Institute for Agricultural and Forest Environment, Polish Academy of Sciences, Bukowska 19, 60-809, Poznań, Poland.
Department of Analytical Chemistry, Adam Mickiewicz University, Uniwersytetu Poznanskiego 8, 61-614, Poznań, Poland.
Sci Rep. 2020 Dec 17;10(1):22262. doi: 10.1038/s41598-020-79329-4.
Very little is known about how the elemental composition (ionome) of an insect cuticle varies as a result of different colouration. Using inductively-coupled plasma optical emission spectrometry (ICP-OES), we established ionomic profiles in microsamples of two adjacent regions of an insect cuticle with a contrasting colour pattern, namely, the black and orange regions of the elytra of the aposematic burying beetle Nicrophorus vespillo. The analysis revealed 53 elements (ranging in atomic weight from Na to Bi) occurring above the detection limit. The frequency of detectability of individual elements varied strongly, and only ten elements (Ba, Cu, Fe, K, Mg, Mn, P, Rb, Sb and Zn) were present in concentrations exceeding the detection limit in all the samples. The sum of concentrations of all elements in the orange regions of the elytra was 9% lower than in the black ones. The opposite distribution was displayed by the rare earth elements (REEs), the sum of which was 17% lower in the black elytral regions than in the orange ones. The concentrations of six elements were significantly higher in the black than in the orange regions: Al (by 97%), Cu (41%), Mn (14%), Na (46%), Se (97%) and W (47%). The concentrations of essential elements measured in both the black and orange regions exhibited very considerable variance: Ca (σ = 1834; 1882, respectively), K (145; 82) P (97; 76), Na (84; 53), Mg (24; 26) and Ba (9; 13). This, in part, could be attributed to individual differences, e.g. those resulting from the consumption of animal carcasses of different quality/chemical composition, but interference between elements and the consequent lowering of measurement quality are also possible. We highlight the fact that deeper insight into the basic relationship between insect colouration and variation in elemental composition requires micro-sampling of the homogeneous layers of an exoskeleton.
关于昆虫外骨骼的元素组成（离子组）因不同颜色而变化的方式，我们知之甚少。本研究使用电感耦合等离子体发射光谱法（ICP-OES），在具有对比色图案的昆虫外骨骼的两个相邻区域的微样本中建立了离子组谱，即具有警戒色的埋葬甲 Nicrophorus vespillo 的鞘翅的黑色和橙色区域。分析结果表明，有 53 种元素（原子量从 Na 到 Bi）的含量高于检测限。个别元素的可检测频率差异很大，只有 10 种元素（Ba、Cu、Fe、K、Mg、Mn、P、Rb、Sb 和 Zn）在所有样本中的浓度均超过检测限。橙色区域中所有元素的浓度总和比黑色区域低 9%。稀土元素（REEs）的分布则相反，黑色鞘翅区域的 REEs 总和比橙色区域低 17%。黑色区域中 6 种元素的浓度明显高于橙色区域：Al（高 97%）、Cu（高 41%）、Mn（高 14%）、Na（高 46%）、Se（高 97%）和 W（高 47%）。黑色和橙色区域中测量的必需元素的浓度表现出非常大的差异：Ca（分别为 σ=1834；1882）、K（145；82）、P（97；76）、Na（84；53）、Mg（24；26）和 Ba（9；13）。这部分可能归因于个体差异，例如，由于食用不同质量/化学成分的动物尸体而导致的差异，但元素之间的干扰和随之而来的测量质量下降也是可能的。我们强调，要深入了解昆虫颜色与元素组成变化之间的基本关系，需要对外骨骼的同质层进行微采样。
