一項研究發(fā)現(xiàn),，一個古老的化石蚊子的腹中含有它最后吸的血,，這證實了這些昆蟲在4600萬年前以血為食。大約1.4萬種現(xiàn)存的昆蟲吸血，包括跳蚤,、蜱和蚊子,。盡管這種覓食策略看上去在一批生物中間獨立進化出來,，這種行為的化石證據(jù)罕見。Dale Greenwalt及其同事報告的證據(jù)顯示一只來自美國蒙大拿西北部的吸飽了血的蚊子在進食之后不久死去,，并且從中始新世以來就保存在頁巖中,。在這個昆蟲的腹部發(fā)現(xiàn)了高濃度的鐵之后，這組科研人員用一種稱為非破壞性質譜法的技術分析了這個樣本,，并且發(fā)現(xiàn)了鐵的來源是血紅素,，即讓血紅蛋白能夠輸送氧的分子實體。這組作者報告說,，盡管諸如DNA等大而脆弱的分子通常不會在石化過程中存在下來,，這只古蚊子證實了某些復雜的有機分子，諸如血紅素,，在適宜的條件下可以長期保存,。此外，這組作者說,，這些發(fā)現(xiàn)把這個昆蟲家族以血為食的化石記錄延長了4600萬年（生物谷Bioon.com）,。

生物谷推薦的英文摘要

Proceedings of the National Academy of the Sciences of the United States of America          doi: 10.1073/pnas.1310885110

Hemoglobin-derived porphyrins preserved in a Middle Eocene blood-engorged mosquito

Dale E. Greenwalta，1,， Yulia S. Gorevab,， Sandra M. Siljestromb，c,，d,， Tim Roseb， and Ralph E. Harbache

Although hematophagy is found in ～14,，000 species of extant insects,， the fossil record of blood-feeding insects is extremely poor and largely confined to specimens identified as hematophagic based on their taxonomic affinities with extant hematophagic insects； direct evidence of hematophagy is limited to four insect fossils in which trypanosomes and the malarial protozoan Plasmodium have been found. Here,， we describe a blood-engorged mosquito from the Middle Eocene Kishenehn Formation in Montana. This unique specimen provided the opportunity to ask whether or not hemoglobin,， or biomolecules derived from hemoglobin， were preserved in the fossilized blood meal. The abdomen of the fossil mosquito was shown to contain very high levels of iron,， and mass spectrometry data provided a convincing identification of porphyrin molecules derived from the oxygen-carrying heme moiety of hemoglobin. These data confirm the existence of taphonomic conditions conducive to the preservation of biomolecules through deep time and support previous reports of the existence of heme-derived porphyrins in terrestrial fossils.