Behavior of males in a reproductive aggregation of the banded demoiselle Calopteryx splendens (Insecta, Odonata)

The view according to which damselfly males practice two alternative reproductive tactics of access to females is critically discussed. It is widely accepted that some males (“territorial” ones) have priority as potential female partners, while others (“sneakers” or “wanderers”) are incapable of retaining an individual territory. They have a chance of mating only by intruding briefly into the area defended by a “territorial” male when a female is present there. Thus, the tactics of a “territorial” male consists in waiting for a female in its territory and copulating with it “by agreement,” whereas non-territorial males resort to forced copulations. By observation of individually marked males (48 out of 118) it was shown that every male could be regarded as “territorial” during a certain period and as a “wanderer” before and after it. Thus, no correlation between the modes of space use by a male (residence/mobility) and the characters of its external morphology and/or signal behavior appears to be possible in principle. According to the data obtained, a more plausible explanation is that the female chooses not the male but the best area for oviposition. In addition, it was ascertained that adherence to forced copulations cannot constitute successful “tactics” since they rarely result in insemination, neither by “territorial” nor “non-territorial” males. In other words, we are dealing not with certain alternative tactics (i.e., specialized adaptive mechanisms that have evolved in the species) but simply with the results of different sets of circumstances at a given moment.     

A re-examination of parturition scars on the human female pelvis

Pits, cavities and depressions located on the dorsal surface of the pubic symphysis of females have been attributed to the trauma of parturition. Earlier research based on human skeletal remains provides inadequate information on the individual's obstetrical history. The 68 female pubic bones that were studied had comprehensive medical records indicating whether or not each female had given birth. Fourteen and one-half percent of the females who had not given birth exhibited trace to small scarring of the pubic symphysis and 23.4% of the females who had not given birth exhibited medium to large scarring. It is suggested that bony changes previously used as an indicator of child bearing must be re-examined in light of the fact that “birth scarring” has been found in women known not to have had children.     

Time-dependent solution to age-structured equations for sexual populations

The continuous age-time theory of a two-sex population, due to Fredrickson and based on M'Kendrick's equation, has been solved by means of the generation expansion. Difficulties due to the nonlinear birth condition which are encountered when the theory is cast in the form of ordinary differential equations for the total male and female populations are thereby avoided. The expansion can be expected to be useful when the time span over which the solution is required is of the order of only a few generations. Thus, it is a “short time” solution, supplementary to the “long time” solution, the steady state of exponential growth.     

Distastefulness as a defense mechanism in Aplysia brasiliana (Mollusca: Gastropoda)

An unusual courtship pattern for fiddler crabs is described from field observations in Panama. This behavior pattern, referred to here as “directing,” differs considerably from the more frequently observed communal courtship system found in close relatives of Uca deichmanni. A male involved in “directing” approaches a female and attempts to carry or maneuver her into his burrow for mating. The female usually struggles to escape from the male. This activity often attracts other males which attempt to “direct” the female if she escapes from the first male. A male is most successful in “directing” a female into his burrow if a) he is larger than the female, b) the female is wandering (a sign of physiological receptivity) prior to the “directing” attempt, and c) several males attempt to “direct” the female at once. The results suggest that females are choosing mates by inciting several males to compete for them. The males which successfully “direct” the struggling females are probably the most fit males.     

Letting the Air Out: <Emphasis Type="Italic">Aire</Emphasis> as an Empty Signifier in Oaxacan Understandings of Illness

“Air (aire, also aigre) in the body” is a frequent explanation of illness according to the traditional medical beliefs in Mexico. Anthropologists have generally scrutinized aire in the context of other common folk illnesses treated by traditional healers (curanderas). However, drawing on my research in the communities of Northern Oaxaca I suggest that aire occupies a more distinct position in the folk medical cosmology than it has usually been credited with. This distinction rests on the notion’s exceptional ambivalence and openness to multiple interpretations. “Air” is recurred to as the cause of illness mainly in situations where every other explanation, either “traditional” or “biomedical,” seems to be inadequate. The physical properties of air—its transparency, invisibility, apparent immateriality, near omnipresence, and virtual “nothingness”—render it a suitable explanation of the last resort. Local understandings of what aire “is” are often vague and elusive, and in many respects the term functions in folk medical discourse as an “empty signifier.”     

Observations of parturition among captive patas monkeys (Erythrocebus patas)

Six cases of labor and delivery by laboratory-housed patas monkeys (Erythrocebus patas) are described. Five of the births occurred during the daytime, and the sixth occurred just after the usual “lights out” time. Although it was impossible to determine the actual onset of labor, the final 1.5–0.5 hr before parturition were observed in all cases. Throughout labor, females tended to begin a contraction every 2–4 min and contractions usually lasted 35–60 sec. Females did not show common patterns of change in contraction frequency or duration as birth neared. It was not possible to describe patas monkey labor and delivery in terms of “stages.” Postpartum, females typically began cleaning their infants within 90 sec and picked them up within 5 min. Placental delivery times varied among females, as did the extent of placental consumption. One “mother-only” - reared female proved to be an inadequate mother.     

Israel: The making of self in the “pioneering” of the nation

The Zionist project was more than a simple “ingathering” of people. All Jews by birth, those who reached Palestine in the early decades of this century were swept into the making of a “new” people with a “new” ethic and a “new” discipline—out of which would emerge the “old‐new” state of Israel. The present article addresses this multiple process with its strains and contradictions, as experiences by the “pioneer” generation and their Palestinian‐born children—the sabra.     

Testing the reproductive and somatic trade‐off in female Columbian ground squirrels

Energetic trade‐offs in resource allocation form the basis of life‐history theory, which predicts that reproductive allocation in a given season should negatively affect future reproduction or individual survival. We examined how allocation of resources differed between successful and unsuccessful breeding female Columbian ground squirrels to discern any effects of resource allocation on reproductive and somatic efforts. We compared the survival rates, subsequent reprodction, and mass gain of successful breeders (females that successfully weaned young) and unsuccessful breeders (females that failed to give birth or wean young) and investigated “carryover” effects to the next year. Starting capital was an important factor influencing whether successful reproduction was initiated or not, as females with the lowest spring emergence masses did not give birth to a litter in that year. Females that were successful and unsuccessful at breeding in one year, however, were equally likely to be successful breeders in the next year and at very similar litter sizes. Although successful and unsuccessful breeding females showed no difference in over winter survival, females that failed to wean a litter gained additional mass during the season when they failed. The next year, those females had increased energy “capital” in the spring, leading to larger litter sizes. Columbian ground squirrels appear to act as income breeders that also rely on stored capital to increase their propensity for future reproduction. Failed breeders in one year “prepare” for future reproduction by accumulating additional mass, which is “carried over” to the subsequent reproductive season.     

EVOLUTION OF INFLORESCENCE DESIGN: THEORY AND DATA

Very low fruit set in milkweeds and other flowering plants often has been attributed to greater sexual selection on inflorescence size via male, rather than female, reproductive success. Although this explanation has been generally accepted, alternate explanations have been presented, and recently the “male function” or “pollen donation” hypothesis has been sharply criticized. In this paper, we make the distinction between selection on total flower number and on the size of inflorescence units, both of which have been termed “inflorescence size.” We present an ESS model for the evolution of inflorescence design that considers reproductive success through male and female function. The model predicts that selection will balance the proportional changes in female and male reproductive success resulting from changes in inflorescence-unit size. We conducted a field study of selection on the size of inflorescence units (umbels) by manipulating umbel size and number in a natural population of Asclepias tuberosa, in southeastern Arizona, during two reproductive seasons. We found that the male fitness function reached a maximum at an intermediate umbel size in both years (although not significantly different from the smallest umbel size in either year), whereas the female fitness function was highest for the smallest umbel size in one year, but was constant across umbel sizes in the other year. We also found that pollinator visitation rate corresponded well with male, but not female, function, and that between-year variation in the male reproductive success of different umbel sizes corresponded with variation in the composition of the pollinator pool. Our empirical results, when inserted in the model, predict ESS umbel sizes similar to those observed in the study population and the species throughout its range.     

Eisbärenzucht (Ursus maritimus Phipps, 1774) im Zoo am Meer Bremerhaven – Fortsetzung einer langen Tradition

Breeding polar bears has a long tradition in the Zoo am Meer, the “Zoo at the Sea” in Bremerhaven. In the years between 1935 and 1974 three female bears gave birth to 32 cubs and 19 of them were successfully raised. In the following years many attempts to tie in with this tradition failed. Bad constructional conditions and disadvantageous animal pairings were the main reasons for the missing breeding success. After completely reconstructing the polar bear enclosure in the year 2002, as well as extending the breeding area with an additional smaller breeding cave in 2012 and pairing male Lloyd and female Valeska in 2013 a new polar bear birth and upbringing could be experienced after 40 years. Offspring Lale is the 35^th cub in Bremerhaven Zoo.     

Sheep-goat hybrid karyotypes

A “Spanish” goat female was bred to a Barbados sheep ram and gave birth to twin offspring, one of each sex. The F_l female was backcrossed to a Barbados ram and also gave birth to twins, one of each sex. The F_l female has goat-like characters and the coloration of the Barbados. Although the female Barbados is polled, the F_l female hybrid has goat-like horns. The F_l male was lost before assessments could be made. The F_l hybrid possesses a diploid chromosome number of 57 and a karyotype containing 3 unpaired metacentrics, 5 unpaired and 23 pairs of acrocentric autosomes. The male and female backcrosses have Barbados characters and coloration; however, the female has goat-like horns. The male has Barbados or sheep-like horns. The backcrosses have diploid chromosome numbers of 55 and karyotypes containing 1 unpaired and 2 pairs of metacentrics and 2 unpaired and 23 pairs of acrocentric autosomes. The sex chromosomes consist of a large acrocentric X and a small bi-armed Y in the male and 2 large acrocentric Xs in the female.     

Sex ratios at birth in a Micronesian atoll population

Abstract

The recent suggestion that typically masculinized sex ratios at birth in Micronesian populations may be related to a distinct “Micronesian pattern” of life‐course coital behavior is applied to data on the sex ratio of livebirths on Butaritari Atoll in Kiribati. The data show that sex ratios on Butaritari are highly masculinized and do not vary significantly with changes in maternal age. However, there is a discernible relationship between the length of closed intervals preceding male and female births. The lack of age‐related change in sex ratios in the Butaritari sample is inconsistent with ethnographic data regarding levels of marital coital activity in relation to increasing age and marriage duration. The Butaritari sex ratio data is argued to support the suggestion of a “Micronesian pattern,” although it is posed that further tests of this association are required.     

Survival of captive-born Ovis canadensis in North American zoos

The survival rate of North American bighorn sheep, Ovis canadensis, housed in several zoological gardens was analyzed. Complete herd histories, including birth and death data as well as causes of mortality, were collected from seven institutions. Lambs were divided into inbred and noninbred animals, with lambs being considered inbred if they had an inbreeding coefficient greater than zero. The rate of survival of inbred and noninbred lambs was compared using “survival equalling one year” and “survival equalling six months.” Another analysis compared the survival rate of male and female inbred lambs and male and female noninbred lambs. Age at death was also compared in inbred and noninbred lambs. The analysis of the data for the seven collections, located in various geographic areas and housing various subspecies, indicates that inbreeding depression is a mortality factor in the captive management of North American bighorn sheep. Therefore, long-term survival of captive or isolated wild populations will depend on maintaining genetic diversity within the herds through careful selection of breeding stock in captive populations and introduction of nonrelated animals into isolated wild populations.     

Modeling the pediatric paradox: Birth weight by gestational age

Abstract

The “pediatric paradox” of African versus European American infant mortality is often observed with respect to birth weight, but rarely to gestational age, even though the two measures are biologically related. This paper models the pediatric paradox by birth weight and gestational age simultaneously, using Covariate Density Defined mixture of logistic regressions (CDDmlr) fitted to 1985–1988 New York State births. The model controls for unobserved heterogeneity and isolates the pediatric paradox in the “compromised” subpopulation. The paradox is not limited to low birth weights and/or short gestational ages, but surrounds the normal birth range. Nevertheless, the pediatric paradox is only observed in the marginal distribution of birth weight and not the marginal distribution of gestational age. These results are consistent with the hypothesis that higher fetal losses in the “compromised” subpopulation may be responsible for the pediatric paradox and that African versus European American infant mortality differentials are underestimated.     

Genetic-gonadal-genitals sex (3G-sex) and the misconception of brain and gender,or, why 3G-males and 3G-females have intersex brain and intersex gender

The categorization of individuals as “male” or “female” is based on chromosome complement and gonadal and genital phenotype. This combined genetic-gonadal-genitals sex, here referred to as 3G-sex, is internally consistent in ~99% of humans (i.e., one has either the “female” form at all levels, or the “male” form at all levels). About 1% of the human population is identified as “intersex” because of either having an intermediate form at one or more levels, or having the “male” form at some levels and the “female” form at other levels. These two types of “intersex” reflect the facts, respectively, that the different levels of 3G-sex are not completely dimorphic nor perfectly consistent. Using 3G-sex as a model to understand sex differences in other domains (e.g., brain, behavior) leads to the erroneous assumption that sex differences in these other domains are also highly dimorphic and highly consistent. But parallel lines of research have led to the conclusion that sex differences in the brain and in behavior, cognition, personality, and other gender characteristics are for the most part not dimorphic and not internally consistent (i.e., having one brain/gender characteristic with the “male” form is not a reliable predictor for the form of other brain/gender characteristics). Therefore although only ~1% percent of humans are 3G-“intersex”, when it comes to brain and gender, we all have an intersex gender (i.e., an array of masculine and feminine traits) and an intersex brain (a mosaic of “male” and “female” brain characteristics).     

Explaining embryological development: Should integration be the goal?

Two approaches to an integration of evolution and development are often distinguished, one “neo-Darwinian” and the other “structuralist”. Should these approaches in turn be integrated? Kelly Smith recently stated that we need a “more complete” theory of biological order, suggesting integration as the ideal. In response to him, I argue that a recognition of different types of scientific questions and causal explanation is more urgent. Do we understand development when we know the crucial factors in the process of differentiation, or rather when we know the laws that govern the transformations of fields? Without a recognition of these different explanatory ideals, “integration” is likely to have the character of annexation.     

Is birth attendance a uniquely human feature? New evidence suggests that Bonobo females protect and support the parturient

Birth attendance has been proposed as a distinguishing feature of humans (Homo sapiens) and it has been linked to the difficulty of the delivery process in our species. Here, we provide the first quantitative study based on video-recordings of the social dynamics around three births in captive bonobos (Pan paniscus), human closest living relative along with the chimpanzee. We show that the general features defining traditional birth attendance in humans can also be identified in bonobos. As in humans, birth in bonobos was a social event, where female attendants provided protection and support to the parturient until the infant was born. Moreover, bystander females helped the parturient during the expulsive phase by performing manual gestures aimed at holding the infant. Our results on bonobos question the traditional view that the “obligatory” need for assistance was the main driving force leading to sociality around birth in our species. Indeed, birth in bonobos is not hindered by physical constraints and the mother is self-sufficient in accomplishing the delivery. Although further studies are needed both in captivity and in the wild, we suggest that the similarities observed between birth attendance in bonobos and humans might be related to the high level of female gregariousness in these species. In our view, the capacity of unrelated females to form strong social bonds and cooperate could have represented the evolutionary pre-requisite for the emergence of human midwifery.     

Origins of female genital diversity: Predation risk and lock‐and‐key explain rapid divergence during an adaptive radiation

The study of male genital diversity has long overshadowed evolutionary inquiry of female genitalia, despite its nontrivial diversity. Here, we identify four nonmutually exclusive mechanisms that could lead to genital divergence in females, and potentially generate patterns of correlated male–female genital evolution: (1) ecological variation alters the context of sexual selection (“ecology hypothesis”), (2) sexually antagonistic selection (“sexual‐conflict hypothesis”), (3) female preferences for male genitalia mediated by female genital traits (“female‐choice hypothesis”), and (4) selection against inter‐population mating (“lock‐and‐key hypothesis”). We performed an empirical investigation of all four hypotheses using the model system of Bahamas mosquitofish inhabiting blue holes that vary in predation risk. We found unequivocal support for the ecology hypothesis, with females exhibiting a smaller genital opening in blue holes containing piscivorous fish. This is consistent with stronger postmating female choice/conflict when predators are present, but greater premating female choice in their absence. Our results additionally supported the lock‐and‐key hypothesis, uncovering a pattern of reproductive character displacement for genital shape. We found no support for the sexual conflict or female choice hypotheses. Our results demonstrate a strong role for ecology in generating female genital diversity, and suggest that lock‐and‐key may provide a viable cause of female genital diversification.