scholarly journals Navigating infection risk during oviposition and larval foraging in a holometabolous insect

2017 ◽  
Author(s):  
Jonathon A. Siva-Jothy ◽  
Katy M. Monteith ◽  
Pedro F. Vale
Keyword(s):  
Larval Stage ◽  
Developmental Stages ◽  
Adult Stage ◽  
Life Stages ◽  
Holometabolous Insect ◽  
Fitness Consequences ◽  
Risk Of Exposure ◽  
Selection For ◽  
Complete Metamorphosis ◽  
Oviposition Sites

AbstractDeciding where to eat and raise offspring carries important fitness consequences for all animals, especially if foraging, feeding and reproduction increase the risk of exposure to pathogens. In insects with complete metamorphosis, foraging occurs mainly during the larval stage, while oviposition decisions are taken by adult-stage females. Selection for infection avoidance behaviours may therefore be developmentally uncoupled. Using a combination of experimental infections and behavioural choice assays, here we tested if Drosophila melanogaster fruit flies avoid potentially infectious environments at distinct developmental stages. When given conspecific fly carcasses as a food source, larval-stage flies did not discriminate between carcasses that were clean or infected with the pathogenic Drosophila C Virus (DCV), even though scavenging was a viable route of DCV transmission. Adult females however, discriminated between different oviposition sites, laying more eggs near a clean rather than an infectious carcass if they were healthy; DCV-infected females did not discriminate between the two environments. While potentially risky, laying eggs near potentially infectious carcasses was always preferred to sites containing only fly medium. Our findings suggest that infection avoidance can play an important role in how mothers provision their offspring, and underline the need to consider infection avoidance behaviours at multiple life-stages.

scholarly journals Persistence of an extracellular systemic infection across metamorphosis in a holometabolous insect

2018 ◽  
Vol 14 (2) ◽  
pp. 20170771 ◽  
Author(s):  
David F. Duneau ◽  
Brian P. Lazzaro
Keyword(s):  
Larval Stage ◽  
Adult Stage ◽  
A Priori ◽  
Adult Life ◽  
Bacterial Pathogen ◽  
Systemic Infection ◽  
Life Cycles ◽  
Life Stages ◽  
Holometabolous Insect ◽  
Complete Metamorphosis

Organisms with complex life cycles can differ markedly in their biology across developmental life stages. Consequently, distinct life stages can represent drastically different environments for parasites. This difference is especially striking with holometabolous insects, which have dramatically different larval and adult life stages, bridged by a complete metamorphosis. There is no a priori guarantee that a parasite infecting the larval stage would be able to persist into the adult stage. In fact, to our knowledge, transstadial transmission of extracellular pathogens has never been documented in a host that undergoes complete metamorphosis. We tested the hypothesis that a bacterial parasite originally sampled from an adult host could infect a larva, then survive through metamorphosis and persist into the adult stage. As a model, we infected the host Drosophila melanogaster with a horizontally transmitted, extracellular bacterial pathogen, Providencia rettgeri . We found that this natural pathogen survived systemic infection of larvae (L3) and successfully persisted into the adult host. We then discuss how it may be adaptive for bacteria to transverse life stages and even minimize virulence at the larval stage in order to benefit from adult dispersal.

scholarly journals Translation initiation in Drosophila melanogaster is reduced by mutations upstream of the AUG initiator codon.

1991 ◽  
Vol 11 (4) ◽  
pp. 2149-2153 ◽  
Author(s):  
Y Feng ◽  
L E Gunter ◽  
E L Organ ◽  
D R Cavener
Keyword(s):  
Translation Initiation ◽  
Larval Stage ◽  
Developmental Stages ◽  
Germ Line ◽  
Adult Stage ◽  
Mutant Gene ◽  
Start Codon ◽  
Fold Reduction

The importance to in vivo translation of sequences immediately upstream of the Drosophila alcohol dehydrogenase (Adh) start codon was examined at two developmental stages. Mutations were introduced into the Adh gene in vitro, and the mutant gene was inserted into the genome via germ line transformation. An A-to-T substitution at the -3 position did not affect relative translation rates of the ADH protein at the second-instar larval stage but resulted in a 2.4-fold drop in translation of ADH at the adult stage. A second mutant gene, containing five mutations in the region -1 to -9, was designed to completely block translation initiation. However, transformant lines bearing these mutations still exhibit detectable ADH, albeit at substantially reduced levels. The average fold reduction at the second-instar larval stage was 5.9, while at the adult stage a 12.5-fold reduction was observed.

scholarly journals Study on the biology of groundnut bruchid, Caryedon serratus Olivier [Coleoptera: Bruchidae] on stored groundnut in Ganye area, Adamawa State, Nigeria

2020 ◽  
Vol 12 (3) ◽  
pp. 272-276
Author(s):  
C.S. Oaya
Keyword(s):  
Life Cycle ◽  
Larval Stage ◽  
Developmental Stages ◽  
Adult Stage ◽  
Pupal Stage ◽  
Male And Female ◽  
Incubation Stage ◽  
Caryedon Serratus ◽  
The Mean ◽  
Total Life

Abstract. Study on the biology of groundnut bruchid, Caryedon serratus Olivier was carried out in the Laboratory of the Department of Agricultural Technology, Adamawa State College of Agriculture, Ganye, Adamawa State from June to September, 2015. The sex of the bruchid (male and female) was assigned the sub-treatment while the period of development was the main treatment and was replicated three times. The work considered the pre-oviposition stage, incubation stage, larval stage, pupal stage, adult stage and the total life cycle of the bruchid (male and female). The experiment was carried out under Laboratory conditions at 30-35°C temperature and 70-90% relative humidity. After the experiment was established, weekly counting of the total number of eggs laid was carried out at intervals. The results showed that, the mean developmental stages in both female and male bruchids were: 6.50 and 6.00 days; 17.00 and 18.00 days; 13.50 and 13.50 days; 12.00 and 13.50 days; 48.00 and 50.00 days for incubation stage, larval stage, pupal stage, adult stage and total life cycle of the bruchids, respectively. Moreover, the mean pre-oviposition and oviposition stages in female adult bruchid were 1.50 and 5.50 days, respectively.

scholarly journals Translation initiation in Drosophila melanogaster is reduced by mutations upstream of the AUG initiator codon

1991 ◽  
Vol 11 (4) ◽  
pp. 2149-2153
Author(s):  
Y Feng ◽  
L E Gunter ◽  
E L Organ ◽  
D R Cavener
Keyword(s):  
Translation Initiation ◽  
Larval Stage ◽  
Developmental Stages ◽  
Germ Line ◽  
Adult Stage ◽  
Mutant Gene ◽  
Start Codon ◽  
Fold Reduction

The importance to in vivo translation of sequences immediately upstream of the Drosophila alcohol dehydrogenase (Adh) start codon was examined at two developmental stages. Mutations were introduced into the Adh gene in vitro, and the mutant gene was inserted into the genome via germ line transformation. An A-to-T substitution at the -3 position did not affect relative translation rates of the ADH protein at the second-instar larval stage but resulted in a 2.4-fold drop in translation of ADH at the adult stage. A second mutant gene, containing five mutations in the region -1 to -9, was designed to completely block translation initiation. However, transformant lines bearing these mutations still exhibit detectable ADH, albeit at substantially reduced levels. The average fold reduction at the second-instar larval stage was 5.9, while at the adult stage a 12.5-fold reduction was observed.

Dietary Change during Development in the Freshwater Calanoid Copepod Epischura lacustris Forbes

1986 ◽  
Vol 43 (5) ◽  
pp. 938-944 ◽  
Author(s):  
Patricia Chow-Fraser ◽  
C. Kim Wong
Keyword(s):  
Developmental Stage ◽  
Calanoid Copepod ◽  
Developmental Stages ◽  
Adult Stage ◽  
Prey Selection ◽  
Ingestion Rate ◽  
Grazing Rate ◽  
Linear Dimensions ◽  
Selection For ◽  
Omnivorous Diet

The diet of the freshwater calanoid copepod Epischura lacustris from C2 to adult stage was examined with predation experiments, grazing experiments, and stomach content analyses. There was a transition from an exclusively herbivorous diet in early copepodid stages to an omnivorous diet in adults. Laboratory predation experiments revealed that C2 and C3 were incapable of ingesting Bosmina (0.25–0.35 mm), but from C4 to C6, ingestion rate of Bosmina increased with developmental stage. The order or prey selection for adult Epischura was Bosmina over Diaptomus and Cyclops. Grazing rate on small algae (<10 μm) increased with developmental stage. Zooplankton remains were only found in the guts of stages older than C2; cladocerans and crustacean eggs were the most common zooplankton food. Algae with longest linear dimensions greater than 10 μm (e.g. Sphaerocystis, Dinobryon, and diatoms) were common in the guts of all developmental stages of Epischura. The occurrence of small unicells (<10 μm) in the guts decreased with developmental stage.

scholarly journals Complete metamorphosis of insects

2019 ◽  
Vol 374 (1783) ◽  
pp. 20190063 ◽  
Author(s):  
Jens Rolff ◽  
Paul R. Johnston ◽  
Stuart Reynolds
Keyword(s):  
Adult Stage ◽  
Pupal Stage ◽  
Life Stages ◽  
Micro Ct ◽  
Larval Form ◽  
Theme Issue ◽  
The Cost ◽  
Ephemeral Resources ◽  
Complete Metamorphosis

The majority of described hexapod species are holometabolous insects, undergoing an extreme form of metamorphosis with an intercalated pupal stage between the larva and adult, in which organs and tissues are extensively remodelled and in some cases completely rebuilt. Here, we review how and why this developmental strategy has evolved. While there are many theories explaining the evolution of metamorphosis, many of which fit under the hypothesis of decoupling of life stages, there are few clear adaptive hypotheses on why complete metamorphosis evolved. We propose that the main adaptive benefit of complete metamorphosis is decoupling between growth and differentiation. This facilitates the exploitation of ephemeral resources and enhances the probability of the metamorphic transition escaping developmental size thresholds. The evolution of complete metamorphosis comes at the cost of exposure to predators, parasites and pathogens during pupal life and requires specific adaptations of the immune system at this time. Moreover, metamorphosis poses a challenge for the maintenance of symbionts and the gut microbiota, although it may also offer the benefit of allowing an extensive change in microbiota between the larval and adult stages. The regulation of metamorphosis by two main players, ecdysone and juvenile hormone, and the related signalling cascades are now relatively well understood. The mechanics of metamorphosis have recently been studied in detail because of the advent of micro-CT and research into the role of cell death in remodelling tissues and organs. We support the argument that the adult stage must necessarily have preceded the larval form of the insect. We do not resolve the still contentious question of whether the larva of insects in general originated through the modification of existing preadult forms or through heterochrony as a modified embryonic stage (pronymph), nor whether the holometabolous pupa arose as a modified hemimetabolous final stage larva. This article is part of the theme issue ‘The evolution of complete metamorphosis’.

Aedes Mosquito: Harbinger of Dread

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Kalpana Singh ◽  
Shilpa Nandan
Keyword(s):  
Yellow Fever ◽  
Zika Virus ◽  
World Health ◽  
Life Stages ◽  
Aedes Mosquito ◽  
Holometabolous Insect ◽  
The World ◽  
Health Organization ◽  
Complete Metamorphosis ◽  
Maxillary Palps

Mosquitoes (Insecta: Diptera) are well known vector for many bacterial, viral and protozoan diseases. The chief culprits belong to mainly three genuses viz. Culex, Anopheles, Aedes. The morphology of Aedes (Diptera: Culicidae) mosquito is unique as they have pattern of light and dark bands on their leg and light and dark scales are found on thorax and abdomen. The females are distinguished by the shape of abdomen which is usually pointed at the tip and their maxillary palps are shorter than their proboscis. It is a holometabolous insect having all the four life stages of complete metamorphosis viz. egg, larvae, pupa and adult. There are about 950 species of Aedes found throughout the world. Aedes females are vector for transmitting the deadly diseases like Dengue, Yellow fever, Chikungunia and Zika virus. According to World Health Organization (W.H.O) about 50-100 million of dengue cases are reported every year.

scholarly journals Temporal Dynamics of ‘Ca. Phytoplasma mali’ Load in the Insect Vector Cacopsylla melanoneura

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 592
Author(s):  
Valentina Candian ◽  
Monia Monti ◽  
Rosemarie Tedeschi
Keyword(s):  
Host Plants ◽  
Developmental Stages ◽  
Temporal Dynamics ◽  
Control Strategies ◽  
Vector Competence ◽  
Insect Vector ◽  
Life Stages ◽  
Candidatus Phytoplasma Mali ◽  
High Infection ◽  
Cacopsylla Melanoneura

The transmission of phytoplasmas is the result of an intricate interplay involving pathogens, insect vectors and host plants. Knowledge of the vector’s competence during its lifespan allows us to define more sustainable well-timed control strategies targeted towards the most worrisome life stages. We investigated the temporal dynamics of ‘Candidatus Phytoplasma mali’ load in Cacopsylla melanoneura in the different developmental stages in Northwest Italy. The phytoplasma load in the vector was evaluated in overwintering adults, nymphs and newly emerged adults after different acquisition access periods. Moreover, we followed the multiplication of the phytoplasma during the aestivation and the overwintering period on conifers. Our results confirmed the ability of remigrants to retain the phytoplasma until the end of winter. We also highlighted the high acquisition efficiency and vector competence, based on phytoplasma load, of nymphs and newly emerged adults. Therefore, particular attention should be paid to the management of overwintered C. melanoneura as soon as they return to the orchards, but also to newly emerged adults, particularly in orchards with a high infection rate and when the migration to conifers is delayed.

scholarly journals Molecular Correlation between Larval, Deutonymph and Adult Stages of the Water Mite Arrenurus (Micruracarus) Novus

Life ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 108
Author(s):  
Pedro María Alarcón-Elbal ◽  
Ricardo García-Jiménez ◽  
María Luisa Peláez ◽  
Jose Luis Horreo ◽  
Antonio G. Valdecasas
Keyword(s):  
Culex Pipiens ◽  
Adult Stage ◽  
Gravid Female ◽  
Morphological Characters ◽  
Species Level ◽  
Life Stages ◽  
Water Mite ◽  
Molecular Correlation ◽  
The Common ◽  
Morphological Transformations

The systematics of many groups of organisms has been based on the adult stage. Morphological transformations that occur during development from the embryonic to the adult stage make it difficult (or impossible) to identify a juvenile (larval) stage in some species. Hydrachnidia (Acari, Actinotrichida, which inhabit mainly continental waters) are characterized by three main active stages—larval, deutonymph and adult—with intermediate dormant stages. Deutonymphs and adults may be identified through diagnostic morphological characters. Larvae that have not been tracked directly from a gravid female are difficult to identify to the species level. In this work, we compared the morphology of five water mite larvae and obtained the molecular sequences of that found on a pupa of the common mosquito Culex (Culex) pipiens with the sequences of 51 adults diagnosed as Arrenurus species and identified the undescribed larvae as Arrenurus (Micruracarus) novus. Further corroborating this finding, adult A. novus was found thriving in the same mosquito habitat. We established the identity of adult and deutonymph A. novus by morphology and by correlating COI and cytB sequences of the water mites at the larval, deutonymph and adult (both male and female) life stages in a particular case of ‘reverse taxonomy’. In addition, we constructed the Arrenuridae phylogeny based on mitochondrial DNA, which supports the idea that three Arrenurus subgenera are ‘natural’: Arrenurus, Megaluracarus and Micruracarus, and the somewhat arbitrary distinction of the species assigned to the subgenus Truncaturus.

Seedling vigour as a preselection criterion for short juvenile period in olive breeding

2006 ◽  
Vol 57 (4) ◽  
pp. 477 ◽  
Author(s):  
R. De la Rosa ◽  
A. I. Kiran ◽  
D. Barranco ◽  
L. León
Keyword(s):  
Adverse Effects ◽  
Adult Stage ◽  
General Context ◽  
Fruit Traits ◽  
Juvenile Period ◽  
Seedling Vigour ◽  
Breeding Programs ◽  
Early Evaluation ◽  
Selection For ◽  
Olive Breeding

The juvenile period represents a serious impediment in olive breeding programs. Seedlings with long juvenile period are of very low interest for the breeder because their evaluation considerably delays the first stages of the breeding process. For this reason, the influence of seedling vigour (measured as plant height or stem diameter) on the characteristics at the adult stage was studied to establish useful negative preselection criteria on the basis of that relationship. Olive progenies from crosses and open pollinations of 12 different parents carried out in 1998 and 1999 were evaluated in the greenhouse and, afterwards, during the first 3 years of bearing in the open field. The results obtained indicate that early evaluation and selection for juvenile period can be performed at the seedling stage in olive progenies on the basis of vigour measurements. Selection for short juvenile period was valid irrespective of parentage and, therefore, could be efficient in a general context. No relationship between juvenile period and yield or fruit traits was found so that this preselection criterion would have no adverse effects on these characters.

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