This thesis examines the reproductive biology of red-tailed phascogales, an obligate male semelparous dasyurid species, which is part of a captive breeding colony at Alice Springs Desert Park. The red-tailed phascogale belongs to a group of dasyurids that shows an unusual reproductive strategy amongst mammals, one which provides opportunity for understanding means by which individuals maximise their reproductive success and the role of sperm competition. The broad aim was to gain an understanding of the reproductive biology of red-tailed phascogales and explore means by which individuals can affect their reproductive success. Examination of the red-tailed phascogale reproductive biology showed that females mated with multiple males and were capable of storing sperm in their oviducts for at least a five day period. Captive female red-tailed phascogales showed greater plasticity in their breeding season than has been observed in Antechinus, which exhibits the same life history strategy. Females were observed to invest heavily into the production of young, producing almost twice as many ova (15.1 ± 1.9) as young they can raise and 76% of females filling six to eight of the eight available teats in a breeding attempt. A 63% male bias was observed in young attaching to the teats, which could be produced through differential attachment of the sexes to teats at birth. Of the 846 young born in the captive breeding colony, 68% were weaned, with weaning occurring between 90-110 days of age and a 53% female bias observed in young being weaned. By weaning, a litter of young weighed 380% of the mothers mass with male young tending to be heavier than females by weaning. No relationship was observed between maternal weight and either litter sex ratio or sex biased growth of young. A positive relationship between maternal body mass and body mass of offspring at weaning was observed, with the body mass of young at weaning correlated with its body mass at maturity. Multiple paternity was observed in more than half of the litters examined, with heavier males having increased siring success compared to lighter males. Genotyping showed that the effective population size for the captive colony was 1.9x that observed from the group managed studbook. Male reproduction was also not as tightly constrained as in Antechinus, with spermatogenic failure not occurring in captive populations until after mating had occurred, meaning males are not reliant on epididymal stores alone for successful breeding. Scrotal diameter showed a positive relationship with testis and epididymal mass across male life, although this relationship was not evident when analysis was restricted to the time of peak sperm production. Captive males showed the opposite pattern of testosterone fluctuations to that observed in wild animals, with lowest levels occurring during the mating period. Captive animals were able to survive up to five years in captivity, in contrast to the obligate semelparity observed in wild males. Although most captive females can survive to breed in a second year and females are known to breed in a second year in the wild, the reproductive strategy of females appears to be aimed at maximising the returns on their first breeding attempt. In males, the need to maximise the investment into the first breeding season is amplified through the complete absence of opportunity to breed again; either through post-mating mortality in the wild or spermatogenic failure in captivity. The results of this study have implications for captive breeding of red-tailed phascogales, with their reproductive biology; spermatogenic failure, restricted breeding season, teat number limiting the number of young raised, high lactational investment into young, sex biases, the need to maintain genetic diversity and biases in siring success; providing challenges for the maintenance of a captive population. The results of this study also provide comparative information that contributes to understanding the unusual life history strategy of Phascogale and Antechinus, and contributes to the growing body of knowledge about mating strategies in marsupials. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1330358 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2008

Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, Discipline of Ecology and Evolutionary Biology, 2008. / "March 2008" -- T.P. Includes author's previously published papers. Bibliography: pages 104-118. Also available in print form.

Although sexual stereotypes paint males as being promiscuous and females as being choosy in order to increase their reproductive success, multiple mating by females is widespread and females of many taxa often produce progeny sired by multiple males – but why? In species in which there are no direct benefits associated with mating, females may adopt promiscuous mating strategies to increase their fitness through the acquisition of genetic benefits. Here, I examine the genetic mating system of map turtles, Graptemys geographica in Lake Opinicon. Based on the most conservative estimate, at least 71% of clutches in this population are sired by multiple males. There did not appear to be any relationship between female body size and frequency of multiple paternity. There was a marginally significant effect of multiple paternity on hatching success and survival of clutches, but there was no effect on hatchling morphology or locomotor performance.

Although sexual stereotypes paint males as being promiscuous and females as being choosy in order to increase their reproductive success, multiple mating by females is widespread and females of many taxa often produce progeny sired by multiple males – but why? In species in which there are no direct benefits associated with mating, females may adopt promiscuous mating strategies to increase their fitness through the acquisition of genetic benefits. Here, I examine the genetic mating system of map turtles, Graptemys geographica in Lake Opinicon. Based on the most conservative estimate, at least 71% of clutches in this population are sired by multiple males. There did not appear to be any relationship between female body size and frequency of multiple paternity. There was a marginally significant effect of multiple paternity on hatching success and survival of clutches, but there was no effect on hatchling morphology or locomotor performance.

Abstract Female ability to exploit conspecifics in reproduction may have unusual expressions. I studied the reproductive behaviour of the golden egg bug (Phyllomorpha laciniata; Heteroptera, Coreidae) experimentally in the field and in the laboratory. Female golden egg bugs lay their eggs mainly on the backs of conspecific males and other females. Non-parental eggs are often carried. Occasionally, the eggs are laid on the food plant (Paronychia spp; Polycarpea, Caryophyllaceae) of the species but typically, those eggs survive poorly due to egg parasitism and predation. I explored the dependence of female reproduction on conspecific presence and encounter rate. I also studied female current reproductive state (which depends on if she has recently oviposited) in relation to her activity as well as male choice of a female. Female bugs preferred to oviposit on conspecifics when presented with a choice between a bug and a food plant. When alone females often did not lay eggs. Increased encounter rate with others increased female egg laying rate. Survival of carried eggs among bugs did not vary significantly although males received more eggs than females. Females with high current fecundity (mature eggs accumulated to reproductive tract) were more active than females with lower current fecundity (recently oviposited). Females with high current fecundity seemed to search for conspecifics to lay eggs on. Males also preferred to court females with high current fecundity. These females were more likely to oviposit immediately after mating, lowering the risk of female remating before oviposition. To conclude, conspecifics are important egg-laying substrates for female golden egg bugs. Conspecific availability affects female egg laying and the rate of egg production in short term. In particular, males are necessary for egg-laying females and they typically receive unrelated eggs when they court females. Sexual interactions resulting from female polyandry are crucial factors that maintain female egg laying on the backs of males and other females in the unique reproductive system of the golden egg bug.

Although sexual stereotypes paint males as being promiscuous and females as being choosy in order to increase their reproductive success, multiple mating by females is widespread and females of many taxa often produce progeny sired by multiple males – but why? In species in which there are no direct benefits associated with mating, females may adopt promiscuous mating strategies to increase their fitness through the acquisition of genetic benefits. Here, I examine the genetic mating system of map turtles, Graptemys geographica in Lake Opinicon. Based on the most conservative estimate, at least 71% of clutches in this population are sired by multiple males. There did not appear to be any relationship between female body size and frequency of multiple paternity. There was a marginally significant effect of multiple paternity on hatching success and survival of clutches, but there was no effect on hatchling morphology or locomotor performance.

Selon la théorie de la sélection de la parentèle, les individus peuvent transmettre des copies de leurs gènes à la génération suivante sans accéder eux-mêmes à la reproduction, mais en aidant des apparentés à augmenter leur propre succès reproductif. Ce concept reste aujourd'hui l'explication la plus probable pour justifier l'évolution de l’altruisme de reproduction dans le règne animal. Les coefficients de corrélations génétiques entre les membres d’un groupe ont une importance capitale, puisqu'ils influencent directement les bénéfices génétiques indirects associés au comportement altruiste. Trois principaux facteurs sont cependant connus pour influencer profondément l'architecture des sociétés: (i) le nombre de reines présentes dans un nid (polygynie), (ii) le nombre d'accouplements des reines (polyandrie), et (iii) l’accouplement entre apparentés (consanguinité). Nous avons étudié les stratégies de reproduction de cinq espèces de fourmis du genre Plagiolepis. Nous avons d’abord déterminé l’origine endogène des signaux de reconnaissance responsables de la fermeture des sociétés (I). Nous avons également identifié les causes proximales de la forte consanguinité observée chez P. pygmaea : une éviction par les ouvrières des mâles étrangers tentant de s’introduire dans leur société et une préférence des femelles vierges à s’accoupler avec des mâles apparentés (II). A l’aide de marqueurs génétiques, nous avons estimé le degré de polygynie, le taux de polyandrie des reines, et le niveau de consanguinité pour quatre espèces libres : P. pygmaea, P. taurica, P. schmitzii et P. maura (III; IV). Enfin, nous avons testé l’hypothèse d’une réversion du nombre d’accouplements vers la monandrie chez les espèces parasites, au travers de P. xene. (V).

Honey bees (Apis mellifera) are the most economically important insect pollinator of agricultural crops in the United States. Honey bee colonies are required for pollination of approximately one-third of the nation’s fruit, vegetable, nut, and forage crops, with an estimated annual value in the billions of dollars. The economic value of a honey bee colony comes from its population size, as large colonies provide the necessary foraging force required for large-scale crop pollination services. A major component of colony strength is its genetic diversity, a consequence of the reproductive mating strategy of the queen known as polyandry. Despite some inherent risks of multiple mating, several studies have demonstrated significant advantages of intracolonial genetic diversity for honey bee colony productivity. Colony-level benefits include better disease resistance, more stable brood nest thermoregulation, and greater colony growth. Instrumental insemination of honey bee queens is a technique to precisely control queen mating, and thereby creates the opportunity to investigate the effects of intracolonial genetic diversity on colony performance. In this dissertation, I first consider the effects of intracolonial genetic diversity on pollen foraging using colonies headed by queens which were instrumentally inseminated with either one or twenty drones to generate colonies of very high or very low intracolonial genetic diversity, respectively. I found that colonies with high intracolonial genetic diversity amass significantly more pollen and rear more brood than colonies with low intracolonial genetic diversity. Of particular interest, colonies with low intracolonial genetic diversity collected a significantly greater variety of pollen types. I discuss these results in the context of scouting and recruiting, and suggest a more efficient foraging strategy exists among genetically diverse colonies. While intracolonial genetic diversity is positively correlated with collected pollen, its effect on the colony’s ability to process and distribute inbound protein resources is unknown. Again using colonies headed by queens instrumentally inseminated with either one or twenty drones, I studied the effects of intracolonial genetic diversity on pollen consumption and digestion by nurse bees, as well as protein allocation among nestmates by assessing total soluble protein concentration of late instar larvae, and total soluble hemolymph protein concentration in both nurses and pollen foragers. I found that nurse bees from colonies with high intracolonial genetic diversity consume and process more protein than nurses from colonies with low intracolonial genetic diversity, even when given equal access to protein resources. Further, both forager hemolymph protein concentrations and larval total protein concentrations were higher among the colonies with high intracolonial genetic diversity. My findings suggest that protein processing and distribution within a honey bee colony is affected by the social context of the hive. I discuss “worker policing”, and the role of nurse bees in modulating the foraging effort. Finally, I assess the standing genetic variability among several colonies sourced from different genetic and geographic locations. Using microsatellite DNA from workers sampled from each colony, I determined allelic richness, gene diversity, and effective mating frequency for each genetic line. I found differences in all three metrics between lines, and for one line in particular, there was no correlation with genetic variation and effective mating frequency, suggesting non-random mating. My results showed very different levels of intracolonial genetic diversity among naturally mated queens. Because of its impact on colony performance, the importance of maintaining genetic diversity in breeding populations is discussed.

Feather ornaments and its role as a signals in sexual selection has been broadly studied topic in avian biology. However, vast majority of studies focus especially on role of male ornamentation and female preferences in sexual selection. Despite this fact, recent work shows, that similar palette of adaptive functions can be found for female feather ornaments, and male preferences for them, respectively. This study focuses on possible importance of female melanin-based ornaments and other individual on breeding performance in the Northern Lapwing (Vanellus vanellus), common polygynous wader breeding in agricultural landscape. No significant predictor of female investment to egg size was found. Long winged females with bigger proportion of secondaries changed during prenuptial moulting and bigger extent of melanin ornaments tended, surprisingly, to later timing of breeding. Contrary to this trend, extent of female ornamentation seems to be sexually selected trait by males. Analysis of male incubation behavior shows, that males incubate more in nests of more ornamented females, as well as in nests in later incubation stage. These findings seems to be in a good agreement with "Differential allocation hypothesis". On the other site, no effect of clutch egg sizes and timing of breeding was found....

Behavioral studies in the green turtle (Chelonia mydas) have indicated that promiscuous mating is commonplace. Though it has been shown that there is much variation in the rate of polyandry (females mating with multiple males), the drivers behind polyandry in this species are unknown. It has been speculated, but never demonstrated, that indirect benefits (fitness benefits resulting from offspring genetic diversity) play a role. However, previous tests of this hypothesis have limited scope of inference due to lack of environmental control. In this thesis, I attempted to study the indirect benefits of polyandry in Archie Carr National Wildlife Refuge (ACNWR) green turtles, limiting environmental variation by selecting nests over two week periods in a small subset of the ACNWR. Through the use of highly polymorphic microsatellite markers, I show that 85.7% of ACNWR green turtle females mate with multiple males, the highest rate yet reported for green turtles. I was successful in limiting environmental variation; however, I was unable to make comparisons among nests with one or multiple fathers because of a limited sample size of single father nests. Regardless, my thesis provides preliminary evidence (number of males per nest) that the density of males off Florida’s beaches may be relatively high, which is expected to be a driver behind the evolution of polyandry and likely plays a large role both in this population and the prevalence of multiple paternity in green turtles as a whole