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No description available.

Despite a long history of study showing that male courtship signals influence female mate choice in many species, we lack a good understanding of how females choose. What are the mechanisms of mate choice, and how do these mechanisms shape the evolution of courtship signals and traits? In this thesis, I use the peacock’s iridescent eyespots to link signal perception with female mate choice decisions and the behaviours males use during courtship. I begin by investigating how a peacock’s eyespot colours influence his mating success, using models of avian colour vision and measurements of eyespot plumage colours taken at light angles that mimic the way the feathers are displayed during courtship. My results suggest that a substantial portion of the variation in peacock mating success can be explained by these plumage colours, demonstrating that signal function is best understood by considering the context in which signals are presented. Next, I examine how females choose to visit different males for courtship. I show that a female’s familiarity with a male as a result of previous courtship encounters affects how she responds to his signals, including his eyespot colours. Lastly, I examine the visual effects of the peacock’s iridescent eyespot colours under different light conditions, and show that typical male courtship behaviours might enhance the eyespots in a way that influences female choice. I also find evidence that light conditions and female sensory biology together may have shaped the evolution of the eyespot colours in two species of peafowl. Overall, the results of this thesis demonstrate that by understanding how animals perceive colour signals, we can gain a better understanding of the function of behaviour on both sides of the courtship signaling exchange. / Thesis (Ph.D, Biology) -- Queen's University, 2013-03-22 14:23:48.991

In many taxa, social structures are mediated by agonistic interactions and the formation of dominance hierarchies. In crayfish, dominance hierarchies may have evolved as a result sexual selection, allowing dominant males greater access to females, thereby increasing their reproductive success. This work tests the hypothesis that high male investment in dominance interactions may have evolved as a result of intra- and/or inter-sexual selection pressures by testing specific predictions in two parts: first, that reproductive males would invest more in agonistic interactions than reproductive females or non-reproductive members of both sexes; and second, that females would prefer odors of dominant males over subordinates, and that dominant males would be either more efficient at mating or be able to mate longer than subordinates. Investment in agonistic interactions was examined in intrasexual pairs of male and female crayfish in both the reproductive and non-reproductive season. As predicted, reproductive males invested more in agonistic interactions overall than reproductive females, while there was no significant difference in investment by non-reproductive males or females. However, no significant difference was found in agonistic investment between reproductive males and non-reproductive males. These data indicate that investment in agonism differs by sex and by reproductive status, and may indicate that dominance interactions are under sexual selection in males. Alternatively, this differential investment may be explained by seasonal changes in the individual costs and benefits of agonism, or by depressed investment by reproductive females. Female odor preference was tested using a y-maze containing control and male treated water. For tests of male mating, time spent in each of three stages of mating was recorded for male-female pairs. Of these tests, the only significant trend produced was that dominant males spent more time associated with the female during and after copulation than subordinates. This may indicate an advantage in fertilization success for males through decreased sperm competition. A pilot study was also conducted testing the predictions that females mated to dominant males invest more in offspring than those mated to subordinates and that such offspring have greater survivability, but no significant conclusions could be drawn from these data.

The thesis presented here utilizes a variety of methods and study systems to address how ecological promote plasticity in reproductive behaviours. We study mate choice, copulation and parental care as the different reproductive behaviours, as they can be envisioned as representatives of different stages of the reproductive cycle and can be subject to different selection pressures. With the use of computer simulations we study the conditions of sex ratio and cost of courting under which a learned mate preference in males or in both sexes can evolve. We found that for males, maternal imprinting is the most advantageous imprinting strategy, but when both sexes imprint, paternal imprinting in both sexes is the most advantageous strategy. We show that environmental change can lead to the evolution of sexual imprinting by both sexes. A study using mesocosm and mating trial experiments, measuring female survival and male mating success was used to study the role of intra- and interspecific interactions in mating behaviour (competition and harassment) in Calopteryx splendens. We showed that intense intraspecific male-male competition reduces harassment over females and increases female survival. On the other side, interspecific reproductive interference can reduce male mating success and can increase female survival. Finally, theory on the use of social learning was tested using Drosophila melanogaster oviposition site choice. We show that fruit flies use social learning more after they experience heterogeneous environments. However, our results suggest that the use of social learning was driven by fruit flies signalling more when they experience heterogeneous environments, instead of driven by copying others decisions, as theoretical predictions suggest. We also show that the use of social learning is an innate trait, opening the opportunity for the study of the genomic basis of social learning.

Thesis (Ph. D.)--Lehigh University, 1999. / Includes vita. Includes bibliographical references (leaves 110-117).

The peacock (Pavo cristatus) has long been considered the quintessential example of a sexually selected animal, and in the last two decades, peafowl have provided widely-cited evidence for female mate choice as well as the genetic benefits of mate preferences for ornamented males. However, previous studies have failed to reach a consensus with respect to the importance of various signaling modalities in peafowl courtship. In this thesis, I repeat two previous studies of peacock train morphology and I describe the use of light by males during their courtship displays, to clarify the role of visual signaling. I confirm previous reports that removing a large number of eyespots decreases male mating success, yet I find substantial variation in mating success among normal males that cannot be explained by eyespot number. I show that these two apparently conflicting results are not contradictory, since the removal treatment modifies males beyond the normal range of eyespot number. Next, I describe the two display behaviours used by males during courtship. When males perform their pre-copulatory “train-rattling” display, they are oriented at about 45° relative to the sun on average, with females directly in front. This directional pattern suggests that train-rattling is involved in the communication of a visual signal. The “wing-shaking” display, on the other hand, is performed with females positioned behind males, and is always elicited when a model female is positioned on the shaded side of a male. The wing-shaking display may therefore allow males to control female viewing geometry. These results indicate that mate choice in peafowl is complex, and that visual signaling is important despite recent claims to the contrary. Females may avoid males missing a large number of eyespots via a threshold-based mechanism, while choosing among full-trained males based on some other (possibly visual) cue. / Thesis (Master, Biology) -- Queen's University, 2008-09-12 16:29:20.772

No description available.

The effect of environmental and social factors on the courtship and mating dynamics of the smooth newt. Triturus v. vulgaris, was studied using laboratory experiments, an individual-based model, a semi-natural population and a field study. In view of the limitations of laboratory experiments and field observation, the semi-natural and modelling approaches are recommended as additional research tools. In the laboratory, the optimal temperature for spermatophore transfer was just below 13°C, at which point the spermatophore deposition rate is high and oxygen availability not limiting. In the wild females determine the timing of mating. They are highly receptive for a brief period after arrival at the breeding site (early spring), subsequently re-mating only sporadically. Therefore, few courtships take place at mid-season, optimal temperatures. In the semi-natural population. deposition occurred in only 3 - 6% of courtships with a median of one deposition per encounter. Male mating success is therefore unlikely to be constrained by physiological capacity for spermatophore production. Female receptivity and immigration patterns are thus the principle determinants of the operational sex ratio (OSR). According to the model, a male-biased OSR develops rapidly at the start of the season, but the strength of bias will depend on the breeding sex ratio. duration of the arrival period and extent to which males arrive before females. The OSR influences the intensity of competition for mates and the potential for sexual selection. Males compete directly for females by sexual interference, a common but low-gain strategy. Males may also compete indirectly by courting unmated and unfamiliar females preferentially (both of which have a higher probability of being receptive) although more research is needed to establish if males differ in their ability to find receptive females. There is variance in male mating success but the relative contributions of environmental factors and phenotypic traits needs further clarification.

Thesis (M.S.)--Eastern Illinois University, 2008. / Includes bibliographical references (leaves 94-104).