A fossilized biting midge found in India preserved in amber dates back some 54 million years, says an international team of paleontologists.
Camptopterohelea odora in amber from Gujarat State, western India. Scale bar – 0.2 mm. Image credit: Frauke Stebner / University of Bonn.
From studying the amber from Gujarat State in western India, the research team led by University of Bonn scientist Frauke Stebner concluded the specimen was a female about 0.9 mm long.
The ancient insect, named Camptopterohelea odora, had an unusual structure at the front edge of the wings.
“C. odora exhibits a complex, pocket shaped structure on the wings, which resembles the wing folds of certain moth flies and scent organs that are only known from butterflies and moths so far,” the scientists said.
They assume that these ‘pockets’ were used by the female midge to collect store and spray disseminate pheromones in an unusually efficient way in order to attract sexual partners.
“Biting midge species alive today do not have these ‘pockets’ on their wings,” Stebner noted.
The structure protrudes from the wings like a bubble that is open at the bottom with an edge made from fine hairs.
“Butterflies have very similar pockets on their front wings, which they use to spray pheromones into the air in order to attract a mate,” Stebner said.
“The position at the edge of the wing makes it possible to spray the messenger substance as widely as possible into the surrounding air. The small hairs clearly ensure, via turbulence, that the distribution is even more successful.”
Present-day biting midges use attractants for their ‘blind dates’ — however, they do not distribute the substances from their wings but instead from their abdomen.
“It is noticeable that the pheromone evaporators in Camptopterohelea odora are much more complex than in present-day biting midges,” said senior author Prof. Jes Rust, also from the University of Bonn.
“The environmental conditions in the 54 million-year-old primeval forests in what is now India clearly made such an adaptation necessary.”
“Presumably there were various species of insect at that time that all wanted to attract their sexual partners using pheromones. Unusually effective distribution techniques were probably necessary in order to thrive in this pheromone concert.”
The team describes Camptopterohelea odora in the latest issue of the journal Scientific Reports.
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Frauke Stebner et al. A fossil biting midge (Diptera: Ceratopogonidae) from early Eocene Indian amber with a complex pheromone evaporator. Scientific Reports 6, article number: 34352; doi: 10.1038/srep34352
