Joop J A van Loon

Wageningen University & Research | WUR · Department of Entomology

The larvae of the black soldier fly (BSFL), Hermetia illucens L. (Diptera: Stratiomyidae), are of economic interest due to their use as livestock feed component. Unraveling their response to a bacterial infection will allow us to gain a better insight into their biology. In the current study, we used RNA-Seq analysis to unravel the transcriptomic r...

Butterflies, like many insects, use gustatory and olfactory cues innately to assess the suitability of an oviposition site and are able to associate colours and leaf shapes with an oviposition reward. Studies on other insects have demonstrated that the quality of the reward is a crucial factor in forming associative memory. We set out to investigat...

The spread of invasive species often follows a jump-dispersal pattern. While jumps are typically fostered by humans, local dispersal can occur due to the specific traits of a species, which are often poorly understood. This holds true for small hive beetles (Aethina tumida), which are parasites of social bee colonies native to sub-Saharan Africa. T...

The larvae of the black soldier fly (BSFL), Hermetia illucens L. (Diptera: Stratiomyidae), are grown on diverse residual organic matter that differ in their protein content and contain a plethora of microorganisms. The effect of dietary protein level on the interaction of BSFL with entomopathogenic bacteria remains unexplored. In this study, we inv...

Contamination of food products with mycotoxins such as aflatoxin B1 (AFB1) poses a severe risk to human health. Larvae of the black soldier fly (BSFL), Hermetia illucens (Diptera: Stratiomyidae), can successfully metabolize AFB1 without any negative consequences on their survival or growth. Organic waste streams contaminated with mycotoxins can be...

Multitrophic plant–insect interactions are mediated by plant volatiles. The emission of herbivore‐induced plant volatiles is influenced by environmental conditions, such as soil microbes and nutrient composition, with consequences for above‐ground trophic interactions. Here, we investigated whether insect exuviae in the soil alter the plant's volat...

Frass, a byproduct of insect rearing, has become popular for its potential use in sustainable agriculture. The rapid growth of insect production results in an increased frass output. This study examined the effects of frass as soil amendment on plant growth and resistance to insect herbivory. In greenhouse experiments, Brassica rapa L. (Brassicacea...

While the response of Arabidopsis thaliana to drought, herbivory or fungal infection has been well‐examined, the consequences of exposure to a series of such (a)biotic stresses are not well studied. This work reports on the genetic mechanisms underlying the Arabidopsis response to single osmotic stress, and to combinatorial stress, either fungal in...

As we transition to a greener economy, the role of insects emerges as a cornerstone for sustainable innovation. Among the myriad of opportunities edible insects offer, frass, a byproduct of their production, stands out, transforming waste into wealth through soil health enhancement and plant growth promotion. This study explores the effect of fras...

In this paper, we take a historical perspective by going back to Verschaffelt’s landmark study published in 1910, in which he found that glucosinolates were used as token stimuli by larvae of Pieris butterflies, specialist feeders on plants in the family Brassicaceae. This classic discovery provided key evidence for Fraenkel (Science 129:1466–1470,...

New approaches to managing the cabbage root fly (Delia radicum L.) are needed because pesticide regulations continue to limit the availability of effective control products. Soil amendment with black soldier fly (Hermetia illucens L.) frass has recently been shown to reduce D. radicum survival. In a greenhouse experiment, soil from a field on which...

Edible insects such as lesser mealworm ( Alphitobius diaperinus ) are a promising new protein source for food and feed. The feed substrate on which these insects are reared may be contaminated with residues of insecticides originating from agricultural products that may impact insect performance. In this study, two generations of A. diaperinus were...

Insects are receiving increasing attention as a possible ingredient for feed and/or food production. When used efficiently, insects can provide a sustainable and economically favourable contribution to global food security. Housefly larvae (HFL) can grow on a variety of organic side streams and upgrade them by partial conversion into high-quality p...

Aims In terrestrial ecosystems, deposition of insect frass and cadavers in the soil influences soil characteristics, including microbial community composition, with consequences for plant growth and development. Insect frass and exuviae are also a major residual stream from insect production for food and feed, that may be used as soil amendment. Ho...

There is a growing interest in the ability of black soldier fly (Hermetia illucens) larvae (BSFL) to convert low-value organic residues into high-value products. This leads to more publications with conversion data for various organic resources. However, these results are rarely comparable between laboratories due to differences in study protocols....

Plants can detect neighbouring plants through a reduction in the ratio between red and far‐red light (R:FR). This provides a signal of plant–plant competition and induces rapid plant growth while inhibiting defence against biotic stress, two interlinked responses designated as the shade avoidance syndrome (SAS). Consequently, the SAS can influence...

Black soldier fly larvae (Hermetia illucens) receive growing interest as a potential alternative animal feed source. These insects may be exposed to insecticide residues in the rearing substrate. This study aimed to investigate the effects of six different pyrethroid and organophosphate insecticides on this insect species' performance. The toxicity...

Novel malaria vector control strategies targeting the odour-orientation of mosquitoes during host-seeking, such as ‘attract-and-kill’ or ‘push-and-pull’, have been suggested as complementary tools to indoor residual spraying and long-lasting insecticidal nets. These would be particularly beneficial if they can target vectors in the peri-domestic sp...

The house cricket, Acheta domesticus, is a commonly reared insect for food and feed purposes. In 1977, a report described a colony collapse, which was caused by the single-stranded DNA virus Acheta domesticus densovirus (AdDV). Currently, there are no confirmed A. domesticus colonies free of AdDV, and viral disease outbreaks are a continuous threat...

Unlabelled: Root herbivores pose a major threat to agricultural crops. They are difficult to control and their damage often goes unnoticed until the larvae reach their most devastating late instar stages. Crop diversification can reduce pest pressure, generally without compromising yield. We studied how different diversified cropping systems affec...

Temperature is an important abiotic factor influencing the survival and fitness of pathogens as well as their hosts. We investigated the effect of three temperatures (18°C, 27°C and 37°C) on survival and performance of black soldier fly larvae (BSFL), Hermetia illucens L., upon infection by an entomopathogenic Gram-negative bacterium, Pseudomonas p...

Climate change alters many environmental parameters with strong consequences for ecological interactions, from species interactions to community dynamics. Temperature is crucial in determining ecosystem dynamics, especially for those involving ectothermic species such as plants or insects. Phenotypic plasticity, the capacity of one genotype to prod...

While the response of Arabidopsis thaliana to either drought, herbivory or fungal infection has been well-examined, the consequences of exposure to a series of such (a)biotic stresses are not well studied. This work reports on the genetic mechanisms underlying Arabidopsis response to single osmotic stress, and to combinatorial stress, either fungal...

The black soldier fly Hermetia illucens Linnaeus (Diptera: Stratiomyidae; BSF) is gaining interest as an alternative protein ingredient for livestock feed. Larval aggregation behaviour occurs commonly in larvae of various dipteran species. However, the cues initiating aggregation behaviour and its occurrence in subsequent larval instars are still u...

Insect exuviae are a chitin-rich by-product of insect farming that is considered to have great potential for contributing to sustainable agriculture. When used as soil amendment, insect exuviae have been suggested to promote plant growth and health by stimulating naturally occurring beneficial microbes. In a greenhouse experiment, the exuviae of bl...

The mass rearing of insects as animal feed is a new and rapidly growing component of circular agriculture, which offers the opportunity to develop it in such a way that it promotes insect health and welfare. Behaviour is an important indicator of animal performance and welfare. In this review, we synthesise the current behavioural knowledge on two...

Novel malaria vector control strategies targeting the odour-orientation of mosquitoes during host-seeking, such as ‘attract-and-kill’ or ‘push-and-pull’, have been suggested as complementary tools to indoor residual spraying and long-lasting insecticidal nets. These would be particularly beneficial if they can target vectors in the peri-domestic sp...

To promote circularity in agriculture, the residual –streams from the production of insects as feed and food, such as insect exuviae (moulted skins), can be a sustainable novel organic soil amendment for crop production. Organic soil amendments can influence soil composition by providing nutrients and stimulating the growth of beneficial microorgan...

Plants perceive and respond to herbivore insect eggs. Upon egg deposition on leaves, a strong hypersensitive response (HR)-like cell death can be activated leading to egg desiccation and/or dropping. In Brassica spp., including many crops, the HR-like mechanism against eggs of cabbage white butterflies (Pieris spp.) is poorly understood. Using two...

BACKGROUND The use of light‐emitting diode (LED) lights in horticulture allows growers to adjust the light spectrum to optimize crop production and quality. However, changes in light quality can also influence plant–arthropod interactions, with possible consequences for pest management. The addition of far‐red light has been shown to interfere with...

Plants can detect neighbouring plants through a reduction in the ratio between red and far-red light (R:FR). This provides a signal of plant-plant competition and induces rapid plant growth while inhibiting defence against biotic stress, two interlinked responses designated as the shade avoidance syndrome (SAS). Consequently, the SAS can influence...

Insect herbivores are amongst the most destructive plant pests, damaging both naturally occurring and domesticated plants. As sessile organisms, plants make use of structural and chemical barriers to counteract herbivores. However, over 75 percent of herbivorous insect species are well adapted to their host’s defenses and these specialists are gene...

Soil composition and herbivory are two environmental factors that can affect plant traits including flower traits, thus potentially affecting plant‐pollinator interactions. Importantly, soil composition and herbivory may interact in these effects, with consequences for plant fitness. We assessed the main effects of aboveground insect herbivory and...

Insect farming is a rapidly expanding agricultural sector with the potential to improve the environmental sustainability of livestock production. A holistic approach is needed to use farmed insects responsibly and effectively with broad benefits across food systems. Full-text access to the paper at: https://rdcu.be/cZkdf

Reliable options to control the cabbage root fly, Delia radicum L., are lacking in many countries as restrictions on insecticide use have tightened due to environmental concerns. Although microbial control agents are often considered as a sustainable alternative, their application in agriculture is constrained by inconsistent efficacy owing to low...

Background Edible insects are a novel source of animal protein. Moreover, edible insects contain iron concentrations similar to meat, potentially making them a valuable iron source for human consumers. Yet, it is unknown to what extent iron from insects is absorbed in humans. Objectives In this exploratory study, we assessed fractional iron absorp...

Background Providing protection from malaria vector bites, both indoors and outdoors, is crucial to curbing malaria parasite transmission. Screening of house entry points, especially with incorporated insecticides, confers significant protection but remains a costly and labour-intensive application. Use of spatial repellents has shown promise in cr...

Plants face attackers aboveground and belowground. Insect root herbivores can lead to severe crop losses, yet the underlying transcriptomic responses have rarely been studied. We studied the dynamics of the transcriptomic response of Brussels sprouts (Brassica oleracea var. gemmifera) primary roots to feeding damage by cabbage root fly larvae (Deli...

Nitrogen (N) losses via ammonia (NH3) emissions from manure is one of the main environmental burdens resulting from livestock production. Feeding manure to black soldier fly larvae (BSFL) is envisioned as a new circular strategy to recover manure-N, reduce its environmental impact, and upgrade it into insect proteins to be used in animal feed. Howe...

Plants interact with a diversity of phytophagous insects above- and belowground. By inducing plant defence, one insect herbivore species can antagonize or facilitate other herbivore species feeding on the same plant, even when they are separated in space and time. Through systemic plant-mediated interactions, leaf-chewing herbivores may affect the...

With climate change, the occurrence of extreme weather events such as heatwaves is expected to increase. Extreme temperature events are short periods of high temperature (i.e., >95th percentile of temperature distribution), and their occurrences are difficult to predict. These extreme temperature events pose great challenges to living organisms, es...

During the last decade the potential of insects for human nutritional protein is increasingly recognised. Direct consumption of insects contributes to a reduction of the ecological footprint of human food production and is claimed to have health benefits. An alternative is feeding poultry (broilers and layers) with insect-derived protein. This offe...

Saprophagous fly larvae interact with a rich community of bacteria in decomposing organic matter. Larvae of some species, such as the black soldier fly, can process a wide range of organic residual streams into edible insect biomass and thus produce protein as a sustainable component of livestock feed. The microbiological safety of the insects and...

The larvae of insect herbivores feed on plants that may vary nutritionally (qualitatively and/or quantitatively) over the course of insect development. Plant quality may change in response to interactions with the biotic environment that in turn may affect development and biomass of the insects feeding on these plants. However, the larvae of many g...

Background: Providing protection from malaria vector bites, both indoors and outdoors, is crucial to curbing malaria parasite transmission. Screening of house entry points, especially with incorporated insecticides, confers significant protection but remains a costly and labour-intensive application. Use of spatial repellents has shown promise in c...

Rearing insects for food and feed is a rapidly growing industry, because it provides excellent opportunities for a sustainable approach to animal protein production. Two fly species, the black soldier fly (BSF) and the house fly (HF), naturally live in decaying organic matter (e.g. compost), and can thus be effectively reared on organic rest stream...

Beneficial soil microorganisms can contribute to biocontrol of plant pests and diseases, induce systemic resistance (ISR) against attackers, and enhance crop yield. Using organic soil amendments has been suggested to stimulate the abundance and/or activity of beneficial indigenous microbes in the soil. Residual streams from insect farming (frass an...

Changing the spectral composition of light has numerous advantages for the production and quality of horticultural crops. However, changing the light spectrum to stimulate growth can have negative consequences for plant responses to biotic stress. Especially changes in the ratio between red and far-red light (R:FR) have an important effect on plant...

The lesser mealworm (LMW, Alphitobius diaperinus (Panzer); Coleoptera: Tenebrionidae) is increasingly used as a novel food and feed source. The feed materials on which this insect species is reared may contain residues of insecticides from agricultural use. The objective of this study was to determine whether selected insecticides, spiked to the su...

In this introductory chapter of the book, the reader is submerged into the fascinating world of the insects. A concise overview is provided to familiarise the reader with terms like hemi-and holometabolous insects. For each of these groups more detailed information is given for the orders and families containing interesting species with regard to f...

The two closely related moth species, Helicoverpa armigera and H. assulta differ strongly in their degree of host-plant specialism. In dual-choice leaf disk assays, caterpillars of the two species that had been reared on standard artificial diet were strongly deterred by the plant-derived alkaloid strychnine. However, caterpillars of both species r...

Plant–soil feedback (PSF) may influence plant–insect interactions. Although plant defense differs between shoot and root tissues, few studies have examined root‐feeding insect herbivores in a PSF context. We examined here how plant growth and resistance against root‐feeding Delia radicum larvae was influenced by PSF. We conditioned soil with cabbag...

Novel protein sources for animal feed are needed, and the use of insects as feed ingredient is explored. The insect production sector offers opportunities for a circular and sustainable approach to feed production by upgrading waste or side streams into high-quality proteins. However, potential food or feed safety issues should be studied in advanc...

Adults of many mosquito species feed on plants to obtain metabolic energy and to enhance reproduction. Mosquitoes primarily rely on olfaction to locate plants and are known to respond to a range of plant volatiles. We studied the olfactory response of the yellow fever mosquito Aedes aegypti to methyl jasmonate (MeJA) and cis -jasmone (CiJA), volati...

Glucosinolates are token stimuli in host selection of many crucifer specialist insects, but the underlying molecular basis for host selection in these insects remains enigmatic. Using a combination of behavioral, electrophysiological, and molecular methods, we investigate glucosinolate receptors in the cabbage butterfly Pieris rapae. Sinigrin, as a...

Worldwide, French beans (Phaseolus vulgaris L.), tomato (Solanum lycopersicum L.), and kales (Brassica oleracea L. var. acephala) are considered economically important food crops. There is a rapid decline in their yield due to severe soil degradation. Thus, high commercial fertilizer inputs are crucial, though they remain expensive and inaccessible...

The acceptance of eco-friendly black soldier fly larvae meal (BSFLM) as sustainable alternative protein ingredient in poultry feeds continues to gain momentum worldwide. This study evaluates the impact of BSFLM in layer chick and grower diets on the growth, carcass quality and economic returns. Mean weekly weight gain and total live weight per chic...

Background: Insects have recently been identified as a more sustainable protein-dense food source and may represent a viable alternative to conventional animal-derived proteins. Objectives: We aimed to compare the impacts of ingesting lesser mealworm- and milk-derived protein on protein digestion and amino acid absorption kinetics, postprandial...

Adults of many mosquito species feed on plants to obtain metabolic energy and to enhance reproduction. Mosquitoes primarily rely on olfaction to locate plants and are known to respond to a range of plant volatiles. We studied the olfactory response of the yellow fever mosquito Aedes aegypti to methyl jasmonate (MeJA) and cis -jasmone (CiJA), volati...

Residues of persistent insecticides may be present in the substrates on which insects are reared for food and feed, which may affect insect growth or survival. In addition, insecticidal substances may bio-accumulate in reared insects. The objective of this study was to assess potential effects of selected insecticides on the growth and survival of...

There is an increased interest for using insects, such as the black soldier fly, to treat surplus manure and upcycle nutrients into the food system. Understanding the influence that BSFL have on nutrient flows and nutrient losses during manure bioconversion is key for sustainability assessments. Here we quantified and compared nutrient balances, nu...