Adult Mealworms Research Articles

Data center excess heat for mealworm farming, an applied analysis for sustainable protein production

Since Sweden joined the EU in 1995, importing food became easier and cheaper, leading to certain parts of the country, such as Norrbotten, becoming highly dependent on imports. This dependency, along with the inherent environmental impact of imports, could be significantly reduced by local farming. The environmental emissions originating from animal farming could be lowered even further by substituting the highly polluting soybean feed with, e.g., insect feed. This study examines the farming of mealworms, utilizing excess heat from a data center, part of a growing industry in Norrbotten county, as a means of alternative feedstock for animal production and a case study for industrial symbiosis. This industrial symbiosis project is in line with the EU's incentive to use other sources of protein and thus lower the EU's reliance on the import of foreign protein. Three different feeding approaches are tested, in a room heated with data center excess heat of 30 °C and at room temperature of about 20 °C. After the adult mealworms were harvested, a sample was taken to analyze their nutritional values. The results show that protein, lipid, and fiber content is 19,1 g, 12,6 g, and 2,7 g per 100 g, respectively. All amino acids except tryptophan were detected. This project concludes that it is possible to reach full-grown mealworms in about 8 weeks, which is about half the time stated in the literature.

Ingestion of Nylon 11 Polymers by the Mealworm (Tenebrio molitor) Beetle and Subsequent Enrichment of Monomer-Metabolizing Bacteria in Fecal Microbiome.

Nylon 11 is a synthetic plastic widely used in commercial products such as tubing for automobiles, offshore oilfields, and medical devices. An increasing amount of nylon and other plastic wastes have been released into various environments, posing ecological threats. The biodegradation of bundled nylon polymers has been considered impossible due to their crystalline structures. Nylon 11 film was created and incubated with adult mealworms. The mass, as well as structures, of nylon 11 films at pre- and post-incubation with beetles were compared. The number of nylon 11 monomer degrading bacteria in feces were determined by culture-dependent approach. The t-test was utilized to examine the statistical significance. We discovered that adult mealworm (Tenebrio molitor) beetle can ingest nylon 11 when stretched thin. The microscopic observation of their feces did not identify the presence of large fragments of nylon 11. The analysis of fecal bacteria revealed that while the total number of culturable bacteria did not change significantly, the number of 11-aminoundecanoic acid-metabolizing bacteria increased by 10,000-fold. Our results suggest that bundled nylon 11 polymers were fragmented into smaller pieces, including monomeric units (11-aminoundecanoic acid) by adult mealworm. The monomers seem to have supported the proliferation of gut microbial communities capable of utilizing 11-aminoundecanoic acid as a carbon and nitrogen source. Our work implies the potential use of the mealworm beetle as a means to fragment nylon polymers for remediation applications.

Extraction and Characterization of Chitin and Chitosan from Tenebrio Molitor Beetles and Investigation of its Antibacterial Effect Against Pseudomonas aeruginosa.

Chitin and chitosan are utilized in many industries such as pharmacy, biotechnology, and medicine. The mealworm beetle, Tenebrio Molitor, is simply breaded and does not require a vast production space. In this study, we extracted chitin and chitosan using two different methods from Tenebrio Molitor adult beetles. Then we studied their physical and chemical properties along with their antibacterial effect. Using two new methods we extracted 13, 3%, and 17.7% chitin from the dry mealworm beetle which was higher than in previous studies. The chitosan yield of the extracted chitin was 78.26% and 76.43%, respectively. The observed FTIR peaks for chitin and chitosan in this study were in accordance with the characteristic peaks. The degree of acetylation of chitin was 95.09% and 92.55% and the degree of deacetylation was 75.84%, and 72.6% from the first and second methods, respectively. The extracted chitosan also showed an antibacterial effect against Pseudomonas aeruginosa. Our study demonstrated that chitin and chitosan extracted from adult mealworm beetles could be considered as a replacement for commercial chitosan and needs further studies.

Atividade da Metilxantina em pó aplicada na cama de frango sobre adultos de Alphitobius diaperinus (Panzer, 1797) (Coleoptera: Tenebrionidae)

Abstract One of the pests that most affect and compromise poultry production worldwide is the insect Alphitobius diaperinus, known as the lesser mealworm. This insect is a vector of diseases that compromise not only chicken production but also human health. This study proposes to examine the efficacy and determine the appropriate rate of methylxanthine (MTX), a natural insecticide extracted from cafeine, for the control of an adult population of lesser mealworms in poultry litter. A total of 2,500 adult mealworms were distributed into five treatments in a completely randomized design using 10 replications with 50 insects per replication. The treatments consisted of a control group and four concentrations of MTX (14, 16, 18, and 20 g/m2) spread in plastic boxes containing reused poultry litter and feed, allocated in a broiler shed, to simulate the farm condition. The experimental period was 18 days, and five readings were performed on days 2, 4, 6, 10, and 18. Methylxanthine affected (P<0.05) the mealworms’ cumulative mortality rate, with the groups of insects housed in boxes treated with 16 g /m2 MTX showing the highest cumulative mortality (86.6%) at the end of the experimental period. In conclusion, MTX has insecticidal action on adults of lesser mealworm and can be used on chicken litter to control the population of this insect in poultry sheds. The MTX concentration of 16 g/m2 showed the greatest effectiveness.

PSXI-4 Beauveria bassiana to control the mealworm Alphitobius diaperinus in chicken barns

Abstract One of the most common insects in poultry houses is the mealworm Alphitobius diaperinus, also known as the darkling beetle. Immature (larvae) and adults feed on seeds spilled on the ground or from poultry droppings. In addition to structural damage, this insect can also be a vector of diseases that can affect birds. In addition, the indigestible shell of the insect can cause digestion problems for birds, and thus affect the profitability of production. It is considered impossible to eliminate the populations of mealworms, and in organic poultry production, the control options are limited. The mycoinsecticide BioCeres WP, based on the fungus Beauveria bassiana, and which controls aphids, has been proposed to control the mealworm A. diaperinus in chicken barns. 450 adult mealworms from a commercial chicken barn were randomly distributed in 9 containers (1 m2) containing 10 cm of wood shavings litter and chicken feed. BioCeres WP was applied by spraying two applications of 40 ml of 10 g/L solution (representing 4 x 10^9 conidia per m2 per application). Mealworms were housed during a broiler batch at the chicken barn they were harvested from and received one of the following treatments: 1) control, water spraying; 2) BioCeres WP treatment. 3 repetitions for control and 6 for BioCeres WP were performed. BioCeres WP increased the mortality rate of mealworms (+101%, P < 0.02; 17.8% vs. 8.6%), compared to untreated mealworms, 28 days after treatment. Mortality rates were affected from day 14 until day 28 after treatment. A trial using 640 broilers in 32 pens revealed no adverse effect on growth performance or health. In summary, BioCeres WP could be involved in a biological strategy to control the mealworm Alphitobius diaperinus in chicken barns.

Predicting Predator Nutrient Intake From Prey Body Contents

Predator-prey interactions can have important consequences for the flow of nutrients through food webs and ecosystems. Given the diversity of predator-prey interactions, it is infeasible to directly measure predator nutrient intake when feeding on each potential prey. Elements are an important measure of nutrient flow through food webs but do not fully account for variation in the quality of nutrients in which they are present. The overall goal of this study was to test if measures of macronutrients, metabolizable protein and lipid, could be used to improve measures of elemental ingestion by predators when feeding on prey. This experiment used two prey that differed widely in exoskeleton content (i.e., larval vs. adult mealworms) because arthropod prey vary widely in this trait and it has the potential to complicate nutritional measurements since it contains nitrogen but is indigestible to most predators. Our results show that the elemental content of whole prey was a poor predictor of elemental consumption by predators. Macronutrient content of whole prey was a strong predictor of macronutrient ingestion by predators, which suggested that it may be a useful measure of predator consumption. Using macronutrient data to create a hybrid element-macronutrient measure of whole prey resulted in better predictions of total elemental ingestion by predators. These results suggest that combining elemental and macronutrient approaches in the study of trophic transfers of nutrients, especially during predator-prey interactions, has the potential to increase our ability to understand and predict the flow of nutrients through food webs and ecosystems.

Consequences of prey exoskeleton content for predator feeding and digestion: black widow predation on larval versus adult mealworm beetles

Predators often feed on a wide range of prey that can vary in behavior, morphology, and physiology. The net benefits that predators gain from prey are likely related to both prey nutrient content and prey morphology or defenses. For invertebrates, the exoskeleton is a morphological trait that varies widely among species and during ontogeny and could affect nutrient extraction by predators. The goal of this study was to determine how prey exoskeleton content affected predator nutrient intake, assimilation, and excretion by comparing spiders feeding on either larval or adult mealworms of similar size. We found that the proportion of prey energy invested in digestion was greatest in spiders consuming adult mealworm beetles which had higher amounts of exoskeleton than larvae. Further, spiders extracted a greater proportion of elements, macronutrients, and energy from the larval mealworms, which had lower amounts of exoskeleton. Interestingly, total nitrogen content of prey was not a predictor of nitrogen assimilation as spiders assimilated more nitrogen from the larval mealworms, which had lower total nitrogen content. While adult beetles had higher total nitrogen content, their discarded remains of prey had large amounts of nitrogen that was nutritionally unavailable for spiders (i.e., exoskeleton). These results suggest that prey exoskeleton can affect assimilation efficiency by predators, and that a combination of macronutrient and elemental analyses may be needed to examine the quality of prey for predators and the potential consequences of predation for nutrient flows (e.g., consumer assimilation, egestion, and excretion) in ecosystems.

Observation of two-dimensional yttrium oxidenanoparticles in mealworm beetles (Tenebriomolitor).

Nanomaterials are being used in medicine, manufacturing and consumer products, but their effects on organisms and the environment are not well understood because of the difficulty in detecting them. Here dual-energy X-ray K-edge subtraction was used to track two-dimensional yttrium oxide nanoparticles (which can be found in such household objects as color televisions) in adult mealworms (Tenebrio molitor). The insects ingested nanoparticle-infused feed for different time periods, up to 24 h, and the nanoparticles could then be identified at several locations in the insects' head, thorax and abdomen, mostly within the digestive tract. In time, all particles were excreted.

The ability of Alphitobius diaperinus homogenates immobilized on plant sorbent to block the development of mouse parkinsonism

Insects have long attracted the attention of researchers as a source of biologically active sub� stances present in the tissues of different species of insects at various stages of their life cycle (1, 2). The analysis of the chemical composition of some species of invertebrates showed that the bee ( Apis mellifera), grasshoppers (family Acrididae), housecricket (Acheta domesticus), American cockroach (Periplan� eta americana), larval and adult mealworms (Tenebrio molitor), as well as larvae of the wax moth (Galleria mellonella), silkworm (Bombyx mori), blowfly (family Calliphoridae), black soldier fly (Hermetia illucens), etc., contain not only proteins and fats, but also chitin, minerals, amino acids, polyunsaturated fatty acids and vitamins, essential oils, and other biologically active sub� stances, including new antimicrobial peptides (3-9). In the scientific literature, there is scarce information about the possible medical use of extracts from the darkling beetle Ulomoides dermestoides from the family Tenebrionidae, which exhibit antiinflammatory and immunomodulating effect (10) and cytotoxicity with respect to A549 (lung adenocarcinoma) tumor cells (11). A species close to Ulomoides dermestoides is the beetle Alphitobius diaperinus, which is also used in folk medicine to treat various diseases, including one of the most socially important—Parkinson's disease. It was assumed that the Alphitobius diaperinus biomass homogenate may exhibit inhibitory activity with respect to MPTP (methylphenyl tetrahydropyri� dine)—a toxin that causes experimental parkinsonism in C57BL/6JSto mice (12, 13).

Intraspecific variation in prey quality: a comparison of nutrient presence in prey and nutrient extraction by predators

Prey quality can have large impacts on the survival, growth and behavior of predators. A number of studies have examined how different species of prey vary in quality. However, far less is known about intraspecific variation in the quality of prey for predators and even less about what nutrients are extracted from prey by predators. We examined how the sex, feeding level and developmental status of prey affected the quantities of nutrients present in prey bodies and the quantities of nutrients that could be extracted from prey by spiders. Female and well‐fed prey were larger and had more nutrients than male and food‐limited prey, respectively. After taking into account differences in prey size, spiders extracted relatively more lipid and less protein from female and well‐fed prey than from male and food‐limited prey, respectively. Mealworms were of higher quality than adult mealworm beetles; spiders were able to extract more lipid, protein and other nutrients from larvae than adults. While lipid present in prey was a good predictor of lipid consumed, protein present in prey was not a reliable predictor of protein consumed. The variation in prey quality that we observed within a single species of prey (i.e. well‐fed vs food‐limited crickets) was as large as variation in quality among the three species of prey used in these experiments. Intraspecific variation in prey quality may be an important factor affecting predatory arthropods, especially in habitats or at times of year when one species of prey is abundant. Further studies are needed to examine the consequences of intraspecific variation in prey quality on the life history and behavior of predators.

Role of allatostatin‐like factors from the brain of Tenebrio molitor females

The effect of brain extract from females of freshly emerged Tenebrio molitor on ovary, oocyte development, total protein content of hemolymph, and ovary was studied in 4-day-old adult mealworm females. Injections of extracts of 2-brain equivalents into intact (unligatured) Tenebrio females did not affect ovarian and oocyte development. Injections of ligated females, however, with 2-brain equivalents on day 1 and 2 after adult emergence strongly inhibited ovarian growth and oocyte development. At day 4, ligated and injected females did not develop their ovaries and pre-vitellogenic oocytes were not found. The changes in ovarian development correlated with an increase in the concentration of soluble proteins in the hemolymph as compared with the saline-injected controls. Additionally, a strong reduction of total protein content in ovarian tissue was observed. Reverse phase HPLC separation of a methanolic brain extract of T. molitor females showed that fraction 5 has a similar retention time to synthetic cockroach allatostatin. Fraction 5 was eluted at 12.88 min, which was closest to the internal standard Dippu-AST I, which eluted at 12.77 min. An ELISA of fraction 5 from the methanolic brain extract using antibodies against allatostatins Grybi-AST A1 and Grybi-AST B1 from cricket Gryllus bimaculatus showed that fraction 5 cross-reacted with Grybi-AST A1 antibodies. The cross-reactivity was similar to the synthetic allatostatin from D. punctata, which was used as a positive control. These observations demonstrate a possible role for allatostatin-like brain factor(s) in regulating the reproductive cycle of Tenebrio molitor.

Feeding activity in captive New Zealand lesser short‐tailed bats (Mystacina tuberculata)

Lesser short‐tailed bats (Mystacina tuberculata) have been reported as commonly feeding on the ground, but few direct observations of the diet and foraging behaviour of these rare and secretive bats have been published. Here, we describe the feeding behaviour of six captive M. tuberculata at Wellington Zoological Gardens, in order to experimentally clarify and validate some of the feeding behaviours previously reported from anecdotal observations. In particular, we focused on food type choice and dependence on nectar. The bats emerged every night 80 ± 30 (mean ± SE) min after sunset, irrespective of the weather, and spent most of their time foraging in leaf litter on the ground (when available) and on the branches of trees. Larvae of meal worms (Tenebrio molitor) and cerambycid beetles (Prionoplus reticularis) were favoured in the diet, followed in diminishing order by adult meal worms, tree weta (Hemideina crassidens) and crickets (Teleogryllus commodus), some nectars, sugar solutions, and finally water. Nectar from Eucalyptus sp. was preferred, followed by nectar of pohutukawa (Metrosideros excelsa), wood rose (Dactylanthus taylorii), and kakabeak (Clianthus puniceus). Nectar of Acacia sp., Hebe sp., and synthetic Dactylanthus nectar were not taken. The bats visited 50 and 25% sugar solutions significantly more frequently (91% of visits) than 12.5 and 0% sugar solutions. Various meats (carrion) and fruit were not eaten. Faecal content fairly represented the invertebrates consumed the previous night, but the volumes of invertebrates consumed could not be reliably estimated from faecal analysis.

Fine Structure of Female Accessory Reproductive Gland in the Mealworm Beetle, Tenebrio molitor

ABSTRACT The fine structure of female accessory reproductive gland (FARG) of the adult mealworm beetle, Tenebrio molitor is studied with light and electron microscopes. The FARG is a simple tubular organ that composed of two kinds of cells‐secretory epithelial cells and duct forming cells. The lumen of FARG is lined with a thin cuticle and filled with secretory materials. Each secretory epithelial cell has its peculiar end apparatus in addition to well‐developed rough endoplasmic reticulum (rER), mitochondria, and secretory vesicles. They are forming basal infolding along the plasma membrane. Along the inner surface of the plasma membrane, numerous secretory vesicles are seen. The glandular secretions of the epithelial secretory cells are synthesized via rER to Golgi apparatus, and are stored in the extracellular cavity in the epithelial cell. These secretions are drained to the lumen through the end apparatus and this type of glandular secretion in the insects is type III. Histochemical reactions reveal the major component of these glandular secretions is an acid mucopolysaccharide.

Immune investment and sperm competition in a beetle

AbstractIndividuals that invest more in immunity may not be able to invest as much in o\ther life history traits. The overall effects on fitness depend on the balance of investment in life history traits and unnecessary investment in immunity may lower fitness. Adult mealworm beetles (Tenebrio molitor L.) modulate their investment according to the perceived risk of infection as larvae; the amount of investment can be assessed by body coloration. This prophylactic investment in immunity can be used to assess the costs of investment when no immune challenge is present. Whether investment in immunity is traded off against sperm competitive ability, another important fitness trait in insects, was investigated. Males that had invested more in immunity (dark males) competed against males that had invested less (light males) for fertilization of offspring. Dark males did lose sperm precedence over time, whereas light males did not. However, this decrease in sperm offensive ability may not result in decreased fitness for darker males under normal female mating frequencies; the decrease in offspring did not occur for 1 week, but females that have constant access to males mate once a day, which would negate any long‐term effects of male mating order. Thus, prophylactic investment in immunity does not produce immediate reductions in a male's ability to gain fertilizations. The costs to immune investment may be born by other fitness traits in T. molitor.

Cuticular colour change after imaginal eclosion is time‐constrained: blacker beetles darken faster

Abstract Adult mealworm beetles, Tenebrio molitor L. (Coleoptera: Tenebrionidae), show density dependent polyphenism in adult cuticular colour that is correlated with prophylactic immunity (Barnes & Siva‐Jothy, 2000). The degree of cuticular colour is important in understanding the biology of a number of insect‐related phenomena (e.g. industrial melanism, thermoregulation). In this paper, the extent of variation in cuticular colour in a large outbred population is documented; the rate of darkening under three different rearing protocols including experimental selection for cuticular colour is examined; and the time taken for cuticular colouring to be completed is determined. The results show that cuticular colouring after eclosion is time‐constrained in T. molitor, regardless of whether beetles are reared in large outbred cultures, inbred cultures, or cultures subjected to selection for darkness or lightness. Blacker beetles always darkened faster. The potential reasons for the constraint and the potential costs of rapid darkening are discussed.

Complete nutrient composition of commercially raised invertebrates used as food for insectivores

AbstractA variety of invertebrates are commonly fed to insectivorous animals by both zoos and hobbyists, but information as to the nutrient composition of most commercially raised species is limited. Adult house crickets, house cricket nymphs (Acheta domesticus), superworms (Zophobas morio larvae), giant mealworm larvae, mealworm larvae and adult mealworms (Tenebrio molitor), waxworm larvae (Galleria mellonella), and silkworm larvae (Bombyx mori) were analyzed for moisture, crude protein, crude fat, ash, acid detergent fiber (ADF), neutral detergent fiber (NDF), minerals, amino acids, fatty acids, and vitamins. Earthworms (Lumbricus terresstris) were analyzed for moisture, crude protein, crude fat, ash, ADF, NDF, minerals, amino acids, and vitamins A and D3. Proximate analyses were variable, with wide ranges found for moisture (57.9–83.6%), crude protein (9.3–23.7%), crude fat (1.6–24.9%), ADF (0.1–7.4%), NDF (0.0–11.5%), and ash (0.6–1.2%). Energy content ranged from a low of 674 kcal/kg for silkworms to 2,741 kcal/kg for waxworms.Using an amino acid scoring pattern for rats, the first limiting amino acid for all invertebrates tested was the total sulfur amino acid methionine+cystine. Deficiencies by nutrient (% of samples deficient vs. NRC requirements for rats on a dry matter (DM) basis) were as follows: calcium (100%), vitamin D3 (100%), vitamin A (89%), vitamin B12 (75%), thiamin (63%), vitamin E (50%), iodine (44%), manganese (22%), methionine‐cystine (22%), and sodium (11%). Deficiencies by invertebrate species (number of nutrients deficient vs. the NRC requirements for rats on a DM basis) were as follows: waxworms (9), superworms (8), giant mealworm larvae (7), adult mealworms (6), mealworm larvae (5), adult house crickets (4), house cricket nymphs (4), silkworms (4), and earthworms (4). These data provide a basis for determining nutrient intake of captive insectivores, and will aid in the development of gut‐loading diets to provide captive insectivorous animals with appropriate levels of necessary nutrients. Zoo Biol 21:269–285, 2002. © 2002 Wiley‐Liss, Inc.

20-Hydroxyecdysone acts in the male pupa to commit accessory glands toward trehalase production in the adult mealworm beetle ( Tenebrio molitor)

During postecdysial adult maturation, the bean-shaped accessory reproductive glands (BAGs) of adult male mealworm beetles produce increasing amounts of trehalase. In order to determine when the BAGs become competent to produce trehalase, we transplanted pupal BAGs into 0-day female adults. After 8 days, trehalase activity had increased in BAGs from 4- and 5-day pupae (at the time of the pupal ecdysteroid peak) but not in those from 1-and 2-day pupae (before the ecdysteroid peak). BAGs from 0- and 2-day pupae were exposed to 20-hydroxyecdysone in vitro before implantation into 0-day female adults. Increase in trehalase activity was dose dependent. Both dose (ED 50, 5 × 10 −6 M) and exposure time (>6 hr) of hormone required are greater for commitment than for acceleration of pupal cell cycling ( T. Yaginuma, H. Kai, and G. M. Happ, 1988, Dev. Biol. 126, 173–181). Since trehalase activity increased markedly in isolated adult male abdomens, factors from the cephalic and thoracic centers are not required to sustain trehalase production in the adult BAGs.

Safrotin as a Residual Spray for Control House Flies and Lesser Mealworms, 1982

Abstract Safrotin 50% EC was investigated for its residual activity against the house fly and the lesser mealworm when applied to 3 plywood panel types; exterior enamel-painted, interior latex-painted, and unpainted. Three different doses of Safrotin 50% EC (0.50%, 0.25%, and 0.125% ai) and a control (water only) were prepared and sprayed onto 1 side of each of 3 panel types with a chromatography sprayer. Dosages were replicated 4 times. Twenty-five adult house flies and 10 adult lesser mealworm beetles were exposed to the surfaces for 1 h, removed and percent mortality was recorded at 24 h post-exposure. Exposure tests were repeated on day 1, 3, 9 and once a week thereafter until residual breakdown was evident.

Humidity behavior and the identification of hygroreceptors in the adult mealworm, Tenebrio molitor

The humidity behavior of undesiccated and desiccated adult Tenebrio molitor was investigated at 72 and 92%r.h. The behavior of the sexes was analyzed separately. The moist responses of desiccated beetles were correlated with the distribution of smooth-surfaced peg organs by removing various antennal segments. The dry responses of undesiccated beetles were associated with grooved and flat-tipped peg organs by removing various types of antennal sensilla with a laser. On the basis of their morphology and the results of the behavioral experiments, it has been concluded that the smooth-surfaced, grooved, and flat-tipped peg organs are likely to function as humidity receptors. A behavioral model has been proposed to explain the humidity responses of the beetle.

Fine structure of antennal sensilla of the adult mealworm beetle, Tenebrio molitor L. (Coleoptera : Tenebrionidae)

The types, numbers and distributions of the antennal sensilla of the adult mealworm beetle, Tenebrio molitor, were studied with the scanning and transmission electron microscopes. The types of sensilla include a sexually dimorphic bristle (sensillum chaeticum), a hair organ (sensillum trichodeum), and thin-walled, thick-walled, grooved, flat-tipped, and smooth-surfaced peg organs (sensilla basiconica). Hair organs and smooth-surfaced pegs are common on all 11 antennal segments. The other sensilla are, generally, most numerous on the distal segment, and progressively decrease in numbers on the distal inner and outer sensory fields of segments 10 through 4. Thick-, thin-walled and grooved pegs have pore systems typical of olfactory sensilla. Sensilla chaetica and thick-walled, grooved, flat-tipped, and smooth-surfaced pegs bear an apical pore suggestive of a gustatory function. Smooth-surfaced pegs, hairs, and bristles have a tubular body normally associated with mechanoreception.