October 28. Bloodsucking parasites and other Jurassic insects

Something like 1,000 species of Jurassic insects have been described. Jurassic dragonflies were smaller than the giants of the Carboniferous, but still large, with wingspans on the order of 7 inches and bodies 5 inches long. They’ve been found in the Solnhofen limestone, and specimens are often offered for sale in the $1,200 to $2,000 range. The basic body plan of dragonflies hasn’t changed much over the history of the group, more than 300,000,000 years. 

Image of scorpionfly Jurassipanorpa sticta holotype. (Scale bar: 1 mm)
from He Ding, Chungkun Shih, Alexei Bashkuev, Yunyun Zhao,
and Dong Ren used under CCA-4.0-International

In 2014, researchers described a strange new insect from the Daohugou beds in northeastern China – an aquatic fly larva that is interpreted to be a salamander parasite, sucking the blood of its host to which it was attached somewhat like a remora on a shark, but only about an inch long. Those rocks in China have yielded more than 300,000 insect fossils, so that’s the source of a lot of our knowledge of Jurassic insects. Some show the color patterns in wings. And because the China locality represents just one tiny little ecosystem, it means that while we know a lot about it, there’s plenty more to know about Jurassic insects. 

One of the earliest examples of mimicry in the insect world is from a Jurassic fly from the Daohuguo beds whose wings look so much like gingko leaves that they were missed by early workers and discarded as “just another gingko leaf.” Such an adaptation would have certainly been advantageous to a bug in a world full of insectivores, from salamanders to early gliding mammals to small reptiles to, probably, early birds.

Beetles, crickets, caddis flies, moths, stoneflies, flea-like bugs, and more have been identified from Jurassic rocks around the world. Clearly, insects had diversified significantly early in their history, well before their explosive radiation that’s tied to the development of flowering plants, which we’ll get to next month.

—Richard I. Gibson

Image of scorpionfly Jurassipanorpa sticta holotype. (Scale bar: 1 mm) from He Ding, Chungkun Shih, Alexei Bashkuev, Yunyun Zhao, and Dong Ren used under CCA-4.0-International


News report:
Bloodsucking parasite