畸翅病毒改變醣類代謝影響蜜蜂工蜂分工之研究

Abstract

蜜蜂 (Apis mellifera) 是一種真社會性昆蟲，具備共同育幼、世代重疊以及生殖分工的特性。除了生殖分工，工蜂還可依工作任務分為內勤蜂和外勤蜂。隨著年齡的增長，工蜂會改變任務，新羽化的工蜂在最初的兩周於蜂巢中負責育幼和蜂巢維護，這段時間過後，它們便轉為外勤蜂外出覓食。但分工並非一成不變的，當殺蟲劑、病原菌等不力於生存的負面因子出現時，族群內的各項分工條件在不同的環境條件下將改變，以對抗外來生存壓力。畸翅病毒 (Deformed Wing Virus, DWV)是全球最廣泛分布之蜜蜂病毒，在台灣約有九成的蜂巢可見其感染蹤跡，也被認為是共同蜂群衰竭失調症 (Colony Collapse Disorder, CCD)的幕後推手之一。當蜜蜂被病毒感染後，內勤蜂會提前轉換為外勤蜂。先前研究表明，感染畸翅病毒的蜜蜂腺苷代謝與健康蜜蜂有很大差異。受感染的蜜蜂體內能量會從大腦轉移到免疫系統，協助蜜蜂對抗病原，這種改變可能導致生理機制改變。目前尚不清楚畸翅病毒感染如何影響工蜂的分工，本實驗透過測量感染畸翅病毒工蜂之ATP、腺苷和醣類濃度和相關基因來了解能量代謝的改變，並分析分工相關激素、基因在不同日齡的變化，嘗試解釋外來病原對能量代謝、激素生理及分工行為上的影響。病毒感染後的蜜蜂腦部能量消耗減少，醣類代謝相關基因表現下降，作為分工依據的青春激素相關基因卻更早受到活化，進而導致青春激素濃度上升，促使工蜂更快轉變為外勤蜂。本研究點出了病毒感染對蜜蜂能量代謝的影響進而導致分工改變的可能，闡明在逆境下相關激素和基因的變化，進而解釋病毒對工蜂分工之影響。

Honeybees (Apis mellifera) are eusocial insects reproductive division of labor. In addition to the division in the reproductive class, worker bees can also be divided into house-keeping bees and forager bees based on the task they carry out. The division of labor is achieved by workers changing tasks as they aged. The newly-emerged worker bees spend their first two to three weeks in the hive. After this period, they will start foraging. Honey bees can be considered as superorganisms because specialized division of labor within hives is essential for their survival. Manipulation of this highly specialized division may help honey bees fight against survival pressure. When honey bees are infected by virus, they start their first forage at an earlier time. Our previous research demonstrates that the adenosine metabolism of honey bees infected with deformed wing virus was greatly different from that of the healthy ones. Energy was transferred from brain to immune system in DWV-infected honeybees and this altered energy transfer subsequently affected several physiological mechanisms. It is not yet known whether DWV infection would affect the division of labor in worker bees. The hormones and genes related to the division of labor in DWV-infected honeybees were measured to elucidate changes in energy metabolism through ATP, adenosine, and hemolymph sugar concentration of worker bees under adversity. As well as analyzing the changes in division of labor-related hormones synthesis genes. After DWV infection, honey bees experience a decrease in brain energy consumption, a reduction in the expression of genes related to carbohydrate metabolism, and an earlier activation of genes associated with juvenile hormone, resulting in an increase in juvenile hormone concentration. The hormonal change accelerates the transition of housekeeping bees into forager bees. This study highlights the impact of viral infection on honey bee energy metabolism, leading to changes in division of labor. It elucidates the alterations