SIZE CORRELATIONS BETWEEN SUCKING LICE AND THEIR HOSTS

Ectoparasite size can be influenced by many factors; one is host size. Harrison’s rule states that larger hosts typically have larger parasites. In this study, sucking lice (Insecta: Anoplura) were used to test this rule. Sucking lice should provide a good test for this rule because they are generally host-specific and because, as a group, they parasitize hosts of different sizes. Also, sucking lice use their tibio-tarsal claws to grasp host hairs, therefore, correlations between claw size and host hair diameters were also tested. Raw analyses including 206 species of slide-mounted sucking lice from throughout the world, followed by analyses of phylogenetically subtracted data, were used to test the hypotheses that sucking louse body size is correlated with host body size and that sucking louse claw size is correlated with host hair diameters. Data from 3 separate louse families, Hoplopleuridae, Linognathidae and Polyplacidae, were also analyzed. Lice, their claws, and hairs were measured using a calibrated graticule fitted into the eyepiece of a compound microscope. The combined raw data showed that louse body and claw size were positively correlated with host body and hair size, respectively. However, afte