Dominance hierarchies occur in numerous social species, and rank within them can greatly influence the quality of life of an animal. In this review, I consider how rank can also influence physiology and health. I first consider whether it is high- or low-ranking animals that are most stressed in a dominance hierarchy; this turns out to vary as a function of the social organization in different species and populations. I then review how the stressful characteristics of social rank have adverse adrenocortical, cardiovascular, reproductive, immunological, and neurobiological consequences. Finally, I consider how these findings apply to the human realm of health, disease, and socioeconomic status.

/pdf/the-influence-of-social-hierarchy-on-primate-health-32f55sz0tn.pdf

The influence of social hierarchy on primate health

Food limitation is generally thought to underlie much of the variation in life history traits of birds. I examined variation and covariation of life history traits of 123 North American Passeriformes and Piciformes in relation to nest sites, nest predation, and foraging sites to examine the possible roles of these ecological factors in life history evolution of birds. Annual fecundity was strongly inversely related to adult survivaI, even when phylogenetic effects were controlled. Only a little of the variation in fecundity and survival was related to foraging sites, whereas these traits varied strongly among nest sites. Interspecific differences in nest predation were correlated with much of the variation in life history traits among nest sites, although energy trade-offs with covarying traits also may account for some variation. For example, increased nest predation is associated with a shortened nestling period and both are associated with more broods per year, but number of broods is inversely correlated with clutch size, possibly due to an energy trade-off. Number of broods was much more strongly correlated with annual fecundity and adult survival among species than was clutch size, suggesting that clutch size may not be the primary fecundity trait on which selection is acting. Ultimately, food limitation may cause trade-offs between annual fecundity and adult survival, but differences among species in tecundity and adult survival may not be explained by differences in food abundance and instead represent differing tactics for partitioning similar levels of food limitation. Variation in fecundity and adult survival is more clearly organized by nest sites and more closely correlated with nest predation; species that use nest sites with greater nest predation have shorter nestling periods and more broods, yielding higher fecundity, which in turn is associated with reduced adult survival. Fecundity also varied with migratory tendencies; short-distance migrants had more broods and greater fecundity than did neotropical migrants and residents using similar nest sites. HowevEr, migratory tendencies and habitat use were confounded, making separation of these two effects difficult. Nonetheless, the conventional view that neotropical migrants have fewer broods than residents was not supported when nest site effects were controlled

/pdf/avian-life-history-evolution-in-relation-to-nest-sites-nest-13hbw844ew.pdf

Avian Life History Evolution in Relation to Nest Sites, Nest Predation, and Food

▪ Abstract The functional causes of life history trade-offs have been a topic of interest to evolutionary biologists for over six decades. Our review of life history trade-offs discusses conceptual issues associated with physiological aspects of trade-offs, and it describes recent advances on this topic. We focus on studies of four model systems: wing polymorphic insects, Drosophila, lizards, and birds. The most significant recent advances have been: (a) incorporation of genetics in physiological studies of trade-offs, (b) integration of investigations of nutrient input with nutrient allocation, (c) development of more sophisticated models of resource acquisition and allocation, (d) a shift to more integrated, multidisciplinary studies of intraspecific trade-offs, and (e) the first detailed investigations of the endocrine regulation of life history trade-offs.

/pdf/the-physiology-of-life-history-trade-offs-in-animals-4smtg4z39z.pdf

The Physiology of Life History Trade-Offs in Animals

synopsis. An understanding of interactions between the thermal physiology and ecology of ectotherms remains elusive, partly because information on the relative performance of whole-animal physiological systems at ecologically relevant body temperatures is limited. After discussing physiological systems that have direct links to ecology (e.g., growth, locomotor ability), we review analytical methods of describing and comparing certain as? pects of performance (including optimal temperature range, thermal performance breadth), apply these techniques in an example on the thermal sensitivity of locomotion in frogs, and evaluate potential applications.

https://faculty.washington.edu/hueyrb/new/HueyStevenson%201989%20Am%20Zool.pdf

Integrating Thermal Physiology and Ecology of Ectotherms: A Discussion of Approaches

http://mama.indstate.edu/angillet/Thermal%20Adaptation/Publications/Angilletta%20et%20al%20(in%20press).pdf

The evolution of thermal physiology in ectotherms

Seasonal and stress related changes in plasma gonadotropins, sex steroids, and corticosterone in the bullfrog, Rana catesbeiana.

Proximate constraints on egg size, number, and total clutch mass in side-blotched lizards were examined by experimentally reducing average clutch size from 4.6 eggs to one, two, and three eggs. Eggs from experimentally altered clutches were larger than those from controls, reflecting the trade-off between egg size and number. Moreover, the increased frequency of females with oviducally bound eggs or eggs that burst at oviposition suggests that egg size in clutches with very few eggs are at a functional upper size limit. These proximate constraints may also limit evolution of egg size in another group of lizards (Anolis) that only produces one-egged clutches.

https://science.sciencemag.org/content/sci/252/5010/1300.full.pdf

Proximate constraints on the evolution of egg size, number, and total clutch mass in lizards.

A new technique developed for the determination of total lactate production in small animals was used to evaluate the role of anaerobiosis during activity at different temperatures in lizards. Measurements on six species of small lizards indicate little interspecific variation or thermal effect in resting lactate levels (0.35 mg lactate/g body weight) or maximal lactate levels achieved at exhaustion (1.4 mg lactate/g). Normally activeAnolis in captivity had a lactate content of 0.5 mg lactate/g. Rates of lactate formation were most rapid during the first 30 sec of activity and had a low thermal dependence (Q10=1.1–1.3 above 20 °C). The lactate formed during activity persists for long periods; e.g., for 30 to 60 min between 20 and 37 °C inAnolis carolinensis (Fig. 1). Recovery rate generally increases with temperature. Muscle lactate concentrations peak at the end of activity, but liver and blood lactate are not maximal until 10 and 30 min, respectively, after activity (Fig. 2). The decrease in the blood lactate is shown to be a poor estimator of total recovery. An estimated 80–90% of the total energy utilized during initial vigorous activity comes from anaerobic sources. Because of its low thermal dependence, anaerobiosis permits high levels of activity in lizards at all body temperatures without requiring high levels of aerobic resting metabolism.

/pdf/anaerobic-metabolism-during-activity-in-lizards-953woyw2tt.pdf

Anaerobic metabolism during activity in lizards

Newly metamorphosed Western toads, Bufo boreas, are diurnally active and thermoregulate by the behavioral exploitation of available microenvironments including exposure to solar radiation. In the laboratory, toads thermoregulate by basking beneath incandescent lamps when placed within a photothermal gradient. Basking depends on feeding, and when food is withheld, individuals abandon the available heat source and assume lower body temperatures. The preferred temperature of feeding individuals is around 26—27 degrees C as determined from animals both in the laboratory and in nature; fasting animals remain between 15—20 degrees C. Growth of young toads with ad libitum food supply was measured at a variety of temperatures. Energy ingestion (appetite), linear growth, weight increase, and gross conversion efficiencies were all maximal at 27 degrees C and were nearly identical to that of toads allowed to thermoregulate in a photothermal gradient. Weight—specific energy ingestion, weight—specific growth, and gross conversion efficiency decreased with age. Survivorship of starved toads in a thermal gradient was prolonged over that of toads maintained at a constant 27 degrees C. Metabolism increased with body temperature over the range 10—33 degrees C. We have concluded that this terrestrial ectotherm has evolved a behavioral thermoregulatory mechanism which maximizes growth and economic utilization of energy. The diurnal behavior patterns of small toads (compared with the more strictly nocturnal adults) may have evolved to maximize the growth rates of younger individuals, thus shortening their time to adult size.

The Role of Behavioral Thermoregulation in the Growth Energetics of the Toad, Bufo Boreas

Publisher Summary It has long been recognized that the control of gonadal function by pituitary hormones (gonadotropins) is a general feature of vertebrate reproductive physiology. Numerous studies on the hormones of eutherian mammals have established the existence of two chemically distinct types of gonadotropin molecules in the pituitary-luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Recent biochemical studies on these molecules have revealed that each is a glycoprotein consisting of two chemically non-identical subunits, designated α and β. The physiological actions of the two gonadotropins in mammals are still subject to intensive investigation; however, it is agreed that FSH and LH have somewhat different roles in the regulation of gonadal function. This chapter describes a flow diagram of the protocol for the fractionation of pituitary hormones, with particular reference to gonadotropins and growth hormone (GH), from various nonmammalian species. The strong resemblance in chromatographic behavior among the fractions identified as FSH and LH from most nonmammalian species and their mammalian counterparts provided preliminary evidence of chemical similarity among the different species of FSH and of LH. Biochemical analyses on the six highly purified species of LH and FSH (chicken, turkey, alligator, snapping turtle, sea turtle, and bullfrog) yielded additional evidence for the homologies between mammalian and nonmammalian hormones.

Paul Licht

Papers

Seasonal and stress related changes in plasma gonadotropins, sex steroids, and corticosterone in the bullfrog, Rana catesbeiana.

Proximate constraints on the evolution of egg size, number, and total clutch mass in lizards.

Anaerobic metabolism during activity in lizards

The Role of Behavioral Thermoregulation in the Growth Energetics of the Toad, Bufo Boreas

Evolution of gonadotropin structure and function.