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Journal of Evolutionary Biology Nov 2013Senescence, a decline in survival and reproductive prospects with age, is controlled by hormones. In insects, juvenile hormone (JH) is involved in senescence with...
Senescence, a decline in survival and reproductive prospects with age, is controlled by hormones. In insects, juvenile hormone (JH) is involved in senescence with captive individuals, but its effect under natural conditions is unknown. We have addressed this gap by increasing JH levels in young and old wild males of the damselfly Hetaerina americana. We assessed survival in males that were treated with a JH analogue (methoprene), which is known to promote sexual activity, and an immune challenge, which is known to promote terminal investment in reproduction in the studied species. We replicated the same procedure in captivity (to control for environmental variation), where males were deprived of any activity or food. We expected old males to show the lowest survival after being treated with JH and immune-challenged, because the effect of terminal investment on senescence would be exacerbated by JH. However, this should be the case for wild animals, but not for captive animals, as the effects of JH and immune challenge should lead to an increase in high energetic-demanding activities only occurring in the wild. Old animals died sooner compared with young animals in both the wild and captivity, confirming that males are subject to senescence. In wild but not captive animals, JH decreased survival in young males and increased it in old males, confirming that JH is sensitive to the environment when shaping animal senescence. Immune challenge had no effect on survival, suggesting no effect of terminal investment on senescence. Additionally, contrary to the expected effects of terminal investment, with an immune challenge, recapture rates increased in young males and decreased in old males. Our results show that male senescence in the wild is mediated by JH and that terminal investment does not cause senescence. One explanation is that animals undergoing senescence and terminal investment modify their feeding behaviour to compensate for their physiological state.
Topics: Aging; Animals; Juvenile Hormones; Male; Methoprene; Odonata; Sexual Behavior, Animal
PubMed: 24016249
DOI: 10.1111/jeb.12241 -
PloS One 2016Scale insects have evolved extreme sexual dimorphism, as demonstrated by sedentary juvenile-like females and ephemeral winged males. This dimorphism is established...
Scale insects have evolved extreme sexual dimorphism, as demonstrated by sedentary juvenile-like females and ephemeral winged males. This dimorphism is established during the post-embryonic development; however, the underlying regulatory mechanisms have not yet been examined. We herein assessed the role of juvenile hormone (JH) on the diverging developmental pathways occurring in the male and female Japanese mealybug Planococcus kraunhiae (Kuwana). We provide, for the first time, detailed gene expression profiles related to JH signaling in scale insects. Prior to adult emergence, the transcript levels of JH acid O-methyltransferase, encoding a rate-limiting enzyme in JH biosynthesis, were higher in males than in females, suggesting that JH levels are higher in males. Furthermore, male quiescent pupal-like stages were associated with higher transcript levels of the JH receptor gene, Methoprene-tolerant and its co-activator taiman, as well as the JH early-response genes, Krüppel homolog 1 and broad. The exposure of male juveniles to an ectopic JH mimic prolonged the expression of Krüppel homolog 1 and broad, and delayed adult emergence by producing a supernumeral pupal stage. We propose that male wing development is first induced by up-regulated JH signaling compared to female expression pattern, but a decrease at the end of the prepupal stage is necessary for adult emergence, as evidenced by the JH mimic treatments. Furthermore, wing development seems linked to JH titers as JHM treatments on the pupal stage led to wing deformation. The female pedomorphic appearance was not reflected by the maintenance of high levels of JH. The results in this study suggest that differential variations in JH signaling may be responsible for sex-specific and radically different modes of metamorphosis.
Topics: Animals; Female; Genes, Insect; Genetic Variation; Hemiptera; Juvenile Hormones; Kruppel-Like Transcription Factors; Male; Molting; Sex Characteristics; Signal Transduction; Transcriptome
PubMed: 26894583
DOI: 10.1371/journal.pone.0149459 -
Scientific Reports Oct 2020Insecticide resistance has recently become a serious problem in the agricultural field. Development of insecticides with new mechanisms of action is essential to...
Insecticide resistance has recently become a serious problem in the agricultural field. Development of insecticides with new mechanisms of action is essential to overcome this limitation. Juvenile hormone (JH) is an insect-specific hormone that plays key roles in maintaining the larval stage of insects. Hence, JH signaling pathway is considered a suitable target in the development of novel insecticides; however, only a few JH signaling inhibitors (JHSIs) have been reported, and no practical JHSIs have been developed. Here, we established a high-throughput screening (HTS) system for exploration of novel JHSIs using a Bombyx mori cell line (BmN_JF&AR cells) and carried out a large-scale screening in this cell line using a chemical library. The four-step HTS yielded 69 compounds as candidate JHSIs. Topical application of JHSI48 to B. mori larvae caused precocious metamorphosis. In ex vivo culture of the epidermis, JHSI48 suppressed the expression of the Krüppel homolog 1 gene, which is directly activated by JH-liganded receptor. Moreover, JHSI48 caused a parallel rightward shift in the JH response curve, suggesting that JHSI48 possesses a competitive antagonist-like activity. Thus, large-scale HTS using chemical libraries may have applications in development of future insecticides targeting the JH signaling pathway.
Topics: Animals; Bombyx; High-Throughput Screening Assays; Insecticides; Juvenile Hormones; Kruppel-Like Transcription Factors; Signal Transduction
PubMed: 33110116
DOI: 10.1038/s41598-020-75386-x -
Recent Progress in Hormone Research 1968
Review
Topics: Animals; Chromatography, Gas; Chromatography, Thin Layer; Ecdysone; Insecta; Invertebrate Hormones; Juvenile Hormones; Metamorphosis, Biological; Spectrum Analysis
PubMed: 4882329
DOI: 10.1016/b978-1-4831-9827-9.50018-6 -
General and Comparative Endocrinology Nov 1977
Comparative Study
Topics: Animals; Corpora Allata; Dose-Response Relationship, Drug; Female; Grasshoppers; Juvenile Hormones; Male; Oocytes; Oogenesis; Oviducts
PubMed: 924134
DOI: 10.1016/0016-6480(77)90060-0 -
Pest Management Science Mar 2023Feeding by pests is one of the most important reasons for reductions in agricultural crop yield. This study aimed to reveal how juvenile hormone (JH) participates in...
BACKGROUND
Feeding by pests is one of the most important reasons for reductions in agricultural crop yield. This study aimed to reveal how juvenile hormone (JH) participates in larval feeding regulation of the Asian corn borer Ostrinia furnacalis.
RESULTS
Larvae of O. furnacalis exhibit a daily circadian feeding rhythm, with a peak at ZT18 and a trough at ZT6 under both photoperiod (LD) and constant dark (DD) conditions, which may be eliminated by application of fenoxycarb, a JH active analogue. JH negatively regulates larval feeding as a downstream factor of neuropeptide F (NPF), in which knocking down JH increases larval feeding amount along with body weight and length. The production of JH in the brain-corpora cardiaca-corpora allata (brain-CC-CA) is regulated by brain NPF rather than gut NPF, which was demonstrated in Drosophila larvae through GAL4/UAS genetic analysis. In addition, feeding regulation of JH is closely related to energy homeostasis in the fat body by inhibiting energy storage and promoting degradation. The JH analogue fenoxycarb is an effective pesticide against O. furnacalis, controlling feeding and metabolism.
CONCLUSION
The brain NPF system regulates JH, with functions in food consumption, feeding rhythms, energy homeostasis and body size. This study provides an important basis for understanding the feeding mechanism and potential pest control of O. furnacalis. © 2022 Society of Chemical Industry.
Topics: Animals; Larva; Juvenile Hormones; Moths; Drosophila
PubMed: 36396604
DOI: 10.1002/ps.7289 -
Archives of Insect Biochemistry and... 1993Juvenile hormone from the hemolymph of adult worker honey bees of known age and behavioral status was extracted and analyzed by two different radioimmunoassays in two... (Comparative Study)
Comparative Study
Juvenile hormone from the hemolymph of adult worker honey bees of known age and behavioral status was extracted and analyzed by two different radioimmunoassays in two independent laboratories. The assays are different in hapten attachment, radiolabeled tracer, and the method by which bound and unbound hormone are separated. Despite these differences in the methods, hormone determinations were in excellent agreement at lower levels (0-50 ng/ml) but diverged as the hormone concentrations increased (> 50 ng/ml). The relative changes are in good agreement, with a correlation coefficient of 0.97.
Topics: Animals; Bees; Juvenile Hormones; Radioimmunoassay; Sesquiterpenes
PubMed: 8347857
DOI: 10.1002/arch.940230306 -
Scientific Reports Oct 2016To begin studies on reproduction in common bed bug, Cimex lectularius, we identified three genes coding for vitellogenin (Vg, a protein required for the reproductive...
To begin studies on reproduction in common bed bug, Cimex lectularius, we identified three genes coding for vitellogenin (Vg, a protein required for the reproductive success of insects) and studied their hormonal regulation. RNA interference studied showed that expression of Vg3 gene in the adult females is a prerequisite for successful completion of embryogenesis in the eggs laid by them. Juvenile hormone (JH) receptor, Methoprene-tolerant (Met), steroid receptor coactivator (SRC) and GATAa but not ecdysone receptor (EcR) or its partner, ultraspiracle (USP) are required for expression of Vg genes. Feeding and mating working through Vg, Met, SRC, EcR, and GATAa regulate oocyte development. Knockdown of the expression of Met, SRC, EcR, USP, BR-C (Broad-Complex), TOR (target of rapamycin), and GATAa in female adults resulted in a reduction in the number eggs laid by them. Interestingly, Kruppel homolog 1 (Kr-h1) knockdown in the adult females did not reduce their fecundity but affected the development of embryos in the eggs laid by females injected with Kr-h1 double-stranded RNA. These data suggest that JH functioning through Met and SRC regulate both vitellogenesis and oogenesis in C. lectularius. However, JH does not work through Kr-h1 but may work through transcription factors not yet identified.
Topics: Animals; Bedbugs; Female; Insect Proteins; Juvenile Hormones; Oocytes; Oviposition
PubMed: 27762340
DOI: 10.1038/srep35546 -
Journal of Insect Science (Online) Jul 2021Worker division of labor is a defining trait in social insects. Many species are characterized by having behavioral flexibility where workers perform non-typical tasks...
Worker division of labor is a defining trait in social insects. Many species are characterized by having behavioral flexibility where workers perform non-typical tasks for their age depending on the colony's needs. Worker division of labor and behavioral flexibility were examined in the little fire ant Wasmannia auropunctata (Roger, 1863), for which age-related division of labor has been found. Young workers perform nursing duties which include tending of brood and queens, and colony defense, while older workers forage. When nurses were experimentally removed from the colony, foragers were observed carrying out nursing and colony defense duties, yet when foragers were removed nurses did not forage precociously. We also administered juvenile hormone analog, methoprene, to workers. When methoprene was applied, foragers increased their nursing and defense activities while nurses became mainly idle. The behavioral flexibility of foragers of the little fire ant may be evidence of an expansion of worker's repertoires as they age; older workers can perform tasks they have already done in their life while young individuals are not capable of performing tasks ahead of time. This may be an important adaptation associated with the success of this ant as an invasive species.
Topics: Animals; Ants; Introduced Species; Juvenile Hormones; Methoprene; Social Behavior
PubMed: 34436597
DOI: 10.1093/jisesa/ieab059 -
Pesticide Biochemistry and Physiology Sep 2018Insect growth regulators (IGRs) are attractive pest control agents due to their high target specificity and relative safety to the environment. Recently, plants have...
Insect growth regulators (IGRs) are attractive pest control agents due to their high target specificity and relative safety to the environment. Recently, plants have been shown to synthesize IGRs that affect the insect juvenile hormone (JH) as a part of their defense mechanisms. Using a yeast two-hybrid system transformed with the Aedes aegypti JH receptor as a reporter system, we identified several JH agonists (JHAs) and antagonists (JHANs) causing retardation in the ovarian development of female Asian tiger mosquito, Aedes albopictus, from plant essential oil compounds. While the JHAs increased the expression of a JH-induced gene, the JHANs caused a reduction in the expression of the same gene. The compounds identified in this study could provide insights into plant-insect interactions and may be useful for the development of novel IGR insecticides.
Topics: Aedes; Animals; Female; Juvenile Hormones; Larva; Oils, Volatile; Plants; Receptors, Cell Surface
PubMed: 30195384
DOI: 10.1016/j.pestbp.2018.06.013