Chapter 28 - Blood Sucking

Abstract

This chapter discusses bloodsucking insects. Bloodsucking insects are of immense importance to humans, primarily because of the diseases they transmit. They also cause huge losses in animal husbandry because of disease transmission and because of direct losses linked to the pain and irritation they cause to animals. Bloodsucking insects in general feed on a range of different hosts, including birds, reptiles, mammals, and amphibians. Even invertebrates such as annelids, arachnids, and other insects are sometimes included in the diet. But any particular bloodsucking insect generally feeds only from a small segment of the available hosts. For example, lice and other bloodsucking insects that are permanently present on the host, finding a new host is simply a matter of moving from one to the other when the hosts are in bodily contact. For bloodsucking insects that are only in temporary contact with the host, finding a host is a more difficult proposition. Also, bloodsucking insects take huge meals. Temporary ectoparasites such as the Tsetse fly typically ingest more than their own unfed body weight in blood. The reasons are twofold. First, taking a blood meal is a very dangerous activity and taking huge blood meals minimizes the number of times an insect must associate with the host. Second, locating the host is often difficult and huge blood meals are a way of making the most of each encounter.