As climate change shifts the geographic ranges in which animals can be found, concern mounts over the effect it has on their parasites. Does an increased range for a host mean new territory for its parasites as well?
Not necessarily, says a team of UC Santa Barbara scientists, including parasitologists Ryan Hechinger and Armand Kuris. In a study published in the Journal of Biogeography, Hechinger, Kuris and colleagues show that for some species, the opposite may happen: Hosts may actually lose their parasites when the hosts shift or increase their range. Theirs is one of very few studies that examine the effects of climate change on the lives of often overlooked but nonetheless significant parasite populations. Also contributing to the paper as lead author is Julie Hopper, now a Ph.D. student at UC Berkeley. Hopper was a student at UCSB when the research was conducted.
"We asked the question: Do hosts that have expanded their range escape their parasites?" said Hopper. The researchers predicted that they might, given previous findings that invasive species species that have also increased their range, but to areas not geographically connected to their historic ranges tend to escape their parasites.
"Invasive species escape parasites for several reasons," said Hechinger, an associate research biologist/professor at UCSB and Scripps Institute of Oceanography. "Many parasites do not come with the invader to begin with they miss the boat." He added that many parasites that accompany their invasive host do not persist because the parasites, many of which live parts of their life cycles in different hosts, no longer have access to the environments or other hosts required to complete their life cycles. On top of this loss of parasites, invasive hosts do not acquire many new ones in their invasive ranges, which explains the hosts' overall escape from parasites.
But what happens when a species expands its range by moving
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University of California - Santa Barbara