Localization of subcuticular iron-containing tissue in the red imported fire ant

Queens, alates, and three worker classes of the red imported fire ant, Solenopsis invicta Buren, were examined for the presence of internal iron concentrations using analytical and anatomical techniques. Iron-specific staining located subcuticular ferric material in the abdomens of major, media, and minor workers; however, tissues of worker heads and thoraces did not consistently contain areas of localized iron. Queens and alates also did not consistently stain for concentrated iron in body tissues. Gut and ommatidial tissues of all ants occasionally revealed iron-containing areas. Iron was confirmed by X-ray spectroscopy in positively stained tissues.