Project description:Mating is fundamental to the success and reproduction of most organisms, although the physiological and transcriptional changes associated with this process have been largely characterized only in Drosophila. In this study, we use honey bees as a model system since their queens undergo massive and permanent physiological and behavioral changes following mating. Previous studies have identified changes associated with the transition from a virgin queen to a fully-mated, egg-laying queen. Here, we further uncouple the mating process to examine the effects of natural mating vs. instrumental insemination and saline vs. semen insemination. We observed significant overlap between our study and analogous studies in Drosophila, suggesting that some post-mating mechanisms are conserved across insect orders.
Project description:We used microarrays to monitor expression patterns of several thousand genes in the brains of same-aged (10 day old) virgin queens, sterile workers, and reproductive workers in honey bees (Apis mellifera).
Project description:Adult reproductive diapause is a powerful overwintering strategy for many continental insect species including bumblebees, which enables queens to survive several months through harsh winter conditions and then build new beehives in the following spring. There are few reports regarding the molecular regulatory mechanism of reproductive diapause in Bombus terrestris, which is an important pollinators of wild plants and crops, and our previous researches identified the conditions for reproductive diapause of year-round mass rearing. Here, we performed combined RNA sequencing transcriptomics and quantitative proteomic analyses in different development phases relate to reproductive diapause. According to the overall analysis, we found these differentially expressed proteins/genes act in the citrate cycle, insect hormone biosynthesis, insulin and mTOR signalling pathway. To get better sense of the reproductive diapause regulated mechanism, some genes regulated JH synthesis, insulin/ TOR signal pathway were detected, the BtRheb, BtTOR, BtVg and BtJHAMT had lower expression levels in diapause queens, and the JH III titers levels and some metabolic enzymes activities were significantly up-regulated in found post-diapause queens. After microinjected insulin-like peptides (ILPs) and JH analog (JHA), some indicators shows the significantly changes of hormones, cold tolerance substances, metabolic enzymes and reproduction. Along with other related researches, a reproductive diapause regulated model during B. terrestris year-round mass rearing process was establishment. This study contribute to a comprehensive view and the molecular regulate mechanism of productive diapause in eusocial insect.
Project description:In many animals living in groups the reproductivestatus of individuals is determined by their social status. In specieswith social hierarchies, the death of dominant individuals typicallyupheaves the social hierarchy and provides an opportunity for subordinateindividuals to improve their social status. Such a phenomenon occursin the monogyne form of the fire ant\emph{, Solenopsis invicta, }wherecolonies typically contain a single wingless reproductive queen, thousandsof workers and hundreds of winged non-reproductive virgin queens.Upon the death of the mother queen, many virgin queens shed theirwings and initiate reproductive development instead of departing ona mating flight. Workers progressively execute almost all of themover the following weeks. The workers base their collective decisionon pheromonal cues associated with the onset of reproductive developmentof the virgin queens which occurs after orphaning. To examine the factors that determine which virgin queens are executed and which survive, we set up artificial competitions between queens from different colonies. Using microarrays, we found that queens from winning colonies showed higher mitochondrial as well as organ development activities 24 hours after orphaning than did queens from colonies that lost the competitions. Furthermore, queens from colonies where queens shed their wings faster after orphaning were more likely to survive competitions. Finally, higher wing shedding speed is linked to higher mitochondrial activity. Eight competitions were initially conducted between queens form pairs of colonies. Six competitions clearly identified one winning colony and one losing colony. We thus have microarray data for six competitions (ie biological replicates), with one winning and one losing colony within each competition. Thus 12 colonies total. For each colony, RNA extracted from five queens was pooled, and hybridized against an unrelated common reference RNA that had been made from a pool of many S. invicta individuals of all castes and developmental stages. Lab work was conducted in blocks (by competition) with randomized order within competition to avoid introducing bias. No technical replication was performed.
Project description:In species with social hierarchies, the death of dominant individuals typically upheaves the social hierarchy and provides an opportunity for subordinate individuals to become reproductives. Such a phenomenon occurs in the monogyne form of the fire ant, Solenopsis invicta, where colonies typically contain a single wingless reproductive queen, thousands of workers and hundreds of winged non-reproductive virgin queens. Upon the death of the mother queen, many virgin queens shed their wings and initiate reproductive development instead of departing on a mating flight. Workers progressively execute almost all of them over the following weeks. To identify the molecular changes that occur in virgin queens as they perceive the loss of their mother queen and begin to compete for reproductive dominance, we collected virgin queens before the loss of their mother queen, six hours after orphaning and 24 hours after orphaning. Their RNA was extracted and hybridized against microarrays to examine the expression levels of approximately 10,000 genes. We identified 297 genes that were consistently differentially expressed after orphaning. These include genes that are putatively involved in the signaling and onset of reproductive development, as well as genes underlying major physiological changes in the young queens. 3 samples: 0h, 6h, 24; five queens pooled per samples; each replicate loop of 3 samples was taken from an independent colony; 8 biological replicates (colonies) used. Hybridization according to a Dye-balanced loop design (no technical replication)
Project description:Mating causes dramatic changes in female insects at the behavioral, physiological, and molecular levels. The factors driving these changes (e.g., seminal proteins, seminal volume) and the molecular pathways by which these factors are operating have been characterized only in a handful of insect species. Here we use instrumental insemination of honey bee queens to examine the role of the insemination substance (saline vs. semen) and volume (1 vs. 8 uL) in triggering post-mating changes. We also examine differences in gene expression patterns in the fat bodies of queens that have high ovary activation to determine if events during copulation can cause long-term changes in gene expression. We found that the instrumental insemination procedure alone caused cessation of mating flights and triggered ovary activation, with insemination volume contributing to increased ovary activation. Hierarchical clustering grouped queens primarily by insemination substance and then insemination volume, suggesting that while volume may trigger short-term physiological changes, substance plays a greater role in regulating long-term transcriptional changes. There was considerable but not a complete overlap in the gene pathways regulated by these two factors. Comparisons with gene lists from previous studies on queen mating revealed that several of the same biological processes and pathways were regulated, but only one gene (defensin) was found to be regulated in all studies. Our results suggest that both insemination substance and volume trigger molecular post-mating changes by altering overlapping gene pathways involved in honey bee reproduction.
Project description:Will be added/updated once the manuscript is finalized. Cardiocondyla obscurior queens. Three treatments: virgin queens, queens mated by real males, queens sham-mated (by sterile males). Queens collected 1 week and 8 week after mating. seven loops for queens collected 1 week after mating; nine loops for queens collected 8 weeks after mating. Five direct comparisons (with dye-swaps... so 10 arrays) were done of between 1 week and 8 week samples of queens mated by real males. Each sample is RNA from two queens (from different colonies). Samples were hybridized against Solenopsis invicta microarrays (signal was detectable for most clones!)
Project description:During the nest-founding phase of the bumble bee colony cycle, queens undergo striking changes in maternal care behavior. Early in the founding phase, prior to the emergence of workers in the nest, queens are reproductive and also provision and feed their offspring. However, later in the founding phase, queens cease feeding offspring and become specialized on reproduction. This transition is synchronized with the emergence of workers in the colony, who assume the task of feeding their siblings. Using a social manipulation experiment, we tested the hypothesis that workers socially regulate the transition from feeding brood to specialization on reproduction in nest-founding bumble bee queens. Consistent with this hypothesis, we found that early-stage queens with workers prematurely added to their nests reduce their brood-feeding behavior and increase egg-laying, and likewise, late-stage queens increase their brood-feeding behavior and decrease egg-laying when workers are removed from their nests. Further, brood-feeding and egg-laying behavior were negatively correlated in these queens. We used an Agilent brain EST-based microarray to explore a second hypothesis, that workers alter brain gene expression in nest-founding queens. We found evidence that brain gene expression in nest-founding queens is altered by the presence of workers, with the effect much stronger in late-stage founding queens. Additionally, expression levels of some genes were correlated with quantitative differences in brood-feeding and egg-laying behavior. This study provides new insights into how the transition from feeding brood to specialization on reproduction in bumble bee queens is regulated during the nest initiation phase of the colony cycle.
Project description:Changes in gene expression in whole Anopheles gambiae female bodies between virgin mosquitoes and females samples at 2h, 6h, and 24h after mating.
Project description:In honey bees (Apis mellifera), the reproductive queen produces a pheromonal signal that regulates many aspects of worker behavior and physiology and is critical for maintaining colony organization. Queen mandibular pheromone (QMP) inhibits worker reproduction, attracts workers from a short distance (retinue response), inhibits the rearing of new queens, modulates age-related division of labor and globally alters brain gene expression in worker bees. Interestingly, substantial variation in worker retinue responses to QMP has been found between colonies, but the molecular and physiological bases for variation in individual responses to the queen have not been characterized. Here, we demonstrate that individual retinue response is negatively correlated with traits associated with reproductive potential. Workers with low response to QMP have more ovarioles and higher levels of vitellogenin transcripts than workers with a high response to QMP, suggesting that workers with greater reproductive potential may be attempting to escape queen control. Retinue response appears to be associated with a suite of behavioral and physiological traits that may be pleiotropically linked. However, while these phenotypes are all correlated at the organismal level, the underlying brain expression patterns and gene networks associated with each trait are independent, suggesting that these phenotypes are uncoupled at the molecular level in adult bees. These studies provide insights into the ultimate and proximate causes of natural variation in pheromone response in honey bees.