title: The distribution of parasite strains among hosts affects disease spread in a social insect.
abstract: Social insects present highly interesting and experimentally amenable systems for the study of disease transmission because they naturally live in dense groups of frequently interacting individuals. Using experimental inoculations of five trypanosomatid strains into groups of its natural host, the bumblebee Bombus terrestris, we investigate the effects of the initial parasite strain distribution across group members on the establishment and transmission success of the different strains to new hosts. For a given number of parasite strains circulating within a host group, transmission to new hosts was increased when the strains were initially inoculated as mixed infections (as opposed to separate single infections), presumably because mixed infections generally favored fast replicating strains. In contrast, separate single infections reduced transmission at least in part through a precedence effect, whereby weak strains appeared to persist by making their host unavailable to superinfection. These results suggest that host groups could benefit from 'compartmentalizing' infections by different parasite strains across different group members, which might be achieved in social insects, for example, by division of labor.
authors: ETH Zurich, Institute of Integrative Biology (IBZ), ETH-Zentrum CHN, Universitätsstrasse 16, CH-8092 Zurich, Switzerland; Laboratory of Insect Social Evolution, The Rockefeller University, 1230 York Avenue, 10065 New York, NY, USA. Electronic address: yulrich@rockefeller.edu.
authors: Yuko
authors: Y
authors: Ulrich
authors: ETH Zurich, Institute of Integrative Biology (IBZ), ETH-Zentrum CHN, Universitätsstrasse 16, CH-8092 Zurich, Switzerland.
authors: Paul
authors: P
authors: Schmid-Hempel
mesh_terms: D000818:Animals; D001516:Bees / Q000469:parasitology*; D003421:Crithidia / Q000145:classification / Q000302:isolation & purification*; D016054:DNA, Protozoan / Q000235:genetics; D056986:Euglenozoa Infections / Q000635:transmission* / Q000662:veterinary*; D005260:Female; D006790:Host-Parasite Interactions; D008297:Male; D015995:Prevalence; D011897:Random Allocation; D012919:Social Behavior
chemical_list: D016054:DNA, Protozoan
keywords: Mixed infection; Prevalence; Social insect; Transmission; Trypanosome