東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Parasitism as a selective force shap...

The University of Wisconsin - Madison.

Linked to FindBook

Google Book

Amazon

博客來

Parasitism as a selective force shaping the ecology and evolution of an ancient ant-fungal-bacterial mutualism.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Parasitism as a selective force shaping the ecology and evolution of an ancient ant-fungal-bacterial mutualism./
Author:	Little, Ainslie Elizabeth Fowler.
Description:	118 p.
Notes:	Adviser: Cameron Currie.
Contained By:	Dissertation Abstracts International68-04B.
Subject:	Biology, Ecology. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3261508

Parasitism as a selective force shaping the ecology and evolution of an ancient ant-fungal-bacterial mutualism.
Little, Ainslie Elizabeth Fowler.

Parasitism as a selective force shaping the ecology and evolution of an ancient ant-fungal-bacterial mutualism. - 118 p.

Adviser: Cameron Currie.

Thesis (Ph.D.)--The University of Wisconsin - Madison, 2007.

Beneficial and antagonistic symbioses have been key sources of evolutionary innovation over the history of life. Although parasitic and mutualistic host-microbe interactions have been studied extensively, studies investigating the interactions between parasites and mutualists are currently lacking. Here I argue that exploitation of mutualisms is an important selective pressure shaping the ecology and evolution of symbioses. I explore this idea using the fungus-growing ant-microbe symbiosis as a model system. Fungus-growing ants have an obligate mutualism with the fungi they cultivate for food, which is exploited by parasites in the genus Escovopsis. To protect their crops from infection ants form a second mutualism with antibiotic-producing bacteria that have activity specific to Escovopsis. I detail the discovery of another level of parasitism within the ant-microbe symbiosis; black yeasts that exploit the ants' mutualistic bacteria and ultimately determine the success of the ant-fungal mutualism by altering symbiont dynamics. I then test the hypothesis that fungus-growing ants have evolved specialized behavioral responses to parasitism and reveal that the ants infrabuccal pocket functions as a specialized sterilization device, killing spores of Escovopsis. This is apparently achieved through symbiotic bacteria in the pocket, which produce antibiotics that inhibit Escovopsis, illustrating that the combination of behavior and microbial symbionts can be a successful host defense strategy. I then investigate how parasitism influences cooperative dynamics in the ant-fungus mutualism. Through empirical experiments and computer simulations I show that parasites help align the selfish interests of mutualists. My results suggest that when two mutualists have a 'common foe' selection favors cooperation over cheating, helping explain the evolutionary stability of mutualisms. Finally, I discuss instances of microbial symbiosis in which the microbe protects its host from natural enemies through secondary metabolite production. I explore ecological and evolutionary pressures that make microbes good defensive partners and suggest that developing of such relationships has been a common theme in the evolution of life. Collectively, these data show that parasitism has profoundly influenced the ecological and evolutionary dynamics of the fungus-growing ant symbiosis. Further, this work clearly illustrates that to better understand symbiosis, we need to research interactions in the symbionts' ecological community.Subjects--Topical Terms:

1017726
Biology, Ecology.

Parasitism as a selective force shaping the ecology and evolution of an ancient ant-fungal-bacterial mutualism.
LDR:03461nam 2200277 a 45 001 852655
005 20100630
008 100630s2007 ||||||||||||||||| ||eng d
035 $a (UMI)AAI3261508
035 $a AAI3261508
040 $a UMI $c UMI
100 1 $a Little, Ainslie Elizabeth Fowler. $3 1018633
245 1 0 $a Parasitism as a selective force shaping the ecology and evolution of an ancient ant-fungal-bacterial mutualism.
300 $a 118 p.
500 $a Adviser: Cameron Currie.
500 $a Source: Dissertation Abstracts International, Volume: 68-04, Section: B, page: 2034.
502 $a Thesis (Ph.D.)--The University of Wisconsin - Madison, 2007.
520 $a Beneficial and antagonistic symbioses have been key sources of evolutionary innovation over the history of life. Although parasitic and mutualistic host-microbe interactions have been studied extensively, studies investigating the interactions between parasites and mutualists are currently lacking. Here I argue that exploitation of mutualisms is an important selective pressure shaping the ecology and evolution of symbioses. I explore this idea using the fungus-growing ant-microbe symbiosis as a model system. Fungus-growing ants have an obligate mutualism with the fungi they cultivate for food, which is exploited by parasites in the genus Escovopsis. To protect their crops from infection ants form a second mutualism with antibiotic-producing bacteria that have activity specific to Escovopsis. I detail the discovery of another level of parasitism within the ant-microbe symbiosis; black yeasts that exploit the ants' mutualistic bacteria and ultimately determine the success of the ant-fungal mutualism by altering symbiont dynamics. I then test the hypothesis that fungus-growing ants have evolved specialized behavioral responses to parasitism and reveal that the ants infrabuccal pocket functions as a specialized sterilization device, killing spores of Escovopsis. This is apparently achieved through symbiotic bacteria in the pocket, which produce antibiotics that inhibit Escovopsis, illustrating that the combination of behavior and microbial symbionts can be a successful host defense strategy. I then investigate how parasitism influences cooperative dynamics in the ant-fungus mutualism. Through empirical experiments and computer simulations I show that parasites help align the selfish interests of mutualists. My results suggest that when two mutualists have a 'common foe' selection favors cooperation over cheating, helping explain the evolutionary stability of mutualisms. Finally, I discuss instances of microbial symbiosis in which the microbe protects its host from natural enemies through secondary metabolite production. I explore ecological and evolutionary pressures that make microbes good defensive partners and suggest that developing of such relationships has been a common theme in the evolution of life. Collectively, these data show that parasitism has profoundly influenced the ecological and evolutionary dynamics of the fungus-growing ant symbiosis. Further, this work clearly illustrates that to better understand symbiosis, we need to research interactions in the symbionts' ecological community.
590 $a School code: 0262.
650 4 $a Biology, Ecology. $3 1017726
650 4 $a Biology, Entomology. $3 1018619
650 4 $a Biology, Microbiology. $3 1017734
690 $a 0329
690 $a 0353
690 $a 0410
710 2 $a The University of Wisconsin - Madison. $3 626640
773 0 $t Dissertation Abstracts International $g 68-04B.
790 $a 0262
790 1 0 $a Currie, Cameron, $e advisor
791 $a Ph.D.
792 $a 2007
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3261508