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1.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34636890

RESUMO

Hexamerins are members of the hemocyanin superfamily and play essential roles in providing amino acids and energy for the nonfeeding stages of insects. In this study, we cloned and analyzed the expression patterns of four hexamerin genes (hex 70a, hex 70b, hex 70c, and hex 110) at different worker development stages and queen diapause statuses in the bumble bee, Bombus terrestris. The results of this study showed that hex 110 has the longest open reading frame (ORF; 3,297 bp) compared to the ORFs of hex 70a (2,034 bp), hex 70b (2,067 bp), and hex 70c (2,055 bp). The putative translation product of Hex 70a, Hex 70b, Hex70c, and Hex 110 has 677, 688, 684, and 1,098aa with predicted molecular mass of 81.13, 79.69, 81.58, and 119 kDa. In the development stages of workers, the expression levels of hex 70a, hex 70b, and hex 70c increased gradually from the larval stage and exhibited high expression levels at the pink eyed and brown eyed pupae stage, whereas hex 110 exhibited the highest expression level at the larval period. Four hexamerin genes were highly expressed at the prediapause status of queen (P < 0.05), and compared to the eclosion queen, the lowest upregulation was 3.7-fold, and the highest upregulation was 1,742-fold. The expression levels of hex 70b, hex 70c, and hex 110 at diapause were significantly higher than those at postdiapause (P < 0.05). In conclusion, hexamerins may play important roles in queen diapause and metamorphosis of larval and pupal stages.


Assuntos
Abelhas , Proteínas de Insetos/genética , Animais , Abelhas/genética , Abelhas/crescimento & desenvolvimento , Abelhas/fisiologia , Diapausa/genética , Diapausa/fisiologia , Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Larva/genética , Larva/crescimento & desenvolvimento , Larva/fisiologia , Metamorfose Biológica/genética , Metamorfose Biológica/fisiologia , Pupa/genética , Pupa/crescimento & desenvolvimento , Pupa/fisiologia
2.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34718645

RESUMO

Radiation is considered as a promising insect pest control strategy for minimizing postharvest yield losses. Among various techniques, irradiation is a method of choice as it induces lethal biochemical or molecular changes that cause a downstream cascade of abrupt physiological abnormalities at the cellular level. In this study, we evaluated the effect of 60Co-γ radiation on various developmental stages of Zeugodacus cucurbitae Coquillett and subsequent carry-over effects on the progeny. For this purpose, we treated eggs with 30- and 50-Gy radiation doses of 60Co-γ. We found that radiation significantly affected cellular antioxidants, insect morphology, and gene expression profiles. Our results indicate that in response to various doses of irradiation reactive oxygen species, catalase, peroxidase, and superoxide dismutase activities were increased along with a significant increase in the malondialdehyde (MDA) content. We observed higher mortality rates during the pupal stage of the insects that hatched from irradiated eggs (50 Gy). Furthermore, the life span of the adults was reduced in response to 50 Gy radiation. The negative effects carried over to the next generation were marked by significantly lower fecundity in the F1 generation of the irradiation groups as compared to control. The radiation induced morphological abnormalities at the pupal, as well as the adult, stages. Furthermore, variations in the gene expression following irradiation are discussed. Taken together, our results signify the utility of 60Co-γ radiation for fruit fly postharvest management.


Assuntos
Apoptose/efeitos da radiação , Raios gama , Expressão Gênica/efeitos da radiação , Tephritidae/efeitos da radiação , Animais , Antioxidantes/metabolismo , Antioxidantes/efeitos da radiação , Apoptose/genética , Catalase/metabolismo , Catalase/efeitos da radiação , Radioisótopos de Cobalto/farmacologia , Controle de Insetos/métodos , Proteínas de Insetos/metabolismo , Proteínas de Insetos/efeitos da radiação , Larva/genética , Larva/metabolismo , Larva/fisiologia , Larva/efeitos da radiação , Longevidade/efeitos da radiação , Malondialdeído/metabolismo , Malondialdeído/efeitos da radiação , Peroxidase/metabolismo , Peroxidase/efeitos da radiação , Controle de Pragas/métodos , Pupa/genética , Pupa/metabolismo , Pupa/fisiologia , Pupa/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Espécies Reativas de Oxigênio/efeitos da radiação , Tephritidae/genética , Tephritidae/metabolismo , Tephritidae/fisiologia
3.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34581410

RESUMO

RNAi is an effective tool for gene function analysis and a promising strategy to provide environmentally friendly control approaches for pathogens and pests. Recent studies support the utility of bacterium-mediated RNAi as a cost-effective method for gene function study and a suitable externally applied delivery mechanism for pest control. Here, we developed a bacterium-mediated RNAi system in Spodoptera frugiperda based on four target genes, specifically, Chitinase (Sf-CHI), Chitin synthase B (Sf-CHSB), Sugar transporter SWEET1 (Sf-ST), and Hemolin (Sf-HEM). RNAi conducted by feeding larvae with bacteria expressing dsRNAs of target genes or injecting pupae and adults with bacterially synthesized dsRNA induced silencing of target genes and resulted in significant negative effects on growth and survival of S. frugiperda. However, RNAi efficiency and effects were variable among different target genes and dsRNA delivery methods. Injection of pupae with dsCHI and dsCHSB induced a significant increase in wing malformation in adults, suggesting that precise regulation of chitin digestion and synthesis is crucial during wing formation. Injection of female moths with dsHEM resulted in lower mating, fecundity, and egg hatching, signifying a critical role of Sf-HEM in the process of egg production and/or embryo development. Our collective results demonstrate that bacterium-mediated RNAi presents an alternative technique for gene function study in S. frugiperda and a potentially effective strategy for control of this pest, and that Sf-CHI, Sf-CHSB, Sf-ST, and Sf-HEM encoding genes can be potent targets.


Assuntos
Interferência de RNA , RNA de Cadeia Dupla/farmacologia , Spodoptera , Animais , Bactérias/genética , Quitinases/efeitos dos fármacos , Quitinases/genética , Fertilidade/efeitos dos fármacos , Genes de Insetos/efeitos dos fármacos , Imunoglobulinas/efeitos dos fármacos , Imunoglobulinas/genética , Proteínas de Insetos/efeitos dos fármacos , Proteínas de Insetos/genética , Larva/efeitos dos fármacos , Larva/genética , Larva/fisiologia , Controle Biológico de Vetores , Pupa/efeitos dos fármacos , Pupa/genética , Pupa/fisiologia , Reprodução/efeitos dos fármacos , Spodoptera/efeitos dos fármacos , Spodoptera/genética , Spodoptera/fisiologia
4.
Sci Rep ; 11(1): 15787, 2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34349192

RESUMO

Recently, we reported a novel mode of action in monarch butterfly (Danaus plexippus) larvae exposed to neonicotinoid insecticides: arrest in pupal ecdysis following successful larval ecdysis. In this paper, we explore arrested pupal ecdysis in greater detail and propose adverse outcome pathways to explain how neonicotinoids cause this effect. Using imidacloprid as a model compound, we determined that final-instar monarchs, corn earworms (Helicoverpa zea), and wax moths (Galleria mellonella) showed high susceptibility to arrested pupal ecdysis while painted ladies (Vanessa cardui) and red admirals (Vanessa atalanta) showed low susceptibility. Fall armyworms (Spodoptera frugiperda) and European corn borers (Ostrinia nubilalis) were recalcitrant. All larvae with arrested ecdysis developed pupal cuticle, but with incomplete shedding of larval cuticle and unexpanded pupal appendages; corn earworm larvae successfully developed into adults with unexpanded appendages. Delayed initiation of pupal ecdysis was also observed with treated larvae. Imidacloprid exposure was required at least 26 h prior to pupal ecdysis to disrupt the molt. These observations suggest neonicotinoids may disrupt the function of crustacean cardioactive peptide (CCAP) neurons, either by directly acting on their nicotinic acetylcholine receptors or by acting on receptors of inhibitory neurons that regulate CCAP activity.


Assuntos
Inseticidas/efeitos adversos , Muda/efeitos dos fármacos , Neonicotinoides/efeitos adversos , Nitrocompostos/efeitos adversos , Pupa/efeitos dos fármacos , Pupa/fisiologia , Animais , Larva/efeitos dos fármacos , Larva/fisiologia , Neurônios/metabolismo , Neurônios/fisiologia , Neuropeptídeos/metabolismo , Receptores Nicotínicos/metabolismo
5.
J Med Entomol ; 58(6): 2247-2254, 2021 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-34279664

RESUMO

To better understand the population dynamics and dispersal ability of insect species, it is often helpful to derive a life table containing fundamental demographic data. The aim of this study was to determine a life table for the predatory necrophagous species Synthesiomyia nudiseta (van der Wulp, 1883) on a pig liver diet and under controlled laboratory conditions (29.5 ± 2. 5°C, RH 50 ± 15%, and a photoperiod of 12:12). This species has medical and veterinary importance and its distribution extends in tropical and subtropical areas and now it has been established in the southwestern of Europe. The mean adult longevity was 36. 18 ± 2. 06 d and the net reproduction rate, R, was 27.65 offspring/female, the mean generation time, T, was 22. 09 d, the finite rate of increase, λ, was 1. 16 d-1, and the intrinsic rate of increase, r, was 0. 15 d-1. These results indicate that S. nudiseta cannot be considered an r-strategist as the most common synanthropic necrophagous blowflies due to its predatory behavior; however, its invasive and colonist abilities are discussed. This is the first life table study of this species from Palearctic region to analyze the effect of its dispersal ability.


Assuntos
Distribuição Animal , Muscidae/fisiologia , Animais , Larva/crescimento & desenvolvimento , Larva/fisiologia , Tábuas de Vida , Muscidae/crescimento & desenvolvimento , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Espanha
6.
J Chem Ecol ; 47(8-9): 788-798, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34269959

RESUMO

There is increasing evidence that microorganisms, particularly fungi and bacteria, emit volatile compounds that mediate the foraging behaviour of insects and therefore have the potential to affect key ecological relationships. However, to what extent microbial volatiles affect the olfactory response of insects across different trophic levels remains unclear. Adult parasitoids use a variety of chemical stimuli to locate potential hosts, including those emitted by the host's habitat, the host itself, and microorganisms associated with the host. Given the great capacity of parasitoids to utilize and learn odours to increase foraging success, parasitoids of eggs, larvae, or pupae may respond to the same volatiles the adult stage of their hosts use when locating their resources, but compelling evidence is still scarce. In this study, using Saccharomyces cerevisiae we show that Trichopria drosophilae, a pupal parasitoid of Drosophila species, is attracted to the same yeast volatiles as their hosts in the adult stage, i.e. acetate esters. Parasitoids significantly preferred the odour of S. cerevisiae over the blank medium in a Y-tube olfactometer. Deletion of the yeast ATF1 gene, encoding a key acetate ester synthase, decreased attraction of T. drosophilae, while the addition of synthetic acetate esters to the fermentation medium restored parasitoid attraction. Bioassays with individual compounds revealed that the esters alone were not as attractive as the volatile blend of S. cerevisiae, suggesting that other volatile compounds also contribute to the attraction of T. drosophilae. Altogether, our results indicate that pupal parasitoids respond to the same volatiles as the adult stage of their hosts, which may aid them in locating oviposition sites.


Assuntos
Himenópteros/fisiologia , Saccharomyces cerevisiae/química , Compostos Orgânicos Voláteis/química , Animais , Comportamento Animal/efeitos dos fármacos , Ésteres/química , Ésteres/metabolismo , Ésteres/farmacologia , Interações Hospedeiro-Parasita/efeitos dos fármacos , Himenópteros/crescimento & desenvolvimento , Análise de Componente Principal , Proteínas/genética , Proteínas/metabolismo , Pupa/efeitos dos fármacos , Pupa/fisiologia , Saccharomyces cerevisiae/metabolismo , Compostos Orgânicos Voláteis/farmacologia
7.
Elife ; 102021 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-34236312

RESUMO

Identifying neural substrates of behavior requires defining actions in terms that map onto brain activity. Brain and muscle activity naturally correlate via the output of motor neurons, but apart from simple movements it has been difficult to define behavior in terms of muscle contractions. By mapping the musculature of the pupal fruit fly and comprehensively imaging muscle activation at single-cell resolution, we here describe a multiphasic behavioral sequence in Drosophila. Our characterization identifies a previously undescribed behavioral phase and permits extraction of major movements by a convolutional neural network. We deconstruct movements into a syllabary of co-active muscles and identify specific syllables that are sensitive to neuromodulatory manipulations. We find that muscle activity shows considerable variability, with sequential increases in stereotypy dependent upon neuromodulation. Our work provides a platform for studying whole-animal behavior, quantifying its variability across multiple spatiotemporal scales, and analyzing its neuromodulatory regulation at cellular resolution.


Assuntos
Drosophila/fisiologia , Músculos/anatomia & histologia , Músculos/fisiologia , Pupa/fisiologia , Animais , Comportamento Animal , Encéfalo/fisiologia , Biologia Computacional , Drosophila melanogaster/fisiologia , Hormônios de Invertebrado/fisiologia , Larva/fisiologia , Muda , Neurônios Motores , Receptores de Peptídeos
8.
Malar J ; 20(1): 259, 2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34107949

RESUMO

BACKGROUND: Despite increasing documentation of insecticide resistance in malaria vectors against public health insecticides in sub-Saharan Africa, there is a paucity of information on the potential fitness costs of pyrethroid resistance in malaria vectors, which is important in improving the current resistant management strategies. This study aimed to assess the fitness cost effects of insecticide resistance on the development and survival of immature Anopheles gambiae from western Kenya. METHODS: Two-hour old, first instar larvae (L1) were introduced and raised in basins containing soil and rainwater in a semi-field set-up. Each day the number of surviving individuals per larval stage was counted and their stage of development were recorded until they emerged as adults. The larval life-history trait parameters measured include mean larval development time, daily survival and pupal emergence. Pyrethroid-resistant colony of An. gambiae sensu stricto and susceptible colony originating from the same site and with the same genetic background were used. Kisumu laboratory susceptible colony was used as a reference. RESULTS: The resistant colony had a significantly longer larval development time through the developmental stages than the susceptible colony. The resistant colony took an average of 2 days longer to develop from first instar (L1) to fourth instar (L4) (8.8 ± 0.2 days) compared to the susceptible colony (6.6 ± 0.2 days). The development time from first instar to pupa formation was significantly longer by 3 days in the resistant colony (10.28 ± 0.3 days) than in susceptible colony (7.5 ± 0.2 days). The time from egg hatching to adult emergence was significantly longer for the resistant colony (12.1 ± 0.3 days) than the susceptible colony (9.6 ± 0.2 days). The pupation rate (80%; 95% (CI: 77.5-83.6) vs 83.5%; 95% (CI: 80.6-86.3)) and adult emergence rate (86.3% vs 92.8%) did not differ between the resistant and susceptible colonies, respectively. The sex ratio of the females to males for the resistant (1:1.2) and susceptible colonies (1:1.07) was significantly different. CONCLUSION: The study showed that pyrethroid resistance in An. gambiae had a fitness cost on their pre-imaginal development time and survival. Insecticide resistance delayed the development and reduced the survivorship of An. gambiae larvae. The study findings are important in understanding the fitness cost of insecticide resistance vectors that could contribute to shaping resistant management strategies.


Assuntos
Anopheles/fisiologia , Aptidão Genética , Resistência a Inseticidas , Animais , Anopheles/genética , Anopheles/crescimento & desenvolvimento , Inseticidas/farmacologia , Quênia , Larva/genética , Larva/crescimento & desenvolvimento , Larva/fisiologia , Pupa/genética , Pupa/crescimento & desenvolvimento , Pupa/fisiologia
9.
J Am Mosq Control Assoc ; 37(1): 10-19, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33857319

RESUMO

Mosquito-borne diseases are a major public health concern in the Caribbean. Domestic water-storage containers are preferred breeding habitats for synanthropic mosquito species, among which Aedes aegypti stands out due to its role in arbovirus transmission. To determine the microenvironmental features associated with container-dwelling mosquitoes, a house-to-house cross-sectional entomological survey was carried out in 9 Dominican provinces affected by Zika virus in 2016. All containers with the potential to store water were sampled, all immature mosquitoes were collected, and information on the type, capacity, volume of stored water, building material, presence of flowers, and house location was documented. The specimens were identified and larval indices (House index [HI], Container index [CI], Breteau index [BI], and Ae. aegypti Breeding Percentage) were applied. A total of 665 dwellings were surveyed across 30 neighborhoods. A total of 1,420 water-filled container habitats were sampled, 19.3% of which harbored immature mosquitoes of 5 species, including 4 important vectors. The dominance of Ae. aegypti was marked, as it was present in all sampled neighborhoods, inhabiting 272 containers (19.1%). Larval indices were higher than the threshold values accepted (5% for the HI and BI, and 3% for the CI) in almost all neighborhoods. The presence of Aedes spp. was associated with the serviceability of water-holding containers (χ2 = 16.56522; P < 0.001), and the difference in volume between water-holding containers was associated with the presence of Aedes spp. infection (χ2 = 4; P < 0.001), the containers up to 5 liters being the most infested. This is the first entomological research based on synanthropic mosquito breeding habitats that cover urban areas of the 3 macro-regions of the Dominican Republic.


Assuntos
Distribuição Animal , Culicidae/fisiologia , Meio Ambiente , Animais , Culicidae/crescimento & desenvolvimento , República Dominicana , Feminino , Larva/crescimento & desenvolvimento , Larva/fisiologia , Masculino , Pupa/crescimento & desenvolvimento , Pupa/fisiologia
10.
Sci Rep ; 11(1): 9133, 2021 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-33911144

RESUMO

Cell recapping is a behavioural trait of honeybees (Apis mellifera) where cells with developing pupae are uncapped, inspected, and then recapped, without removing the pupae. The ectoparasitic mite Varroa destructor, unarguably the most destructive pest in apiculture world-wide, invades the cells of developing pupae to feed and reproduce. Honeybees that target mite infested cells with this behaviour may disrupt the reproductive cycle of the mite. Hence, cell recapping has been associated with colony-level declines in mite reproduction. In this study we compared the colony-level efficacy of cell recapping (how often infested cells are recapped) to the average mite fecundity in A. mellifera. Our study populations, known to be adapted to V. destructor, were from Avignon, France, Gotland, Sweden, and Oslo, Norway, and were compared to geographically similar, treated control colonies. The results show that colonies with a higher recapping efficacy also have a lower average mite reproductive success. This pattern was likely driven by the adapted populations as they had the largest proportion of highly-targeted cell recapping. The consistent presence of this trait in mite-resistant and mite-susceptible colonies with varying degrees of expression may make it a good proxy trait for selective breeding on a large scale.


Assuntos
Abelhas/parasitologia , Varroidae/crescimento & desenvolvimento , Animais , Abelhas/crescimento & desenvolvimento , Feminino , Interações Hospedeiro-Parasita , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Reprodução , Varroidae/fisiologia
11.
Elife ; 102021 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-33885361

RESUMO

Vertebrate macrophages are a highly heterogeneous cell population, but while Drosophila blood is dominated by a macrophage-like lineage (plasmatocytes), until very recently these cells were considered to represent a homogeneous population. Here, we present our identification of enhancer elements labelling plasmatocyte subpopulations, which vary in abundance across development. These subpopulations exhibit functional differences compared to the overall population, including more potent injury responses and differential localisation and dynamics in pupae and adults. Our enhancer analysis identified candidate genes regulating plasmatocyte behaviour: pan-plasmatocyte expression of one such gene (Calnexin14D) improves wound responses, causing the overall population to resemble more closely the subpopulation marked by the Calnexin14D-associated enhancer. Finally, we show that exposure to increased levels of apoptotic cell death modulates subpopulation cell numbers. Taken together this demonstrates macrophage heterogeneity in Drosophila, identifies mechanisms involved in subpopulation specification and function and facilitates the use of Drosophila to study macrophage heterogeneity in vivo.


Assuntos
Apoptose , Drosophila melanogaster/fisiologia , Macrófagos/fisiologia , Animais , Apoptose/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Expressão Gênica , Larva/crescimento & desenvolvimento , Larva/fisiologia , Pupa/crescimento & desenvolvimento , Pupa/fisiologia
12.
J Vis Exp ; (169)2021 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-33779612

RESUMO

The control of such human diseases as dengue, Zika, and chikungunya relies on the control of their vector, the Aedes aegypti mosquito, because there is no prevention. Control of mosquito vectors can rely on chemicals applied to the immature and adult stages, which can contribute to the mortality of non-targets and more importantly, lead to insecticide resistance in the vector. The sterile insect technique (SIT) is a method of controlling populations of pests through the release of sterilized adult males that mate with wild females to produce non-viable offspring. This paper describes the process of producing sterile males for use in an operational SIT program for the control of Aedes aegypti mosquitoes. Outlined here are the steps used in the program including rearing and maintaining a colony, separating male and female pupae, irradiating and marking adult males, and shipping Aedes aegypti males to the release site. Also discussed are procedural caveats, program limitations, and future objectives.


Assuntos
Aedes/fisiologia , Fertilidade/efeitos da radiação , Resistência a Inseticidas , Controle de Mosquitos/métodos , Mosquitos Vetores/fisiologia , Pupa/fisiologia , Esterilização Reprodutiva/métodos , Aedes/efeitos da radiação , Animais , Feminino , Humanos , Masculino , Mosquitos Vetores/efeitos da radiação , Pupa/efeitos da radiação
13.
Arch Insect Biochem Physiol ; 107(1): e21782, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33724519

RESUMO

In Leptinotarsa decemlineata, a final-instar wandering larva typically undergoes an ontogenetic niche shift (ONS), from potato plant during the foraging stage to its pupation site below ground. Using high-throughput sequencing of the bacterial 16S ribosomal RNA gene, we determined the hypothesis that the L. decemlineata pupae harbor stage-specific bacteria to meet the physiological requirements for underground habitat. We identified 34 bacterial phyla, comprising 73 classes, 208 orders, 375 families, and 766 genera in the collected specimens. Microbes across phyla Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes were enriched in the pupae, while those in the phylum Proteobacteria, Tenericutes, Firmicutes, and Bacteroidetes dominated in the larvae and adults. A total of 18 genera, including Blastococcus, Corynebacterium_1, Gordonia, Microbacterium, Nocardia, Nocardioides, Rhodococcus, Solirubrobacter, Tsukamurella, Enterococcus, Acinetobacter, Escherichia_Shigella, Lysobacter, Pseudomonas, and Stenotrophomonas, were specifically distributed in pupae. Moreover, soil sterilizing removed a major portion of bacteria in pupae. Specifically, both Enterococcus and Pseudomonas were eliminated in the soil sterilizing and antibiotic-fed beetle groups. Furthermore, the pupation rate and fresh pupal weight were similar, whereas the emergence rate and adult weight were decreased in the antibiotic-fed beetles, compared with controls. The results demonstrate that a switch of bacterial communities occurs in the pupae; the pupal-specific bacteria genera are mainly originated from soil; this bacterial biodiversity improves pupa performance in soil. Our results provide new insight into the evolutionary fitness of L. decemlineata to different environmental niches.


Assuntos
Besouros/microbiologia , Microbiota , Pupa/microbiologia , Animais , Bactérias/classificação , Besouros/fisiologia , Ecossistema , Genes Bacterianos , Larva/microbiologia , Larva/fisiologia , Metagenômica/métodos , Metamorfose Biológica , Microbiota/genética , Pupa/fisiologia , RNA Ribossômico 16S/genética
14.
J Insect Physiol ; 130: 104200, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33607160

RESUMO

Holometabolous insects exhibit complex life cycles in which both morphology and ecological niche change dramatically during development. In the larval stage, many insects have soft, slow-moving bodies and poor vision, limiting their ability to respond to environmental threats. Artificial light at night (ALAN) is an environmental perturbation known to severely impact the fitness of adult insects by disrupting both temporal and spatial orientation. The impact of ALAN on earlier life stages, however, is largely unknown. We conducted a series of laboratory experiments to investigate how two distinct forms of ALAN affect the development and movement of immature Photuris sp. and Photinus obscurellus fireflies. Although long-term exposure to dim light at night (dLAN), akin to urban skyglow, did not impact overall survivorship or duration of egg, larval, and pupal stages in either species, it did accelerate weight gain in early-instar Photuris larvae. Late-instar Photuris exposed to point sources of ALAN at the start of their nightly foraging period were also significantly more likely to burrow beneath the soil surface, rather than disperse across it. ALAN may therefore impede dispersal of firefly larvae away from illuminated areas, which could have downstream consequences for the reproductive fitness of adults.


Assuntos
Distribuição Animal , Vaga-Lumes/fisiologia , Luz/efeitos adversos , Iluminação/efeitos adversos , Animais , Vaga-Lumes/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Movimento , Óvulo/crescimento & desenvolvimento , Óvulo/fisiologia , Pupa/crescimento & desenvolvimento , Pupa/fisiologia
15.
BMC Biol ; 19(1): 39, 2021 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-33632227

RESUMO

BACKGROUND: Krüppel homolog 1 (Kr-h1) is a critical transcription factor for juvenile hormone (JH) signaling, known to play a key role in regulating metamorphosis and adult reproduction in insects. Kr-h1 can also be induced by molting hormone 20-hydroxyecdysone (20E), however, the underlying mechanism of 20E-induced Kr-h1 expression remains unclear. In the present study, we investigated the molecular mechanism of Kr-h1 induction by 20E in the reproductive system of a model lepidopteran insect, Bombyx mori. RESULTS: Developmental and tissue-specific expression analysis revealed that BmKr-h1 was highly expressed in ovaries during the late pupal and adult stages and the expression was induced by 20E. RNA interference (RNAi)-mediated depletion of BmKr-h1 in female pupae severely repressed the transcription of vitellogenin receptor (VgR), resulting in the reduction in vitellogenin (Vg) deposition in oocytes. BmKr-h1 specifically bound the Kr-h1 binding site (KBS) between - 2818 and - 2805 nt upstream of BmVgR and enhanced the transcription of BmVgR. A 20E cis-regulatory element (CRE) was identified in the promoter of BmKr-h1 and functionally verified using luciferase reporter assay, EMSA and DNA-ChIP. Using pull-down assays, we identified a novel transcription factor B. mori Kr-h1 regulatory protein (BmKRP) that specifically bound the BmKr-h1 CRE and activated its transcription. CRISPR/Cas9-mediated knockout of BmKRP in female pupae suppressed the transcription of BmKr-h1 and BmVgR, resulting in arrested oogenesis. CONCLUSION: We identified BmKRP as a new transcription factor mediating 20E regulation of B. mori oogenesis. Our data suggests that induction of BmKRP by 20E regulates BmKr-h1 expression, which in turn induces BmVgR expression to facilitate Vg uptake and oogenesis.


Assuntos
Bombyx/fisiologia , Ecdisterona/metabolismo , Regulação da Expressão Gênica , Proteínas de Insetos/genética , Oócitos/fisiologia , Oogênese/genética , Animais , Bombyx/genética , Bombyx/crescimento & desenvolvimento , Feminino , Proteínas de Insetos/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Pupa/crescimento & desenvolvimento , Pupa/fisiologia
16.
Parasit Vectors ; 14(1): 46, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33436074

RESUMO

BACKGROUND: The main challenge to the successful mass-rearing of the tsetse fly in insectaries, especially in Africa, is a sustainable supply of high-quality blood meals. As such, the collection of high-quality blood in large quantities can be an important constraint to production. One possible strategy to lessen the impact of this constraint is to modify the blood-feeding frequency. In the study reported here, we evaluated the effect of three blood-feeding frequencies on the colony performance of Glossina palpalis gambiensis, a riverine tsetse fly species. METHODS: The effect of three, four and six blood-feedings per week on female survival and productivity were evaluated over a 30-day period. Progeny emergence rate and flight ability were also evaluated. RESULTS: Female survival was significantly higher in flies fed four times per week (87%) than in those fed three (72%) and six times per week (78%; P < 0.05). Productivity was similar between flies fed four and six times per week (457 and 454 larvae) but significantly reduced in flies fed three times per week (280 larvae produced; P < 0.05). Both emergence rate and flight ability rate were also similar between flies fed four times per week (97 and 94%, respectively) and six times per week (96 and 97%, respectively), but they were significantly reduced when flies were fed three times per week (89 and 84%, respectively; P < 0.05). CONCLUSIONS: Blood-feeding frequency could be reduced from six times per week to four times per week without affecting mass-rearing production and progeny quality. The implications of these results on tsetse mass-rearing production are discussed.


Assuntos
Sangue , Comportamento Alimentar , Moscas Tsé-Tsé/fisiologia , Animais , Feminino , Larva/fisiologia , Gado/sangue , Gado/parasitologia , Masculino , Pupa/fisiologia , Reprodução
17.
J Therm Biol ; 95: 102808, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33454038

RESUMO

The expansion of the invasive mosquito Aedes aegypti L. (Diptera: Culicidae) towards temperate regions in the Americas is causing concern because of its public health implications. As for other insects, the distribution limits of Ae. aegypti have been suggested to be related to minimum temperatures and to be controlled mainly by cold tolerance. The aim of this study was to assess the daily mortality of immature stages of Ae. aegypti under natural winter conditions in Buenos Aires, Argentina, in relation to preceding thermal conditions. The experiment was performed outdoors, and one cohort of larvae was started each week for 16 weeks, and reared up to the emergence of the adults. Three times a week, larvae, pupae and emerged adults were counted, and these data were used to calculate the daily mortality of larvae, pupae and adults and to analyze their relationship with thermal conditions. The results showed that mortality was generally low, with a few peaks of high mortality after cold front events. The mortality of pupae and larvae showed a higher correlation with the cooling degree hours of previous days than with the minimum, maximum or mean temperatures. Pupae and adults showed to be more vulnerable to low temperatures than larvae. A delay in mortality was observed in relation to the low temperature events, with a proportion of individuals dying in a later stage after the end of the cold front. These results suggest that thermal conditions during cold fronts in Buenos Aires are close to the tolerance limit of the local Ae. aegypti population. The wide range of responses of different individuals suggests that low winter temperatures may constitute a selective force, leading the population to a higher tolerance to low temperatures, which might favor the further expansion of this species towards colder regions.


Assuntos
Aclimatação , Aedes/fisiologia , Resposta ao Choque Frio , Aedes/crescimento & desenvolvimento , Animais , Biomassa , Temperatura Baixa , Larva/fisiologia , Pupa/fisiologia , Estações do Ano
18.
J Med Entomol ; 58(1): 333-342, 2021 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-32785582

RESUMO

We provide the first evidence of a recent invasion of Aedes aegypti (Linnaeus in Hasselquist, 1762) and Aedes albopictus (Skuse 1894), followed by dengue virus, in tropical montane cities in south-eastern Brazil, Mariana, and Ouro Preto, at mid and high altitudes, respectively. Long-term temperature variation, dengue public data, and sampling of immature and adult mosquitoes (ovitraps and mosquitraps) in contrasting habitats were used to explain the distribution of Aedes in what in these two cities. From 1961 to 2014, the annual temperature increased significantly due to increases in winter temperatures. In the 1990s/2000s, the winter temperature was 1.3°C warmer than in the 1960s, when it varied from 21.2 to 18.9°C. After 2007, the winter temperatures increased and ranged from 21.6 to 21.3°C. The first autochthonous dengue cases in Mariana and Ouro Preto were in 2007, followed by few occurrences until in 2012, when the mean numbers increased three-fold, and peak at 2013. The continuous 'warmer winter' may have trigged the Aedes invasion. Aedes species benefited from higher winter temperatures, which was an important driver of their invasion of the state of Minas Gerais in the 1980s and, more recently, in the remaining montane urban habitats in this region. In both 2009 and 2011, we found more Aedes in Mariana than Ouro Preto, and more Ae. albopictus in green areas and Ae. aegypti in houses, the expected pattern for well-established populations.


Assuntos
Aedes/fisiologia , Distribuição Animal , Ecossistema , Tempo (Meteorologia) , Aedes/crescimento & desenvolvimento , Altitude , Animais , Brasil , Cidades , Clima , Larva/crescimento & desenvolvimento , Larva/fisiologia , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Estações do Ano
19.
Bull Entomol Res ; 111(2): 238-245, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32967744

RESUMO

With the purpose of broadening knowledge on the evolution of life history strategies and behaviour of fruit flies within the tribe Carpomyini, the natural history and mating behaviour of the poorly known species Rhagoletotrypeta pastranai Aczél, are described for the first time. Larvae of R. pastranai were recovered from infested Celtis tala Gillies ex Planch and Celtis iguanaea (Jacq.) Sarg. during a 2-month fruiting period. Adults emerged from the recovered pupae after an average of 144.9 ± 3.9 days for females and 143.2 ± 3.38 days for males, suggesting that most individuals became dormant. Results of a variable winter length study suggested that environmental factors other than winter length may regulate dormancy/diapause duration in this subtropical species. Under laboratory conditions, R. pastranai adults lived an average of 51.13 ± 3.06 days in case of females and 48.08 ± 3.76 days in case of males, and required 5-15 days to reach sexual maturity. Behavioural observations under confinement revealed scarce sexual activity but sufficed to determine that, as in other members of the tribe Carpomyini, R. pastranai exhibits a male resource defence mating system. We discuss our findings emphasizing the importance of documenting the natural history and behaviour of unknown species of family Tephritidae and additionally, we highlight the necessity of future research to understand factors regulating dormancy/diapause and the evolution of life history strategies and sexual behaviour of subtropical species.


Assuntos
Tephritidae/fisiologia , Animais , Evolução Biológica , Diapausa , Larva/crescimento & desenvolvimento , Larva/fisiologia , Traços de História de Vida , Masculino , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Reprodução , Estações do Ano , Comportamento Sexual Animal , Tephritidae/crescimento & desenvolvimento
20.
Bull Entomol Res ; 111(3): 257-269, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32807245

RESUMO

Helicoverpa armigera is a pest of several crops causing significant economic impact. We evaluated the insect development on different vegetative and reproductive structures of cotton, maize, and soybean compared to artificial diet. One hundred individuals were evaluated per structure (cotton leaves and bolls; maize leaves, grains, and silk; soybean leaves and pods) and artificial diet. Centesimal analyses were performed on quantifiable nutrient contents in diets. The viability of immatures (eggs, larvae, and pupae) ranged from 30% on maize leaf to 74% on cotton bolls, while on the artificial diet, it was 70%. Maize, cotton, and soybean leaves provided viability of 30, 37, and 42%, respectively, revealing these leaves tissues are less favorable to the development of H. armigera immatures compared to 'reproductive tissues'. Centesimal composition of diets compared 14 common components in all diets, which correlated significantly with larval and pupal stages and/or pupal weight. Of the 12 dietary components that significantly affected larval development time, half were negatively correlated, indicating a decrease in developmental time from their increments. In general, when insects were confined separately to substrates, the artificial diet was the most suitable for H. armigera development compared to the evaluated natural diets. However, in natural conditions, the variability of available hosts must be considered. In addition, it is acceptable for moths to select more suitable hosts for oviposition, while their larvae move to other more suitable tissues of the same plant or even migrate to other plants.


Assuntos
Ração Animal/análise , Mariposas , Animais , Peso Corporal , Produtos Agrícolas , Dieta , Comportamento Alimentar , Gossypium , Larva/crescimento & desenvolvimento , Larva/fisiologia , Mariposas/crescimento & desenvolvimento , Mariposas/fisiologia , Nutrientes/análise , Oviposição , Controle de Pragas , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Reprodução , Soja , Zea mays
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