scholarly journals Host-Symbiont Interactions for Potentially Managing Heteropteran Pests

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Simone Souza Prado ◽  
Tiago Domingues Zucchi
Keyword(s):  
Molecular Techniques ◽  
Microbial Interactions ◽  
Disease Vectors ◽  
Bacterial Symbionts ◽  
Agricultural Pests ◽  
True Bugs ◽  
Control Programs ◽  
Biological Aspects ◽  
Alternative Techniques ◽  
Insect Group

Insects in the suborder Heteroptera, the so-called true bugs, include over 40,000 species worldwide. This insect group includes many important agricultural pests and disease vectors, which often have bacterial symbionts associated with them. Some symbionts have coevolved with their hosts to the extent that host fitness is compromised with the removal or alteration of their symbiont. The first bug/microbial interactions were discovered over 50 years ago. Only recently, mainly due to advances in molecular techniques, has the nature of these associations become clearer. Some researchers have pursued the genetic modification (paratransgenesis) of symbionts for disease control or pest management. With the increasing interest and understanding of the bug/symbiont associations and their ecological and physiological features, it will only be a matter of time before pest/vector control programs utilize this information and technique. This paper will focus on recent discoveries of the major symbiotic systems in Heteroptera, highlighting how the understanding of the evolutionary and biological aspects of these relationships may lead to the development of alternative techniques for efficient heteropteran pest control and suppression of diseases vectored by Heteroptera.

scholarly journals Odonata: Who They Are and What They Have Done for Us Lately: Classification and Ecosystem Services of Dragonflies

Insects ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 62 ◽  
Author(s):  
Michael May
Keyword(s):  
Ecosystem Services ◽  
Aquatic Ecosystems ◽  
Insect Flight ◽  
Economic Importance ◽  
Molecular Techniques ◽  
Disease Vectors ◽  
Agricultural Pests ◽  
Top Predators ◽  
New Information ◽  
And Control

Odonata (dragonflies and damselflies) are well-known but often poorly understood insects. Their phylogeny and classification have proved difficult to understand but, through use of modern morphological and molecular techniques, is becoming better understood and is discussed here. Although not considered to be of high economic importance, they do provide esthetic/spiritual benefits to humans, and may have some impact as predators of disease vectors and agricultural pests. In addition, their larvae are very important as intermediate or top predators in many aquatic ecosystems. More recently, they have been the objects of study that have yielded new information on the mechanics and control of insect flight.

scholarly journals Capturing the transcription factor interactome in response to sub-lethal insecticide exposure

2020 ◽  
Author(s):  
Victoria A Ingham ◽  
Sara Elg ◽  
Sanjay C Nagi ◽  
Frank Dondelinger
Keyword(s):  
Transcription Factors ◽  
Time Course ◽  
Lethal Dose ◽  
Resistance Mechanisms ◽  
Dynamic Bayesian Networks ◽  
Disease Vectors ◽  
Anopheles Coluzzii ◽  
Pest Species ◽  
Agricultural Pests ◽  
Insecticide Exposure

AbstractThe increasing levels of pesticide resistance in agricultural pests and disease vectors represents a threat to both food security and global health. As insecticide resistance intensity strengthens and spreads, the likelihood of a pest encountering a sub-lethal dose of pesticide dramatically increases. Here, we apply dynamic Bayesian networks to a transcriptome time-course generated using sub-lethal pyrethroid exposure on a highly resistant Anopheles coluzzii population. The model accounts for circadian rhythm and ageing effects allowing high confidence identification of transcription factors with key roles in pesticide response. The associations generated by this model show high concordance with lab-based validation and identifies 44 transcription factors regulating insecticide-responsive transcripts. We identify six key regulators, with each displaying differing enrichment terms, demonstrating the complexity of pesticide response. The considerable overlap of resistance mechanisms in agricultural pests and disease vectors strongly suggests that these findings are relevant in a wide variety of pest species.

scholarly journals Incursion pathways of the Asian tiger mosquito (Aedes albopictus) into Australia contrast sharply with those of the yellow fever mosquito (Aedes aegypti)

2020 ◽  
Author(s):  
Thomas L Schmidt ◽  
Jessica Chung ◽  
Anthony R. van Rooyen ◽  
Angus Sly ◽  
Andrew R Weeks ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Aedes Albopictus ◽  
Species Differences ◽  
Invasive Disease ◽  
Disease Vectors ◽  
Pacific Region ◽  
Control Methods ◽  
Asian Tiger Mosquito ◽  
Control Programs ◽  
Asian Tiger

AbstractBACKGROUNDUnderstanding pest incursion pathways is critical for preventing new invasions and for stopping the transfer of alleles that reduce the efficacy of local control methods. The mosquitoes Aedes albopictus (Skuse) and Ae. aegypti (Linnaeus) are both highly invasive disease vectors, and through a series of ongoing international incursions are continuing to colonise new regions and spread insecticide resistance alleles among established populations. This study uses high-resolution molecular markers and a set of 241 reference genotypes to trace incursion pathways of Ae. albopictus into mainland Australia, where no successful invasions have yet been observed. We contrast these results with incursion pathways of Ae. aegypti, investigated previously.RESULTSAssignments successful identified China, Japan, Singapore and Taiwan as source locations. Incursion pathways of Ae. albopictus were entirely different to those of Ae. aegypti, despite broad sympatry of these species throughout the Indo-Pacific region. Incursions of Ae. albopictus appeared to have come predominantly along marine routes from key trading locations, while Ae. aegypti was mostly linked to aerial routes from tourism hotspots.CONCLUSIONThese results demonstrate how genomics can help decipher otherwise cryptic incursion pathways. The inclusion of reference genotypes from the Americas may help resolve some unsuccessful assignments. While many congeneric taxa will share common incursion pathways, this study highlights that this is not always the case, and incursion pathways of important taxa should be specifically investigated. Species differences in aerial and marine incursion rates may reflect the efficacy of ongoing control programs such as aircraft disinsection.

Selfish DNA as a method of pest control

1994 ◽  
Vol 344 (1309) ◽  
pp. 313-324 ◽  
Keyword(s):  
Genetic Load ◽  
Single Copy ◽  
Mendelian Inheritance ◽  
Host Population ◽  
Molecular Techniques ◽  
Uniparental Inheritance ◽  
Pest Species ◽  
Agricultural Pests ◽  
Selfish Dna ◽  
Host Fitness

The inheritance of most genes is tightly controlled, governed by the rules of mendelian inheritance if nuclear or uniparental inheritance if cytoplasmic. A few notable genes and cytoplasmic genomes have escaped this regulation. Such genes may spread by increasing their own rate of transmission despite reducing host fitness and may be regarded as ‘selfish’. Their population genetics are described and it appears they may impose a significant genetic load on the host population. Modern molecular techniques may enable similar loads to be imposed on pest species either by transferring selfish genes between species, or by linking deleterious genes to a selfish locus. Alternatively, ‘modifier’ genes that eliminate the virulent, or disease vectorial capacity, of the pest population may be introduced by linkage to a selfish locus. Selfish elements present in multiple copies may be preferable to single-copy elements as the former are capable of a larger reduction in host fitness. The practical application of these agents depends on five factors: (i) the rate of ‘reversion’ to a non-selfish form; (ii) the evolution of host repressor systems; (iii) their effect on host fitness, which determines their rate of invasion; (iv) the mechanism regulating host population size in the field; and (v) their ease of manipulation in the laboratory. The first two factors are the most uncertain in most systems, but should be amenable to experimental analysis. It is proposed that the development of such techniques may result in powerful new methods of population control which may be applied to both agricultural pests and disease vectors.

scholarly journals Gut Symbionts from Distinct Hosts Exhibit Genotoxic Activity via Divergent Colibactin Biosynthesis Pathways

2014 ◽  
Vol 81 (4) ◽  
pp. 1502-1512 ◽  
Author(s):  
Philipp Engel ◽  
Maria I. Vizcaino ◽  
Jason M. Crawford
Keyword(s):  
Dna Damage ◽  
Secondary Metabolites ◽  
Biosynthetic Pathway ◽  
Tumor Formation ◽  
Microbial Interactions ◽  
Eukaryotic Cells ◽  
Dependent Manner ◽  
Bacterial Symbionts ◽  
Content Type ◽  
E Coli

ABSTRACTSecondary metabolites produced by nonribosomal peptide synthetase (NRPS) or polyketide synthase (PKS) pathways are chemical mediators of microbial interactions in diverse environments. However, little is known about their distribution, evolution, and functional roles in bacterial symbionts associated with animals. A prominent example is colibactin, a largely unknown family of secondary metabolites produced byEscherichia colivia a hybrid NRPS-PKS biosynthetic pathway that inflicts DNA damage upon eukaryotic cells and contributes to colorectal cancer and tumor formation in the mammalian gut. Thus far, homologs of this pathway have only been found in closely relatedEnterobacteriaceae, while a divergent variant of this gene cluster was recently discovered in a marine alphaproteobacterialPseudovibriostrain. Herein, we sequenced the genome ofFrischella perraraPEB0191, a bacterial gut symbiont of honey bees and identified a homologous colibactin biosynthetic pathway related to those found inEnterobacteriaceae. We show that the colibactin genomic island (GI) has conserved gene synteny and biosynthetic module architecture acrossF. perrara,Enterobacteriaceae, and thePseudovibriostrain. Comparative metabolomics analyses ofF. perraraandE. colifurther reveal that these two bacteria produce related colibactin pathway-dependent metabolites. Finally, we demonstrate thatF. perrara, likeE. coli, causes DNA damage in eukaryotic cellsin vitroin a colibactin pathway-dependent manner. Together, these results support that divergent variants of the colibactin biosynthetic pathway are widely distributed among bacterial symbionts, producing related secondary metabolites and likely endowing its producer with functional capabilities important for diverse symbiotic associations.

scholarly journals An ammonium transporter is a non-canonical olfactory receptor for ammonia

2021 ◽  
Author(s):  
Alina Vulpe ◽  
Hyong S. Kim ◽  
Sydney Ballou ◽  
Shiuan-Tze Wu ◽  
Veit Grabe ◽  
...  
Keyword(s):  
Olfactory Receptor ◽  
Ectopic Expression ◽  
Behavioral Responses ◽  
Olfactory Receptors ◽  
Ammonium Transporter ◽  
Disease Vectors ◽  
Agricultural Pests ◽  
Neuron Populations ◽  
Transporter Family ◽  
New Type

SummaryTwo families of ligand-gated ion channels function as olfactory receptors in insects. Here, we show that these canonical olfactory receptors are not necessary for responses to ammonia, a key ecological odor that is attractive to many insects including disease vectors and agricultural pests. Instead, we show that a member of the ancient electrogenic ammonium transporter family, Amt, is a new type of olfactory receptor. We report two hitherto unidentified olfactory neuron populations that mediate neuronal and behavioral responses to ammonia. Their endogenous ammonia responses are Amt-dependent, and ectopic expression of either Drosophila or Anopheles Amt confers ammonia sensitivity. Amt is the first transporter known to function as an olfactory receptor in animals, and its role may be conserved across insect species.

scholarly journals A Review of the Control of Aedes aegypti (Diptera: Culicidae) in the Continental United States

2020 ◽  
Author(s):  
Bethany L McGregor ◽  
C Roxanne Connelly
Keyword(s):  
Aedes Aegypti ◽  
Mosquito Control ◽  
Effective Control ◽  
Source Reduction ◽  
Viral Pathogens ◽  
Control Programs ◽  
Lack Of Information ◽  
Dengue Outbreaks ◽  
Nuisance Species ◽  
Alternative Techniques

Abstract Aedes aegypti (L) is an anthropophilic mosquito involved in the transmission of a variety of viral pathogens worldwide including dengue, chikungunya, yellow fever, and Zika viruses. This species, native to Africa, is well established in the continental U.S. (CONUS) and occasionally contributes to localized outbreaks of viral diseases. In the last seven decades, mosquito control programs in the CONUS have been focused on vectors of eastern equine encephalitis, St. Louis encephalitis, and West Nile viruses, as well as nuisance species. Aedes aegypti receives little control focus except during outbreak periods, which has led to a lack of information on appropriate and effective control options targeting Ae. aegypti in the CONUS. As such, in the event of an Ae. aegypti-borne arboviral outbreak in the CONUS, there are limited evidence-based control recommendations or protocols in place. Autochthonous outbreaks of Ae. aegypti-borne pathogens have occurred recently in the CONUS, including dengue outbreaks in 2010 and 2013, a chikungunya outbreak in 2014, and the 2016 outbreak of Zika virus. The increasing frequency of Ae. aegypti-borne outbreaks necessitates increased attention and research on control of this species to prevent and mitigate future outbreaks. This review consolidates and synthesizes the available literature on control of Ae. aegypti, specifically within the CONUS, focusing on data generated through operational applications as well as field and semifield experiments. The purpose of this review is to identify and highlight areas where additional research is needed. The review covers chemical control and insecticide resistance, biological control, source reduction, trapping, and alternative techniques.

scholarly journals Evolutionary simulations of Z -linked suppression gene drives

2019 ◽  
Vol 286 (1912) ◽  
pp. 20191070 ◽  
Author(s):  
Luke Holman
Keyword(s):  
Invasive Species ◽  
Sex Determination ◽  
Disease Vectors ◽  
Agricultural Pests ◽  
Low Frequencies ◽  
Linked Gene ◽  
Lepidopteran Pests ◽  
Evolutionary Simulations ◽  
Linked Suppression ◽  
Gene Drives

Synthetic gene drives may soon be used to suppress or eliminate populations of disease vectors, pathogens, invasive species, and agricultural pests. Recent proposals have focused on using Z -linked gene drives to control species with ZW sex determination, which include Lepidopteran pests, parasitic trematodes, and cane toads. These proposals include Z -linked ‘ W -shredders’, which would suppress populations by cleaving the W chromosome and causing females to produce only sons, as well as Z -linked female-sterilizing gene drives. Here, I use eco-evolutionary simulations to evaluate the potential of some proposed Z -linked gene drives, and to produce recommendations regarding their design and use. The simulations show that W -shredders are likely to be highly effective at eradicating populations provided that resistance to W -shredding cannot evolve. However, W -shredder alleles can invade populations from very low frequencies, making it difficult to eliminate specific populations while leaving nearby populations untouched; this issue may restrict their possible uses.

scholarly journals Locust Bacterial Symbionts: An Update

Insects ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 655
Author(s):  
Omer Lavy ◽  
Uri Gophna ◽  
Eran Gefen ◽  
Amir Ayali
Keyword(s):  
Reproductive Organs ◽  
The Other ◽  
Future Research ◽  
Bacterial Symbionts ◽  
Agricultural Pests ◽  
Bacterial Composition ◽  
Current State

As one of the world’s most infamous agricultural pests, locusts have been subjected to many in-depth studies. Their ability at one end of their behavioral spectrum to live as solitary individuals under specific conditions, and at the other end of the spectrum to form swarms of biblical scale, has placed them at the focus of vast research efforts. One important aspect of locust ecology is that of their interactions with the bacteria that reside in and on them. Although this aspect of locust ecology has been little studied relative to the mainstream locust research, these bacteria have been shown both to affect locust immunity and to participate in maintaining swarm integrity through the secretion of attractant volatiles. The interaction between locusts and their bacteria seems, however, to be bi-directional, with the bacteria themselves, as recently shown, being influenced by their host’s swarming tendencies. This seems to be a consequence of the bacterial composition in the locust’s gut, reproductive organs, and integument undergoing change with the change in their host’s behavior. In this review we describe the current state of knowledge of the locust–bacteria interactions (data exists mainly for the desert and the migratory locusts), as well as highlighting some newly-gained understanding; and offer perspectives for future research.

scholarly journals Farmers’ pesticide usage practices in the malaria endemic region of North-Western Tanzania: implications to the control of malaria vectors

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Anitha Philbert ◽  
Sylvester Leonard Lyantagaye ◽  
Gamba Nkwengulila
Keyword(s):  
Public Health ◽  
Vector Control ◽  
Susceptibility Test ◽  
Health Concern ◽  
Malaria Vectors ◽  
Disease Vectors ◽  
Endemic Region ◽  
Phenotypic Resistance ◽  
Control Programs ◽  
Pesticide Usage

Abstract Background Pesticides remain the mainstay for the control of agricultural pests and disease vectors. However, their indiscriminate use in agriculture has led to development of resistance to both crop pests and disease vectors. This threatens to undermine the success gained through the implementation of chemical based vector control programs. We investigated the practices of farmers with regard to pesticide usage in the vegetable growing areas and their impact on susceptibility status of An. gambiae s.l. Methods A stratified multistage sampling technique using the administrative structure of the Tanzanian districts as sampling frame was used. Wards, villages and then participants with farms where pesticides are applied were purposively recruited at different stages of the process, 100 participants were enrolled in the study. The same villages were used for mosquito larvae sampling from the farms and the surveys were complimented by the entomological study. Larvae were reared in the insectary and the emerging 2–3 days old female adults of Anopheles gambiae s.l were subjected to susceptibility test. Results Forty eight pesticides of different formulations were used for control of crop and Livestock pests. Pyrethroids were the mostly used class of pesticides (50%) while organophosphates and carbamates were of secondary importance. Over 80% of all farmers applied pesticides in mixed form. Susceptibility test results confirmed high phenotypic resistance among An. gambiae populations against DDT and the pyrethroids (Permethrin-0.75%, Cyfluthrin-0.15%, Deltametrin-0.05% and Lambdacyhalothrin-0.05%) with mortality rates 54, 61, 76 and 71%, respectively. Molecular analysis showed An. arabiensis as a dominant species (86%) while An. gambiae s.s constituted only 6%. The kdr genes were not detected in all of the specimens that survived insecticide exposures. Conclusion The study found out that there is a common use of pyrethroids in farms, Livestocks as well as in public health. The study also reports high phenotypic resistance among An. gambiae s.l against most of the pyrethroids tested. The preponderance of pyrethroids in agriculture is of public health concern because this is the class of insecticides widely used in vector control programs and this calls for combined integrated pest and vector management (IPVM).

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