Host–parasite interactions in a fragmented landscape

• Published in: International journal for parasitology 2013-01, Vol.43 (1), p.27-35
• Main Authors: Renwick, A.R., Lambin, X.
• Format: Article
• Language: English
• Subjects: Alternative hosts; Animals; Biological and medical sciences; Dilution effect; Ecosystem; Female; Fleas; Fundamental and applied biological sciences. Psychology; Habitat loss; Host-Parasite Interactions; Insecta; Invertebrates; Life cycle. Host-agent relationship. Pathogenesis; Male; Mammals; Population Density; Prevalence; Protozoa; Thresholds; Tick Infestations - epidemiology; Tick Infestations - veterinary; Ticks
• ISSN: 0020-7519; 1879-0135
• DOI: 10.1016/j.ijpara.2012.10.012

[Display omitted] ► Theory predicts that habitat fragmentation should reduce the risk of being parasitized. ► Ecto-parasites on field voles within a fragmented agro-ecosystem were collected. ► The probability of being infested with ecto-parasites decreased with host abundance. ► This suggests the presence of a type of dilution effect. Theory suggests that habitat fragmentation should reduce the risk of being parasitised due to reduced size and increased isolation of the host population. It is predicted that a threshold host population size exists, below which parasites will not be able to persist. Small mammals were trapped and their ecto-parasites removed in 14 field margins of varying widths over 2years in a highly fragmented agro-ecosystem. No evidence to suggest the presence of a threshold in parasite prevalence was found, which may be due to the high rate of host movement and transiency within the system. Contrary to expectation, the probability of infestation decreased with host abundance and the abundance of alternative hosts, suggesting a dilution effect. The relatively long life cycle of small mammal specialist tick and flea species present under the prevailing environmental conditions may have left the parasites unable to keep up with the rate of reproduction and dispersal of the host. It is important to consider changes in the behaviour of the host and the presence of alternative hosts when predicting the effects of habitat fragmentation on disease spread.