Carrion Beetles Visiting Pig Carcasses during Early Spring in Urban, Forest and Agricultural Biotopes of Western Europe

Carrion beetles are important in terrestrial ecosystems, consuming dead mammals and promoting the recycling of organic matter into ecosystems. Most forensic studies are focused on succession of Diptera while neglecting Coleoptera. So far, little information is available on carrion beetles postmortem colonization and decomposition process in temperate biogeoclimatic countries. These beetles are however part of the entomofaunal colonization of a dead body. Forensic entomologists need databases concerning the distribution, ecology and phenology of necrophagous insects, including silphids. Forensic entomology uses pig carcasses to surrogate human decomposition and to investigate entomofaunal succession. However, few studies have been conducted in Europe on large carcasses. The work reported here monitored the presence of the carrion beetles (Coleoptera: Silphidae) on decaying pig carcasses in three selected biotopes (forest, crop field, urban site) at the beginning of spring. Seven species of Silphidae were recorded: Nicrophorus humator (Gleditsch), Nicrophorus vespillo (L.), Nicrophorus vespilloides (Herbst), Necrodes littoralis L., Oiceoptoma thoracica L., Thanatophilus sinuatus (Fabricius), Thanatophilus rugosus (L.). All of these species were caught in the forest biotope, and all but O. thoracica were caught in the agricultural biotope. No silphids were caught in the urban site

Earthworms Use Odor Cues to Locate and Feed on Microorganisms in Soil

Earthworms are key components of temperate soil ecosystems but key aspects of their ecology remain unexamined. Here we elucidate the role of olfactory cues in earthworm attraction to food sources and document specific chemical cues that attract Eisenia fetida to the soil fungi Geotrichum candidum. Fungi and other microorganisms are major sources of volatile emissions in soil ecosystems as well as primary food sources for earthworms, suggesting the likelihood that earthworms might profitably use olfactory cues to guide foraging behavior. Moreover, previous studies have documented earthworm movement toward microbial food sources. But, the specific olfactory cues responsible for earthworm attraction have not previously been identified. Using olfactometer assays combined with chemical analyses (GC-MS), we documented the attraction of E. fetida individuals to filtrate derived from G. candidum colonies and to two individual compounds tested in isolation: ethyl pentanoate and ethyl hexanoate. Attraction at a distance was observed when barriers prevented the worms from reaching the target stimuli, confirming the role of volatile cues. These findings enhance our understanding of the mechanisms underlying key trophic interactions in soil ecosystems and have potential implications for the extraction and collection of earthworms in vermiculture and other applied activities

Integrated pest management of Tuta absoluta: practical implementations across different world regions

The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most Afro-Eurasian countries and is threatening worldwide tomato production. Various strategies have been developed and implemented to manage this pest. Here, we present a timely review on the up-to-date development and practical implementation of integrated pest management (IPM) programs for tomato crops across different world regions infested by T. absoluta. While insecticide resistance is a growing concern, biological control via releasing or conserving arthropod natural enemies and sex pheromone-based biotechnical control are the most successful management practices. Agronomic control-related research is an emerging area where the soil fertilization and/or irrigation, as well as breeding of resistant cultivars, has the potential to enhance IPM effectiveness. Grower survey responses in the native areas (i.e., South America), early-invaded areas (i.e., first report between 2006 and 2012) and newly invaded areas (i.e., first report after 2012) showed that the control programs evolved along with the areas and time since invasion. Growers in the early-invaded areas shifted more rapidly from chemical control to biological control compared to those from the native area. In all concerned regions, the pest control failure risk following chemical insecticide applications and the high cost associated with either biological or biotechnical control methods have been the greatest concerns for growers. The information gathered from the native and/or early-invaded areas may help achieve a more effective management in newly invaded areas. Lastly, researchers are expected to break the bottlenecks of some key issues that would enable lowering application cost of novel biorational alternative management options

Choosing an aphid partner: a matter of taste and smell

Honeydew is the keystone upon which ants and aphids build their mutualistic relationship. We have investigated how sugar and volatile compounds from honeydew are involved in the discovery, the recognition and the exploitation of aphid colonies by the black garden ant Lasius niger. In addition to semiochemicals produced by aphids, honeydew volatile compounds are used by ant scouts to orient themselves and distantly recognize myrmecophilous species. Once discovered, aphid colonies producing sugars which are the most beneficial to the ants are preferentially tended. In this respect, the ways each sugar acts upon the feeding behavior of ant foragers and triggers the laying of a recruitment trail are essential to understand how their collective exploitation of aphid colonies proceeds and why mutualistic interactions between ants and aphids are maintained. Sensitivity of ant scouts to honeydew sugars was also investigated. Dose-response curves revealed between-sugar differences with foragers being very sensitive even to small amounts of melezitose, a sugar specifically produced by aphid colonies. We discuss about the relevance of honeydew cues used by ants in the selection of sugary resources, the recognition of their honeydew-producing partners as well as in the assessment of size and nutritive value of exploited aphid colonies

Behavioral and Immunological Features Promoting the Invasive Performance of the Harlequin Ladybird Harmonia axyridis

The harlequin ladybird Harmonia axyridis is now established as a model to test hypotheses explaining why some species become successfully invasive, while others, even closely related ones, do not. In this review, we evaluate behavioral and immunological features that may play a role in the invasive performance of this model species. We discuss the behavioral traits and associated semiochemicals that promote the invasive success of H. axyridis. In particular, we consider (1) the aggregative behavior and the particular role of long-chain hydrocarbons; (2) the importance of sex pheromones and non-volatile chemicals in mate location and selection; (3) the use of allelochemicals for prey location; and (4) the nature of chemicals that protect against natural enemies. We also highlight the superior immune system of H. axyridis, which encompasses a broader spectrum of antimicrobial peptides (and higher inducible expression levels) compared with native ladybird beetles such as Adalia bipunctata and Coccinella septempunctata. The chemical defense compound harmonine and the antimicrobial peptides are thought to confer resistance against the abundant microsporidia carried by H. axyridis. These parasites can infect and kill native ladybird species feeding on H. axyridis eggs or larvae, supporting the hypothesis that intraguild predation plays a role in the ability of H. axyridis to outcompete native ladybird species in newly-colonized areas

Predation of the Peach Aphid Myzus persicae by the mirid Predator Macrolophus pygmaeus on Sweet Peppers: Effect of Prey and Predator Density

Integrated Pest Management strategies are widely implemented in sweet peppers. Aphid biological control on sweet pepers includes curative applications of parasitoids and generalist predators, but with limited efficiency. Macrolophus pygmaeus is a zoophytophagous predator which has been reported to predate on aphids, but has traditionally been used to control other pests, including whiteflies. In this work, we evaluate the effectiveness of M. pygmaeus in controlling Myzus persicae (Homoptera: Aphididae) by testing different combinations of aphid and predator densities in cage-experiments under greenhouse conditions. The impact of the presence of an alternative factitious prey (E. kuehniella eggs) was also investigated. Macrolophus pygmaeus, at densities of four individuals/plant, caused rapid decline of newly established aphid populations. When aphid infestations were heavy, the mirid bug reduced the aphid numbers but did not fully eradicate aphid populations. The availability of a factitious prey did not influence M. pygmaeus predation on aphids. Based on our data, preventive application of M. pygmaeus, along with a supplementary food source , is recommended to control early infestations of aphids

2-Pentylfuran: an aggregation attractant for wireworms

peer reviewedWireworms (Coleoptera: Elateridae) are generalist insect pests that aggregate and feed on the roots of various crops, including maize. It remains unclear how they find and choose host plants. Several studies have focused on volatile organic compounds released by roots infested by wireworms, revealing the presence of 2-pentylfuran. We hypothesized that 2-pentylfuran could be a key aggregation cue that attracts wireworms towards roots colonized by conspecifics. In a series of olfactometer assays, we first investigated whether the larvae of click beetles indeed use volatile organic compounds (VOCs) as cues to locate maize roots that are already under attack by conspecifics. Surprisingly, wireworms were found to not only orient towards conspecific larvae feeding on the maize roots, but also to larvae alone. VOCs collections from plants and larvae revealed the presence of 2-pentylfuran, particularly in treatments where larvae were present. In subsequent dual-choice olfactometer assays wireworms exhibited significant attraction to 2-pentylfuran. These results imply that 2-pentylfuran is involved in wireworm aggregation behaviour, and open up opportunities for the development of an attract-and-kill strategy

Insecticide susceptibility level and control failure likelihood estimation of Sub‐Saharan African populations of tomato leafminer: Evidence from Burkina Faso

The South American tomato pinworm, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is a leafminer species currently considered as one of the major pests of fresh tomatoes around the world. The species settled in north Africa in 2007, before being observed in the entire continent. Widespread insecticide use has led to the emergence of resistant populations in South America and Europe, but no large-scale insecticide resistance assessment has been performed in Sub-Saharan Africa so far. In this study, we collected T. absoluta larvae from locations widely distributed in Burkina Faso, where the pest was first detected in 2016. Acute toxicity of the all available molecules in Burkina Faso was evaluated in the laboratory on F1 individuals,including acetamiprid, abamectin, spinosad, cypermethrin, chlorpyrifos, λ-cyhalothrin, deltamethrin, and Bacillus thuringiensis. No LC50 differences among T. absoluta populations were highlighted, except for Bacillus thuringiensis. Insects were still highly susceptible to abamectin [LC50 < 0.4 mg/L; Control failure likelihood (CFL) =−25%], spinosad (LC50 < 0.6 mg/L; CFL = 25%) and chlorpyrifos-ethyl (LC50 between 254 and 458 mg/L; CFL = −15%), but were less susceptible to acetamiprid (CFL ranging from 72% to 91%), cypermethrin (CFL = 80%), λ-cyhalothrin (CFL =79%), and deltamethrin (CFL ranging from 51% to 66%), with LC50 values for these insecticides ranging between 100 and 525 mg/L. Pending a proper communication strategy, we hope this work could help producers avoiding the most inefficient active substances

Mothflies (Diptera: Psychodidae) in hospitals: A guide to their identification and methods for their control

Repeated observation of "mothflies" at CHU Brugmann (Horta site hospital in Brussels) is not an isolated incident. Many public buildings have been infested by these Diptera of the Psychodidae Family. Although the species currently seen in Belgium is not a danger to human health, any infestation should be swiftly eradicated so as to limit the risks of a massive proliferation, source of hygiene problems and of potential bacterial dissemination. A good knowledge of adult and larval biology allows the potential sites of infestation to be quickly identified. The method to be envisaged to solve the problem will combine different approaches such as removing the risk factors (decomposing organic matter), monitoring egg-laying sites, applying caustic soda-based products and possibly treating with insecticide.SCOPUS: ar.jinfo:eu-repo/semantics/publishe