Sperm competition is one of the forces that have led to high variability in insect sperm shapes, or morphology.

1. sperm from Eosentonon transitorium

2. fishlike sperm from Telmatoscopus albipuntu

3. sperm bundle from the fishfly Parachauliodes japonicus

4. 1 mm sperm from the dung beetle Onthophagu taurus

5. short and long sperm from Plodia interpunctella

6. paired sperm from the water beetle Dytiscus marginalis

7. giant 58 mm sperm from Drosophila bifurca

8. hook-headed sperm from Tessellata tesselata