The UK’s freshwater great diving beetle (Dytiscus marginalis) spends its life underwater. It hunts, feeds, and procreates in freshwater environments – which presents a physical challenge for those beetles looking to mount their mistress and sire a next generation of young larvae in the local pond.
Spike Walker – winner of a Wellcome Image Award 2011 – has taken a wonderfully colourful polarised micrograph image of how this aquatic dwelling beastie manages to pull off this underwater acrobatic feat (below). The colours were accomplished through a technique known as Rheinberg illumination, where light is passed through coloured filters onto the specimen.
The males have developed “plate-like proximal tarsal joints on their front legs”, and suckers with which they literally stick onto the females during mating (a certain song by Lionel Richie comes to mind… the title at least). The micrograph shows part of a joint, showing two large suckers and five rows of smaller suckers.