1 |
Sexual Selection on Females: Comparing Two Estimates of Mating Success in a Sex-role Reversed InsectRobson, Laura J. 15 February 2010 (has links)
While there has long been interest in the form of sexual selection in males, studies characterizing this selection in females remain sparse. Sexual selection on females is predicted for sex-role reversed Mormon crickets, where males are choosy of mates and nutrient-deprived females compete for matings to gain nutritious nuptial gifts. I used selection analyses to describe the strength and form of sexual selection on female morphology. There was no positive sexual selection on the female body size traits predicted to be associated with male preferences and female competition. Instead, I detected selection for decreasing head width and mandible length. Additionally, I tested the validity of a commonly-used instantaneous measure of mating success (mated vs. unmated) by comparing selection results with those determined using a more detailed fitness measure (cumulative mating rate). The two fitness measures yielded similar patterns of selection, supporting the common sampling method comparing mated and unmated fractions.
|
2 |
Sexual Selection on Females: Comparing Two Estimates of Mating Success in a Sex-role Reversed InsectRobson, Laura J. 15 February 2010 (has links)
While there has long been interest in the form of sexual selection in males, studies characterizing this selection in females remain sparse. Sexual selection on females is predicted for sex-role reversed Mormon crickets, where males are choosy of mates and nutrient-deprived females compete for matings to gain nutritious nuptial gifts. I used selection analyses to describe the strength and form of sexual selection on female morphology. There was no positive sexual selection on the female body size traits predicted to be associated with male preferences and female competition. Instead, I detected selection for decreasing head width and mandible length. Additionally, I tested the validity of a commonly-used instantaneous measure of mating success (mated vs. unmated) by comparing selection results with those determined using a more detailed fitness measure (cumulative mating rate). The two fitness measures yielded similar patterns of selection, supporting the common sampling method comparing mated and unmated fractions.
|
3 |
SPATIAL ECOLOGY OF SNAPPING TURTLE (CHELYDRA SERPENTINA) WITHIN AN URBAN WETLAND COMPLEXZachary Robert Kellogg (11559850) 22 November 2021 (has links)
The
conversion of natural habitat to urban areas has lasting impacts on wildlife
and biodiversity. Known effects to urban wildlife include direct mortality
while crossing roads, reduced species diversity, and habitat fragmentation and degradation.
Among wildlife occupying urban areas, turtle populations can be particularly
impacted in anthropogenic landscapes. Snapping Turtle (<i>Chelydra serpentina</i>)
is one of the most common species found within urban wetlands, but populations
are beginning to show declines in northern portions of their geographic range.
The preservation and management of this species is aided by knowledge related
to its spatial ecology. I investigated <i>C.
serpentina</i> home range, movement, habitat use, and habitat selection in a midwestern
USA urban wetland complex during two active seasons (May-August 2019 and 2020)
using radiotelemetry. Home range sizes and movement did not differ between sex
or sample year except the mean movement of males decreased from 2019 to 2020.
No differences in mean monthly movement were found between sexes but mean
monthly movement did differ between month and year. Habitat use was skewed
during the active season and did not differ between sex or year, but there were
positive habitat associations between forested wetlands and modal centers of
activity (MCA). Habitat selection was tested at two spatial scales by comparing
random points to home ranges and turtle locations using Euclidean Distance
Analysis. Turtles appeared to select home ranges from available habitat site-wide
but did not select habitat within home ranges. Home range selection included
semi-permanent open water, trail, road/barrier, permanent open water, scrub-shrub,
ditches, shoreline, and vegetated ponds, while upland forest, field and
agriculture habitat were avoided. Home ranges appear to be constrained by
available habitat and movement differences between years may be due to anthropogenic
change in water levels. The use of space seems to be more affected by wetland
size and connectivity than proximity to barriers, which suggests that
management practices that protect turtles from accessing roads and railways
will benefit populations. Additionally, habitat selection and association
indicate that ditches are utilized as corridors between wetland areas. When
feasible, increasing the connectivity of large wetlands containing many habitat
types should have positive impacts on the persistence of populations in human
dominated landscapes.
|
4 |
Redundancy in the Genetic Code: Selection Analysis and its Implications for Reconstruction of Ancestral Protein SequencesTehfe, Ali 03 January 2024 (has links)
Ancestral Sequence Reconstruction is a technique used to statistically infer the
most likely ancestor of a set of evolutionarily related sequences, but research which relies
solely on protein data has the disadvantage of sequence information being lost upon
translation of a protein from its gene transcript, due to the redundancy inherent in the
genetic code. In this project, the amino acid sequences, and separately the corresponding
codon sequences, of 184 homologous Acetylcholine receptor protein sequences were
aligned, and phylogenetic analysis and ancestral sequence reconstruction was performed
based on both alignments to infer several ancestral sequences representing important
milestones in the evolutionary history of the homologous protein family. To further
extract meaningful information from the nucleotide sequences, positive selection analysis
was performed on the codon alignment using the Mixed Effects Model of Evolution
method, which estimates and compares between the rates of synonymous and non-
synonymous mutations across the alignment to detect the occurrence of positive selection
events throughout their evolution. The Mixed Effects Model of Evolution can infer
positive selection across both sites and evolutionary branches in a sequence alignment,
thus highlighting residues along the evolutionary trajectory of the proteins which may
have been functionally important in their evolution. Positive selection analysis detected
positive selection at a multitude of sites and branches, and by mapping signatures at
which selection is strongest with changes in the trajectory of ancestral states, several
important sites were chosen as likely to be most valuable for future experimental testing.
The implications of this study on the benefits of conducting ancestral sequence
reconstruction with protein and codon sequences are discussed.
|
5 |
The interplay between sexual selection, inbreeding and inbreeding avoidance in the guppy, Poecilia reticulataZajitschek, Susanne, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW January 2008 (has links)
Inbreeding can have profound negative effects on individuals by reducing fertility and viability. In populations, inbreeding depression can reduce growth rates and increases extinction risk. The aims of this thesis are to investigate inbreeding depression in male guppies (Poecilia reticulata) and to study the evolution of mechanisms for inbreeding avoidance in females, using guppies from a feral population in Queensland, Australia. Male guppies are highly polymorphic in their sexual ornamentation, indeed they show one of the most extreme polymorphisms observed in nature. Female guppies exhibit complex mate choice based on preferences for ornamentation, as well as social context. I aim is to examine how these factors of inbreeding avoidance alter sexual selection. In male guppies I found strong inbreeding depression in male sperm numbers, which is amplified under semi-natural compared to laboratory conditions (Chapter 2). Moreover, inbreeding depression results in low fertility under sperm competition: an experiment using artificial insemination techniques reveals that highly inbred males are heavily disadvantaged in gaining paternity (Chapter 3). On population level, inbreeding depression is manifest in reduced growth rates, predominantly in the early stages of inbreeding (Chapter 4). Population growth at inbreeding coefficients f=0.375-0.59 did not seem to lead to inbreeding depression, whereas lower levels of inbreeding reduced population growth. Although the growth rates in inbred populations appear normal, severe inbreeding depression is uncovered after outbred immigrants are added. Specifically, male immigrants are most efficient in short-term genetic rescue, probably due to insemination of large numbers of females whereas females are limited in the number of eggs they can produce (Chapter 4). Male ornamental traits show significant inbreeding depression in semi-natural conditions only (Chapters 2 & 3). Inbreeding avoidance mechanisms seem to have evolved in females: they prefer courtship displays of non-inbred males (Chapter 2), unfamiliar males (Chapter 5) and males with rare patterns (Chapter 6). This preference might increase the mating success of immigrants, and may have evolved to facilitate the avoidance of inbreeding. Together with context-independent preferences for ornament combinations (Chapter 6), it also offers an explanation for the maintenance of polymorphism in this species.
|
6 |
The interplay between sexual selection, inbreeding and inbreeding avoidance in the guppy, Poecilia reticulataZajitschek, Susanne, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW January 2008 (has links)
Inbreeding can have profound negative effects on individuals by reducing fertility and viability. In populations, inbreeding depression can reduce growth rates and increases extinction risk. The aims of this thesis are to investigate inbreeding depression in male guppies (Poecilia reticulata) and to study the evolution of mechanisms for inbreeding avoidance in females, using guppies from a feral population in Queensland, Australia. Male guppies are highly polymorphic in their sexual ornamentation, indeed they show one of the most extreme polymorphisms observed in nature. Female guppies exhibit complex mate choice based on preferences for ornamentation, as well as social context. I aim is to examine how these factors of inbreeding avoidance alter sexual selection. In male guppies I found strong inbreeding depression in male sperm numbers, which is amplified under semi-natural compared to laboratory conditions (Chapter 2). Moreover, inbreeding depression results in low fertility under sperm competition: an experiment using artificial insemination techniques reveals that highly inbred males are heavily disadvantaged in gaining paternity (Chapter 3). On population level, inbreeding depression is manifest in reduced growth rates, predominantly in the early stages of inbreeding (Chapter 4). Population growth at inbreeding coefficients f=0.375-0.59 did not seem to lead to inbreeding depression, whereas lower levels of inbreeding reduced population growth. Although the growth rates in inbred populations appear normal, severe inbreeding depression is uncovered after outbred immigrants are added. Specifically, male immigrants are most efficient in short-term genetic rescue, probably due to insemination of large numbers of females whereas females are limited in the number of eggs they can produce (Chapter 4). Male ornamental traits show significant inbreeding depression in semi-natural conditions only (Chapters 2 & 3). Inbreeding avoidance mechanisms seem to have evolved in females: they prefer courtship displays of non-inbred males (Chapter 2), unfamiliar males (Chapter 5) and males with rare patterns (Chapter 6). This preference might increase the mating success of immigrants, and may have evolved to facilitate the avoidance of inbreeding. Together with context-independent preferences for ornament combinations (Chapter 6), it also offers an explanation for the maintenance of polymorphism in this species.
|
7 |
The interplay between sexual selection, inbreeding and inbreeding avoidance in the guppy, Poecilia reticulataZajitschek, Susanne, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW January 2008 (has links)
Inbreeding can have profound negative effects on individuals by reducing fertility and viability. In populations, inbreeding depression can reduce growth rates and increases extinction risk. The aims of this thesis are to investigate inbreeding depression in male guppies (Poecilia reticulata) and to study the evolution of mechanisms for inbreeding avoidance in females, using guppies from a feral population in Queensland, Australia. Male guppies are highly polymorphic in their sexual ornamentation, indeed they show one of the most extreme polymorphisms observed in nature. Female guppies exhibit complex mate choice based on preferences for ornamentation, as well as social context. I aim is to examine how these factors of inbreeding avoidance alter sexual selection. In male guppies I found strong inbreeding depression in male sperm numbers, which is amplified under semi-natural compared to laboratory conditions (Chapter 2). Moreover, inbreeding depression results in low fertility under sperm competition: an experiment using artificial insemination techniques reveals that highly inbred males are heavily disadvantaged in gaining paternity (Chapter 3). On population level, inbreeding depression is manifest in reduced growth rates, predominantly in the early stages of inbreeding (Chapter 4). Population growth at inbreeding coefficients f=0.375-0.59 did not seem to lead to inbreeding depression, whereas lower levels of inbreeding reduced population growth. Although the growth rates in inbred populations appear normal, severe inbreeding depression is uncovered after outbred immigrants are added. Specifically, male immigrants are most efficient in short-term genetic rescue, probably due to insemination of large numbers of females whereas females are limited in the number of eggs they can produce (Chapter 4). Male ornamental traits show significant inbreeding depression in semi-natural conditions only (Chapters 2 & 3). Inbreeding avoidance mechanisms seem to have evolved in females: they prefer courtship displays of non-inbred males (Chapter 2), unfamiliar males (Chapter 5) and males with rare patterns (Chapter 6). This preference might increase the mating success of immigrants, and may have evolved to facilitate the avoidance of inbreeding. Together with context-independent preferences for ornament combinations (Chapter 6), it also offers an explanation for the maintenance of polymorphism in this species.
|
8 |
The interplay between sexual selection, inbreeding and inbreeding avoidance in the guppy, Poecilia reticulataZajitschek, Susanne, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW January 2008 (has links)
Inbreeding can have profound negative effects on individuals by reducing fertility and viability. In populations, inbreeding depression can reduce growth rates and increases extinction risk. The aims of this thesis are to investigate inbreeding depression in male guppies (Poecilia reticulata) and to study the evolution of mechanisms for inbreeding avoidance in females, using guppies from a feral population in Queensland, Australia. Male guppies are highly polymorphic in their sexual ornamentation, indeed they show one of the most extreme polymorphisms observed in nature. Female guppies exhibit complex mate choice based on preferences for ornamentation, as well as social context. I aim is to examine how these factors of inbreeding avoidance alter sexual selection. In male guppies I found strong inbreeding depression in male sperm numbers, which is amplified under semi-natural compared to laboratory conditions (Chapter 2). Moreover, inbreeding depression results in low fertility under sperm competition: an experiment using artificial insemination techniques reveals that highly inbred males are heavily disadvantaged in gaining paternity (Chapter 3). On population level, inbreeding depression is manifest in reduced growth rates, predominantly in the early stages of inbreeding (Chapter 4). Population growth at inbreeding coefficients f=0.375-0.59 did not seem to lead to inbreeding depression, whereas lower levels of inbreeding reduced population growth. Although the growth rates in inbred populations appear normal, severe inbreeding depression is uncovered after outbred immigrants are added. Specifically, male immigrants are most efficient in short-term genetic rescue, probably due to insemination of large numbers of females whereas females are limited in the number of eggs they can produce (Chapter 4). Male ornamental traits show significant inbreeding depression in semi-natural conditions only (Chapters 2 & 3). Inbreeding avoidance mechanisms seem to have evolved in females: they prefer courtship displays of non-inbred males (Chapter 2), unfamiliar males (Chapter 5) and males with rare patterns (Chapter 6). This preference might increase the mating success of immigrants, and may have evolved to facilitate the avoidance of inbreeding. Together with context-independent preferences for ornament combinations (Chapter 6), it also offers an explanation for the maintenance of polymorphism in this species.
|
9 |
The interplay between sexual selection, inbreeding and inbreeding avoidance in the guppy, Poecilia reticulataZajitschek, Susanne, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW January 2008 (has links)
Inbreeding can have profound negative effects on individuals by reducing fertility and viability. In populations, inbreeding depression can reduce growth rates and increases extinction risk. The aims of this thesis are to investigate inbreeding depression in male guppies (Poecilia reticulata) and to study the evolution of mechanisms for inbreeding avoidance in females, using guppies from a feral population in Queensland, Australia. Male guppies are highly polymorphic in their sexual ornamentation, indeed they show one of the most extreme polymorphisms observed in nature. Female guppies exhibit complex mate choice based on preferences for ornamentation, as well as social context. I aim is to examine how these factors of inbreeding avoidance alter sexual selection. In male guppies I found strong inbreeding depression in male sperm numbers, which is amplified under semi-natural compared to laboratory conditions (Chapter 2). Moreover, inbreeding depression results in low fertility under sperm competition: an experiment using artificial insemination techniques reveals that highly inbred males are heavily disadvantaged in gaining paternity (Chapter 3). On population level, inbreeding depression is manifest in reduced growth rates, predominantly in the early stages of inbreeding (Chapter 4). Population growth at inbreeding coefficients f=0.375-0.59 did not seem to lead to inbreeding depression, whereas lower levels of inbreeding reduced population growth. Although the growth rates in inbred populations appear normal, severe inbreeding depression is uncovered after outbred immigrants are added. Specifically, male immigrants are most efficient in short-term genetic rescue, probably due to insemination of large numbers of females whereas females are limited in the number of eggs they can produce (Chapter 4). Male ornamental traits show significant inbreeding depression in semi-natural conditions only (Chapters 2 & 3). Inbreeding avoidance mechanisms seem to have evolved in females: they prefer courtship displays of non-inbred males (Chapter 2), unfamiliar males (Chapter 5) and males with rare patterns (Chapter 6). This preference might increase the mating success of immigrants, and may have evolved to facilitate the avoidance of inbreeding. Together with context-independent preferences for ornament combinations (Chapter 6), it also offers an explanation for the maintenance of polymorphism in this species.
|
10 |
Cumulative effects of human landscape change, predators, and natural habitat drive distributions of an invasive ungulateDarlington, Siobhan 07 December 2018 (has links)
Human footprint - in which land is converted for human use - is a leading contributor to global habitat and biodiversity loss. The accelerated rate of human landscape change to meet our growing needs has led to the direct loss of critical habitat and shifts in species distributions, interactions, and behaviour. These altered conditions affect species’ ability to adapt to environmental stressors, while some species thrive and others decline. In North America, one ungulate has successfully invaded new habitat in conjunction with human land use – the white-tailed deer. Across the continent, the invasion of white-tailed deer has led to increased competition with other ungulate species including mule deer, moose, and woodland caribou. In regions with abundant apex predators, they have become a source of primary prey as their populations increase. The mechanisms by which deer occupy landscapes in the northern extents of their geographic range are not well studied outside of the winter months, or how deer respond behaviourally to various types of human disturbance in a predator-rich environment.
To address these knowledge gaps, I examined population scale resource selection across seasons and individual movement behaviour in white-tailed deer in northeastern Alberta’s intensively developed oil and gas landscape. I used previously developed models of predator frequency to spatially extrapolate wolf and black bear occurrence across my study region as indicators of indirect predation risk. I used two approaches to habitat modeling to examine deer responses to various modes of human landscape change, including roads, seismic lines, and cut blocks in addition to predators and natural habitat. Deer were best described by cumulative effects – or the combination of all of these factors – across all seasons with proximity to linear features explaining the most variation among the parameters tested. Most prominently in winter, deer strongly selected for habitat features expected to contain abundant natural sources of forage, and linear features, despite a potential increased risk of predation by wolves – suggesting that deer make energetic trade-offs between forage availability and predation risk. At the individual level, deer significantly increased their rate of movement when occupying habitat associated with predation risk. I suggest that deer make greater energetic trade-offs during winter when mobility is limited to evade predators and energetic costs are higher.
The continued use of anthropogenic features post-winter, increased rate of movement and spread of landscape occupancy by deer may allude to the importance of human disturbance in maintaining deer in northern climates. Linear corridors may be an important mechanism by which deer are able to successfully colonize new areas at the northern extents of their range. My results shed light on the drivers of deer distributions in human altered landscapes for managing populations where the invasion of deer is complicit in the decline of other ungulate species such as woodland caribou in Alberta’s boreal forest. / Graduate
|
Page generated in 0.1038 seconds