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Aphid honeydew impact on the tritrophic relationships between host-plants, phytophagous insects and their natural enemies. Tritrophic relations between plants, phytophagous insects and beneficials are based on the presence of chemical cues in the environment. In this context, honeydew (the aphid excretory product), rich in sugars and amino-acids, constitutes a nutritional resource for beneficials but also acts as a volatile and a contact kairomone. On one hand, honeydew volatile chemicals cues guide beneficials to a food source, hosts or preys but also stimulate particular behaviors: searching, preys/hosts locations and attacks. On the other hand, a contact with honeydew induces the oviposition especially for syrphids (Episyrphus balteatus, etc.). The use of an artificial honeydew could be a way for enhancing the biological control efficiency in fields by increasing the number of beneficials but also the predation and parasitic rates.

Origin and evolution of cannibalism in the animal populations: why to eat conspecific? The term «Cannibalism» is a linguistic distortion resulting from Arawak terminology (Amerindians in the Antilles) caribal that means courageous. Columbus uses it to describe Caribbean Indians identified as eaters of human flesh. Cannibalism behavior is widespread in the animal kingdom. It has occurred in human society since the paleolithic and many typologies of cannibalism have recently been described. Identifying the evolutionary causes and benefits of cannibalism in animal populations may provide information about its taxonomic diversity. In general cannibalism is favored by ecological factors related to the low availability of alternative food. It may also depend to varying degrees upon population density. Social factors, like competition for mates and offspring parental care when food is scare may also promote cannibalism behavior. Significant nutritional and energy benefits combined to a territorial advantage were provided by cannibalism. For many species cannibalism can strongly affect population dynamics and mortality rates with enhancing the risk of infection from parasites and viruses.

Aphidophagous hoverflies forage according two different host-finding mechanisms: they forage for suitable food sources (for their energy-expensive hovering flight, and for protein to mature their reproductive system), and for suitable oviposition sites. Syrphids are highly mobile, enabling them to lay eggs over large areas, and to locate aphid colonies earlier in the season than other aphidophaga. The result is that most syrphid eggs tend to be laid close to aphid colonies. The choice of oviposition sites may be crucial for offspring performance because the neonate larvae have limited dispersal ability. Selection of aphid patches should therefore reflect nutritional value, risk of predation and competition pressure. Several factors are known to affect the choice of oviposition site: habitat, host plant, aphid species, aphid availability, semiochemicals, the presence of intra- or interspecific competitors and female age. We review here the available information on these factors in order to understand the mechanisms of decision-making by syrphid females during their egg-laying behavior, a crucial aspect of their effective use in strategies of the biological control of aphids.

Aphid – ant mutualism: an outdoor study of the benefits for Aphis fabae. Aphid – ant relationships are common examples of mutualism. Aphids are indeed submitted to predation and therefore require protection, while ants are continuously looking for new sugar sources. The present work aimed to study the benefits that a mutualistic relationship with Lasius niger (Hymenoptera, Formicidae) could bring to the black bean aphid Aphis fabae (Homoptera, Aphididae). Several parameters were observed in the field, on broad bean plants infested with an initial amount of 100 A. fabae and in presence or not of a L. niger colony. More aphids were observed on plants being visited by ants as well as a higher proportion of winged individuals. One explanation is that fewer predators were observed on plants being visited by ants, demonstrating their protective role. However, the number of parasitized aphids was not reduced in presence of L. niger. On the other hand, fewer different aphid species were present on plants foraged by ants, what suggests that they could exert a predation on unattended aphids. Our observations do not allow to conclude on any impact of L. niger on the fitness of the aphid host plant, although fewer exuvia and honeydew spots were observed when they were present. All these results confirm that L. niger increase the fitness of A. fabae colonies mainly by decreasing the number of predators and by reducing competition from aphid species unattended by ants.

Isoprenoid metabolism in aphids: a new target for bio-insecticides development? Currently, the control of aphids is largely dependent on the use of broad-spectrum chemical insecticides. Their adverse effects on the environment, combined with the ability of insects to quickly develop resistance to them, has prompted a search for alternative control products. One of the approaches currently under consideration involves the design of novel bio-rational insecticides targeting and disrupting specific biochemical processes in the insect. As a result of their high specificity, these pest control products generally present little risk to the environment, non-target organisms and human health. In the context of aphid control, isoprenoid metabolism and, more specifically, enzymes of the short-chain isoprenyl diphosphate synthases family constitute promising targets for the development of new control products. Indeed, in aphids, isoprenoid metabolism is associated with the production of mono- and sesquiterpenes, which are compounds playing important roles in the physiology of these insects.

Vermicomposting technique in South Vietnam. Earthworms play a major role in organic matter transformation. The vermicomposting allows to combine several advantages: the management of diversified organic wastes, and the production of earthworms and vermicompost. Crop residues and other plant wastes mixed with animal manure from individual farms can be used. In South Vietnam, farmers are rearing some livestock and growing a few number of crop species. From several years, an increasing number of vermicomposting units were set in many farms from the Ho Chi Minh City region. Two kinds of infrastructure materials are used: baked clay blocks or bamboo stems with plastic covers. In South Vietnam, all conditions are pooled to ensure an efficient earthworm production: suitable climate, available organic wastes and materials to build the vermicomposting structures. Both field plot fertility and protein feed for livestock (pigs, poultry, etc.) can be provided by rearing earthworms.

L'acétylcholinestérase (AChE, EC 3.1.1.7) est une enzyme indispensable de la transmission synaptique cholinergique. Son inhibition par les organophosphorés et les carbamates est à la base de certains traitements insecticides et nématicides utilisés en agriculture. Les faunes sauvage (en particulier les poissons) et domestique sont exposées aux résidus des traitements anticholinestérasiques. La mesure de l'inhibition de l'activité AChE chez ces espèces est un marqueur fiable de l'exposition. Ceci est montré ici pour l'AChE de carpes exposées expérimentalement au carbofuran (carbamate). Nous présentons parallèlement des données sur le gène de l'AChE chez Danio rerio et sur les formes moléculaires de l'enzyme chez Danio, Cyprinus carpio et Oncorhynchus mykiss. Contrairement à ce qui est observé chez d'autres vertébrés, le gène d'AChE de Danio ne possède pas d'exon H et seules les sous-unités de type T ont pu être identifiées chez ces trois espèces. Des résultats préliminaires d'hybridation in situ sur les embryons sont présentés et nous discutons l'intérêt des expériences de transgenèse dans l'oeuf de Danio pour étudier d'éventuelles fonctions morphogénétiques de l'AChE au début du développement.

Insect and mite resistance mechanisms to insecticides. Insecticide resistance is documented in nearly all insects and mitesin which it has been studied. It is a major obstacle to control agriculturally important pests. Next to the already ancientknowledge on resistance this review discusses recent major breakthroughs in understanding the mechanisms, at molecularlevel, by which insects acquire resistance to natural, synthetic or bioengineered insecticides. Resistance is due either to amodification of the target affinity for the pesticide or to an increase of detoxification through some enzymatic systems. Nowthe challenge is to isolate the DNA encoding for these various proteins in order to understand what happens at the geneticlevel when an insect acquires resistance to insecticides. In this paper we review several types of resistance mechanisms(behavioural, physiological and biochemical) and we indicate the application that can be expected from this knowledge,mainly for the managing of the resistance genes in natural populations and for ecotoxicological studies.

Abstract Background Aphid adaptation to harsh winter conditions is illustrated by an alternation of their reproductive mode. Aphids detect photoperiod shortening by sensing the length of the night and switch from viviparous parthenogenesis in spring and summer, to oviparous sexual reproduction in autumn. The photoperiodic signal is transduced from the head to the reproductive tract to change the fate of the future oocytes from mitotic diploid embryogenesis to haploid formation of gametes. This process takes place in three consecutive generations due to viviparous parthenogenesis. To understand the molecular basis of the switch in the reproductive mode, transcriptomic and proteomic approaches were used to detect significantly regulated transcripts and polypeptides in the heads of the pea aphid Acyrthosiphon pisum. Results The transcriptomic profiles of the heads of the first generation were slightly affected by photoperiod shortening. This suggests that trans-generation signalling between the grand-mothers and the viviparous embryos they contain is not essential. By analogy, many of the genes and some of the proteins regulated in the heads of the second generation are implicated in visual functions, photoreception and cuticle structure. The modification of the cuticle could be accompanied by a down-regulation of the N-β-alanyldopamine pathway and desclerotization. In Drosophila, modification of the insulin pathway could cause a decrease of juvenile hormones in short-day reared aphids. Conclusion This work led to the construction of hypotheses for photoperiodic regulation of the switch of the reproductive mode in aphids.

Background: The role played by large-scale repetitive SARS-CoV-2 screening programs within university populations interacting continuously with an urban environment, is unknown. Our objective was to develop a model capable of predicting the dispersion of viral contamination among university populations dividing their time between social and academic environments., Methods: Data was collected through real, large-scale testing developed at the University of Liège, Belgium, during the period Sept. 28th-Oct. 29th 2020. The screening, offered to students and staff (n = 30,000), began 2 weeks after the re-opening of the campus but had to be halted after 5 weeks due to an imposed general lockdown. The data was then used to feed a two-population model (University + surrounding environment) implementing a generalized susceptible-exposed-infected-removed compartmental modeling framework., Results: The considered two-population model was sufficiently versatile to capture the known dynamics of the pandemic. The reproduction number was estimated to be significantly larger on campus than in the urban population, with a net difference of 0.5 in the most severe conditions. The low adhesion rate for screening (22.6% on average) and the large reproduction number meant the pandemic could not be contained. However, the weekly screening could have prevented 1393 cases (i.e. 4.6% of the university population; 95% CI: 4.4-4.8%) compared to a modeled situation without testing., Conclusion: In a real life setting in a University campus, periodic screening could contribute to limiting the SARS-CoV-2 pandemic cycle but is highly dependent on its environment., (© 2022. The Author(s).)

Mealworms are new food products in Europe, but consumers do not know how to cook them. Although cooking could increase the safety, acceptability, palatability, and digestibility of insects, the heating process could have deleterious effects on protein and lipid quality. Therefore, this study characterized the effects of different household cooking methods (boiling, pan-frying, vacuum cooking, and oven cooking) on the microbial load and nutritive value of mealworms, with a focus on protein digestibility and fatty acid composition. Boiling and cooking under vacuum were the most efficient techniques to reduce microbial load while maintaining the high levels of protein and polyunsaturated fatty acids of mealworms. Cooking method-related changes were very low on macronutrients content except for pan-fried mealworms which exhibited the highest lipid content. Cooking slightly changed fatty acid composition of mealworms by principally decreasing their level of saturated fatty acids but also increased the in vitro crude protein digestibility of mealworms., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Edible insects are gaining more and more attention as a sustainable source of animal protein for food and feed in the future. In Belgium, some insect products can be found on the market, and consumers are sourcing fresh insects from fishing stores or towards traditional markets to find exotic insects that are illegal and not sanitarily controlled. From this perspective, this study aims to characterize the microbial load of edible insects found in Belgium (i.e., fresh mealworms and house crickets from European farms and smoked termites and caterpillars from a traditional Congolese market) and to evaluate the efficiency of different processing methods (blanching for all species and freeze-drying and sterilization for European species) in reducing microorganism counts. All untreated insect samples had a total aerobic count higher than the limit for fresh minced meat (6.7 log cfu/g). Nevertheless, a species-dependent blanching step has led to a reduction of the total aerobic count under this limit, except for one caterpillar species. Freeze-drying and sterilization treatments on European species were also effective in reducing the total aerobic count. Yeast and mold counts for untreated insects were above the Good Manufacturing Practice limits for raw meat, but all treatments attained a reduction of these microorganisms under this limit. These results confirmed that fresh insects, but also smoked insects from non-European trades, need a cooking step (at least composed of a first blanching step) before consumption. Therefore, blanching timing for each studied insect species is proposed and discussed.

Background: The health status of the indigenous people of Ratanakiri Province, Cambodia, is significantly lower compared with that of the rest of the nation. The domestication and mass production of insects may represent a sustainable, cost effective and high quality alternative source of protein to traditional livestock. This study aimed to optimise a cheap and residential cricket breeding system based on unused wild resources. The development of crickets, Teleogryllus testaceus (Walker), under seven diets composed of taro aerial parts, young cassava leaves, young cashew leaves and brown rice flour (with or without banana slices), versus a traditionally used broiler feed diet was studied., Results: Cricket mortality was low in all diets, except the two cashew-based diets. Total biomass was significantly higher under the broiler feed, in addition to the two diets containing a combination of cassava leaf powder and brown rice. Yet, crickets fed with the taro diet had the highest percentage of protein. Concerning the breeding system cost, units using cassava leaves were the cheapest., Conclusion: Diets based on cassava leaves seem to be the most promising. Nevertheless, to produce crickets with a high body mass and a high protein level, a new experiments must be devised in which cassava leaf maturity will be adapted to fit with the cricket growth stage. Moreover, to reduce the cost of the breeding units, handmade local products should be used instead of purchased components., (© 2015 Society of Chemical Industry.)

The Colorado potato beetle (CPB) has been a major insect pest to potato farming for over 150 years and various control methods have been established to reduce its impact on potato fields. Crop rotation and pesticide use are currently the most widely used approaches, although alternative methods are being developed. Here we review the role of various volatile and nonvolatile chemicals involved in behavior changes of CPB that may have potential for their control. First, we describe all volatile and nonvolatile chemicals involved in host plant localization and acceptance by CPB beetles, including glycoalcaloids and host plant volatiles used as kairomones. In the second section, we present the chemical signals used by CPB in intraspecific communication, including sex and aggregation pheromones. Some of these chemicals are used by natural enemies of CPBs to locate their prey and are presented in the third section. The last section of this review is devoted a discussion of the potential of some natural chemicals in biological control of CPB and to approaches that already reached efficient field applications.