Journal articles on the topic 'Insectes – Reproduction (biologie)'

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1

Nageleisen, Louis-Michel, and Jean-Claude Grégoire. "Une vie de typographe : point des connaissances sur la biologie d'<i>Ips typographus</i> (Linnaeus 1758)." Revue forestière française 73, no. 4 (June 14, 2022): 479–98. http://dx.doi.org/10.20870/revforfr.2021.5565.

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Le typographe (Ips typographus) est un scolyte (Coléoptère scolytinae) dont l’hôte principal en Europe est l’Epicéa commun. Capable de développer plusieurs générations dans l’année en fonction des conditions climatiques, des pullulations sont régulièrement observées après des événements lui offrant d’innombrables sites de reproduction comme les chablis après tempête ou des peuplements affaiblis par des sécheresses. À la suite d’une lente coévolution entre l’insecte et son hôte, le typographe a développé une stratégie de colonisation lui permettant de dépasser les réactions de défense de l’arbre et de coloniser des arbres sains en période de pullulation. Cette caractéristique en fait le plus important tueur d’arbres parmi les insectes en Europe. A la suite de canicules et sécheresses inédites au cours des dernières années, le forestier est confronté à des dommages très importants dans les pessières, dans un contexte socioéconomique tel qu’il est difficile d’intervenir efficacement pour contrer l’épidémie en cours.
2

Jouault, Thierry. "Avant-propos." médecine/sciences 35, no. 2 (February 2019): 152. http://dx.doi.org/10.1051/medsci/2019011.

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Pour éclairer la série que nous vous proposons, il nous a semblé important de rappeler les règles définissant ce que sont les organismes-modèles ainsi que la réglementation en vigueur quant à leur utilisation en recherche biomédicale. Les études in vitro ou ex vivo, sur cellules ou tissus, ou les analyses in silico ne permettent pas d’aborder des problématiques complexes. Elles sont certes utiles pour des analyses mécanistiques, mais ne permettent pas l’étude de réponses biologiques intégrées qui nécessitent l’analyse d’un organisme entier. Ces organismes sont soumis à une réglementation stricte. Elle les distingue selon qu’ils sont vertébrés ou invertébrés. Si les mammifères modélisent nombre de pathologies humaines, certains organismes simples permettent également de mener ce type d’études et de répondre à des questions liées à la génétique. Leur intérêt est leur rapidité et leur capacité de reproduction qui facilitent les expérimentations. Le poisson zèbre en est un bon exemple avec les nombreuses versions de morphants qui ont été développés et qui ont permis de révéler les conséquences d’altérations génomiques sur un phénotype particulier. Cet organisme-modèle est donc particulièrement utilisé pour l’étude de pathologies monogéniques ou pour déterminer le rôle d’un gène dans l’étiologie de diverses pathologies. La transparence du poisson zèbre rend de plus les investigations plus faciles. Caenorhabditis elegans est également un excellent modèle d’organisme simple et qui, contrairement au poisson zèbre, ne relève pas de la réglementation concernant l’expérimentation animale. Son utilisation est ainsi, comme pour les insectes, plus aisée. Connaître les différences entre les organismes-modèles, leurs avantages et leurs limites, et les règles dictant leur utilisation est donc primordial pour la réalisation d’expérimentations qui restent nécessaires à l’acquisition de nouvelles connaissances dans le domaine de la biologie et de la santé.
3

Li, Xiaokang, Yan Zhou, and Kongming Wu. "Biological Characteristics and Energy Metabolism of Migrating Insects." Metabolites 13, no. 3 (March 17, 2023): 439. http://dx.doi.org/10.3390/metabo13030439.

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Through long-distance migration, insects not only find suitable breeding locations and increase the survival space and opportunities for the population but also facilitate large-scale material, energy, and information flow between regions, which is important in maintaining the stability of agricultural ecosystems and wider natural ecosystems. In this study, we summarize the changes in biological characteristics such as morphology, ovarian development, reproduction, and flight capability during the seasonal migration of the insect. In consideration of global research work, the interaction between flight and reproduction, the influence and regulation of the insulin-like and juvenile hormone on the flight and reproductive activities of migrating insects, and the types of energy substances, metabolic processes, and hormone regulation processes during insect flight are elaborated. This systematic review of the latest advances in the studies on insect migration biology and energy metabolism will help readers to better understand the biological behavior and regulation mechanism of the energy metabolism of insect migration.
4

Pamminger, Tobias, David Treanor, and William O. H. Hughes. "Pleiotropic effects of juvenile hormone in ant queens and the escape from the reproduction–immunocompetence trade-off." Proceedings of the Royal Society B: Biological Sciences 283, no. 1822 (January 13, 2016): 20152409. http://dx.doi.org/10.1098/rspb.2015.2409.

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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.
5

Blacher, Pierre, Timothy J. Huggins, and Andrew F. G. Bourke. "Evolution of ageing, costs of reproduction and the fecundity–longevity trade-off in eusocial insects." Proceedings of the Royal Society B: Biological Sciences 284, no. 1858 (July 12, 2017): 20170380. http://dx.doi.org/10.1098/rspb.2017.0380.

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Eusocial insects provide special opportunities to elucidate the evolution of ageing as queens have apparently evaded costs of reproduction and reversed the fecundity–longevity trade-off generally observed in non-social organisms. But how reproduction affects longevity in eusocial insects has rarely been tested experimentally. In this study, we took advantage of the reproductive plasticity of workers to test the causal role of reproduction in determining longevity in eusocial insects. Using the eusocial bumblebee Bombus terrestris , we found that, in whole colonies, in which workers could freely ‘choose’ whether to become reproductive, workers' level of ovarian activation was significantly positively associated with longevity and ovary-active workers significantly outlived ovary-inactive workers. By contrast, when reproductivity was experimentally induced in randomly selected workers, thereby decoupling it from other traits, workers' level of ovarian activation was significantly negatively associated with longevity and ovary-active workers were significantly less long-lived than ovary-inactive workers. These findings show that workers experience costs of reproduction and suggest that intrinsically high-quality individuals can overcome these costs. They also raise the possibility that eusocial insect queens exhibit condition-dependent longevity and hence call into question whether eusociality entails a truly reversed fecundity–longevity trade-off involving a fundamental remodelling of conserved genetic and endocrine networks underpinning ageing.
6

Oldroyd, Benjamin P., and Boris Yagound. "Parent-of-origin effects, allele-specific expression, genomic imprinting and paternal manipulation in social insects." Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1826 (April 19, 2021): 20200425. http://dx.doi.org/10.1098/rstb.2020.0425.

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Haplo-diploidy and the relatedness asymmetries it generates mean that social insects are prime candidates for the evolution of genomic imprinting. In single-mating social insect species, some genes may be selected to evolve genomic mechanisms that enhance reproduction by workers when they are inherited from a female. This situation reverses in multiple mating species, where genes inherited from fathers can be under selection to enhance the reproductive success of daughters. Reciprocal crosses between subspecies of honeybees have shown strong parent-of-origin effects on worker reproductive phenotypes, and this could be evidence of such genomic imprinting affecting genes related to worker reproduction. It is also possible that social insect fathers directly affect gene expression in their daughters, for example, by placing small interfering RNA molecules in semen. Gene expression studies have repeatedly found evidence of parent-specific gene expression in social insects, but it is unclear at this time whether this arises from genomic imprinting, paternal manipulation, an artefact of cyto-nuclear interactions, or all of these. This article is part of the theme issue ‘How does epigenetics influence the course of evolution?’
7

Amarasinghe, Harindra E., Crisenthiya I. Clayton, and Eamonn B. Mallon. "Methylation and worker reproduction in the bumble-bee ( Bombus terrestris )." Proceedings of the Royal Society B: Biological Sciences 281, no. 1780 (April 7, 2014): 20132502. http://dx.doi.org/10.1098/rspb.2013.2502.

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Insects are at the dawn of an epigenetics era. Numerous social insect species have been found to possess a functioning methylation system, previously not thought to exist in insects. Methylation, an epigenetic tag, may be vital for the sociality and division of labour for which social insects are renowned. In the bumble-bee Bombus terrestris , we found methylation differences between the genomes of queenless reproductive workers and queenless non-reproductive workers. In a follow up experiment, queenless workers whose genomes had experimentally altered methylation were more aggressive and more likely to develop ovaries compared with control queenless workers. This shows methylation is important in this highly plastic reproductive division of labour. Methylation is an epigenetic tag for genomic imprinting (GI). It is intriguing that the main theory to explain the evolution of GI predicts that GI should be important in this worker reproduction behaviour.
8

Straub, Lars, Laura Villamar-Bouza, Selina Bruckner, Panuwan Chantawannakul, Laurent Gauthier, Kitiphong Khongphinitbunjong, Gina Retschnig, et al. "Neonicotinoid insecticides can serve as inadvertent insect contraceptives." Proceedings of the Royal Society B: Biological Sciences 283, no. 1835 (July 27, 2016): 20160506. http://dx.doi.org/10.1098/rspb.2016.0506.

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There is clear evidence for sublethal effects of neonicotinoid insecticides on non-target ecosystem service-providing insects. However, their possible impact on male insect reproduction is currently unknown, despite the key role of sex. Here, we show that two neonicotinoids (4.5 ppb thiamethoxam and 1.5 ppb clothianidin) significantly reduce the reproductive capacity of male honeybees (drones), Apis mellifera . Drones were obtained from colonies exposed to the neonicotinoid insecticides or controls, and subsequently maintained in laboratory cages until they reached sexual maturity. While no significant effects were observed for male teneral (newly emerged adult) body mass and sperm quantity, the data clearly showed reduced drone lifespan, as well as reduced sperm viability (percentage living versus dead) and living sperm quantity by 39%. Our results demonstrate for the first time that neonicotinoid insecticides can negatively affect male insect reproductive capacity, and provide a possible mechanistic explanation for managed honeybee queen failure and wild insect pollinator decline. The widespread prophylactic use of neonicotinoids may have previously overlooked inadvertent contraceptive effects on non-target insects, thereby limiting conservation efforts.
9

Labeyrie, Vincent. "EFFETS MATERNELS ET BIOLOGIE DES POPULATIONS D'INSECTES." Memoirs of the Entomological Society of Canada 120, S146 (1988): 153–69. http://dx.doi.org/10.4039/entm120146153-1.

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AbstractMaternal influences on an insect population must be assessed within a numerically and spatially restricted enclave; it is difficult to demonstrate the impact within a large polymorphic group whose qualitative and quantitative evolution is subject to a number of conflicting influences. When a variety of selective factors is involved, the problem is to isolate, from the polymorphism, the portion that can be attributed to maternal effects.In short-lived organisms such as insects, direct maternal effects on the progeny have an advantage over slower, indirect responses to selective pressures. Direct effects allow progeny to adapt sooner to ecological trends that began or were operating during the parental generation. The peculiarities of insect embryonic development allow maternal influences to act directly on the F1 adults through their deferred effects on the imaginal discs. Species that deposit organized egg masses provide the best material for studying maternal effects.Behaviour at oviposition can lead to special types of progeny distributions that affect the offspring's survival. In parasitoids, for example, maternal behaviour can introduce a kind of "arena selection" generating superparasitism by aggregative oviposition.The next generation's ecological response that is produced by maternal effects is mediated by changes at the behavioural, metabolic and ovarian levels during the mother's reproductive activity. In this way, she provides a key part of the next generation's functional polymorphism.
10

Negroni, Matteo Antoine, Maide Nesibe Macit, Marah Stoldt, Barbara Feldmeyer, and Susanne Foitzik. "Molecular regulation of lifespan extension in fertile ant workers." Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1823 (March 8, 2021): 20190736. http://dx.doi.org/10.1098/rstb.2019.0736.

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The evolution of sociality in insects caused a divergence in lifespan between reproductive and non-reproductive castes. Ant queens can live for decades, while most workers survive only weeks to a few years. In most organisms, longevity is traded-off with reproduction, but in social insects, these two life-history traits are positively linked. Once fertility is induced in workers, e.g. by queen removal, worker lifespan increases. The molecular regulation of this positive link between fecundity and longevity and generally the molecular underpinnings of caste-specific senescence are not well understood. Here, we investigate the transcriptomic regulation of lifespan and reproduction in fat bodies of three worker groups in the ant Temnothorax rugatulus . In a long-term experiment, workers that became fertile in the absence of the queen showed increased survival and upregulation of genes involved in longevity and fecundity pathways. Interestingly, workers that re-joined their queen after months exhibited intermediate ovary development, but retained a high expression of longevity and fecundity genes. Strikingly, the queen's presence causes a general downregulation of genes in worker fat bodies. Our findings point to long-term consequences of fertility induction in workers, even after re-joining their queen. Moreover, we reveal longevity genes and pathways modulated during insect social evolution. This article is part of the theme issue ‘Ageing and sociality: why, when and how does sociality change ageing patterns?’
11

Recart, Wilnelia, Rover Bernhard, Isabella Ng, Katherine Garcia, and Arietta E. Fleming-Davies. "Meta-Analysis of the Effects of Insect Pathogens: Implications for Plant Reproduction." Pathogens 12, no. 2 (February 18, 2023): 347. http://dx.doi.org/10.3390/pathogens12020347.

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Despite extensive work on both insect disease and plant reproduction, there is little research on the intersection of the two. Insect-infecting pathogens could disrupt the pollination process by affecting pollinator population density or traits. Pathogens may also infect insect herbivores and change herbivory, potentially altering resource allocation to plant reproduction. We conducted a meta-analysis to (1) summarize the literature on the effects of pathogens on insect pollinators and herbivores and (2) quantify the extent to which pathogens affect insect traits, with potential repercussions for plant reproduction. We found 39 articles that fit our criteria for inclusion, extracting 218 measures of insect traits for 21 different insect species exposed to 25 different pathogens. We detected a negative effect of pathogen exposure on insect traits, which varied by host function: pathogens had a significant negative effect on insects that were herbivores or carried multiple functions but not on insects that solely functioned as pollinators. Particular pathogen types were heavily studied in certain insect orders, with 7 of 11 viral pathogen studies conducted in Lepidoptera and 5 of 9 fungal pathogen studies conducted in Hymenoptera. Our results suggest that most studies have focused on a small set of host–pathogen pairs. To understand the implications for plant reproduction, future work is needed to directly measure the effects of pathogens on pollinator effectiveness.
12

Blacher, Pierre, Boris Yagound, Emmanuel Lecoutey, Paul Devienne, Stéphane Chameron, and Nicolas Châline. "Drifting behaviour as an alternative reproductive strategy for social insect workers." Proceedings of the Royal Society B: Biological Sciences 280, no. 1771 (November 22, 2013): 20131888. http://dx.doi.org/10.1098/rspb.2013.1888.

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Restricted reproduction is traditionally posited as the defining feature of eusocial insect workers. The discovery of worker reproduction in foreign colonies challenges this view and suggests that workers’ potential to pursue selfish interests may be higher than previously believed. However, whether such reproductive behaviour truly relies on a reproductive decision is still unknown. Workers’ reproductive decisions thus need to be investigated to assess the extent of workers’ reproductive options. Here, we show in the bumblebee Bombus terrestris that drifting is a distinct strategy by which fertile workers circumvent competition in their nest and reproduce in foreign colonies. By monitoring workers’ movements between colonies, we show that drifting is a remarkably dynamic behaviour, widely expressed by both fertile and infertile workers. We demonstrate that a high fertility is, however, central in determining the propensity of workers to enter foreign colonies as well as their subsequent reproduction in host colonies. Moreover, our study shows that the drifting of fertile workers reflects complex decision-making processes associated with in-nest reproductive competition. This novel finding therefore adds to our modern conception of cooperation by showing the previously overlooked importance of alternative strategies which enable workers to assert their reproductive interests.
13

Zijp, Jan-Piet, and Leo H. M. Blommers. "Survival Mode between the Yearly Reproduction Periods, and Reproductive Biology of Scambus pomorum (Hymenoptera: Ichneumonidae: Pimplinae), a Parasitoid of the Apple Blossom Weevil Anthonomus pomorum (Coleoptera: Curculionidae)." Entomologia Generalis 26, no. 1 (March 1, 2002): 29–46. http://dx.doi.org/10.1127/entom.gen/26/2002/29.

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Pickett, John A., Michael A. Birkett, Christine M. Woodcock, and Jing-Jiang Zhou. "Scents and sex: Insect pheromones." Biochemist 31, no. 2 (April 1, 2009): 28–32. http://dx.doi.org/10.1042/bio03102028.

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Pheromones are chemical signals (semiochemicals) that act between members of the same species, sex pheromones being the signals that facilitate sexual reproduction. Many organisms use such semiochemicals, but it is insects to which the main research attention has been directed. This article will therefore concentrate on the insect sex pheromones.
15

Gijbels, Marijke, Sam Schellens, Tine Schellekens, Evert Bruyninckx, Elisabeth Marchal, and Jozef Vanden Broeck. "Precocious Downregulation of Krüppel-Homolog 1 in the Migratory Locust, Locusta migratoria, Gives Rise to An Adultoid Phenotype with Accelerated Ovarian Development but Disturbed Mating and Oviposition." International Journal of Molecular Sciences 21, no. 17 (August 22, 2020): 6058. http://dx.doi.org/10.3390/ijms21176058.

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Krüppel-homolog 1 (Kr-h1) is a zinc finger transcription factor maintaining the status quo in immature insect stages and promoting reproduction in adult insects through the transduction of the Juvenile Hormone (JH) signal. Knockdown studies have shown that precocious silencing of Kr-h1 in the immature stages results in the premature development of adult features. However, the molecular characteristics and reproductive potential of these premature adult insect stages are still poorly understood. Here we report on an adult-like or ‘adultoid’ phenotype of the migratory locust, Locusta migratoria, obtained after a premature metamorphosis induced by the silencing of LmKr-h1 in the penultimate instar. The freshly molted adultoid shows precocious development of adult features, corresponding with increased transcript levels of the adult specifier gene LmE93. Furthermore, accelerated ovarian maturation and vitellogenesis were observed in female adultoids, coinciding with elevated expression of LmCYP15A1 in corpora allata (CA) and LmKr-h1 and vitellogenin genes (LmVg) in fat body, whereas LmE93 and Methoprene-tolerant (LmMet) transcript levels decreased in fat body. In adultoid ovaries, expression of the Halloween genes, Spook (LmSpo) and Phantom (LmPhm), was elevated as well. In addition, the processes of mating and oviposition were severely disturbed in these females. L. migratoria is a well-known, swarm-forming pest insect that can destroy crops and harvests in some of the world’s poorest countries. As such, a better understanding of factors that are capable of significantly reducing the reproductive potential of this pest may be of crucial importance for the development of novel locust control strategies.
16

Kennedy, Anissa, Jacob Herman, and Olav Rueppell. "Reproductive activation in honeybee ( Apis mellifera ) workers protects against abiotic and biotic stress." Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1823 (March 8, 2021): 20190737. http://dx.doi.org/10.1098/rstb.2019.0737.

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Social insect reproductives exhibit exceptional longevity instead of the classic trade-off between somatic maintenance and reproduction. Even normally sterile workers experience a significant increase in life expectancy when they assume a reproductive role. The mechanisms that enable the positive relation between the antagonistic demands of reproduction and somatic maintenance are unclear. To isolate the effect of reproductive activation, honeybee workers were induced to activate their ovaries. These reproductively activated workers were compared to controls for survival and gene expression patterns after exposure to Israeli Acute Paralysis Virus or the oxidative stressor paraquat. Reproductive activation increased survival, indicating better immunity and oxidative stress resistance. After qPCR analysis confirmed our experimental treatments at the physiological level, whole transcriptome analysis revealed that paraquat treatment significantly changed the expression of 1277 genes in the control workers but only two genes in reproductively activated workers, indicating that reproductive activation preemptively protects against oxidative stress. Significant overlap between genes that were upregulated by reproductive activation and in response to paraquat included prominent members of signalling pathways and anti-oxidants known to affect ageing. Thus, while our results confirm a central role of vitellogenin, they also point to other mechanisms to explain the molecular basis of the lack of a cost of reproduction and the exceptional longevity of social insect reproductives. Thus, socially induced reproductive activation preemptively protects honeybee workers against stressors, explaining their longevity. This article is part of the theme issue ‘Ageing and sociality: why, when and how does sociality change ageing patterns?'
17

Gallan, Diego Z., Maressa O. Henrique, and Marcio C. Silva-Filho. "The Phytopathogen Fusarium verticillioides Modifies the Intestinal Morphology of the Sugarcane Borer." Pathogens 12, no. 3 (March 11, 2023): 443. http://dx.doi.org/10.3390/pathogens12030443.

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Background: In tropical sugarcane crops, the fungus Fusarium verticillioides, the agent responsible for the occurrence of the red rot complex, occurs in association with the sugarcane borer Diatraea saccharalis. This fungus, in addition to being transmitted vertically, can manipulate both the insect and the plant for its own dissemination in the field. Due to the complex interaction between F. verticillioides and D. saccharalis, and the high incidence of the fungus in the intestinal region, our objective was to investigate whether F. verticillioides could alter the intestinal structure of the insect. Methods: We combined analysis of scanning electron microscopy and light microscopy to identify whether the presence of the fungus F. verticillioides, in artificial diets or in sugarcane, could lead to any alteration or regional preference in the insect’s intestinal ultrastructure over the course of its development, or its offspring development, analyzing the wall and microvillous structures of the mid-digestive system. Results: Here, we show that the fungus F. verticillioides alters the intestinal morphology of D. saccharalis, promoting an increase of up to 3.3 times in the thickness of the midgut compared to the control. We also observed that the phytopathogen colonizes the intestinal microvilli for reproduction, suggesting that this region can be considered the gateway of the fungus to the insect’s reproductive organs. In addition, the colonization of this region promoted the elongation of microvillous structures by up to 180% compared to the control, leading to an increase in the area used for colonization. We also used the fungus Colletotrichum falcatum in the tests, and it did not differ from the control in any test, showing that this interaction is specific between D. saccharalis and F. verticillioides. Conclusions: The phytopathogenic host F. verticillioides alters the intestinal morphology of the vector insect in favor of its colonization.
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Chak, Solomon Tin Chi, J. Emmett Duffy, and Dustin R. Rubenstein. "Reproductive skew drives patterns of sexual dimorphism in sponge-dwelling snapping shrimps." Proceedings of the Royal Society B: Biological Sciences 282, no. 1809 (June 22, 2015): 20150342. http://dx.doi.org/10.1098/rspb.2015.0342.

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Sexual dimorphism is typically a result of strong sexual selection on male traits used in male–male competition and subsequent female choice. However, in social species where reproduction is monopolized by one or a few individuals in a group, selection on secondary sexual characteristics may be strong in both sexes. Indeed, sexual dimorphism is reduced in many cooperatively breeding vertebrates and eusocial insects with totipotent workers, presumably because of increased selection on female traits. Here, we examined the relationship between sexual dimorphism and sociality in eight species of Synalpheus snapping shrimps that vary in social structure and degree of reproductive skew. In species where reproduction was shared more equitably, most members of both sexes were physiologically capable of breeding. However, in species where reproduction was monopolized by a single individual, a large proportion of females—but not males—were reproductively inactive, suggesting stronger reproductive suppression and conflict among females. Moreover, as skew increased across species, proportional size of the major chela—the primary antagonistic weapon in snapping shrimps—increased among females and sexual dimorphism in major chela size declined. Thus, as reproductive skew increases among Synalpheus , female–female competition over reproduction appears to increase, resulting in decreased sexual dimorphism in weapon size.
19

Lamb, Richard Y., and Robert B. Willey. "Cytological mechanisms of thelytokous parthenogenesis in insects." Genome 29, no. 2 (April 1, 1987): 367–69. http://dx.doi.org/10.1139/g87-062.

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The eight female parthenogenetic mechanisms recognized in insects are organized under the broad categories "ploidy restoration" and "ploidy stasis." Each term replaces three imprecise and inappropriate existing names. Of the eight mechanisms, two are given names for the first time, and a table brings together all mechanisms in a new manner that shows the exact point in meiosis during which the DNA is doubled. Key words: insect reproduction, parthenogenesis, parthenogenetic mechanisms.
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Ozan, Martina, Heikki Helanterä, and Liselotte Sundström. "The value of oviposition timing, queen presence and kinship in a social insect." Proceedings of the Royal Society B: Biological Sciences 280, no. 1766 (September 7, 2013): 20131231. http://dx.doi.org/10.1098/rspb.2013.1231.

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Reproductive cooperation confers benefits, but simultaneously creates conflicts among cooperators. Queens in multi-queen colonies of ants share a nest and its resources, but reproductive competition among queens often results in unequal reproduction. Two mutually non-exclusive factors may produce such inequality in reproduction: worker intervention or queen traits. Workers may intervene by favouring some queens over others, owing to either kinship or queen signals. Queens may differ in their intrinsic fecundity at the onset of oviposition or in their timing of the onset of oviposition, leading to their unequal representation in the brood. Here, we test the role of queen kin value (relatedness) to workers, timing of the onset of oviposition and signals of presence by queens in determining the maternity of offspring. We show that queens of the ant Formica fusca gained a significantly higher proportion of sexuals in the brood when ovipositing early, and that the presence of a caged queen resulted in a significant increase in both her share of sexual brood and her overall reproductive share. Moreover, the lower the kin value of the queen, the more the workers invested in their own reproduction by producing males. Our results show that both kinship and breeding phenology influence the outcome of reproductive conflicts, and the balance of direct and indirect fitness benefits in the multi-queen colonies of F. fusca .
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Tasaki, Eisuke, Mamoru Takata, and Kenji Matsuura. "Why and how do termite kings and queens live so long?" Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1823 (March 8, 2021): 20190740. http://dx.doi.org/10.1098/rstb.2019.0740.

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Lifespan varies greatly across the tree of life. Of the various explanations for this phenomenon, those that involve trade-offs between reproduction and longevity have gained considerable support. There is an important exception: social insect reproductives (queens and in termites, also kings) exhibit both high reproductive outputs and extraordinarily long lives. As both the ultimate and proximate mechanisms underlying the absence of the fecundity/longevity trade-off could shed light on the unexpected dynamics and molecular mechanisms of extended longevity, reproductives of social insects have attracted much attention in the field of ageing research. Here, we highlight current ecological and physiological studies on ageing and discuss the various possible evolutionary and molecular explanations of the extended lifespans of termite reproductives. We integrate these findings into a coherent framework revealing the evolution of longevity in these reproductives. Studies on termites may explain why and how ageing is shaped by natural selection. This article is part of the theme issue ‘Ageing and sociality: why, when and how does sociality change ageing patterns?’
22

von Aderkas, Patrick, Gaëlle Rouault, Rebecca Wagner, René Rohr, and Alain Roques. "Seed parasitism redirects ovule development in Douglas fir." Proceedings of the Royal Society B: Biological Sciences 272, no. 1571 (June 21, 2005): 1491–96. http://dx.doi.org/10.1098/rspb.2005.3061.

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Many parasitic species of insects complete their entire development in seeds. They feed off storage reserves within the ovule. These reserves only normally accumulate in fertilized ovules. Consequently, female insects that oviposit their eggs directly into the plant ovule need to be able to select correctly, as unfertilized ovules of conifers normally become so-called empty seed. We provide clear evidence that in conifers, seed-parasitizing insects do not need to discriminate between fertilized and unfertilized plant ovules when ovipositing their eggs. A host-specific insect, the chalcid Megastigmus spermotrophus Wachtl (Hymenoptera: Torymidae), lays its eggs in ovules of Douglas fir ( Pseudotsuga menziesii (Mirbel) Franco) before fertilization has taken place in the plant. Oviposition not only prevents the expected degeneration and death of unfertilized ovules, but it induces energy reserve accumulation. Ovules that would otherwise develop as empty seed are redirected in their development by the insect to provide food for the developing larvae. Instead of the insect exploiting normal events during seed development, the insect manipulates seed development for its own reproductive advantage.
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Pringle, Elizabeth G. "Harnessing ant defence at fruits reduces bruchid seed predation in a symbiotic ant–plant mutualism." Proceedings of the Royal Society B: Biological Sciences 281, no. 1785 (June 22, 2014): 20140474. http://dx.doi.org/10.1098/rspb.2014.0474.

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In horizontally transmitted mutualisms, mutualists disperse separately and reassemble in each generation with partners genetically unrelated to those in the previous generation. Because of this, there should be no selection on either partner to enhance the other's reproductive output directly. In symbiotic ant–plant mutualisms, myrmecophytic plants host defensive ant colonies, and ants defend the plants from herbivores. Plants and ants disperse separately, and, although ant defence can indirectly increase plant reproduction by reducing folivory, it is unclear whether ants can also directly increase plant reproduction by defending seeds. The neotropical tree Cordia alliodora hosts colonies of Azteca pittieri ants. The trees produce domatia where ants nest at stem nodes and also at the node between the peduncle and the rachides of the infloresence. Unlike the stem domatia, these reproductive domatia senesce after the tree fruits each year. In this study, I show that the tree's resident ant colony moves into these ephemeral reproductive domatia, where they tend honeydew-producing scale insects and patrol the nearby developing fruits. The presence of ants significantly reduced pre-dispersal seed predation by Amblycerus bruchid beetles, thereby directly increasing plant reproductive output.
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Guan, Guang-Xiang, Xiao-Ping Yu, and Dan-Ting Li. "Post-Mating Responses in Insects Induced by Seminal Fluid Proteins and Octopamine." Biology 12, no. 10 (September 26, 2023): 1283. http://dx.doi.org/10.3390/biology12101283.

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Following insect mating, females often exhibit a series of physiological, behavioral, and gene expression changes. These post-mating responses (PMRs) are induced by seminal fluid components other than sperm, which not only form network proteins to assist sperm localization, supplement female-specific protein requirements, and facilitate the formation of specialized functional structures, but also activate neuronal signaling pathways in insects. This review primarily discusses the roles of seminal fluid proteins (SFPs) and octopamine (OA) in various PMRs in insects. It explores the regulatory mechanisms and mediation conditions by which they trigger PMRs, along with the series of gene expression differences they induce. Insect PMRs involve a transition from protein signaling to neuronal signaling, ultimately manifested through neural regulation and gene expression. The intricate signaling network formed as a result significantly influences female behavior and organ function, contributing to both successful reproduction and the outcomes of sexual conflict.
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Ferrari, Julia, and Fabrice Vavre. "Bacterial symbionts in insects or the story of communities affecting communities." Philosophical Transactions of the Royal Society B: Biological Sciences 366, no. 1569 (May 12, 2011): 1389–400. http://dx.doi.org/10.1098/rstb.2010.0226.

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Bacterial symbionts are widespread in insects and other animals. Most of them are predominantly vertically transmitted, along with their hosts' genes, and thus extend the heritable genetic variation present in one species. These passengers have a variety of repercussions on the host's phenotypes: besides the cost imposed on the host for maintaining the symbiont population, they can provide fitness advantages to the host or manipulate the host's reproduction. We argue that insect symbioses are ideal model systems for community genetics. First, bacterial symbionts directly or indirectly affect the interactions with other species within a community. Examples include their involvement in modifying the use of host plants by phytophagous insects, in providing resistance to natural enemies, but also in reducing the global genetic diversity or gene flow between populations within some species. Second, one emerging picture in insect symbioses is that many species are simultaneously infected with more than one symbiont, which permits studying the factors that shape bacterial communities; for example, horizontal transmission, interactions between host genotype, symbiont genotype and the environment and interactions among symbionts. One conclusion is that insects' symbiotic complements are dynamic communities that affect and are affected by the communities in which they are embedded.
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Garcia Bulle Bueno, Francisco, Rosalyn Gloag, Tanya Latty, and Isobel Ronai. "Irreversible sterility of workers and high-volume egg production by queens in the stingless bee Tetragonula carbonaria." Journal of Experimental Biology 223, no. 18 (July 31, 2020): jeb230599. http://dx.doi.org/10.1242/jeb.230599.

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ABSTRACTSocial insects are characterised by a reproductive division of labour between queens and workers. However, in the majority of social insect species, the workers are only facultatively sterile. The Australian stingless bee Tetragonula carbonaria is noteworthy as workers never lay eggs. Here, we describe the reproductive anatomy of T. carbonaria workers, virgin queens and mated queens. We then conduct the first experimental test of absolute worker sterility in the social insects. Using a controlled microcolony environment, we investigate whether the reproductive capacity of adult workers can be rescued by manipulating the workers' social environment and diet. The ovaries of T. carbonaria workers that are queenless and fed unrestricted, highly nutritious royal jelly remain non-functional, indicating they are irreversibly sterile and that ovary degeneration is fixed prior to adulthood. We suggest that T. carbonaria might have evolved absolute worker sterility because colonies are unlikely to ever be queenless.
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Wang, Ni, Chao Zhang, Min Chen, Zheyi Shi, Ying Zhou, Xiaoxiao Shi, Wenwu Zhou, and Zengrong Zhu. "Characterization of MicroRNAs Associated with Reproduction in the Brown Planthopper, Nilaparvata lugens." International Journal of Molecular Sciences 23, no. 14 (July 15, 2022): 7808. http://dx.doi.org/10.3390/ijms23147808.

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Insects have a robust capacity to produce offspring for propagation, and the reproductive events of female insects have been achieved at the molecular and physiological levels via regulatory gene pathways. However, the roles of MicroRNAs (miRNAs) in the reproductive development of the brown planthopper (BPH), Nilaparvata lugens, remain largely unexplored. To understand the roles of miRNAs in reproductive development, miRNAs were identified by Solexa sequencing in short-winged (SW) female adults of BPH. Small RNA libraries derived from three developmental phases (1 day, 3 days, and 5 days after emergence) were constructed and sequenced. We identified 905 miRNAs, including 263 known and 642 novel miRNAs. Among them, a total of 43 miRNAs were differentially expressed in the three developmental phases, and 14,568 putative targets for 43 differentially expressed miRNAs (DEMs) were predicted by TargetScan and miRanda. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the predicted miRNA targets illustrated the putative roles for these DEMs in reproduction. The progress events were annotated, including oogenesis, lipid biosynthetic process, and related pathways such as apoptosis, ABC transporters, and amino acid metabolism. Four highly abundant DEMs (miR-9a-5p, miR-34-5p, miR-275-3p, and miR-317-3p) were further screened, and miR-34-5p was confirmed to be involved in the regulation of reproduction. Overexpression of miR-34-5p via injecting its mimics reduced fecundity and decreased Vg expression. Moreover, target genes prediction for miR-34-5p showed they might be involved in 20E signaling cascades, apoptosis, and gonadal development, including hormone receptor 4 (HR4), caspase-1 (Cp-1), and spermatogenesis-associated protein 20 (SPATA20). These findings provide a valuable resource for future studies on the role of miRNAs in BPH reproductive development.
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Wilcox, Alana A. E., Amy E. M. Newman, and D. Ryan Norris. "Developmental and reproductive effects of clothianidin exposure in monarch butterflies (Lepidoptera: Nymphalidae)." Canadian Entomologist 153, no. 3 (March 16, 2021): 327–42. http://dx.doi.org/10.4039/tce.2021.5.

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AbstractNeonicotinoid insecticides are used to reduce crop damage caused by insect pests, but sublethal levels could affect development and reproduction in nontarget insects, such as monarch butterflies (Danaus plexippus) (Lepidoptera: Nymphalidae). To investigate the impact of field-realistic concentrations of the neonicotinoid clothianidin on monarch butterflies, we grew swamp milkweed (Asclepias incarnata) (Apocynaceae) in either low (15 ng/g of soil) or high (25 ng/g of soil) levels of clothianidin, or in a control (0 ng/g), then raised monarchs on the milkweed. Morphological traits of monarch caterpillars were measured during development and, once they eclosed, were mated as adults to quantify egg size and mass and the number of eggs laid. Although the effects of the treatment had complex effects on caterpillar length, width and volume of late-instar caterpillars were negatively affected. Fifth-instar caterpillars from the high-dose insecticide treatment had lower mass than other groups. Adult monarch butterflies raised on treated milkweed were larger than controls, but clothianidin exposure did not affect the number of eggs laid or egg size. Although the magnitude of the effect depends on clothianidin concentration, our results suggest that exposure to clothianidin during early life can impact monarch caterpillar development but is unlikely to reduce female reproductive output.
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Scheys, Freja, Els J. M. Van Damme, Jarne Pauwels, An Staes, Kris Gevaert, and Guy Smagghe. "N-glycosylation Site Analysis Reveals Sex-related Differences in Protein N-glycosylation in the Rice Brown Planthopper (Nilaparvata lugens)." Molecular & Cellular Proteomics 19, no. 3 (January 10, 2020): 529–39. http://dx.doi.org/10.1074/mcp.ra119.001823.

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Glycosylation is a common modification of proteins and critical for a wide range of biological processes. Differences in protein glycosylation between sexes have already been observed in humans, nematodes and trematodes, and have recently also been reported in the rice pest insect Nilaparvata lugens. Although protein N-glycosylation in insects is nowadays of high interest because of its potential for exploitation in pest control strategies, the functionality of differential N-glycosylation between sexes is yet unknown. In this study, therefore, the occurrence and role of sex-related protein N-glycosylation in insects were examined. A comprehensive investigation of the N-glycosylation sites from the adult stages of N. lugens was conducted, allowing a qualitative and quantitative comparison between sexes at the glycopeptide level. N-glycopeptide enrichment via lectin capturing using the high mannose/paucimannose-binding lectin Concanavalin A, or the Rhizoctonia solani agglutinin which interacts with complex N-glycans, resulted in the identification of over 1300 N-glycosylation sites derived from over 600 glycoproteins. Comparison of these N-glycopeptides revealed striking differences in protein N-glycosylation between sexes. Male- and female-specific N-glycosylation sites were identified, and some of these sex-specific N-glycosylation sites were shown to be derived from proteins with a putative role in insect reproduction. In addition, differential glycan composition between males and females was observed for proteins shared across sexes. Both lectin blotting experiments as well as transcript expression analyses with complete insects and insect tissues confirmed the observed differences in N-glycosylation of proteins between sexes. In conclusion, this study provides further evidence for protein N-glycosylation to be sex-related in insects. Furthermore, original data on N-glycosylation sites of N. lugens adults are presented, providing novel insights into planthopper's biology and information for future biological pest control strategies.
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Norman, Victoria C., Tobias Pamminger, Fabio Nascimento, and William O. H. Hughes. "The role of juvenile hormone in regulating reproductive physiology and dominance in Dinoponera quadriceps ants." PeerJ 7 (March 1, 2019): e6512. http://dx.doi.org/10.7717/peerj.6512.

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Unequal reproductive output among members of the same sex (reproductive skew) is a common phenomenon in a wide range of communally breeding animals. In such species, reproductive dominance is often acquired during antagonistic interactions between group members that establish a reproductive hierarchy in which only a few individuals reproduce. Rank-specific syndromes of behavioural and physiological traits characterize such hierarchies, but how antagonistic behavioural interactions translate into stable rank-specific syndromes remains poorly understood. The pleiotropic nature of hormones makes them prime candidates for generating such syndromes as they physiologically integrate environmental (social) information, and often affect reproduction and behaviour simultaneously. Juvenile hormone (JH) is one of several hormones that occupy such a central regulatory role in insects and has been suggested to regulate reproductive hierarchies in a wide range of social insects including ants. Here we use experimental manipulation to investigate the effect of JH levels on reproductive physiology and social dominance in high-ranked workers of the eusocial ant Dinoponera quadriceps, a species that has secondarily reverted to queenless, simple societies. We show that JH regulated reproductive physiology, with ants in which JH levels were experimentally elevated having more regressed ovaries. In contrast, we found no evidence of JH levels affecting dominance in social interactions. This could indicate that JH and ovary development are decoupled from dominance in this species, however only high-ranked workers were investigated. The results therefore confirm that the regulatory role of JH in reproductive physiology in this ant species is in keeping with its highly eusocial ancestors rather than its secondary reversion to simple societies, but more investigation is needed to disentangle the relationships between hormones, behaviour and hierarchies.
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Larose, Chloé, Darren J. Parker, and Tanja Schwander. "Fundamental and realized feeding niche breadths of sexual and asexual stick insects." Proceedings of the Royal Society B: Biological Sciences 285, no. 1892 (November 28, 2018): 20181805. http://dx.doi.org/10.1098/rspb.2018.1805.

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The factors contributing to the maintenance of sex over asexuality in natural populations remain unclear. Ecological divergences between sexual and asexual lineages could help to maintain reproductive polymorphisms, at least transiently, but the consequences of asexuality for the evolution of ecological niches are unknown. Here, we investigated how niche breadths change in transitions from sexual reproduction to asexuality. We used host plant ranges as a proxy to compare the realized feeding niche breadths of five independently derived asexual Timema stick insect species and their sexual relatives at both the species and population levels. Asexual species had systematically narrower realized niches than sexual species, though this pattern was not apparent at the population level. To investigate how the narrower realized niches of asexual species arise, we performed feeding experiments to estimate fundamental niche breadths but found no systematic differences between reproductive modes. The narrow realized niches found in asexual species are therefore probably a consequence of biotic interactions such as predation or competition, that constrain realized niche size in asexuals more strongly than in sexuals.
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Loxdale, Hugh D., and Gugs Lushai. "Slaves of the environment: the movement of herbivorous insects in relation to their ecology and genotype." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 354, no. 1388 (August 29, 1999): 1479–95. http://dx.doi.org/10.1098/rstb.1999.0492.

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The majority of insect species do not show an innate behavioural migration, but rather populations expand into favourable new habitats or contract away from unfavourable ones by random changes of spatial scale. Over the past 50 years, the scientific fascination with dramatic long–distance and directed mass migratory events has overshadowed the more universal mode of population movement, involving much smaller stochastic displacement during the lifetime of the insects concerned. This may be limiting our understanding of insect population dynamics. In the following synthesis, we provide an overview of how herbivorous insect movement is governed by both abiotic and biotic factors, making these animals essentially ‘slaves of their environment’. No displaced insect or insect population can leave a resource patch, migrate and flourish, leaving descendants, unless suitable habitat and/or resources are reached during movement. This must have constrained insects over geological time, bringing about species–specific adaptation in behaviour and movements in relation to their environment at a micro– and macrogeographical scale. With insects that undergo long–range spatial displacements, e.g. aphids and locusts, there is presumably a selection against movement unless overruled by factors, such as density–dependent triggering, which cause certain genotypes within the population to migrate. However, for most insect species, spatial changes of scale and range expansion are much slower and may occur over a much longer time–scale, and are not innate (nor directed). Ecologists may say that all animals and plants are figuratively speaking ‘slaves of their environments’, in the sense that their distribution is defined by their ecology and genotype. But in the case of insects, a vast number must perish daily, either out at sea or over other hostile habitats, having failed to find suitable resources and/or a habitat on which to feed and reproduce. Since many are blown by the vagaries of the wind, their chances of success are serendipitous in the extreme, especially over large distances. Hence, the strategies adopted by mass migratory species (innate pre–programmed flight behaviour, large population sizes and/or fast reproduction), which improve the chances that some of these individuals will succeed. We also emphasize the dearth of knowledge in the various interactions of insect movement and their environment, and describe how molecular markers (protein and DNA) may be used to examine the details of spatial scale over which movement occurs in relation to insect ecology and genotype.
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Geissmann, Quentin, Paul K. Abram, Di Wu, Cara H. Haney, and Juli Carrillo. "Sticky Pi is a high-frequency smart trap that enables the study of insect circadian activity under natural conditions." PLOS Biology 20, no. 7 (July 7, 2022): e3001689. http://dx.doi.org/10.1371/journal.pbio.3001689.

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In the face of severe environmental crises that threaten insect biodiversity, new technologies are imperative to monitor both the identity and ecology of insect species. Traditionally, insect surveys rely on manual collection of traps, which provide abundance data but mask the large intra- and interday variations in insect activity, an important facet of their ecology. Although laboratory studies have shown that circadian processes are central to insects’ biological functions, from feeding to reproduction, we lack the high-frequency monitoring tools to study insect circadian biology in the field. To address these issues, we developed the Sticky Pi, a novel, autonomous, open-source, insect trap that acquires images of sticky cards every 20 minutes. Using custom deep learning algorithms, we automatically and accurately scored where, when, and which insects were captured. First, we validated our device in controlled laboratory conditions with a classic chronobiological model organism, Drosophila melanogaster. Then, we deployed an array of Sticky Pis to the field to characterise the daily activity of an agricultural pest, Drosophila suzukii, and its parasitoid wasps. Finally, we demonstrate the wide scope of our smart trap by describing the sympatric arrangement of insect temporal niches in a community, without targeting particular taxa a priori. Together, the automatic identification and high sampling rate of our tool provide biologists with unique data that impacts research far beyond chronobiology, with applications to biodiversity monitoring and pest control as well as fundamental implications for phenology, behavioural ecology, and ecophysiology. We released the Sticky Pi project as an open community resource on https://doc.sticky-pi.com.
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Gutierrez, A. P., F. Schulthess, L. T. Wilson, A. M. Villacorta, C. K. Ellis, and J. U. Baumgaertner. "ENERGY ACQUISITION AND ALLOCATION IN PLANTS AND INSECTS: A HYPOTHESIS FOR THE POSSIBLE ROLE OF HORMONES IN INSECT FEEDING PATTERNS." Canadian Entomologist 119, no. 2 (February 1987): 109–29. http://dx.doi.org/10.4039/ent119109-2.

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AbstractA distributed delay age structure model is presented for plants and insects that describes the dynamics of per capita energy (dry matter) acquisition and allocation patterns, and the within-organism subunit (e.g. leaves, fruit, ova) number dynamics that occur during growth, reproduction, and development. Four species of plants (common bean, cassava, cotton, and tomato) and two species of insects (pea aphid and a ladybird beetle) are modeled. A common acquisition (i.e. functional response) submodel is used to estimate the daily photosynthetic rates in plants and consumption rates in pea aphid and the ladybird beetle. The focus of this work is to capture the essence of the common attributes between trophic levels across this wide range of taxa. The models are compared with field or laboratory data. A hypothesis is proposed for the observed patterns of reproduction in pea aphid and in a ladybird beetle.
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Uzsák, Adrienn, James Dieffenderfer, Alper Bozkurt, and Coby Schal. "Social facilitation of insect reproduction with motor-driven tactile stimuli." Proceedings of the Royal Society B: Biological Sciences 281, no. 1783 (May 22, 2014): 20140325. http://dx.doi.org/10.1098/rspb.2014.0325.

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Tactile stimuli provide animals with important information about the environment, including physical features such as obstacles, and biologically relevant cues related to food, mates, hosts and predators. The antennae, the principal sensory organs of insects, house an array of sensory receptors for olfaction, gustation, audition, nociception, balance, stability, graviception, static electric fields, and thermo-, hygro- and mechanoreception. The antennae, being the anteriormost sensory appendages, play a prominent role in social interactions with conspecifics that involve primarily chemosensory and tactile stimuli. In the German cockroach ( Blattella germanica ) antennal contact during social interactions modulates brain-regulated juvenile hormone production, ultimately accelerating the reproductive rate in females. The primary sensory modality mediating this social facilitation of reproduction is antennal mechanoreception. We investigated the key elements, or stimulus features, of antennal contact that socially facilitate reproduction in B. germanica females. Using motor-driven antenna mimics, we assessed the physiological responses of females to artificial tactile stimulation. Our results indicate that tactile stimulation with artificial materials, some deviating significantly from the native antennal morphology, can facilitate female reproduction. However, none of the artificial stimuli matched the effects of social interactions with a conspecific female.
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Zhang, Yinqiao, Hu Li, Juan Du, Junzheng Zhang, Jie Shen, and Wanzhi Cai. "Three Melanin Pathway Genes, TH, yellow, and aaNAT, Regulate Pigmentation in the Twin-Spotted Assassin Bug, Platymeris biguttatus (Linnaeus)." International Journal of Molecular Sciences 20, no. 11 (June 3, 2019): 2728. http://dx.doi.org/10.3390/ijms20112728.

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Pigmentation plays a vital role in insect survival and reproduction. Many melanin pathway genes have been studied in holometabolous insects; however, they have only been studied in two hemimetabolous insect genera, Oncopeltus and Periplaneta. Here we analyzed three melanin pathway genes (TH, yellow, and aaNAT) using RNA interference (RNAi) in another hemimetabolous insect, namely the twin-spotted assassin bug, Platymeris biguttatus. TH was highly expressed in freshly molted nymphs and adults. TH RNAi resulted in a complete loss of black pigment, with yellow coloration maintained. Therefore, black pigment in this assassin bug is solely generated from the melanin pathway, whereas yellow pigment is generated from other unknown pigmentation pathways. yellow and aaNAT were highly expressed in the white spot of the hemelytra. Downregulation of yellow caused a brown phenotype with high mortality, indicating an important role of yellow functions in cuticle formation and in the process of converting melanin from brown to black. Interestingly, aaNAT RNAi caused not only loss of white pigment, but also loss of yellow and red pigments. This phenotype of aaNAT has not been reported in other insects. Our results provide new information for understanding the melanin pathway in which aaNAT is essential for the formation of colorless patterns.
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Morris, O. N. "SUSCEPTIBILITY OF 31 SPECIES OF AGRICULTURAL INSECT PESTS TO THE ENTOMOGENOUS NEMATODES STEINERNEMA FELTIAE AND HETERORHABDITIS BACTERIOPHORA." Canadian Entomologist 117, no. 4 (April 1985): 401–7. http://dx.doi.org/10.4039/ent117401-4.

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AbstractThe susceptibility of 31 species of agricultural insect pests representing 7 families of Lepidoptera, 3 of Diptera, and 3 of Coleoptera to the entomogenous nematodes Steinernema feltiae Filipjev and Heterorhabditis bacteriophora Poinar, were investigated in the laboratory. Of the 27 species found susceptible to S. feltiae, 19 are reported for the first time. Of the 21 species killed by H. bacteriophora, 15 are reported for the first time. The Lepidoptera as a group were highly susceptible to the nematodes. On the basis of larval mortality caused by the nematodes, of nematode reproduction in insect cadavers, and of the known economic importance and life histories of the test insects, S. feltiae was judged to warrant further research as a possible biological-control agent against Euxoa ochrogaster (Guenée), E. auxiliaris (Grote), Agrotis orthogonia (Morr.), Actebia fennica (Tauscher), Mamestra configurata Walker, Delia radicum (L.), D. antiqua (Meig.), and Zygogramma exclamationis (F.).
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Richardson, Kelly M., Perran A. Ross, Brandon S. Cooper, William R. Conner, Tom Schmidt, and Ary A. Hoffmann. "A male-killing Wolbachia endosymbiont is concealed by another endosymbiont and a nuclear suppressor." PLOS Biology 21, no. 3 (March 22, 2023): e3001879. http://dx.doi.org/10.1371/journal.pbio.3001879.

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Bacteria that live inside the cells of insect hosts (endosymbionts) can alter the reproduction of their hosts, including the killing of male offspring (male killing, MK). MK has only been described in a few insects, but this may reflect challenges in detecting MK rather than its rarity. Here, we identify MK Wolbachia at a low frequency (around 4%) in natural populations of Drosophila pseudotakahashii. MK Wolbachia had a stable density and maternal transmission during laboratory culture, but the MK phenotype which manifested mainly at the larval stage was lost rapidly. MK Wolbachia occurred alongside a second Wolbachia strain expressing a different reproductive manipulation, cytoplasmic incompatibility (CI). A genomic analysis highlighted Wolbachia regions diverged between the 2 strains involving 17 genes, and homologs of the wmk and cif genes implicated in MK and CI were identified in the Wolbachia assembly. Doubly infected males induced CI with uninfected females but not females singly infected with CI-causing Wolbachia. A rapidly spreading dominant nuclear suppressor genetic element affecting MK was identified through backcrossing and subsequent analysis with ddRAD SNPs of the D. pseudotakahashii genome. These findings highlight the complexity of nuclear and microbial components affecting MK endosymbiont detection and dynamics in populations and the challenges of making connections between endosymbionts and the host phenotypes affected by them.
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Kaczmarek, Agata, and Mieczysława Boguś. "The metabolism and role of free fatty acids in key physiological processes in insects of medical, veterinary and forensic importance." PeerJ 9 (December 22, 2021): e12563. http://dx.doi.org/10.7717/peerj.12563.

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Insects are the most widespread group of organisms and more than one million species have been described. These animals have significant ecological functions, for example they are pollinators of many types of plants. However, they also have direct influence on human life in different manners. They have high medical and veterinary significance, stemming from their role as vectors of disease and infection of wounds and necrotic tissue; they are also plant pests, parasitoids and predators whose activities can influence agriculture. In addition, their use in medical treatments, such as maggot therapy of gangrene and wounds, has grown considerably. They also have many uses in forensic science to determine the minimum post-mortem interval and provide valuable information about the movement of the body, cause of the death, drug use, or poisoning. It has also been proposed that they may be used as model organisms to replace mammal systems in research. The present review describes the role of free fatty acids (FFAs) in key physiological processes in insects. By focusing on insects of medical, veterinary significance, we have limited our description of the physiological processes to those most important from the point of view of insect control; the study examines their effects on insect reproduction and resistance to the adverse effects of abiotic (low temperature) and biotic (pathogens) factors.
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Khotimah, Khusnul, Eming Sudiana, and Hery Pratiknya. "Dampak Perubahan Iklim Terhadap Fenologi Phaseolus vulgaris L Faklutas Biologi Universitas Jenderal Soedirman." Bioma : Berkala Ilmiah Biologi 24, no. 1 (June 12, 2022): 1–7. http://dx.doi.org/10.14710/bioma.24.1.1-7.

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Climate change is a condition characterized by changing world climate patterns which results in erratic weather phenomena. Altitude is one of the climate control factors that have a strong influence on air temperature. There is a correlation between changes in air temperature and altitude in Indonesia. The increase in altitude causes the air temperature to decrease and the O2 content is getting thinner. Altitude also affects the biophysics and reproduction of agricultural plants a lot, which includes the response of a decrease in temperature to the growth of agricultural plants and their production. This study aims to determine the effect of climate change on the flowering phenology of green beans (Phaseolus vulgaris L.) and the diversity of insect pollinators. Sampling was done by purposive sampling to collect flower data while Scan sampling was used to collect insect data. Samples were taken as many as 24 bean plants from the population at each location. There are six locations, namely 50 m asl, 200 m asl, 400 m asl, 600 m asl, 800 m asl, and 1,000 m asl. Plant parameters observed were plant height, number of leaves, number of branches, number of flowers, size of flowers and time of bloom and diversity of insect pollinators. The data obtained were analyzed using analysis of variance (ANOVA) and regression correlation analysis. The results of the analysis showed the influence of altitude on the time the flowers first appeared, the number of flowers and flower size. Beans grow and develop optimally at an altitude of 800 - 1,000 m asl.
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Xu, Wei, Naiyong Liu, Yalin Liao, and Alisha Anderson. "Molecular characterization of sugar taste receptors in the cotton bollworm Helicoverpa armigera." Genome 60, no. 12 (December 2017): 1037–44. http://dx.doi.org/10.1139/gen-2017-0086.

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Insects utilize sugars as their essential energy and nutrient sources; therefore, the sense of sugar detection plays a critical role in insect behaviours. Previously, using genomic and transcriptomic approaches, we identified eight putative sugar gustatory receptor (GR) genes from the cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). Here, we further validated these annotated sugar receptor genes (HarmGr4–HarmGr8 and HarmGr10–HarmGr12) and found HarmGr10 may be a pseudogene carrying a stop codon in the open reading frame. Sequence alignment revealed H. armigera sugar GR sequences are conserved at C-terminus and phylogenetic analysis showed that insect sugar GRs have evolved in a family-specific manner. Interestingly, all eight H. armigera sugar GRs are localized in a tandem array on the same scaffold of the genome. In silico gene expression and reverse transcription (RT)-PCR analysis showed that HarmGr10 is specifically expressed in male adult testes while HarmGr11 is specifically expressed in female adult ovaries, suggesting H. armigera sugar GRs may be involved in reproduction-related functions. This study improves our knowledge on insect sugar receptors and gustatory systems.
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Raines, Katherine E., Penelope R. Whitehorn, David Copplestone, and Matthew C. Tinsley. "Chernobyl-level radiation exposure damages bumblebee reproduction: a laboratory experiment." Proceedings of the Royal Society B: Biological Sciences 287, no. 1937 (October 21, 2020): 20201638. http://dx.doi.org/10.1098/rspb.2020.1638.

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The consequences for wildlife of living in radiologically contaminated environments are uncertain. Previous laboratory studies suggest insects are relatively radiation-resistant; however, some field studies from the Chernobyl Exclusion Zone report severe adverse effects at substantially lower radiation dose rates than expected. Here, we present the first laboratory investigation to study how environmentally relevant radiation exposure affects bumblebee life history, assessing the shape of the relationship between radiation exposure and fitness loss. Dose rates comparable to the Chernobyl Exclusion Zone (50–400 µGy h −1 ) impaired bumblebee reproduction and delayed colony growth but did not affect colony weight or longevity. Our best-fitting model for the effect of radiation dose rate on colony queen production had a strongly nonlinear concave relationship: exposure to only 100 µGy h −1 impaired reproduction by 30–45%, while further dose rate increases caused more modest additional reproductive impairment. Our data indicate that the practice of estimating effects of environmentally relevant low-dose rate exposure by extrapolating from high-dose rates may have considerably underestimated the effects of radiation. If our data can be generalized, they suggest insects suffer significant negative consequences at dose rates previously thought safe; we therefore advocate relevant revisions to the international framework for radiological protection of the environment.
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Korb, Judith, Karen Meusemann, Denise Aumer, Abel Bernadou, Daniel Elsner, Barbara Feldmeyer, Susanne Foitzik, et al. "Comparative transcriptomic analysis of the mechanisms underpinning ageing and fecundity in social insects." Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1823 (March 8, 2021): 20190728. http://dx.doi.org/10.1098/rstb.2019.0728.

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The exceptional longevity of social insect queens despite their lifelong high fecundity remains poorly understood in ageing biology. To gain insights into the mechanisms that might underlie ageing in social insects, we compared gene expression patterns between young and old castes (both queens and workers) across different lineages of social insects (two termite, two bee and two ant species). After global analyses, we paid particular attention to genes of the insulin/insulin-like growth factor 1 signalling (IIS)/target of rapamycin (TOR)/juvenile hormone (JH) network, which is well known to regulate lifespan and the trade-off between reproduction and somatic maintenance in solitary insects. Our results reveal a major role of the downstream components and target genes of this network (e.g. JH signalling, vitellogenins, major royal jelly proteins and immune genes) in affecting ageing and the caste-specific physiology of social insects, but an apparently lesser role of the upstream IIS/TOR signalling components. Together with a growing appreciation of the importance of such downstream targets, this leads us to propose the TI–J–LiFe ( T OR/ I IS– J H– Li fespan and Fe cundity) network as a conceptual framework for understanding the mechanisms of ageing and fecundity in social insects and beyond. This article is part of the theme issue ‘Ageing and sociality: why, when and how does sociality change ageing patterns?’
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WYATT, G. R. "Gene Regulation in Insect Reproduction." Invertebrate Reproduction & Development 20, no. 1 (August 1991): 1–35. http://dx.doi.org/10.1080/07924259.1991.9672174.

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BELLÉS, XAVIER, and JOSÉ LUIS MAESTRO. "Endocrine peptides and insect reproduction." Invertebrate Reproduction & Development 47, no. 1 (January 2005): 23–37. http://dx.doi.org/10.1080/07924259.2005.9652144.

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YANG, YUNG-YU, CHUAN-CHAN WANG, and HOW-JING LEE. "Timing regulation in insect reproduction." Invertebrate Reproduction & Development 48, no. 1-3 (January 2005): 185–96. http://dx.doi.org/10.1080/07924259.2005.9652184.

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Korb, Judith, and Jürgen Heinze. "Ageing and sociality: why, when and how does sociality change ageing patterns?" Philosophical Transactions of the Royal Society B: Biological Sciences 376, no. 1823 (March 8, 2021): 20190727. http://dx.doi.org/10.1098/rstb.2019.0727.

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Individual lifespans vary tremendously between and also within species, but the proximate and ultimate causes of different ageing speeds are still not well understood. Sociality appears to be associated with the evolution of greater longevity and probably also with a larger plasticity of the shape and pace of ageing. For example, reproductives of several termites and ants reach lifespans that surpass those of their non-reproductive nestmates by one or two decades. In this issue, 15 papers explore the interrelations between sociality and individual longevity in both, group-living vertebrates and social insects. Here, we briefly give an overview of the contents of the various contributions, including theoretical and comparative studies, and we explore the similarities and dissimilarities in proximate mechanisms underlying ageing among taxa, with particular emphasis on nutrient-sensing pathways and, in insects, juvenile hormone. These studies point to an underestimated role of more downstream processes. We highlight the need for reliable transcriptomic markers of ageing and a comprehensive ageing theory of social animals, which includes the reproductive potential of workers, and considers the fact that social insect queens reach maturity only after a prolonged period of producing non-reproductive workers. This article is part of the theme issue ‘Ageing and sociality: why, when and how does sociality change ageing patterns?’
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Beekman, Madeleine, and Francis L. W. Ratnieks. "Power over reproduction in social Hymenoptera." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 358, no. 1438 (August 31, 2003): 1741–53. http://dx.doi.org/10.1098/rstb.2002.1262.

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Inclusive fitness theory has been very successful in predicting and explaining much of the observed variation in the reproductive characteristics of insect societies. For example, the theory correctly predicts sex–ratio biasing by workers in relation to the queen's mating frequency. However, within an insect society there are typically multiple reproductive optima, each corresponding to the interest of different individual(s) or parties of interest. When multiple optima occur, which party's interests prevail? Presumably, the interests of the party with the greatest ‘power’; the ability to do or act. This article focuses on factors that influence power over colony reproduction. In particular, we seek to identify the principles that may cause different parties of interest to have greater or lesser power. In doing this, we discuss power from two different angles. On the one hand, we discuss general factors based upon non–idiosyncratic biological features (e.g. information, access to and ability to process food) that are likely to be important to all social Hymenoptera. On the other hand, we discuss idiosyncratic factors that depend upon the biology of a taxon at any hierarchical level. We propose that a better understanding of the diversity of reproductive characteristics of insect societies will come from combining inclusive fitness theory with a wide range of other factors that affect relative power in a conflict situation.
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Markov, A. V., and I. A. Zakharov. "Sexual Reproduction of Insects Is Regulated by Cytoplasmic Bacteria." Russian Journal of Developmental Biology 36, no. 4 (July 2005): 230–39. http://dx.doi.org/10.1007/s11174-005-0038-2.

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Maino, James L., and Michael R. Kearney. "Testing mechanistic models of growth in insects." Proceedings of the Royal Society B: Biological Sciences 282, no. 1819 (November 22, 2015): 20151973. http://dx.doi.org/10.1098/rspb.2015.1973.

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Insects are typified by their small size, large numbers, impressive reproductive output and rapid growth. However, insect growth is not simply rapid; rather, insects follow a qualitatively distinct trajectory to many other animals. Here we present a mechanistic growth model for insects and show that increasing specific assimilation during the growth phase can explain the near-exponential growth trajectory of insects. The presented model is tested against growth data on 50 insects, and compared against other mechanistic growth models. Unlike the other mechanistic models, our growth model predicts energy reserves per biomass to increase with age, which implies a higher production efficiency and energy density of biomass in later instars. These predictions are tested against data compiled from the literature whereby it is confirmed that insects increase their production efficiency (by 24 percentage points) and energy density (by 4 J mg −1 ) between hatching and the attainment of full size. The model suggests that insects achieve greater production efficiencies and enhanced growth rates by increasing specific assimilation and increasing energy reserves per biomass, which are less costly to maintain than structural biomass. Our findings illustrate how the explanatory and predictive power of mechanistic growth models comes from their grounding in underlying biological processes.

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