0000000001036246
AUTHOR
Kati Saarinen
Lierojen parittelumenestyksen yhteys sää- ja ympäristöoloihin, yksilötiheyteen ja yksilön kokoon
Yksilön kelpoisuus riippuu jälkeläistuotosta, ja parittelumenestys on yksi jälkeläistuoton avaintekijöistä. Monien eläinlajiryhmien lisääntymistä on tutkittu laajasti sekä laboratorio-oloissa että luonnossa, mutta lierojen lisääntymismenestykseen vaikuttavia tekijöitä luonnonpopulaatioissa ei vielä juurikaan tunneta. Tämän tutkimuksen tavoitteena oli selvittää, miten kahden ekologialtaan erilaisen lierolajin parittelumenestys riippuu ympäristöoloista, yksilötiheydestä ja yksilön koosta. Tutkimuksessa käytettiin tietoja lieronäytteistä, jotka oli kerätty syksyinä 2004 ja 2005 viljelymailta eri puolilta Suomea. Spermatoforien esiintymistä yksilöillä käytettiin indikaattorina näytteenottoa ede…
FLUCTUATING TEMPERATURE LEADS TO EVOLUTION OF THERMAL GENERALISM AND PREADAPTATION TO NOVEL ENVIRONMENTS
Environmental fluctuations can select for generalism, which is also hypothesized to increase organisms' ability to invade novel environments. Here, we show that across a range of temperatures, opportunistic bacterial pathogen Serratia marcescens that evolved in fluctuating temperature (daily variation between 24°C and 38°C, mean 31°C) outperforms the strains that evolved in constant temperature (31°C). The growth advantage was also evident in novel environments in the presence of parasitic viruses and predatory protozoans, but less clear in the presence of stressful chemicals. Adaptation to fluctuating temperature also led to reduced virulence in Drosophila melanogaster host, which suggests…
Experimental evolution in fluctuating environments: tolerance measurements at constant temperatures incorrectly predict the ability to tolerate fluctuating temperatures
The ability to predict the consequences of fluctuating environments on species distribution and extinction often relies on determining the tolerances of species or genotypes in different constant environments (i.e. determining tolerance curves). However, very little is known about the suitability of measurements made in constant environments to predict the level of adaptation to rapidly fluctuating environments. To explore this question, we used bacterial clones adapted to constant or fluctuating temperatures and found that measurements across a range of constant temperatures did not indicate any adaptation to fluctuating temperatures. However, adaptation to fluctuating temperatures was onl…
Invasion triple trouble : environmental fluctuations, fluctuation-adapted invaders and fluctuation-mal-adapted communities all govern invasion success
AbstractIt has been suggested that climate change will lead to increased environmental fluctuations, which will undoubtedly have evolutionary consequences for all biota. For instance, fluctuations can directly increase the risk of invasions of alien species into new areas, as these species have repeatedly been proposed to benefit from disturbances. At the same time increased environmental fluctuations may also select for better invaders. However, selection by fluctuations may also influence the resistance of communities to invasions, which has rarely been tested. We tested eco-evolutionary dynamics of invasion with bacterial clones, evolved either in constant or fluctuating temperatures, an…
Propagule pressure increase and phylogenetic diversity decrease community’s susceptibility to invasion
Background Invasions pose a large threat to native species, but the question of why some species are more invasive, and some communities more prone to invasions than others, is far from solved. Using 10 different three-species bacterial communities, we tested experimentally if the phylogenetic relationships between an invader and a resident community and the propagule pressure affect invasion probability. Results We found that greater diversity in phylogenetic distances between the members of resident community and the invader lowered invasion success, and higher propagule pressure increased invasion success whereas phylogenetic distance had no clear effect. In the later stages of invasion,…
Adaptation to fluctuations in temperature by nine species of bacteria
Rapid environmental fluctuations are ubiquitous in the wild, yet majority of experimental studies mostly consider effects of slow fluctuations on organism. To test the evolutionary consequences of fast fluctuations, we conducted nine independent experimental evolution experiments with bacteria. Experimental conditions were same for all species, and we allowed them to evolve either in fluctuating temperature alternating rapidly between 20°C and 40°C or at constant 30°C temperature. After experimental evolution, we tested the performance of the clones in both rapid fluctuation and in constant environments (20°C, 30°C and 40°C). Results from experiments on these nine species were combined meta…
The evolution of temperature tolerance and invasiveness in a fluctuating thermal environment
The consequences of the climate change on species are still uncertain, despite of intensive research. Currently, rising temperature is not the only concern, since the climate change scenarios also predict increases in the amount of disturbances, such as storms, floods, and thermal fluctuations. Disturbances have also been shown to affect species’ evolution, for example by selecting for traits that are advantageous in fluctuating environments but are also facilitating invasiveness. In this thesis, I study the consequences of evolving in a fluctuating thermal environment by utilizing bacterial microcosms. First I tested the effects of fluctuating vs. constant temperature on the evolution of t…
Data from: Fluctuating temperature leads to evolution of thermal generalism and preadaptation to novel environments
Environmental fluctuations can select for generalism, which is also hypothesized to increase organisms’ ability to invade novel environments. Here, we show that across a range of temperatures, opportunistic bacterial pathogen Serratia marcescens that evolved in fluctuating temperature (daily variation between 24°C and 38°C, mean 31°C) outperforms the strains that evolved in constant temperature (31°C). The growth advantage was also evident in novel environments in the presence of parasitic viruses and predatory protozoans, but less clear in the presence of stressful chemicals. Adaptation to fluctuating temperature also led to reduced virulence in Drosophila melanogaster host, which suggests…
Data from: Propagule pressure increase and phylogenetic diversity decrease community’s susceptibility to invasion
Invasions pose a large threat to native species, but the question of why some species are more invasive, and some communities more prone to invasions than others, is far from solved. Using ten different three-species bacterial communities, we tested experimentally if the phylogenetic relationships between an invader and a resident community and propagule pressure affect invasion probability. We found that greater diversity in phylogenetic distances between the resident community members and the invader lowered invasion success, and higher propagule pressure increased invasion success whereas phylogenetic distance had no clear effect. In the later stages of invasion phylogenetic diversity ha…