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Host inbreeding increases susceptibility to ectoparasitism
Author(s) -
LUONG L. T.,
HEATH B. D.,
POLAK M.
Publication year - 2007
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2006.01226.x
Subject(s) - biology , inbreeding , inbreeding depression , genetics , parasitism , host (biology) , population , allele , population fragmentation , zoology , evolutionary biology , gene , demography , sociology
Inbreeding, which increases homozygosity throughout the genome by increasing the proportion of alleles that are identical by descent, is expected to compromise resistance against parasitism. Here, we demonstrate that host inbreeding increases susceptibility to ectoparasitism in a natural fruit fly ( Drosophila nigrospiracula ) – mite ( Macrocheles subbadius ) association, and that this effect depends on host genetic background. Moreover, flies generated from reciprocal crosses between susceptible inbred lines exhibited elevated levels of resistance similar to that in the mass‐bred base population, confirming in reverse direction the causative link between expected heterozygosity and resistance. We also show that inbreeding reduces the host's ability to sustain energetically expensive behaviours, and that host exhaustion dramatically increases susceptibility. These findings suggest that inbreeding depression for resistance results from an inability to sustain defensive behaviours because of compromised physiological competence.