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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effects of climate on phenological synchrony between butterflies and their host plants

Posledovich, Diana January 2015 (has links)
Shifts in species’ phenologies and phenological asynchronies between the interacting organisms have received a lot of attention in the context of climate change. Changes in temporal overlap between species, caused by phenological asynchrony, make species depending on one another become so separated in time that they can no longer interact. This may have important consequences both for single species, like fluctuations in abundances, and for the functioning of whole communities by creating mismatches between trophic levels and rearrangements of community structure. This thesis focuses on the impact of temperatures on spring timing and phenological synchrony in a herbivorous insect – host plant system, consisting of the orange tipbutterfly Anthocharis cardamines and five of its Brassicaceae host plant species. Paper I demonstrates that diapause duration and winter thermal conditions can determine the timing of spring emergence in the herbivore, and these traits may differ between species with different feeding strategies. In paper II we show that thermal reaction norms of post-winterdevelopment of A. cardamines display cogradient latitudinal variation.Paper III shows that temperature-mediated phenological plasticity of A. cardamines butterflies and a majority of the most used host plant species is similar within populations originating from different latitudes. Thus, the species’ timing appeared well conserved in response to thermal variation. In paper IV we explored the importance of the butterfly’s adult emergence and thermal conditions on the succeeding part of the butterfly’s life-cycle – larval development. The outcome from the interaction was examined for both the insect and the plant side. The degree in phenological overlap between the female butterflies and host plants as well as temperatures during larval development were found to influence larval development but had no effect on plant reproductive fitness. The four papers of the presented thesis demonstrate that developmental preadaptations, evolvedin a herbivore to maintain phenological synchrony with host plants across yearly variation of spring conditions, can prevent disruption of the interaction under a wide range of temperatures. This indicates that temporary constrained interactions are not always vulnerable to decoupling, particularly if they involve generalist strategy. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Submitted.</p> / Ekoklim
2

Phenotypic Variation in the Social Behaviour of the Spider Anelosimus studiosus Along a Latitudinal Gradient

Riechert, Susan, Jones, Thomas C. 01 June 2008 (has links)
We investigated the behavioural mechanism underlying the recently discovered latitudinal variation in the social structure of the spider Anelosimus studiosus through population censuses, behavioural interaction trials, reciprocal nest transplants to different temperature environments and breeding experiments. Nest censuses completed at replicated sites at 2° changes in latitude between south Florida (26°) and east Tennessee (36°) indicated that the dominant social structure is a solitary female nest. Multifemale nests consisting of cooperative females and their young first appeared in the populations at 30° latitude and increased in frequency of representation with further increases in latitude as did number of females within multifemale nests. Interaction trials showed that communication and physical contact underlie the two social structures. Females from solitary female nests and F1 offspring reared in the laboratory demanded space (asocial phenotype), whereas individuals of multifemale nest origin (from same and foreign nests) were attracted to one another (social phenotype). Field experiments further showed that (1) individuals that dispersed from multifemale nests dispersed shorter distances and (2) nest coalescence was observed only at the higher latitudes, coincident with the presence of multifemale nests. Habitat transplants suggested that the behaviour underlying social structure is not plastic in this system, and breeding experiments eliminated a cryptic species alternative to the presence of different social structure phenotypes. Although both asocial and social phenotypes were present at all latitudes, the frequency of the social phenotype was rare at lower latitudes.
3

Latitudinal Variation in Lifetime Survival and Reproduction in a Burying Beetle

Laidlaw, Clinton T. 01 March 2015 (has links) (PDF)
Temperature variation experienced across a latitudinal range is tied to changes in lifespan and life history across multiple taxa. Two patterns of adaptation to latitudinal temperature variation have been documented – counter-gradient (or co-gradient) variation, and local adaptation. To determine how natural selection has shaped life history variation in a burying beetle, Nicrophorus orbicollis, we quantified lifetime patterns of reproduction in two populations that represent the geographic and temperature extremes occupied by the species. Lifetime reproduction was quantified at two temperatures that represented conditions typical for each population. Burying beetles from different extremes of their geographic range show considerable variation in lifetime survival and reproduction at different temperatures. Patterns are generally consistent with the local adaptation hypothesis. However, at the higher temperature both populations have lower and equal numbers of offspring over a lifetime. High temperatures may create a constraint on offspring production because of the increased cost of maintaining the food source against bacterial decomposition. This temperature constraint on reproductive success may partially explain the absence of burying beetles from tropical environments, and may predict reductions in latitudinal range as global climate change proceeds.
4

Crescimento e dinâmica reprodutiva do camarão-ferrinho Rimapenaeus constrictus (Stimpson, 1874) (Penaeoidea) no litoral norte do estado de São Paulo síntese de cinco anos de estudo /

Lopes, Ana Elisa Bielert January 2017 (has links)
Orientador: Antonio Leão Castilho / Resumo: This is the first study to evaluate in broad spatiotemporal scales the growth parameters and population structure of Rimapenaeus constrictus, a barely damaged species composing the bycatch from shrimp fishing in the Western Atlantic. The abundance and size-class frequency distribution, growth, longevity and sex ratio were evaluated from monthly samples obtained in the northern littoral of São Paulo state from Jan/1998 to Jun/2003. We measured 5,812 individuals in which the sex ratio was skewed toward females; this was more evident in size classes greater than 10 mm in CL (carapace length) (binomial test, p<0.05). We selected 16 growth cohorts of females, and 8 of males, the majority consisting of younger individual cohorts excluded from the fisheries closure period. Growth estimates resulted in a CL∞ of 17.42 mm, a growth coefficient of 0.008 and a longevity of 579 days (1.60 year) for females, as well as a CL∞ of 16.3 mm, a growth coefficient of 0.01 and a longevity of 425 days (1.17 year) for males. Our results provide information of incontestable relevance to our knowledge of fishing management. We therefore strongly recommend that the fisheries closure period be changed to protect this species’ recruitment period and consequently its adult individuals. The reproduction and recruitment were analyzed in order to determine the size at the onset of sexual maturity, the reproductive and recruitment patterns and the copulation period. In our study, 6,456 shrimps were captured a... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
5

Crescimento e dinâmica reprodutiva do camarão-ferrinho Rimapenaeus constrictus (Stimpson, 1874) (Penaeoidea) no litoral norte do estado de São Paulo: síntese de cinco anos de estudo / Growth and reproductive dynamics of the roughneck shrimp Rimapenaeus constrictus (Stimpson, 1874) (Penaeoidea) on the north coast of the São Paulo state: synthesis of a five-year study

Lopes, Ana Elisa Bielert [UNESP] 02 August 2017 (has links)
Submitted by ANA ELISA BIELERT LOPES null (anaelisa_lopes@hotmail.com) on 2017-09-29T18:51:09Z No. of bitstreams: 1 Dissertação Ana Elisa B. Lopes - com artigo anexado.pdf: 3755415 bytes, checksum: 2f9f1960e6fda6593835653e5f78966a (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-09-29T19:28:01Z (GMT) No. of bitstreams: 1 lopes_aeb_me_bot.pdf: 3755415 bytes, checksum: 2f9f1960e6fda6593835653e5f78966a (MD5) / Made available in DSpace on 2017-09-29T19:28:01Z (GMT). No. of bitstreams: 1 lopes_aeb_me_bot.pdf: 3755415 bytes, checksum: 2f9f1960e6fda6593835653e5f78966a (MD5) Previous issue date: 2017-08-02 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / This is the first study to evaluate in broad spatiotemporal scales the growth parameters and population structure of Rimapenaeus constrictus, a barely damaged species composing the bycatch from shrimp fishing in the Western Atlantic. The abundance and size-class frequency distribution, growth, longevity and sex ratio were evaluated from monthly samples obtained in the northern littoral of São Paulo state from Jan/1998 to Jun/2003. We measured 5,812 individuals in which the sex ratio was skewed toward females; this was more evident in size classes greater than 10 mm in CL (carapace length) (binomial test, p<0.05). We selected 16 growth cohorts of females, and 8 of males, the majority consisting of younger individual cohorts excluded from the fisheries closure period. Growth estimates resulted in a CL∞ of 17.42 mm, a growth coefficient of 0.008 and a longevity of 579 days (1.60 year) for females, as well as a CL∞ of 16.3 mm, a growth coefficient of 0.01 and a longevity of 425 days (1.17 year) for males. Our results provide information of incontestable relevance to our knowledge of fishing management. We therefore strongly recommend that the fisheries closure period be changed to protect this species’ recruitment period and consequently its adult individuals. The reproduction and recruitment were analyzed in order to determine the size at the onset of sexual maturity, the reproductive and recruitment patterns and the copulation period. In our study, 6,456 shrimps were captured among which 5,774 were measured, which 4,322 were females and 1,452 were males. The estimated maturity was 8.3 mm and 11.2 mm, for males and females, respectively. Reproductive females were found over the 5-year study. These results suggests a continuous reproduction pattern, with peaks in summer and in spring. We verified a positive significant relation between reproductive females and temperature (lag +1 and +3), although the decrease in bottom water temperature in some peaks of reproductive activity (spawning), which was probably induced due to SACW intrusion. The recruitment was considered episodic and even though no significant relation was found between immatures and reproductive females, we suggested that the main recruitment peaks observed were a consequence of the major reproductive activities a few months prior to it. The copulation period was continuous in the sampled period, and ISP females (recently copulated) were significant correlated with reproductive males (lag 0). Thus, we propose that during this period the sexual proportion is 1:1, probably due to the migration of reproductive males, attracted to copulate. Our results provide information of incontestable relevance to our wide knowledge of the species’ reproductive biology, in order to support an accurate fishing management. / FAPESP: 2015/13639-5
6

Biological and Ecological Trait Associations and Analysis of Spatial and Intraspecific Variation in Fish Traits

Henebry, Michael Lee 21 July 2011 (has links)
Traits provide an informative approach to examine species-environment interactions. Often, species-by-species approaches are inefficient to generate generalizable ecological relationships and do not predict species responses to environmental changes based on specific traits species possess. Multiple lines of inquiry and multi-scale approaches are best for assessing environment-trait responses. This thesis examines important questions not specifically addressed before in traits-based research. Chapter one explores biological and ecological trait associations incorporating ontogenetic diet shifts for New River fishes. Niche shift analysis as a chapter one sub-objective quantitatively support where species-specific diet shifts likely occur. Strong biological-ecological trait associations, some intuitive and others not so intuitive, were found that relate biological structure to ecological function. Improved understanding of trait associations, including what factors influence others, supports inference of ecology of fishes. Chapters two and three examine spatial and intraspecific trait variability. Chapter two specifically examines large-scale life history trait variability along latitudinal gradients for twelve widely distributed fish species, including directionality of trait variation, and hypothesizing how optimal traits change with large-scale environmental factors. Strong positive and negative patterns found include average total length of newly hatched larvae, average total length at maturation, average spawning temperature, average egg diameter, and maximum length. These five traits are correlated with other adaptive attributes (i.e. growth rate, reproductive output, and longevity/population turnover rate). In contrast to latitudinal scale, Chapter three examines trait variability of white sucker (Catostomus commersonii) and fantail darter (Etheostoma flabellare) as a function of small-watershed scale spatial factors and anthropogenic disturbance. Toms Creek and Chestnut Creek white sucker and fantail darter displayed positive response to disturbance, contrary to past studies. Lower resource competition, and / or competitive exclusion of fishes with similar niche requirements are possible mechanisms. All three objectives support understanding of trait association and variability as a useful foundation in ecological applications and for formulating plans for conservation and management of species. / Master of Science

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