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Pollination Biology of the Endemic Erigeron lemmonii A. Gray, and its Insect Visitor Networks Compared to two Widespread Congeners Erigeron arisolius G.L. Nesom and Erigeron neomexicanus A. Gray (Asteraceae)

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Title: Pollination Biology of the Endemic Erigeron lemmonii A. Gray, and its Insect Visitor Networks Compared to two Widespread Congeners Erigeron arisolius G.L. Nesom and Erigeron neomexicanus A. Gray (Asteraceae)
Author: Bailey, Pamela
Department: Environmental Biology
Program: Environmental Sciences
Advisor: Kevan, PeterVoroney, Paul
Abstract: This thesis is an investigation of network analysis to understand differences between how three congeners have adapted pollination network strategies to ensure adequate gene flow. This study will focus on three species of Erigeron (Fleabanes), one endemic species adapted to cliff wall habitat in one canyon fragmented by topography (E. lemmonii) at Fort Huachuca Military Reserve, and two others (E. arisolius and E. neomexicanus) adapted to more diverse habitat conditions in a larger range in Arizona, USA. Sustainability of military lands and protected species are primary concerns for Army land management, and these findings will be made available to the U.S. Army, and U.S. Fish and Wildlife Service resource managers to use in their respective management plans. UCINET software was used to construct the insect flower visitor networks for the three Erigeron species by recording insect visitors / plant interactions and comparing their visitation networks to each other. Erigeron arisolius and E. neomexicanus have redudndant network architecture, compared to E. lemmonii which has a fragile network supporting a unique insect community. If the E. lemmonii population disappears, a collapse of its dependent insect visitors may also occur. Other new botanical information was discovered and recorded for E. lemmonii. It has a xenogamous mating system, and can also reproduce by vegetative means. An individual capitulum has a three week flowering period, and the population has individual plants blooming over a six month flowering season with May being the peak. It grows in highly organic soil on cliff face crevices in the Scheelite Canyon. Another aspect was to develop and publish genetic microsatellite markers for the three species of Erigeron, which are the first microsatellite markers to be identified for this genus. This included determining the chromosome number of E. lemmonii, before the genetic markers could be identified for this species. Eight microsatellite markers were identified for E. lemmonii and nine markers were identified for E. arisolius. However, no markers for E. neomexicanus were identified because of confounding results. Erigeron lemmonii has less genetic diversity, lower mean heterozygosity and fewer alleles, than E. arisolius.
URI: http://hdl.handle.net/10214/6373
Date: 2013-04


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