Males once sucked blood too
Last month, the oldest known mosquito was described, named and published in the scientific journal Current Biology.
The two beautifully preserved fossils were in 135millionyearold Lower Cretaceous amber from Lebanon. The mosquitoes had long piercing stylet mouthparts, with modifications that indicate they almost certainly sucked blood.
This finding is completely unprecedented, because in modern mosquitoes, only females suck blood — to obtain iron and protein which enables them to mature eggs.
Males of all living mosquito species feed exclusively on plant nectar.
The two fossil males have exceptionally sharp, long, mouthparts, the mandible and lacinia with small toothlike denticles.
The new mosquito is named Libanoculex intermedius and is placed in its own newly created subfamily, Libanoculicinae.
The lead author of the paper, Danny Azar, found the fossil mosquitoes in Lebanon a decade ago, and was finally able to examine them closely with the very advanced optics and methods available in China at the
Laboratory of Palaeobiology and Stratigraphy, Centre for Excellence in Life and Palaeoenvironment, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences.
Bloodsucking in insects likely arose from species with piercing and sucking mouthparts that had evolved for feeding on plant fluids.
It is not known why all living male mosquitoes evolved away from bloodeating. It may have been to avoid being attacked by the irritated animals on whose blood they were feeding.
Male mosquitoes have thus moved from sucking plant juices, to sucking blood, and then black to feeding only from plant juices.
There are about 3600 species of mosquitoes, which comprise the family Culicidae of the order Diptera (true flies).
Mosquitoes have a slender body, one pair of wings, three pairs of long legs, elongated sucking mouthparts comprising stylets, long thin branched antennae which are larger and bushier in the male, and small scales like those of butterflies and moths on the wing veins and on the body. Eggs are laid in rafts on the water surface. The legless larva is aquatic and filterfeeds on small particles. The pupa also is aquatic and swims actively.
Mosquitoes are well known as carriers of protozoan and viral diseases. DNA studies indicate mosquitoes arose in the Jurassic period.
Flowering plants arose later, during the Cretaceous period, perhaps providing an adequate but less dangerous food source for male mosquitoes, which unlike the females, have no need for dietary iron and protein present in blood.