A Critical Examination of the Model for Insect Body Size Determination: the Mechanisms of Body Size Variation in Bees

昆虫体型测定模型的批判性检验：蜜蜂体型变化的机制

• 批准号: 1557940
• 负责人: Julia Bowsher
• 金额: $ 67.36万
• 依托单位: North Dakota State University Fargo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1557940&HistoricalAwards=false
• 关键词: Critical; Examination; Model; Insect; Body

Growth rate and the timing of when growth stops determine body size, an important trait for survival and reproduction. The cues that stop growth are not fully understood, even in well-studied model species. Solitary bees provision their offspring, restricting the food available for larval growth. Experiments indicate that the complete consumption of these provisions induces metamorphosis. Studying the cues to metamorphosis in solitary bees provides a unique opportunity to physiologically compare individuals of the same age and size that either have or have not transitioned to metamorphosis. The proposed research will investigate (1) whether the hormonal cues underlying starvation-triggered metamorphosis in solitary bees are the same as those found in insects that metamorphose upon reaching a particular size, (2) how variation in the timing of metamorphosis predicts body size variation in natural populations and different bee species, and (3) how the determinants of adult size in bees shape differences between queens and workers in honeybees. Bee body size predicts pollination performance, and a physiological understanding of body size control has direct implications for pollinator health and performance in both natural and managed bee species, whether solitary or social. Undergraduates, graduate students and a postdoctoral fellow will participate in this research, and K-12 learning modules on pollinator life cycles will be developed.Body size is an important organismal trait that correlates with most aspects of performance and fitness. In determinant-growing organisms, body size becomes fixed at maturation; therefore the mechanisms regulating maturation also influence size variation among individuals. Insects grow as larvae until attainment of a critical weight, at which point the mechanisms regulating metamorphosis are irreversibly initiated. This established model of body size control may not be generalizable to species with larval ecologies that differ from model insect species. Preliminary data demonstrate that completely consuming the larval provision initiates metamorphosis in the solidary bee Osmia lignaria. This result challenges the existing conceptual model for insect body size by suggesting that the critical weight is not a universal trait in insects. The proposed research will address three central aims: 1) characterizing the physiological regulation of metamorphosis in the solitary bee Osmia lignaria, 2) characterizing factors determining body size variation among populations and species of solitary bees that share similar larval ecologies; and 3) testing the degree to which diet quantity contributes to caste differences in eusocial bees. These mechanisms have the potential to explain much of the body size variation observed among Hymenopterans. Finally, the proposed research will develop a mechanistically explicit understanding of body size determination for bees, which are key pollinators for natural and managed ecosystems. A deeper, mechanistic understanding of body size variation may yield insights into improving pollinator health at the scale of individuals or even populations. Results from these studies will be disseminated in peer reviewed journals and through presentations at scientific meetings.

生长速度和生长停止的时间决定了体型，这是生存和繁殖的重要特征。即使在经过充分研究的模式物种中，停止生长的线索仍未被完全理解。独居蜜蜂为它们的后代提供食物，限制了幼虫生长所需的食物。实验表明，完全食用这些食物会引起变态。研究独居蜜蜂变态的线索提供了一个独特的机会，可以在生理上比较具有或尚未转变为变态的相同年龄和体型的个体。拟议的研究将调查（1）孤独蜜蜂饥饿引发变态的激素线索是否与达到特定尺寸后变态的昆虫相同，（2）变态时间的变化如何预测自然种群和不同蜜蜂物种的体型变化，以及（3）蜜蜂成年体型的决定因素如何影响蜂王和工蜂之间的差异 蜜蜂。蜜蜂的体型大小可以预测授粉性能，对体型控制的生理学理解对自然和管理蜂种（无论是独居还是群居）的传粉者健康和性能具有直接影响。本科生、研究生和博士后将参与这项研究，并将开发有关传粉媒介生命周期的 K-12 学习模块。体型是一个重要的生物体特征，与表现和健康的大多数方面相关。在决定性生长的生物体中，体型在成熟时就固定了。因此，调节成熟的机制也会影响个体之间的体型差异。昆虫作为幼虫生长，直到达到临界重量，此时调节变态的机制不可逆地启动。这种已建立的体型控制模型可能无法推广到具有与模式昆虫物种不同的幼虫生态的物种。初步数据表明，完全消耗幼虫供给会引发团结蜂 Osmia lignaria 的变态。这一结果挑战了现有的昆虫体型概念模型，表明临界重量并不是昆虫的普遍特征。拟议的研究将解决三个中心目标：1）表征独居蜂Osmia lignaria变态的生理调节，2）表征决定具有相似幼虫生态的独居蜂种群和物种之间体型变化的因素； 3）测试饮食量对社会性蜜蜂种姓差异的影响程度。这些机制有可能解释膜翅目动物中观察到的大部分体型变化。最后，拟议的研究将从机械上明确理解蜜蜂的体型决定，蜜蜂是自然和管理生态系统的关键传粉媒介。对体型变化进行更深入、机械的了解可能有助于改善个体甚至群体规模的传粉媒介健康。 这些研究的结果将在同行评审期刊上以及通过在科学会议上的演讲进行传播。

项目成果

Metamorphosis is induced by food absence rather than a critical weight in the solitary bee, Osmia lignaria

• DOI: 10.1073/pnas.1703008114
• 发表时间: 2017-10-10
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Helm, Bryan R.;Rinehart, Joseph P.;Bowsher, Julia H.
• 通讯作者: Bowsher, Julia H.

Micro-computed tomography of pupal metamorphosis in the solitary bee Megachile rotundata

• DOI: 10.1016/j.asd.2018.05.001
• 发表时间: 2018-09-01
• 期刊: ARTHROPOD STRUCTURE & DEVELOPMENT
• 影响因子: 2
• 作者: Helm, Bryan R.;Payne, Scott;Greenlee, Kendra J.
• 通讯作者: Greenlee, Kendra J.

Body size allometry impacts flight-related morphology and metabolic rates in the solitary bee Megachile rotundata

• DOI: 10.1016/j.jinsphys.2021.104275
• 发表时间: 2021-07-17
• 期刊: JOURNAL OF INSECT PHYSIOLOGY
• 影响因子: 2.2
• 作者: Grula, Courtney C.;Rinehart, Joseph P.;Bowsher, Julia H.
• 通讯作者: Bowsher, Julia H.

Environmental history impacts gene expression during diapause development in the alfalfa leafcutting bee, Megachile rotundata

• DOI: 10.1242/jeb.173443
• 发表时间: 2018-07
• 期刊: Journal of Experimental Biology
• 影响因子: 2.8
• 作者: G. Yocum;Anna K. Childers;J. Rinehart;A. Rajamohan;T. Pitts‐Singer;K. Greenlee;J. Bowsher

Physiological responses to fluctuating temperatures are characterized by distinct transcriptional profiles in a solitary bee

独居蜜蜂对温度波动的生理反应具有独特的转录特征

• DOI: 10.1242/jeb.156695
• 发表时间: 2017
• 期刊: Journal of Experimental Biology
• 影响因子: 2.8
• 作者: Torson, Alex S.;Yocum, George D.;Rinehart, Joseph P.;Nash, Sean A.;Kvidera, Kally M.;Bowsher, Julia H.
• 通讯作者: Bowsher, Julia H.