A trade-off between thickness and length in the zebra finch sperm mid-piece. Issue 1883 (25th July 2018)

• Record Type: Journal Article
• Authors: Mendonca, Tania; Birkhead, Tim R.; Cadby, Ashley J.; Forstmeier, Wolfgang; Hemmings, Nicola
• Is Part Of: Proceedings. Volume 285:Issue 1883(2018)
• Publication Date: 2018-07-25
• Subjects: zebra finch -- sperm morphology -- mitochondrial helix -- mid-piece volume -- ATP -- cristae density; Biology -- Periodicals; 570.5
• DOI: 10.1098/rspb.2018.0865
• Languages: English
• ISSNs: 0962-8452

Abstract

Abstract : The sperm mid-piece has traditionally been considered to be the engine that powers sperm. Larger mid-pieces have therefore been assumed to provide greater energetic capacity. However, in the zebra finch Taeniopygia guttata, a recent study showed a surprising negative relationship between mid-piece length and sperm energy content. Using a multi-dimensional approach to study mid-piece structure, we tested whether this unexpected relationship can be explained by a trade-off between mid-piece length and mid-piece thickness and/or cristae density inside the mitochondrial helix. We used selective plane illumination microscopy to study mid-piece structure from three-dimensional images of zebra finch sperm and used high-resolution transmission electron microscopy to quantify mitochondrial density. Contrary to the assumption that longer mid-pieces are larger and therefore produce or contain a greater amount of energy, our results indicate that the amount of mitochondrial material is consistent across mid-pieces of varying lengths, and longer mid-pieces are simply proportionately 'thinner'.