Featured Research

from universities, journals, and other organizations

Galapagos hawks hand down lice like family heirlooms

Date:
August 6, 2014
Source:
University of Arizona
Summary:
Studying Galápagos hawks and their lice, biologists provide some of the first field evidence for co-divergence between parasites and hosts as a major driver of biodiversity. As the birds diversify into distinct populations on each island, their parasites diversify with them. The findings help explain the rapid rate of parasite evolution.

A Galápagos hawk nesting on Isla Fernandina, Galapagos.
Credit: Photo by Noah Whiteman

A UA-led study provides some of the first evidence for the hypothesis of co-divergence between parasites and hosts acting as a major driver of biodiversity. Say what you will about the parasitic lifestyle, but in the game of evolution, it's a winner.

Given that about half of all known species are parasites, biologists have long hypothesized that the strategy of leeching off other organisms is a major driver of biodiversity. Studying populations of Galápagos hawks (Buteo galapagoensis) and feather lice that live in their plumage (Degeeriella regalis), a group led by University of Arizona ecologists and evolutionary biologists has gathered some of the first field evidence suggesting that a phenomenon called co-divergence between parasites and hosts is indeed an important mechanism driving the evolution of biodiversity.

"The idea is really simple," said the study's lead author, Jennifer Koop, who is a postdoctoral fellow in the lab of Noah Whiteman in the UA's Department of Ecology and Evolutionary Biology. "Each time a host population splits into separate populations that potentially become different species, we predict that their parasites could do the same thing."

However, biologists have long struggled to test this hypothesis, as parasites are elusive.

"Often, the evolutionary trees of parasites and their hosts are congruent -- they look like mirror images of one another," said Whiteman, who is an assistant professor in EEB, a joint assistant professor in the Department of Entomology and the School of Plant Sciences, and a member of the UA's BIO5 Institute. "But because parasites tend to be inside or attached to hosts, their distributions are difficult to study."

"We found the lice are passed on from mother to babies during brooding, almost like genes," Whiteman said. "They're evolutionary heirlooms, like your family's silverware or engagement ring diamond."

Because the hawks pass on the feather lice from generation to generation, the researchers wanted to know whether the louse populations diverge between populations of hawks and between individual hawks, or whether the populations of the birds and the lice diverged independently of each other.

Remarkably, the findings, which are published in the journal Biology Letters of the Royal Society, revealed that the population structure of the lice matched that of the birds across the archipelago, even though the two are very different species.

"To the lice, each bird is an island, and their populations are very different from bird to bird," Whiteman said. "The same pattern is repeated between bird populations on different islands. It's like Russian dolls."

In other words, the lice living on any one bird and its offspring are more closely related than the lice living on a different bird. As the birds diversify into distinct populations on each island, their parasites diversify with them. The findings help explain the rapid rate of parasite evolution, according to the research team.

"You have to be in the right spot at the right time to see this process happening," Koop said. "Our study empirically demonstrates an important evolutionary process in which the hawks separate into different populations, and the lice living on them do the same."

This process is hypothesized to lead to the formation of different species, in this case different species of hawks and lice, and may explain some of the extraordinary diversity seen among parasites, she said.

The team chose the Galápagos Islands, located 575 miles off the west coast of Ecuador, for the study because the species that colonized the geologically young group of islands have evolved in isolation, making the area an ideal natural laboratory.

"Of all the vertebrate species native to the Galápagos, the Galápagos hawk is the most recent arrival," Whiteman said. "So whatever is happening in terms of evolution of the bird population and the parasite population is most likely in the earliest stages of that process."

In four years of fieldwork on eight major islands, the team caught hundreds of Galápagos hawks -- which later were released unharmed -- and collected blood samples and feather lice for genomic analysis, in a partnership with the Galápagos National Park. Whiteman said the hawks' lice are specialized on their host species and the feathers they consume, and unable to survive on any other species.

Co-authors Karen DeMatteo and Patricia Parker, both at the Department of Biology at the University of Missouri-St. Louis, then used the DNA from the samples to generate a genetic fingerprint of each population. Parker helped with the fieldwork.

A better understanding of how parasites and their hosts coevolve has implications for biomedical sciences, according to Whiteman. In addition, it can help researchers who study parasites as evolutionary tags of the host species.

"The fact that we were able to work with these birds, which are the top predators in their habitat, and reveal some answers to fundamental questions in biology shows why such places should continue to be preserved," Whiteman said.

The study was supported by grants from the National Science Foundation, the Saint Louis Zoo's Field Research for Conservation, the University of Missouri Research Board, the John Templeton Foundation, a UA Faculty Seed Grant to Noah Whiteman and a National Institutes of Health-PERT postdoctoral fellowship to Jennifer Koop.


Story Source:

The above story is based on materials provided by University of Arizona. The original article was written by Daniel Stolte. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jennifer A. H. Koop, Karen E. Dematteo, Patricia G. Parker, and Noah K. Whiteman. Birds are islands for parasites. Biology Letters, 2014 DOI: 10 8 20140255

Cite This Page:

University of Arizona. "Galapagos hawks hand down lice like family heirlooms." ScienceDaily. ScienceDaily, 6 August 2014. <www.sciencedaily.com/releases/2014/08/140806173840.htm>.
University of Arizona. (2014, August 6). Galapagos hawks hand down lice like family heirlooms. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2014/08/140806173840.htm
University of Arizona. "Galapagos hawks hand down lice like family heirlooms." ScienceDaily. www.sciencedaily.com/releases/2014/08/140806173840.htm (accessed September 30, 2014).

Share This



More Plants & Animals News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Newsy (Sep. 30, 2014) — A new study published by the World Wide Fund for Nature found that more than half of the world's wildlife population has declined since 1970. Video provided by Newsy
Powered by NewsLook.com
Dolphins Might Use Earth's Magnetic Field As A GPS

Dolphins Might Use Earth's Magnetic Field As A GPS

Newsy (Sep. 30, 2014) — A study released Monday suggests dolphins might be able to sense the Earth's magnetic field and possibly use it as a means of navigation. Video provided by Newsy
Powered by NewsLook.com
How To Battle Stink Bug Season

How To Battle Stink Bug Season

Newsy (Sep. 30, 2014) — Homeowners in 33 states grapple with stink bugs moving indoors at this time of year. Here are a few tips to avoid stink bug infestations. Video provided by Newsy
Powered by NewsLook.com
California University Designs Sustainable Winery

California University Designs Sustainable Winery

Reuters - US Online Video (Sep. 27, 2014) — Amid California's worst drought in decades, scientists at UC Davis design a sustainable winery that includes a water recycling system. Vanessa Johnston reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins