Chemical entrapment and killing of insects by bacteria

Abstract Actinobacteria such as the filamentous streptomycetes are widely known for their ability to produce specialized metabolites that include antibacterial and antifungal compounds. In addition, a growing body of work demonstrates that many insects harbour actinobacteria on their bodies and in their nests. The result of these mutualistic relationships is the protection of their offspring or food sources by virtue of the bacterially encoded specialized metabolites. However, some actinobacteria produce molecules that are toxic to insects and the relevance of this toxicity in nature is unknown. We have explored interactions between streptomycetes and the fruit fly Drosophila. We find that many streptomycetes produce specialized metabolites that have potent larvicidal effects against the fly. Larvae that ingest spores of the species that produce these toxic molecules die as a result. Strikingly, the mechanism of toxicity is specific to the bacterium’s chemical arsenal: cosmomycin D producing cells induce a relatively slow-acting cell death-like response in the larval digestive tract and avermectin producing cells induce rapid onset, whole-body paralysis. We further show that fruit flies are attracted to the volatile terpene 2-methylisoborneol that is produced by most streptomycetes. This interaction can influence their food choice and egg-laying destination such that they preferentially deposit their eggs on contaminated food sources. As a result, the larvae that hatch in these toxic environments are subsequently killed. This phenomena of terpene-mediated attraction and specialized metabolite toxicity must pose a significant risk to insects in nature.

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Chemical entrapment and killing of insects by bacteria

Nature Communications ◽

10.1038/s41467-020-18462-0 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Louis K. Ho ◽

Martin Daniel-Ivad ◽

Swathi P. Jeedigunta ◽

Jing Li ◽

Konstantin G. Iliadi ◽

...

Keyword(s):

Growth And Development ◽

Fruit Fly ◽

Food Sources ◽

Specialized Metabolites ◽

Low Concentrations ◽

Mechanism Of Toxicity ◽

Contaminated Food ◽

A Cell ◽

Volatile Terpenes ◽

Antibacterial And Antifungal

Abstract Actinobacteria produce antibacterial and antifungal specialized metabolites. Many insects harbour actinobacteria on their bodies or in their nests and use these metabolites for protection. However, some actinobacteria produce metabolites that are toxic to insects and the evolutionary relevance of this toxicity is unknown. Here we explore chemical interactions between streptomycetes and the fruit fly Drosophila melanogaster. We find that many streptomycetes produce specialized metabolites that have potent larvicidal effects against the fly; larvae that ingest spores of these species die. The mechanism of toxicity is specific to the bacterium’s chemical arsenal: cosmomycin D producing bacteria induce a cell death-like response in the larval digestive tract; avermectin producing bacteria induce paralysis. Furthermore, low concentrations of volatile terpenes like 2-methylisoborneol that are produced by streptomycetes attract fruit flies such that they preferentially deposit their eggs on contaminated food sources. The resulting larvae are killed during growth and development. The phenomenon of volatile-mediated attraction and specialized metabolite toxicity suggests that some streptomycetes pose an evolutionary risk to insects in nature.

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Next-Generation Sequencing reveals relationship between the larval microbiome and food substrate in the polyphagous Queensland fruit fly

Scientific Reports ◽

10.1038/s41598-019-50602-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Rajib Majumder ◽

Brodie Sutcliffe ◽

Phillip W. Taylor ◽

Toni A. Chapman

Keyword(s):

Next Generation Sequencing ◽

Illumina Miseq ◽

Fruit Fly ◽

Egg Laying ◽

Food Sources ◽

Natural Food ◽

Next Generation ◽

North East ◽

Host Fruit ◽

Generation Sequencing

Abstract Insects typically host substantial microbial communities (the ‘microbiome’) that can serve as a vital source of nutrients and also acts as a modulator of immune function. While recent studies have shown that diet is an important influence on the gut microbiome, very little is known about the dynamics underpinning microbial acquisition from natural food sources. Here, we addressed this gap by comparing the microbiome of larvae of the polyphagous fruit fly Bactrocera tryoni (‘Queensland fruit fly’) that were collected from five different fruit types (sapodilla [from two different localities], hog plum, pomegranate, green apple, and quince) from North-east to South-east Australia. Using Next-Generation Sequencing on the Illumina MiSeq platform, we addressed two questions: (1) what bacterial communities are available to B. tryoni larvae from different host fruit; and (2) how does the microbiome vary between B. tryoni larvae and its host fruit? The abundant bacterial taxa were similar for B. tryoni larvae from different fruit despite significant differences in the overall microbial community compositions. Our study suggests that the bacterial community structure of B. tryoni larvae is related less to the host fruit (diet) microbiome and more to vertical transfer of the microbiome during egg laying. Our findings also suggest that geographic location may play a quite limited role in structuring of larval microbiomes. This is the first study to use Next-Generation Sequencing to analyze the microbiome of B. tryoni larvae together with the host fruit, an approach that has enabled greatly increased resolution of relationships between the insect’s microbiome and that of the surrounding host tissues.

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Side Effects of Pesticides on the Olive Fruit Fly Parasitoid Psyttalia concolor (Szépligeti): A Review

Agronomy ◽

10.3390/agronomy10111755 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1755

Author(s):

Lara A. Pinheiro ◽

Beatriz Dáder ◽

Andrea C. Wanumen ◽

José Alberto Pereira ◽

Sónia A. P. Santos ◽

...

Keyword(s):

Sublethal Effects ◽

Sublethal Effect ◽

Fruit Fly ◽

Field Studies ◽

Food Sources ◽

Olive Fruit Fly ◽

Chemical Treatments ◽

Contaminated Food ◽

Psyttalia Concolor ◽

The Impact

Pesticide applications in olive orchards could alter the biological control of parasitoid Psyttalia concolor Szépligeti (Hymenoptera: Braconidae) on the key pest Bactrocera oleae Rossi (Diptera: Tephritidae). Psyttalia concolor adults can be contaminated by exposure to spray droplets, contact with treated surfaces or oral uptake from contaminated food sources. Pesticides impact both pest and parasitoid populations when they coexist in time and space, as they reduce pest numbers available for parasitoids and might cause toxic effects to parasitoids from which they need to recover. Therefore, the appropriate timing and application of selective chemical treatments provides the opportunity to incorporate this parasitoid in the IPM of B. oleae. This manuscript reviews the current literature on lethal and sublethal effects of insecticides, fungicides, herbicides, and biopesticides on P. concolor. Insecticides were generally more toxic, particularly organophosphates and pyrethroids, while herbicides and biopesticides had less effects on mortality and reproductive parameters. Some fungicides were quite harmful. Most of the studies were conducted in laboratory conditions, focused on reproduction as the only sublethal effect, exclusively considered the effect of a single pesticide and persistence was hardly explored. Field studies, currently quite scarce, are absolutely needed to satisfactorily assess the impact of pesticides on P. concolor.

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FMRFa receptor stimulated Ca2+ signals alter the activity of flight modulating central dopaminergic neurons in Drosophila melanogaster

10.1101/336768 ◽

2018 ◽

Cited By ~ 1

Author(s):

Preethi Ravi ◽

Deepti Trivedi ◽

Gaiti Hasan

Keyword(s):

Drosophila Melanogaster ◽

Dopaminergic Neurons ◽

Neuronal Excitability ◽

Insect Flight ◽

Fruit Fly ◽

Egg Laying ◽

Flight Behavior ◽

Food Sources ◽

Membrane Excitability ◽

Release Channel

AbstractNeuropeptide signaling influences animal behavior by modulating neuronal activity and thus altering circuit dynamics. Insect flight is a key innate behavior that very likely requires robust neuromodulation. Cellular and molecular components that help modulate flight behavior are therefore of interest and require investigation. In a genetic RNAi screen for G-protein coupled receptors that regulate flight bout durations, we earlier identified several receptors, including the receptor for the neuropeptide FMRFa (FMRFaR). To further investigate modulation of insect flight by FMRFa we generated CRISPR-Cas9 mutants in the gene encoding the Drosophila FMRFaR. The mutants exhibit significant flight deficits with a focus in dopaminergic cells. Expression of a receptor specific RNAi in adult central dopaminergic neurons resulted in progressive loss of sustained flight. Further, genetic and cellular assays demonstrated that FMRFaR stimulates intracellular calcium signaling through the IP3R and helps maintain neuronal excitability in a subset of dopaminergic neurons for positive modulation of flight bout durations.Author summaryNeuropeptides play an important role in modulating neuronal properties such as excitability and synaptic strength and thereby influence innate behavioral outputs. In flying insects, neuromodulation of flight has been primarily attributed to monoamines. In this study, we have used the genetically amenable fruit fly, Drosophila melanogaster to identify a neuropeptide receptor that is required in adults to modulate flight behavior. We show from both knockdown and knockout studies that the neuropeptide receptor, FMRFaR, present on a few central dopaminergic neurons, modulates the duration of flight bouts. Overexpression of putative downstream molecules, the IP3R, an intracellular Ca2+-release channel, and CaMKII, a protein kinase, significantly rescue the flight deficits induced by knockdown of the FMRFaR. Our data support the idea that FMRFaR and CaMKII help maintain optimal membrane excitability of adult dopaminergic neurons required to sustain longer durations of flight bouts. We speculate that the ability to maintain longer flight bouts in natural conditions enhances the individual’s capacity to search and reach food sources as well as find sites suitable for egg laying.

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Whole body extract of Mediterranean fruit fly males elicits high attraction in virgin females

Entomologia Experimentalis et Applicata ◽

10.1111/j.1570-7458.2008.00672.x ◽

2008 ◽

Vol 127 (1) ◽

pp. 20-29 ◽

Cited By ~ 6

Author(s):

Vassilis G. Mavraganis ◽

Constandinos Liaropoulos ◽

Nikos T. Papadopoulos ◽

Nikos A. Kouloussis ◽

Theodoros Broumas

Keyword(s):

Fruit Fly ◽

Mediterranean Fruit Fly ◽

Whole Body ◽

Body Extract ◽

High Attraction

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Social modulation of oogenesis and egg-laying in Drosophila melanogaster

10.1101/2021.09.13.460109 ◽

2021 ◽

Author(s):

Bailly Tiphaine ◽

Philip Kohlmeier ◽

Rampal Etienne ◽

Bregje Wertheim ◽

Jean-Christophe Billeter

Keyword(s):

Drosophila Melanogaster ◽

Social Context ◽

Social Systems ◽

Fruit Fly ◽

Egg Laying ◽

Physiological Adaptation ◽

Group Members ◽

Selection For ◽

Underlying Mechanisms ◽

Gravid Females

Being part of a group facilitates cooperation between group members, but also creates competition for limited resources. This conundrum is problematic for gravid females who benefit from being in a group, but whose future offspring may struggle for access to nutrition in larger groups. Females should thus modulate their reproductive output depending on their social context. Although social-context dependent modulation of reproduction is documented in a broad range of species, its underlying mechanisms and functions are poorly understood. In the fruit fly Drosophila melanogaster, females actively attract conspecifics to lay eggs on the same resources, generating groups in which individuals may cooperate or compete. The tractability of the genetics of this species allows dissecting the mechanisms underlying physiological adaptation to their social context. Here, we show that females produce eggs increasingly faster as group size increases. By laying eggs faster in group than alone, females appear to reduce competition between offspring and increase their likelihood of survival. In addition, females in a group lay their eggs during the light phase of the day, while isolated females lay them during the night. We show that responses to the presence of others are determined by vision through the motion detection pathway and that flies from any sex, mating status or species can trigger these responses. The mechanisms of this modulation of egg-laying by group is connected to a lifting of the inhibition of light on oogenesis and egg-laying by stimulating hormonal pathways involving juvenile hormone. Because modulation of reproduction by social context is a hallmark of animals with higher levels of sociality, our findings represent a protosocial mechanism in a species considered solitary that may have been the target of selection for the evolution of more complex social systems.

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Contamination of food with cadmium and dioxins – influence on the human body

Pomeranian Journal of Life Sciences ◽

10.21164/pomjlifesci.598 ◽

2019 ◽

Vol 65 (3) ◽

Author(s):

Aleksandra Słojewska ◽

Izabela Gutowska

Keyword(s):

General Population ◽

Health Effects ◽

Human Body ◽

Bone Mineralization ◽

The Body ◽

Food Sources ◽

Hormonal Balance ◽

Small Doses ◽

Contaminated Food

Introduction: Food is a carrier of many pollutants nowadays. For cadmium and dioxins, it is the main source of these compounds in the general population. Hence, the aim of this work was to collect data on the health effects associated with exposure to cadmium and dioxins which get into the human body through food.Materials and methods: A literature review was conducted by searching the scientific Medline database (PubMed) and Google Scholar.Results: Health effects associated with a long-term exposure to low doses of cadmium and dioxins may be nonspecific and are rarely attributed to food sources. These may cause disorders affecting hormonal balance, kidney function, lipid metabolism, fertility, cognitive function, bone mineralization, and susceptibility to diseases and allergies. These compounds may also lead to cancer development.Conclusions: The general population faces the problem of longterm exposure to small doses of these substances due to their accumulation in the body, even if their amounts do not exceed the relevant standards. The health effects of this type of exposure may be significantly delayed and are not likely to be attributed to the consumption of contaminated food. Consumers wishing to reduce the amounts of these compounds delivered to the body should limit the consumption of grilled and smoked products, and should also opt for organic food.

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Non-canonical function of theSex-lethalgene controls the protogyny phenotype inDrosophila melanogaster

10.1101/2021.03.02.433534 ◽

2021 ◽

Author(s):

Ki-Hyeon Seong ◽

Siu Kang

Keyword(s):

Dosage Compensation ◽

Sexual Maturation ◽

Fruit Fly ◽

Fruit Flies ◽

Activity Monitoring ◽

Whole Body ◽

Human Beings ◽

Canonical Function ◽

Individual Activity ◽

Time Points

AbstractMany animal species exhibit sex differences in the time period prior to reaching sexual maturity. However, the underlying mechanism for such biased maturation remains poorly understood. Females of the fruit flyDrosophila melanogastereclose 4 h faster on average than males, owing to differences in the pupal period between the sexes; this characteristic is referred to as the protogyny phenotype. Here, we aimed to elucidate the mechanism underlying the protogyny phenotype in the fruit fly using our newly developedDrosophilaIndividual Activity Monitoring and Detecting System (DIAMonDS), which can continuously detect the precise timing of both pupariation and eclosion of individual flies. Via this system, following the laying of eggs, we detected the precise time points of pupariation and eclosion of a large number of individual flies simultaneously and succeeded in identifying the tiny differences in pupal duration between females and males. We first explored the role of physiological sex by establishing transgender flies via knockdown of the sex-determination gene,transformer(tra) and its co-factortra2, which retained the protogyny phenotype. In addition, disruption of dosage compensation bymale-specific lethal(msl-2) knockdown did not affect the protogyny phenotype. TheDrosophilamaster sex switch gene—Sxlpromotes female differentiation viatraand turns off male dosage compensation through the repression ofmsl-2.However, we observed that stage-specific whole-body knockdown and mutation ofSxlinduced disturbance of the protogyny phenotype. These results suggest that an additional, non-canonical function ofSxlinvolves establishing the protogyny phenotype inD. melanogaster.Author summaryA wide variety of animals show differences in time points of sexual maturation between sexes. For example, in many mammals, including human beings, females mature faster than males. This maturation often takes several months or years, and precisely detecting the time point of maturation is challenging, because of the continuity of growth, especially in mammals. Moreover, the reason behind the difference in sexual maturation time points between sexes is not fully understood. The fruit flyDrosophila—a model organism—also shows biased maturation between the sexes, with females emerging 4 h faster than males (a characteristic known as the protogyny phenotype). To understand the mechanism underlying the protogyny phenotype, we used our newly developed system,DrosophilaIndividual Activity Monitoring and Detecting System (DIAMonDS), to detect the precise eclosion point in individual fruit flies. Surprisingly, our analysis of transgender flies obtained by knockdown and overexpression techniques indicated that a physiological gender might not be necessary requirement for protogyny and that a non-canonical novel function of the fruit fly master sex switch gene,Sxl, regulates protogyny in fruit flies.

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Spring poisoning hazards

Livestock ◽

10.12968/live.2020.25.2.78 ◽

2020 ◽

Vol 25 (2) ◽

pp. 78-85

Author(s):

Nicola Bates

Keyword(s):

Treatment Options ◽

Clinical Signs ◽

Rapid Onset ◽

Food Sources ◽

Poisonous Plants ◽

Allium Species ◽

Cardiac Effects ◽

Conium Maculatum ◽

Toxic Plants ◽

Neurological Effects

Poisoning in the spring may occur in livestock from exposure to glyphosate which is used prior to sowing of plant crops or from ingestion of poisonous plants. Glyphosate is of low toxicity but many products contain a carrier which is irritant to tissues. Plant poisoning may occur because other forage is unavailable and hungry animals will eat unpalatable toxic plants if other food sources are scare. Some plants such as bluebell (Hyacinoides species) and ransom (wild garlic, Allium urinsum) grow in profusion in the spring. Bluebells cause gastrointestinal and cardiac effects and Allium species cause anaemia. Some plants are more toxic in the spring as concentrations of toxic compounds are high compared with other times of the year. This is the case with hemlock (Conium maculatum) and water hemlock (Cicuta virosa). Both these plants cause neurological effects and water hemlock, in particular, causes very rapid onset of clinical signs. Spring flowering plants such as Rhododendron and Pieris species are commonly associated with poisoning, particularly in ruminants. Both these species contain grayanotoxins which cause gastrointestinal and cardiac effects. Access to areas where poisonous plants are known to grow should be restricted and good quality forage provided. Treatment options for management of poisoning in livestock are limited and, in some cases, the only sign of exposure is sudden death.

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Neonicotinoids disrupt circadian rhythms and sleep in honey bees

Scientific Reports ◽

10.1038/s41598-020-72041-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Michael C. Tackenberg ◽

Manuel A. Giannoni-Guzmán ◽

Erik Sanchez-Perez ◽

Caleb A. Doll ◽

José L. Agosto-Rivera ◽

...

Keyword(s):

Circadian Rhythms ◽

Honey Bee ◽

Honey Bees ◽

Fruit Fly ◽

Food Sources ◽

Nicotinic Cholinergic Receptors ◽

Cholinergic Signaling ◽

Neonicotinoid Pesticides ◽

Circadian Behavior ◽

Light Input

Abstract Honey bees are critical pollinators in ecosystems and agriculture, but their numbers have significantly declined. Declines in pollinator populations are thought to be due to multiple factors including habitat loss, climate change, increased vulnerability to disease and parasites, and pesticide use. Neonicotinoid pesticides are agonists of insect nicotinic cholinergic receptors, and sub-lethal exposures are linked to reduced honey bee hive survival. Honey bees are highly dependent on circadian clocks to regulate critical behaviors, such as foraging orientation and navigation, time-memory for food sources, sleep, and learning/memory processes. Because circadian clock neurons in insects receive light input through cholinergic signaling we tested for effects of neonicotinoids on honey bee circadian rhythms and sleep. Neonicotinoid ingestion by feeding over several days results in neonicotinoid accumulation in the bee brain, disrupts circadian rhythmicity in many individual bees, shifts the timing of behavioral circadian rhythms in bees that remain rhythmic, and impairs sleep. Neonicotinoids and light input act synergistically to disrupt bee circadian behavior, and neonicotinoids directly stimulate wake-promoting clock neurons in the fruit fly brain. Neonicotinoids disrupt honey bee circadian rhythms and sleep, likely by aberrant stimulation of clock neurons, to potentially impair honey bee navigation, time-memory, and social communication.

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