Starvation stress affects iron metabolism in honeybee Apis mellifera

Food and water shortages seriously affect the individual survival and population distribution of insects in nature. Iron plays a vital role in almost all physiological and biochemical processes of cells. However, little is known about insect iron metabolism under starvation conditions following food and water deprivation. This study is the first to investigate the effects of starvation without food and water on iron metabolism in insects using the honeybee Apis mellifera as a model. The findings revealed that bees suffered severe iron overload, iron homeostasis imbalance, and high mortality. Notably, when starvation caused an iron overload in the fat body and thorax, the expression of ferritin ( AmFerLCH ), which has been closely linked to reducing iron overload and maintaining cellular iron homeostasis, was induced to upregulation. AmFerLCH may help reduce iron overload caused by starvation stress. Midgut iron homeostasis was more susceptible to starvation than the fat body and thorax because the iron concentration did not increase as much as in the fat body and thorax, and the expression of ferritin AmFerLCH was also not synchronized with the change in iron concentration. These results suggested that the response of iron metabolism to starvation stress exhibited tissue-specific differences. Moreover, metabolomic analysis revealed that starvation altered the content of six metabolites closely related to iron chelation, including ascorbic acid. In summary, starvation stress without food and water severely affected iron metabolism and disrupted iron homeostasis in bees.