The geometry of nutrient space–based life-history trade-offs: Sex-specific effects of macronutrient intake on the trade-off between encapsulation ability and reproductive effort in decorated crickets

This is the final version of the article. Available from University of Chicago Press via the DOI in this record.Life-history theory assumes that traits compete for limited resources, resulting in trade-offs. The most commonly manipulated resource in empirical studies is the quantity or quality of diet. Recent studies using the geometric framework for nutrition, however, suggest that trade-offs are often regulated by the intake of specific nutrients, but a formal approach to identify and quantify the strength of such trade-offs is lacking. We posit that trade-offs occur whenever life-history traits are maximized in different regions of nutrient space, as evidenced by nonoverlapping 95% confidence regions of the global maximum for each trait and large angles (θ) between linear nutritional vectors and Euclidean distances (d) between global maxima. We then examined the effects of protein and carbohydrate intake on the trade-off between reproduction and aspects of immune function in male and female Gryllodes sigillatus. Female encapsulation ability and egg production increased with the intake of both nutrients, whereas male encapsulation ability increased with protein intake but calling effort increased with carbohydrate intake. The trade-offs between traits was therefore larger in males than in females, as demonstrated by significant negative correlations between the traits in males, nonoverlapping 95% confidence regions, and larger estimates of θ and d. Under dietary choice, the sexes had similar regulated intakes, but neither optimally regulated nutrient intake for maximal trait expression. We highlight the fact that greater consideration of specific nutrient intake is needed when examining nutrient space–based trade-offs.S.K.S. was funded by the National Science Foundation (NSF; IOS-1118160 and IOS-1654028). C.M.H. was funded by a Leverhulme Early Career Fellowship. J.H. was funded by a Royal Society Fellowship (UF120087) and Equipment Grant (RG090854) and by the Natural Environment Research Council (NERC; NE/G00949X/1). J.R. was funded by a NERC studentship (awarded to J.H.). E.D.C. was partially funded by NSF grant CMII 1634878

What's in the Gift? Towards a Molecular Dissection of Nuptial Feeding in a Cricket.

Journal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.Nuptial gifts produced by males and transferred to females during copulation are common in insects. Yet, their precise composition and subsequent physiological effects on the female recipient remain unresolved. Male decorated crickets Gryllodes sigillatus transfer a spermatophore to the female during copulation that is composed of an edible gift, the spermatophylax, and the ampulla that contains the ejaculate. After transfer of the spermatophore, the female detaches the spermatophylax and starts to eat it while sperm from the ampulla are evacuated into the female reproductive tract. When the female has finished consuming the spermatophylax, she detaches the ampulla and terminates sperm transfer. Hence, one simple function of the spermatophylax is to ensure complete sperm transfer by distracting the female from prematurely removing the ampulla. However, the majority of orally active components of the spermatophylax itself and their subsequent effects on female behavior have not been identified. Here, we report the first analysis of the proteome of the G. sigillatus spermatophylax and the transcriptome of the male accessory glands that make these proteins. The accessory gland transcriptome was assembled into 17,691 transcripts whilst about 30 proteins were detected within the mature spermatophylax itself. Of these 30 proteins, 18 were encoded by accessory gland encoded messages. Most spermatophylax proteins show no similarity to proteins with known biological functions and are therefore largely novel. A spermatophylax protein shows similarity to protease inhibitors suggesting that it may protect the biologically active components from digestion within the gut of the female recipient. Another protein shares similarity with previously characterized insect polypeptide growth factors suggesting that it may play a role in altering female reproductive physiology concurrent with fertilization. Characterization of the spermatophylax proteome provides the first step in identifying the genes encoding these proteins in males and in understanding their biological functions in the female recipient.Max Planck GesellschaftNational Science FoundationBBSRRoyal Societ

Relationship Norm Strength: Measurement Structure, Dyadic Interdependence, Correlates, Causes and Consequences

The study of norms and close relationships are two pillars of social psychological scholarship, yet the two topics are rarely studied in tandem. When relationship norms have been the subject of empirical study, researchers have focused on evaluating the importance of their content for relational processes. In the present dissertation, I propose the strength of relationship norms as a topic worthy of empirical attention. Across five studies, including correlational, quasi-experimental, experimental, and dyadic designs, I evaluated the primary hypothesis that relationship norms would be stronger in relationships characterized by greater affiliative motivation, opertationalized both in terms of organically occurring relationship types, and ratings of relationship quality. Throughout the five studies, I also tested secondary hypotheses related to the association between relationship norm strength and perceived similarity, asset and resource sharing, and conflict between relationship partners, as well as the extent to which members of romantic couples abided by the norms of their relationship. In Study 1, participants (n = 100) perceived relationship types implying greater commitment (e.g., committed romantic relationships) as having stronger norms than those implying lesser commitment (e.g., casual sex relationships). In Study 2, I piloted a multidimensional measure of relationship norm strength and documented similar differences in norm strength and relationship quality among participants (n = 312) who were currently in the relationship types examined in Study 1. In Study 3, some aspects of relationship norm strength and relationship quality were positively associated for members of romantic dyads (ncouples = 25, nindividuals = 11). Individuals in a relationship with stronger norms generally reported complying with their relationship’s norms to a greater extent, though the opposite was sometimes true of their partner; individuals also exhibited a large amount of bias in appraising their partner’s level of norm compliance. In Study 4, participants currently in a romantic relationship (n = 286) primed to recall memories of high relationship quality reported feeling stronger norms in their romantic relationship, relative to those primed to recall moments of low relationship quality. Finally, in Study 5, participants currently in a romantic relationship (n = 239) primed to perceive their relationship norms as strong perceived their relationship as being higher quality than those in a control condition. These five studies provide initial promising support for the hypothesized role of relationship norm strength. I discuss their implications and the importance of continued investigations of relationship norm strength

Functional equivalence of grasping cerci and nuptial food gifts in promoting ejaculate transfer in katydids.

The function of nuptial gifts has generated longstanding debate. Nuptial gifts consumed during ejaculate transfer may allow males to transfer more ejaculate than is optimal for females. However, gifts may simultaneously represent male investment in offspring. Evolutionary loss of nuptial gifts can help elucidate pressures driving their evolution. In most katydids (Orthoptera: Tettigoniidae), males transfer a spermatophore comprising two parts: the ejaculate-containing ampulla and the spermatophylax-a gelatinous gift that females eat during ejaculate transfer. Many species, however, have reduced or no spermatophylaces and many have prolonged copulation. Across 44 katydid species, we tested whether spermatophylaces and prolonged copulation following spermatophore transfer are alternative adaptations to protect the ejaculate. We also tested whether prolonged copulation was associated with (i) male cercal adaptations, helping prevent female disengagement, and (ii) female resistance behavior. As predicted, prolonged copulation following (but not before) spermatophore transfer was associated with reduced nuptial gifts, differences in the functional morphology of male cerci, and behavioral resistance by females during copulation. Furthermore, longer copulation following spermatophore transfer was associated with larger ejaculates, across species with reduced nuptial gifts. Our results demonstrate that nuptial gifts and the use of grasping cerci to prolong ejaculate transfer are functionally equivalent

The Evolution of the Canada Development Corporation

This study has been divided into two levels of analysis. The first and most important level is concerned with examining the evolution of the Canada Development Corporation, hereafter referred to as the CDC. The emphasis of the thesis is on the factors which shaped the Corporation's form and functions. These include national and international economic variables, the personalities and political orientations of decision-makers, specific political circumstances and the decision-making process itself. The most significant contribution that this thesis makes to knowledge is that it has developed an elite model for explaining the evolution of the CDC. It is argued that Canada's indigenous economic elite had the greatest input into the policy process which created the CDC. This is considered to be the most important factor which shaped the CDC's evolution. As a result of this elite's influence, the federal government structured the CDC so that its primary functions were buttress and promote elitism and capitalism in Canada. The second level of analysis is of a macroscopic nature. Here the focus has been on four questions. What does the CDC as a case study say about the role the state has played in the development of the Canadian economy since 1960? is the CDC a defensive of offensive policy response to the problems of foreign investment, capital formation and economic growth in Canada? What have been the implications of using an elite model to analyze the Corporation and its evolution? And finally, what does the CDC's evolution say about the study of public policy?Master of Arts (MA

Prezygotic Male Reproductive Effort in Insects: Why Do Males Provide More than Sperm

Males\u27 incentives for providing benefits to females and/or their offspring are ambiguous during the period prior to zygote formation. The benefits may function to increase the number of available eggs fertilized by a male and/or enhance the production and survival of his offspring. In some cases, male prezygotic investment may be an adaptation to secure fertilizations despite the fact that it incidentally benefits the female or her offspring. More often, the benefits to offspring production and survival are not simply incidental and probably account, in part, for the magnitude of the male investment. Regardless of the adaptive significance of male provided benefits, they typically reduce the females\u27 costs of producing surviving offspring while raising the males\u27 costs. The extent to which provisioning of benefits increases males\u27 costs and decreases females\u27 costs will affect the degree to which females limit male reproduction (or vice versa). If male-provided benefits (prezygotic or otherwise) are more costly than female costs of offspring production, reproductively-ready males will act as resources limiting female reproduction. From an evolutionary perspective it is important to consider the effect of male-provided benefits. The primary function of the investment (e.g., to maximize sperm transfer) is irrelevant in terms of the degree to which one sex limits the other\u27s reproduction

Song Structure of Male Northern House Wrens and Patterns of Song Production and Delivery Across the Nesting Cycle

Studies of the role of bird song in avian communication have revealed numerous functions across many species, including its critical importance in female mate choice (intersexual selection) and male-male competition (intrasexual selection). A first step in understanding the role of song in different contexts is to describe the note, syllable, and song-types that occur, as well as their patterns of production within a population. Here, we do so for a north-central Illinois, USA, population of Northern House Wrens (Troglodytes aedon). As has been described in other populations, most songs (≈ 1–3 s in duration) contain an introductory section of soft, broadband notes followed by a terminal section of loud, frequency-modulated syllables that tend to be trilled. In characterizing the contents of 3.919 songs produced by 32 males throughout the breeding season, we identified 62 distinct notes, from which 76 syllables were produced. These syllables were organized in patterns largely unique to the individual—most notes and syllables were shared across the population, but almost no song-types were produced by more than one male. Singing declined over the course of the nesting cycle, and throughout the breeding season. Song production was at its minimum while fertile females were egg-laying, suggesting that males may change singing behaviour to guard against extra-pair copulations, which tend to occur at this time

Interpopulational and seasonal variation in the chemical signals of the lizard Gallotia galloti

Communicative traits are strikingly diverse and may vary among populations of the same species. Within a population, these traits may also display seasonal variation. Chemical signals play a key role in the communication of many taxa. However, we still know far too little about chemical communication in some vertebrate groups. In lizards, only a few studies have examined interpopulational variation in the composition of chemical cues and signals and only one study has explored the seasonal effects. Here we sampled three subspecies of the Tenerife lizards (Gallotia galloti) and analyze the lipophilic fraction of their femoral gland secretions to characterize the potential interpopulational variation in the chemical signals. In addition, we assessed whether composition of these secretions differed between the reproductive and the non-reproductive season. We analyzed variations in both the overall chemical profile and the abundance of the two main compounds (cholesterol and vitamin E). Our results show interpopulational and seasonal differences in G. gallotia chemical profiles. These findings are in accordance with the high interpopulational variability of compounds observed in lizard chemical signals and show that their composition is not only shaped by selective factors linked to reproductive season

Harmful and Helpful Therapy Practices with Consensually Non-Monogamous Clients: Toward an Inclusive Framework

Drawing on minority stress perspectives, we investigated the therapy experiences of individuals in consensually nonmonogamous (CNM) relationships. Method: We recruited a community sample of 249 individuals engaged in CNM relationships across the U.S. and Canada. Confirmatory factor analysis structural equation modeling was used to analyze client perceptions of therapist practices in a number of exemplary practices (affirming of CNM) or inappropriate practices (biased, inadequate, or not affirming of CNM), and their associations with evaluations of therapy. Open-end responses about what clients found very helpful and very unhelpful were also analyzed. Results: Exemplary and inappropriate practices constituted separate but related patterns of therapist conduct. As expected, perceptions of exemplary and inappropriate practices predicted therapist helpfulness ratings and whether participants prematurely terminated their therapeutic relationships. Qualitative results point toward the importance of having/pursuing knowledge about CNM and using affirming, nonjudgmental practices. Conclusions: Therapists are positioned to either combat or perpetuate the minority stress faced by individuals engaged in CNM. The results of this study highlight the need for additional research, training, and guidelines regarding CNM clients and their therapy experiences

Strategizing About Work-Family Integration During the Transition to Parenthood: Longitudinal Processes and Ideological Influences

The transition to parenthood is often associated with shifts towards traditional gender roles in families related to women’s and men’s participation in paid work and caring for children. Mothers maintain more responsibility than fathers for the day-to-day care of children and breadwinning remains a central task of fathering. The persistence of gendered parenting roles in contemporary families is somewhat perplexing given the apparent cultural dominance of co-parenting and involved father ideologies. Still more research is required to understand the individual level processes that shape mothers’ and fathers’ strategies for integration of paid work and child care in relation to their sociocultural and institutional context, processes that often lead to adoption of traditional gender roles. I conducted a longitudinal, qualitative investigation of men’s and women’s strategizing about work-family integration over a five-year period during their transitions to parenthood. My longitudinal study used selected key principles of the methodological approach of institutional ethnography (IE), developed by Dorothy Smith (1987), that is focused on elucidating the coordination of individual behaviors by dominant institutions and their ideological discourses. The first paper in this dissertation, It All Comes Out in the Wash, is an investigation of alternative trajectories of strategizing about work-family integration by first-time mothers as shaped by their institutional and ideological context. Two trajectories of strategizing were delineated. The first trajectory, the washing machine trajectory, was characterized by a cyclical process of strategizing and by considerable change in mothers’ work-family integration approaches over time. In addition, the work-family integration approaches of mothers who followed this trajectory became increasingly similar despite marked early variation in their work-family integration preferences. In contrast, mothers who followed the second trajectory, the career maintenance trajectory, followed a linear process of strategizing and their work-family integration trajectory was characterized by stability of work-family integration arrangements over time. The two trajectories were shaped by different orientations to dominant ideologies and by different interpretations of and responses to work-family integration challenges. The second paper, The Pathway to the Practice of Contemporary Fathering and the Slowly Evolving Gender Order, focuses on the process of development of a practice of contemporary fathering and the influences of ideological and relational context on the process. The findings demonstrated that first-time fathers were committed to the ideology of involved fatherhood but that beliefs about gender shaped their early work-family integration choices. They consequently moved into a role of secondary parent, relative to mothers, and into a role of main earner for their families. Established as secondary parents, fathers demonstrated their commitment to involved fatherhood ideology through performance of a “fathers’ child care shift” around the boundaries of their paid work commitments. In the fathers’ child care shift, fathers prioritized caring for children over all other activities. Fathers’ intrinsic commitment to performance of their child care shift seemed to be the measure by which both fathers and mothers judged successful fulfillment of the ideology of involved fatherhood. The final paper, Making the Invisible Visible, outlines an analytical strategy for elucidating the process of development of new social relations during life course transitions, such as the transition to parenthood. This paper builds on analytical principles of IE and of qualitative longitudinal research. Analytical principles from these two bodies of literature informed an analytical strategy that consists of an integrated recurrent cross-sectional thematic analysis and a trajectory analysis. Through integration of the cross-sectional and trajectory analyses, I illuminated the temporal nature of two key concepts from IE, an expanded concept of work, and the coordinating power of discourse. This paper contributes to the scant literature about data analysis in IE. Using data from my study about women’s trajectories of work-family integration strategizing during the transition to parenthood, I demonstrated the utility of the analytical strategy