Potent Ant Deterrents Emitted from Nematode-Infected Insect Cadavers

Most known species of entomopathogenic nematodes (EPNs) are generalist obligate parasites of insects. They kill their hosts within days after infection and mortality is mainly caused by toxins produced by bacteria that co-infect the hosts and serve as food for the nematodes. EPNs can infect a very broad spectrum of insects and these insects can therefore be expected to have evolved strategies to avoid infection. Indeed, ants are known to avoid feeding on EPN-infected insect cadavers, most likely because they are repelled by semiochemicals that emanate from the cadavers. The source and nature of these repellents are so far unknown. In a series of behavioral and chemical analytical experiments we identified hexadecanal and 2-heptadecanone as two compounds that are emitted by insect larva that are infected by the EPN Steinernema feltiae, but not by uninfected larvae. When spiking honey water with the two semiochemicals, they were confirmed to be highly deterrent to the ant Lasius niger. The environmentally benign hexadecanal and 2-heptadecanone could be employed to ward off ants and possibly other pests. Additional experiments are needed to fully determine their application potential.

Polyvinyl Chloride Biodegradation Fuels Survival of Invasive Insect Larva and Intestinal Degrading Strain of Klebsiella

Microbial degradation of polyvinyl chloride (PVC) is eco-friendly and economically attractive, but extremely challenging due to the lack of mechanistic understanding on the degrading strains and enzymes. Motivated by an accidental discovery that the larva of an agricultural invasive pest, Spodoptera frugiperda, effectively survived solely on PVC film, we profiled the intestinal microbiota of S. frugiperda and screened for PVC-degrading strains. The results showed PVC film feeding significantly changed the larvae intestinal microbiota through selective enrichment of Enterococcus, Ochrobactrum and Klebsiella. From the larva intestines, we isolated and named a biofilm-forming strain EMBL-1, and experimentally verified it as the first Klebsiella bacterium that can actively degrade and utilize PVC based on various classic physicochemical and morphological analyses. We further used multi-omics analyses that complementarily integrate whole genomic, transcriptomic, proteomic, and metabolic insights to identify enzyme-coding genes responsible for PVC degradation and proposed a putative biodegradation pathway by the bacterial strain. All in all, both S. frugiperda and its intestinal strain EMBL-1 are discovered to effectively survive on PVC film by exploiting its polymer as a sole energy source. Moreover, this work exemplifying PVC biodegradation provides reference for discovering more degrading microbes and enzymatic resources of other recalcitrant plastics.

Sand throwing in a pit-building antlion larva from a soil mechanical perspective

Sandy pitfall traps are an elaborate construction to capture prey and antlions are well-known representatives of this predation technique. From a soil mechanical perspective, antlions exploit the interactions between the particles of their habitat and engineer a stable trap. This construction is close to the unstable state, where a prey item will immediately slide towards the center - towards the ambushing antlion - when accidently entering the trap. This method is efficient, but requires permanent pit maintaining. According to the present knowledge, antlions throw sand at their prey, to distract it, and/or cause sand slides towards the center of the pit. Using sand throwing and escape experiments, as well as finite element analysis, we supported this hypothesis. Furthermore, we added new hypothesis about maintaining the pitfall trap. We showed that sand that accumulates in the center of the pit will be continuously removed, which lead to the slope maintenance close to an unstable condition. This avoids self-burial of the antlion, as well as decreasing the chance of prey item escapes by keeping the slope angle steep. This demonstrates the interaction of an insect larva with its abiotic environment from a novel perspective and adds further insights into longstanding entomological hypotheses.

Extreme suction attachment performance from specialised insects living in mountain streams (Diptera: Blephariceridae)

Suction is widely used by animals for strong controllable underwater adhesion but is less well understood than adhesion of terrestrial climbing animals. Here we investigate the attachment of an aquatic insect larva (Blephariceridae), which clings to rocks in torrential streams using the only known muscle-actuated suction organs in insects. We measured their attachment forces on well-defined rough substrates and found their adhesion was much less reduced by micro-roughness than terrestrial climbing insects. In vivo visualisation of the suction organs in contact with microstructured substrates revealed that they can mould around large asperities to form a seal. Moreover, we showed that spine-like microtrichia on the organ are stiff cuticular structures that only make tip contact on smooth and microstructured substrates. Our results highlight the performance and versatility of blepharicerid suction organs and introduce a new study system to explore biological suction.

Soil and entomopathogenic fungi with potential for biodegradation of insecticides: degradation of flubendiamide in vivo by fungi and in vitro by laccase

Purpose Flubendiamide is a highly toxic and persistent insecticide that causes loss of insect muscle functions leading to paralysis and death. The objective was to screen for filamentous fungi in soils where insecticides had been applied, to isolate entomopathogenic fungi from insect larva (Anticarsia gemmatalis) that infest soybean crops, and to use these in biodegradation of insecticides. Method Filamentous fungi were isolated from soils, and growth inhibition was evaluated on solid medium containing commercial insecticides, Belt® (flubendiamide) and Actara® (thiamethoxam). A total of 133 fungi were isolated from soil and 80 entomopathogenic fungi from insect larva. Based on growth inhibition tests, ten soil fungi, 2 entomopathogenic fungi, and Botryosphaeria rhodina MAMB-05 (reference standard) were selected for growth on commercial insecticides in solid media. Fungi were grown in submerged fermentation on media containing commercial insecticides and assayed for laccase activity. Result Isolates JUSOLCL039 (soil), JUANT070 (insect), and MAMB-05 performed best, and were respectively inhibited by 48.41%, 75.97%, and 79.23% when cultivated on 35 g/L Actara®, and 0.0, 5.42%, and 43.39% on 39.04 g/L Belt®. JUSOLCL039 and JUANT070 were molecularly identified as Trichoderma koningiopsis and Neurospora sp., respectively. The three fungal isolates produced laccase constitutively, albeit at low activities. Fungal growth on pure flubendiamide and thiamethoxam resulted in only thiamethoxam inducing high laccase titers (10.16 U/mL) by JUANT070. Neurospora sp. and B. rhodina degraded flubendiamide by 27.4% and 9.5% in vivo, while a crude laccase from B. rhodina degraded flubendiamide by 20.2% in vitro. Conclusion This is the first report of fungi capable of degrading flubendiamide, which have applications in bioremediation.

Be Jubel Dan Be Ancruk Kuliner Ekstrim Langka Di Bali

Jubel is a caterpillar-shaped water insect larva that lives in muddy waters. Ancruk, in the form of a white elongated caterpillar, is known as a sago caterpillar. This article aims to (1) describe gastronomic beams and features. (2) obtain a strategy of avoiding the extinction of the living resources of jubel and ancruk. The research used gastronomic theory and the theory of revitalization. The data collection techniques used are interviews and literature. The results of the research show that be jubel and ancruk have good savor for the human body. They are of high protein (supports growth and maintenance of body tissues), free of cholesterol, contain essential amino acids, vitamins, minerals, and can maintain stamina and low fat. The strategy that can be done is to revitalize the living sources of the main ingredients, such as physical intervention by limiting development in the green zone. Improving the quality of existing rice fields, implementing an organic farming system. Meanwhile, to save ancruk is to maintain the existence of their plants habitat and to do cultivation. Keywords: Jubel, Ancruk, Rare, Bali