Posted by: Didapper PJ12 MAR 2009
I have been musing of late on the names bestowed on caterpillars by the authors of children’s books. As one does.
Children’s literature is full of stories about dull little grubs that eventually metamorphose into gorgeous butterflies. The best known example is surely Eric Carle’s nameless Very Hungry Caterpillar, but other authors have given their caterpillars a variety of monikers, including Bob, Caleb, Cameron, Catie, Charlie, Clara, Hermie, Hubert, Katie, Percival, Sam and Zeke.
How do they choose such names? If I were writing about a butterfly caterpillar I would be tempted to call it Cordelia, Cressida, Greta, Imelda, Juditha, Lucia, Pamela, Patricia, Una or Vanessa. Why?
Because those are all names bestowed by taxonomists on genera of butterflies in the real world. Vanessa, for instance, is the genus that includes the widespread red admiral (V atalanta) and painted lady (V cardui).
Of the others I have listed, Cressida is of some interest if only because C cressida, the sole species in the genus, has one of the least appealing vernacular names in all lepidopterology. An Australian swallowtail, it has been dubbed “big greasy” because of the oily appearance of its semi-transparent forewings.
You are no doubt wondering where all this is leading. Well here comes the pharmaceutical bit. One of Cressida’s cousins is a huge swallowtail known as the Madagascan birdwing.
And its name is Pharmacophagus antenor.
Pharmacophagus? The name means drug-eater, and it gets that name because its caterpillars feed on a species of Aristolochia, a large genus of vines that have been used medicinally since the time of the Ancient Egyptians.
The vines contain poisonous compounds, dubbed aristolochic acids, which the caterpillars are able to tolerate. And by sequestering the toxins they make themselves unpalatable to predators.
One of aristolochia’s English names is birthwort, because the juice from its stems was once used to induce labour or to expel the placenta. Several aristolochia species have been used to treat snakebite — perhaps justifiably, since there is some evidence that aristolochic acids can bind with and deactivate a phospholipase found in some snake venoms.
The plants have also been used in traditional Chinese medicine for the treatment of fluid retention and rheumatic symptoms.
Aristolochic acids are said to stimulate white blood cell activity and aid wound healing, but they have also been shown to cause kidney failure and cancer.
Because of this, the medicinal use of aristolochia is now banned in the UK under the Medicines (Aristolochia and Mu Tong etc) (Prohibition) Order 2001. But at least Britain’s butterfly houses can still grow it as nosh for the larvae of their tropical beauties.