Pollen Alone or a Mixture of Pollen Types? Assessing Their Suitability for Mass Rearing of Neoseiulus cucumeris (Acari: Phytoseiidae) Over 20 Generations

The generalist predatory mite, Neoseiulus cucumeris (Oudemans) is known as one of the most effective natural enemies on many pests. This economically important biocontrol agent was reared for 20 generations on date palm and castor bean pollen as well as a mixture of pollen types, including date palm, castor bean, and almond. The performance of this predator was evaluated by comparing its life table parameters after different generations (G1-G20) fed on each diet in a laboratory at 25 ± 1°C, 60 ± 5% RH, and a photoperiod of 16:8 (L: D) h. The development time of the predator reared on all tested diets had no significant difference in G20. The intrinsic rate of increase (r) of N. cucumeris by feeding on the mixed pollen (0.197 day-1) was significantly higher than that on castor bean, or date palm pollen (0.146 or 0.152 day-1 in G1, respectively). Our results indicated that the predator's performance was not affected by long-term feeding on the pollen diets, as well as there was no considerable difference between pollen alone and pollen mixture diets. Furthermore, mites reared on pollen diets had higher quality than those reared on natural prey, Tetranychus urticae Koch.

Impact of the Cooking Process on Metabolite Profiling of Acanthocereus tetragonus, a Plant Traditionally Consumed in Mexico

Acanthocereus tetragonus (L.) Hummelinck is used as an alternative food source in some Mexican communities. It has been shown that the young stems of A. tetragonus provide crude protein, fiber, and essential minerals for humans. In this work, we analyzed the phytochemical profile, the total phenolic content (TPC), and the antioxidant activity of cooked and crude samples of A. tetragonus to assess its functional metabolite contribution to humans. The phytochemical profile was analyzed using Ultra-High-Performance Liquid Chromatography coupled to High-Resolution Mass Spectrometry (UHPLC-PDA-HESI-Orbitrap-MS/MS). Under the proposed conditions, 35 metabolites were separated and tentatively identified. Of the separated metabolites, 16 occurred exclusively in cooked samples, 6 in crude samples, and 9 in both crude and cooked samples. Among the detected compounds, carboxylic acids, such as threonic, citric, and malic acids, phenolic acids, and glycosylated flavonoids (luteolin-O-rutinoside) were detected. The TPC and antioxidant activity were analyzed using the Folin–Ciocalteu method and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical inhibition method, respectively. The TPC and antioxidant activity were significantly reduced in the cooked samples. We found that some metabolites remained intact after the cooking process, suggesting that A. tetragonus represents a source of functional metabolites for people who consume this plant species.

Evaluation of Natural and Factitious Food Sources for Pronematus ubiquitus on Tomato Plants

Simple Summary

Biocontrol practitioners have increasingly released generalist predators to control a variety of greenhouse pests. In this study, the effects of alternative food sources on the oviposition rate and the population dynamics of the mite Pronematus ubiquitus were assessed. The alternative food sources were selected among those the mite may encounter or be applied to the tomato crop.

Abstract

Pronematus ubiquitus (McGregor) is a small iolinid mite that is capable of establishing on tomato plants. Once established, this mite has been shown to control both tomato russet mite, Aculops lycopersici (Tryon) (Acari: Eriophyidae), and tomato powdery mildew (Oidium neolycopersici L. Kiss). In the present study, we explored the effects of a number of alternative food sources on the oviposition rate in the laboratory. First, we assessed the reproduction on food sources that P. ubiquitus can encounter on a tomato crop: tomato pollen and powdery mildew, along with tomato leaf and Typha angustifolia L. In a second laboratory experiment, we evaluated the oviposition rate on two prey mites: the astigmatid Carpoglyphus lactis L. (Acari: Carpoglyphidae) and the tarsonemid Tarsonemus fusarii Cooreman (Acari: Tarsonemidae). Powdery mildew and C. lactis did not support reproduction, whereas tomato pollen and T. fusarii did promote egg laying. However, T. angustifolia pollen resulted in a higher oviposition in both experiments. In a greenhouse trial on individual caged tomato plants, we evaluated the impact of pollen supplementation frequency on the establishment of P. ubiquitus. Here, a pollen addition frequency of every other week was required to allow populations of P. ubiquitus to establish.

Nutritional Composition of Honey Bee Drones of Two Subspecies Relative to Their Pupal Developmental Stages

Simple Summary

Despite the use of honey bee brood as food among several communities of the world, the nutritional potential of drones remained unexplored for a long time. In the recent past some scientific endeavour, including our own previous work, has been undertaken to explore the nutrient quality of this food source. Due to their limited socio-biological role, honey bee drones would be a suitable candidate to compare their nutrient content with that of worker honey bees. We therefore investigated the nutrient composition of honey bee drones belonging to two subspecies, namely Apis mellifera carnica and A. m. mellifera covering their pupal developmental period. To possess information of the drones’ nutritional value during their development would help in choosing the most suitable developmental stage for the commercial production of drone brood as food.

Abstract

We examined the contents of nutritional importance, i.e., amino acids, fatty acids and minerals of different developmental stages of drones of two honey bee subspecies, namely Apis mellifera carnica and A. m. mellifera. The results revealed that, in general, individual amino acid amounts and therefore the total protein increased along with the developmental stages of the drones. No statistically significant differences were found between the same developmental stages of the two subspecies. The reverse, i.e., a decrease with developmental stage occurred in relation to the fatty acid composition. Most of the minerals were higher at advanced developmental stages. Overall, the high protein content (31.4–43.4%), small amount of fat (9.5–11.5%) and abundance of minerals such asiron and zinc, make drones a suitable nutritional resource. Even though nutrient content, especially protein, was higher in the pupae than the prepupae, we propose prepupae also as a commercial product based on their higher biomass production. Provided standard production protocols maintaining hygiene and safety will be adhered to, we propose that drone honey bees can be utilized as human food or animal feed.

High Variability in Pre-Oviposition Time Independent of Diet Available at Eclosion: A key Reproductive Trait in the Ladybird Beetle Harmonia axyridis (Coleoptera: Coccinellidae) in Its Native Range

While insect predators need high-quality food to reach sexual maturity and reproduce, starvation following adult eclosion may occur when prey are missing in agroecosystems. This study explores whether the type of diet available at eclosion determines the future fecundity of newly emerged adult predators. In a laboratory experiment, three different diets (i.e., flowers of Perilla frutescens (L.) Britton, eggs of Ephestia kuehniella Zeller as prey, or no food) were offered to adult females of the ladybird beetle Harmonia axyridis Pallas during their first three days after adult eclosion. On the fourth day, each female was paired with a prey-fed male and the pair was subsequently fed with prey. Diet at eclosion did not affect pre-oviposition time, the number of eggs oviposited daily, or the viability of egg batches. High variability in pre-oviposition time among females was observed for all diets. Significant negative linear relationships were found between pre-oviposition time and both the number of eggs oviposited daily and the viability of egg batches. This study clarifies that the food readily available at adult eclosion does not affect the capacity of H. axyridis to reproduce, provided that adults find prey within a few days. More generally, it shows that the reproductive traits of H. axyridis allow this generalist predator to be highly adapted to heterogenous environments in its native range. It is concluded that the variety of habitats offered by diversified agroecosystems may highly benefit the ladybird beetle H. axyridis, and potentially enhance its ability to biologically regulate crop pests.

Challenges facing arthropod biological control: identifying traits for genetic improvement of predators in protected crops

Biological control is an efficient pest control method but there are still limitations that are hindering its wider adoption. Genetic improvement of biological control agents (BCAs) can help to overcome these constraints, but the choice of key attributes for better performance that need to be selected is still an open question. Several characteristics have been suggested but the harsh reality is that selective breeding of BCAs has received a lot of attention but resulted in very little progress. Identifying the appropriate traits to be prioritized may be the first step to reverse this situation. In our opinion, the best way is to look at the factors limiting the performance of key BCAs, especially generalist predators (pesticide compatibility, prey-density dependence, non-suitable crops, and extreme environmental conditions), and according to these challenges, to choose the attributes that would allow BCAs to overcome those limitations. The benefits of selection for higher resistance to toxins, whether artificially applied (pesticides) or plant produced (plant defenses); increased fitness when feeding on non-prey food (supplemented or plant-derived); and better adaptation to extreme temperature and humidity are discussed. In conclusion, genetic improvement of BCAs can bring about new opportunities to biocontrol industry and users to enhance biocontrol resilience. © 2020 Society of Chemical Industry.

Preliminary Automated Determination of Edibility of Alternative Foods: Non-Targeted Screening for Toxins in Red Maple Leaf Concentrate

Alternative food supplies could maintain humanity despite sun-blocking global catastrophic risks (GCRs) that eliminate conventional agriculture. A promising alternative food is making leaf concentrate. However, the edibility of tree leaves is largely uncertain. To overcome this challenge, this study provides the methods for obtaining rapid toxics screening of common leaf concentrates. The investigation begins with a non-targeted approach using an ultra-high-resolution hybrid ion trap orbitrap mass spectrometer with electrospray ionization (ESI) coupled to an ultra-high pressure two-dimensional liquid chromatograph system on the most common North American leaf: the red maple. Identified chemicals from this non-targeted approach are then cross-referenced with the OpenFoodTox database to identify toxic chemicals. Identified toxins are then screened for formula validation and evaluated for risk as a food. The results after screening show that red maple leaf concentrate contains at least eight toxic chemicals, which upon analysis do not present substantial risks unless consumed in abundance. This indicates that red maple leaf is still a potential alternative food. The results are discussed in the context of expanding the analysis with open science and using leaf extract from other plants that are not traditionally used as foods to offset current global hunger challenges, and move to a more sustainable food system while also preparing for GCRs.

Positioning Food Cultures: 'Alternative' Food as Distinctive Consumer Practice

Many sociological studies to date have explored the role of food in marking distinctions between groups. Less well understood is how 'alternative' means of food consumption become figured in such relations. Drawing on accounts of food practice derived from 20 in-depth interviews and a two-year period of participant observation, this article considers the role of class culture in the practice of alternative food consumption. As participants speak their position, expressions of class arise through discussions of food practice. Having explored how food plays a part in marking boundaries of distinction between foods 'for us' and 'for them', we are reminded that in reproducing certain ideas about proper eating, we confine our imagining of alternative food futures to a limited politics of the possible. The article highlights implications for future development of equitable alternatives to conventional foodways.