diet for in vivo Production of Entomopathogenic Nematodes.

To facilitate improved in vivo culture of entomopathogenic nematodes, production of both insect hosts and nematodes should be optimized for maximum fitness, quality, and cost efficiency. In previous studies, we developed an improved diet for Tenebrio molitor, a host that is used for in vivo nematode production, and we demonstrated that single insect diet components (e.g., lipids and proteins) can have a positive or negative impact on entomopathogenic nematode fitness and quality. In this study, we tested components of our improved T. molitor diet (lipids, cholesterol, and a salt [MnSO4]) alone and in combination for effects on host susceptibility and reproductive capacity of Heterorhabditis indica and Steinernema carpocapsae. Our results indicated that moderate levels of lipids (10%) increased host susceptibility to S. carpocapsae but did not affect H. indica, whereas cholesterol and MnSO4 increased host susceptibility to H. indica but not S. carpocapsae. The combined T. molitor diet (improved for increased insect growth) increased host susceptibility to S. carpocapsae and had a neutral effect on H. indica; interactions among single diet ingredients were observed. No effects of insect host diet were detected on the reproductive capacity of either nematode species in T. molitor. Subsequently, progeny infective juveniles, derived from nematodes grown in T. molitor that were fed diets with varying nutritive components were tested for virulence to and reproduction capacity in the target pest Diaprepes abbreviatus. The progeny nematodes produced from differing T. molitor diet treatments did not differ in virulence except H. indica derived from a diet that lacked cholesterol or MnS04 (but contained lipids) did not cause significant D. abbreviatus suppression relative to the water control. We conclude that the improved insect host diet is compatible with production of H. indica and S. carpocapsae, and increases host susceptibility in S. carpocapsae. Furthermore, in a general sense, our results indicate host diets can be optimized for improved in vivo entomopathogenic nematode production efficiency. This is the first report of an insect diet that was optimized for both host and entomopathogenic nematode production. Additionally, our study indicates that host diet may impact broader aspects of entomopathogenic nematode ecology and pest control efficacy.

Tri-trophic level impact of host plant linamarin and lotaustralin on Tetranychus urticae and its predator Phytoseiulus persimilis.

The impact of linamarin and lotaustralin content in the leaves of lima beans, Phaseolus lunatus L., on the second and third trophic levels was studied in the two-spotted spider mite, Tetranychus urticae (Koch), and its predator Phytoseiulus persimilis Athias-Henriot. The content of linamarin was higher in terminal trifoliate leaves (435.5 ppm) than in primary leaves (142.1 ppm) of Henderson bush lima beans. However, linamarin concentrations were reversed at the second trophic level showing higher concentrations in spider mites feeding on primary leaves (429.8 ppm) than those feeding on terminal trifoliate leaves (298.2 ppm). Concentrations of linamarin in the predatory mites were 18.4 and 71.9 ppm when feeding on spider mites grown on primary and terminal leaves, respectively. The concentration of lotaustralin in primary lima bean leaves was 103.12 ppm, and in spider mites feeding on these leaves was 175.0 ppm. Lotaustralin was absent in lima bean terminal trifoliate leaves and in mites feeding on these leaves. Fecundity of spider mites feeding on lima bean leaves (primary or trifoliate) was not significantly different from mites feeding on red bean, Phaseolus vulgaris L., primary leaves. However, the progeny sex ratio (in females per male) of spider mites feeding on lima bean leaves was significantly lower than progeny of spider mites feeding on red bean leaves (control). Fecundity and progeny sex ratio of P. persimilis were both significantly affected by the concentration of linamarin present in the prey. Changes in concentration of linamarin in living tissue across the three trophic levels are discussed.

Effects of a novel entomopathogenic nematode-infected host formulation on cadaver integrity, nematode yield, and suppression of Diaprepes abbreviatus and Aethina tumida.

An alternative approach to applying entomopathogenic nematodes entails the distribution of nematodes in their infected insect hosts. Protection of the infected host from rupturing, and improving ease of handling, may be necessary to facilitate application. In this study our objective was to test the potential of a new method of formulating the infected hosts, i.e., enclosing the infected host in masking tape. Tenebrio molitor L. cadavers infected with Heterorhabditis indica Poinar, Karunakar and David or Steinernema carpocapsae (Weiser) were wrapped in tape using an automatic packaging machine; the machine was developed to reduce labor and to standardize the final product. The effects of the tape formulation on the ability to protect the cadavers from mechanical damage, nematode yield, and pest control efficacy were tested. After exposure to mechanical agitation at 7-d-post-infection, S. carpocapsae cadavers in tape were more resistant to rupture than cadavers without tape, yet H. indica cadavers 7-d-post-infection were not affected by mechanical agitation (with or without tape), nor was either nematode affected when 4-d-old cadavers were tested. Experiments indicated that infective juvenile yield was not affected by the tape formulation. Laboratory experiments were conducted measuring survival of the root weevil, Diaprepes abbreviatus (L.), or the small hive beetle, Aethina tumida Murray, after the application of two H. indica-infected hosts with or without tape per 15 cm pot (filled with soil). A greenhouse experiment was also conducted in a similar manner measuring survival of D. abbreviatus. In all experiments, both the tape and no-tape treatments caused significant reductions in insect survival relative to the control, and no differences were detected between the nematode treatments. Fifteen days post-application, the infected host treatments caused up to 78% control in A. tumida, 91% control in D. abbreviatus in the lab, and 75% in the greenhouse. These results indicate potential for using the tape-formulation approach for applying nematode infected hosts.