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Here is a little graphical palate cleanser: we visualized the life cycle of the parasite Schistocephalus solidus, which requires ingestion by a copepod, a fish and a bird—in that order—to survive and reproduce.

The parasitic cestode Schistocephalus solidus requires a much larger host—specifically, a three-spined stickleback fish—to grow in and then a bird to breed in.

In an echo of the ancient Roman system of libra, solidus and denarius, a pound was divided into 12 shillings and 240 silver pennies.

And if he shall have taken nothing, or have escaped by flight, he shall, for the housebreaking alone, be sentenced to 1,200 denarii, which make 30 solidi.

Another creature that is likely to flourish in warmer waters is the Schistocephalus solidus tapeworm.