The origin of blood-feeding is largely discussed among entomologists to the extent that no common agreement exists. It relies heavily on paleontological records, which are most of the time incomplete and unreliable. However many authors agreed that hematophagous arthropods arose during the Cretaceous and Jurassic eras (145-65 MYA) (Balashkov, 1995). What is interesting, regardless of its origin, blood feeding evolved independently several times among different insect orders, and even within insect orders, such as the Diptera (Ribeiro, 1995).
Two possible evolutionary pathways to blood-feeding have been suggested. In the first route, blood-feeding arose among lineages that derived from ancestors that were morphologically adapted for piercing and consuming tissues (Waage, 1979), that accidently punctured the skin of vertebrates and found the blood more nutritious; consequently shifted their feeding preference to hematophagy.
This would have been the case of entomophagous arthropods that were attracted to nests and burrows with potentially more concentration of insects and ultimately increased their contact with vertebrates, or this contact may have occurred near sources of water (Lehane, 2005). Another possibility is that phytophagous insects may have also followed the same pattern to shift their feeding style to hematophagy.
However, in some insect order like Lepidoptera, hematophagy has developed very rarely despite them having ancestors that were pre-adapted to piercing and consuming tissues. The second evolutionary pathway would be the case of arthropods that had no pre-adaptations for piercing tissues.
They are believed to have developed intimate associations with potentials vertebrate hosts by living in nests and burrows with high abundance of food and more heat (Lehane, 2005). These arthropods would have first fed on organic matter, then on dead skin and eventually from the live skin, shifted their feeding habits on blood. For instance, ticks are believed to have evolved from a scavenger ancestor that feed.Whatever the case is, this hop to hematophagy had had a high selection value that required several adaptations to become very successful in this lifestyle. This is supported by the small number of arthropod species that feed on blood.