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Proceedings. Biological Sciences Jan 2016The ubiquitous trade-off between survival and costly reproduction is one of the most fundamental constraints governing life-history evolution. In numerous animals,...
The ubiquitous trade-off between survival and costly reproduction is one of the most fundamental constraints governing life-history evolution. In numerous animals, gonadotropic hormones antagonistically suppressing immunocompetence cause this trade-off. The queens of many social insects defy the reproduction-survival trade-off, achieving both an extraordinarily long life and high reproductive output, but how they achieve this is unknown. Here we show experimentally, by integrating quantification of gene expression, physiology and behaviour, that the long-lived queens of the ant Lasius niger have escaped the reproduction-immunocompetence trade-off by decoupling the effects of a key endocrine regulator of fertility and immunocompetence in solitary insects, juvenile hormone (JH). This modification of the regulatory architecture enables queens to sustain a high reproductive output without elevated JH titres and suppressed immunocompetence, providing an escape from the reproduction-immunocompetence trade-off that may contribute to the extraordinary lifespan of many social insect queens.
Topics: Animals; Ants; Hierarchy, Social; Immunocompetence; Juvenile Hormones; Longevity; Reproduction
PubMed: 26763704
DOI: 10.1098/rspb.2015.2409 -
Chemosphere Dec 2003The water flea Daphnia magna reproduces primarily by cyclic parthenogenesis. Environmental stimuli that signal a change to adverse conditions induce the organisms to... (Comparative Study)
Comparative Study
The water flea Daphnia magna reproduces primarily by cyclic parthenogenesis. Environmental stimuli that signal a change to adverse conditions induce the organisms to switch from parthenogenesis to gamogenetic reproduction. During the gamogenetic period, they produce male daphnids and dormant resting eggs, which can survive prolonged periods of environmental adversity. However, little is known about the mechanisms associated with the switch from parthenogenesis to gamogenetic reproduction. We investigated the effects of several juvenoids on sex determination in Daphnia. Females less than 24 h old were exposed to various concentrations of the test substance and were observed for 21 days. It was found that they can trigger the appearance of male daphnids: the percentage of males in the population increases to a level greater than what occurs under ordinary environmental conditions. We found that methylfarnesoate, juvenile hormone III, methoprene, and the phenoxyphenoxy derivatives pyriproxyfen and fenoxycarb (both insecticides) reduced the production of offspring and produced sex ratios dominated by male daphnids. Pyriproxyfen and fenoxycarb showed striking effects at low concentrations. Exposure to either of these chemicals at a concentration of 330 ngl(-1) caused adult females to produce almost all male neonates. Methylfarnesoate, juvenile hormone III, and methoprene showed an effect in inducing male production at higher concentrations (3.7 x 10(3), 3.3 x 10(5), and 1.3 x 10(5) ngl(-1), respectively). Our findings suggest that juvenile hormone agonists, including some insecticides, affect the chemical signaling responsible for inducing the production of male offspring.
Topics: Animals; Carbamates; Daphnia; Female; Juvenile Hormones; Male; Parthenogenesis; Phenylcarbamates; Pyridines; Sex Ratio; Signal Transduction
PubMed: 14505703
DOI: 10.1016/S0045-6535(03)00761-6 -
Journal of Experimental Zoology. Part... Jul 2018The evolution of division of labor between sterile and fertile individuals represents one of the major transitions in biological complexity. A fascinating gradient in...
The evolution of division of labor between sterile and fertile individuals represents one of the major transitions in biological complexity. A fascinating gradient in eusociality evolved among the ancient hemimetabolous insects, ranging from noneusocial cockroaches through the primitively social lower termites-where workers retain the ability to reproduce-to the higher termites, characterized by lifetime commitment to worker sterility. Juvenile hormone (JH) is a prime candidate for the regulation of reproductive division of labor in termites, as it plays a key role in insect postembryonic development and reproduction. We compared the expression of JH pathway genes between workers and queens in two lower termites (Zootermopsis nevadensis and Cryptotermes secundus) and a higher termite (Macrotermes natalensis) to that of analogous nymphs and adult females of the noneusocial cockroach Blattella germanica. JH biosynthesis and metabolism genes ranged from reproductive female-biased expression in the cockroach to predominantly worker-biased expression in the lower termites. Remarkably, the expression profile of JH pathway genes sets the higher termite apart from the two lower termites, as well as the cockroach, indicating that JH signaling has undergone major changes in this eusocial termite. These changes go beyond mere shifts in gene expression between the different castes, as we find evidence for positive selection in several termite JH pathway genes. Thus, remodeling of the JH pathway may have played a major role in termite social evolution, representing a striking case of convergent molecular evolution between the termites and the distantly related social hymenoptera.
Topics: Animals; Blattellidae; Evolution, Molecular; Female; Gene Expression Regulation, Developmental; Isoptera; Juvenile Hormones; Nymph; Social Behavior
PubMed: 29845724
DOI: 10.1002/jez.b.22805 -
Journal of Comparative Physiology. A,... Aug 2017We investigated the effects of juvenile hormone analogue (methoprene) and 20-hydroxyecdysone on female and male reproduction in a nymphalid butterfly, Polygonia...
We investigated the effects of juvenile hormone analogue (methoprene) and 20-hydroxyecdysone on female and male reproduction in a nymphalid butterfly, Polygonia c-aureum. This butterfly has a facultative adult diapause controlled by the corpora allata and brain. Methoprene seems to terminate reproductive diapause, although transplantation experiments indicate that the activity of the corpora allata does not affect male mating behavior Endo (Dev Growth Differ 15:1-10, 1973a), suggesting that the brain may be involved in diapause. We found that exposure to methoprene promoted the development of ovaries and of the male accessory glands and simplex. On the other hand, exposure to 20-hydroxyecdysone did not promote the development of female and male reproductive organs and eupyrene sperm movement from the testis to the duplex in the adult stage. Ecdysteroid titer in both sexes was consistently low in adults. These results suggest that imaginal diapause is largely regulated by juvenile hormone in this butterfly.
Topics: Animals; Diapause; Ecdysterone; Female; Juvenile Hormones; Lepidoptera; Male; Methoprene; Reproduction
PubMed: 28497253
DOI: 10.1007/s00359-017-1179-3 -
Science (New York, N.Y.) Aug 1975A high incidence of mortality of the endoparasitoid Aphidius nigripes was observed when its host. Macrosiphum euphorbiae, was treated with juvenile hormone analogs....
A high incidence of mortality of the endoparasitoid Aphidius nigripes was observed when its host. Macrosiphum euphorbiae, was treated with juvenile hormone analogs. Larval and pupal stages of the parasitoid were susceptible. Off-target effects on natural enemies may seriously limit the use of juvenile hormone analogs, especially in integrated control programs.
Topics: Animals; Aphids; Hymenoptera; Insecticides; Juvenile Hormones; Structure-Activity Relationship
PubMed: 1162346
DOI: 10.1126/science.1162346 -
Insect Biochemistry and Molecular... Mar 2016Juvenile hormone (JH) controls many biological events in insects by triggering dramatic changes in gene expression in target cells. The Methoprene-tolerant (MET)...
Juvenile hormone (JH) controls many biological events in insects by triggering dramatic changes in gene expression in target cells. The Methoprene-tolerant (MET) protein, an intracellular JH receptor, acts as a transcriptional regulator and binds to the promoters of tissue- and stage-specific JH target genes when JH is present. Our recent study has demonstrated that the transcriptional activation by MET is modulated by a membrane-initiated JH signaling pathway, involving phospholipase C (PLC) and calcium/calmodulin-dependent protein kinase II (CaMKII). Here we report that protein kinase C (PKC) is another essential intermediate of this pathway. PKC was activated by JH and this action was PLC-dependent. Inhibition of the PKC activity substantially weakened the JH-induced gene expression in mosquito cells. RNAi experiments indicated that several PKC isoforms were involved in the JH action during the post-emergence development of adult female mosquitoes. JH treatment considerably increased the binding of MET to the promoters of JH response genes in cultured mosquito abdomens that were collected from newly emerged female adults. The JH-induced DNA binding of MET was hindered when the abdomens were treated with a PKC inhibitor and JH. Therefore, the results suggest that PKC modulates the transactivation activity of MET by enhancing the binding of MET to JH response elements in the JH target genes. This mechanism may allow for variable and stage- and tissue-specific genomic responses to JH.
Topics: Aedes; Animals; Cell Line; Juvenile Hormones; Methoprene; Protein Kinase C; Receptors, Cell Surface; Transcriptional Activation
PubMed: 26689644
DOI: 10.1016/j.ibmb.2015.12.001 -
Proceedings of the National Academy of... Jun 2013
Topics: Aedes; Animals; Female; Gene Expression Profiling; Juvenile Hormones; Methoprene
PubMed: 23720307
DOI: 10.1073/pnas.1307487110 -
Nature Ecology & Evolution Aug 2022Sex differentiation and hormones are essential for the development of sexual signals in animals, and the regulation of sexual signals involves complex gene networks....
Sex differentiation and hormones are essential for the development of sexual signals in animals, and the regulation of sexual signals involves complex gene networks. However, it is unknown whether a core gene is able to connect the upstream regulators for controlling sexual signal outputs and behavioural consequences. Here, we identify a single gene that integrates both sex differentiation and hormone signalling with sexual attractiveness in an insect model. CYP4PC1 in the German cockroach, Blattella germanica, controls the rate-limiting step in producing female-specific contact sex pheromone (CSP) that stimulates male courtship. As revealed by behavioural, biochemical, molecular, genetic and bioinformatic approaches, in sexually mature females, CYP4PC1 expression and CSP production are coordinately induced by sex differentiation genes and juvenile hormone (JH) signalling. In adult males, direct inhibition of CYP4PC1 expression by doublesex binding in gene promoter and lack of the gonadotropic hormone JH prevent CSP production, thus avoiding male-male attraction. By manipulating the upstream regulators, we show that wild-type males prefer to court cockroaches with higher CYP4PC1 expression and CSP production in a dose-dependent manner, regardless of their sex. These findings shed light on how sex-specific and high sexual attractiveness is conferred in insects.
Topics: Animals; Blattellidae; Female; Juvenile Hormones; Male
PubMed: 35788705
DOI: 10.1038/s41559-022-01808-w -
Bioorganic & Medicinal Chemistry Letters Apr 2019Allatostatins (AST) are neuropeptides originally described as inhibitors of juvenile hormone (JH) synthesis in insects. Consequently, they have been considered as...
Allatostatins (AST) are neuropeptides originally described as inhibitors of juvenile hormone (JH) synthesis in insects. Consequently, they have been considered as potential lead compounds for the discovery of new insect growth regulators (IGRs). In the present work, receptor-based three-dimensional quantitative structure-activity relationship (3D-QSAR) was studied with 48 AST analogs, and a general approach for novel potent bioactive AST analogs is proposed. Hence, six novel AST analogs were designed and synthesized. Bioassays indicated that the majority novel analogs exhibited potent JH inhibitory activity, especially analog A6 (IC: 3.79 nmol/L), which can be used as lead compound to develop new IGRs.
Topics: Animals; Binding Sites; Cockroaches; Insect Proteins; Juvenile Hormones; Molecular Docking Simulation; Molecular Structure; Neuropeptides; Protein Binding; Quantitative Structure-Activity Relationship; Receptors, Neuropeptide
PubMed: 30765188
DOI: 10.1016/j.bmcl.2019.02.001 -
PLoS Genetics 2012
Topics: Aging; Animals; Bombyx; Insect Proteins; Juvenile Hormones
PubMed: 22412393
DOI: 10.1371/journal.pgen.1002591