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.     

Delayed parturition: constraint or coping mechanism in a viviparous gekkonid?

The extended gestation of fully developed embryos in viviparous reptiles can be the consequence of a lack of appropriate environmental conditions and/or an adaptive contribution to increased offspring viability. I examined the cause and effects of extended gestation in a gekkonid lizard Hoplodactylus maculatus , which delays parturition of developed embryos for up to 9 months from autumn into a second spring. Comparisons of microhabitat temperatures showed that thermal opportunities were equally conducive to birth in autumn and spring. The responsiveness of females to a hormonal stimulant for parturition also did not differ between these seasons. Multiple offspring traits were measured, including body size, locomotory ability and lipid reserves, and were found not to increase with extended gestation. Incorporating these results with previously published evidence for microhabitat thermal variation, I discuss whether delayed parturition may be an adaptive mechanism maintained by the selective pressures of an uncertain thermal environment on components of reproduction, including vitellogenesis, maternal birthing cues and neonatal survival.     

Late stage deferral of parturition in the viviparous lizard Niveoscincus ocellatus (Gray 1845): implications for offspring quality and survival

The ability of viviparous lizards to defer parturition after completion of embryonic development is a potentially key strategy for enhancing offspring fitness. Using the spotted snow skink, Niveoscincus ocellatus , we investigated the ability of females to defer birth if placed into cold conditions at the same time, for 1, 2 or 3 weeks at the end of gestation. The ability to defer birth was compared between two populations at each end of the species' altitudinal range. We hypothesized that females from the high elevation population would be less likely to defer parturition under extended periods of poor conditions, thus ensuring that young were not born too late in the season. In all but the 3-week treatment group from the high elevation population, females were able to defer birth when placed under cold conditions: for all groups, there was no treatment effect on offspring phenotype at birth, dispersal distance or survivorship after release. However, there was a significant negative effect of treatment on offspring growth measured after release, with the results differing between the populations. Females from the high elevation population were less able to defer birth under long periods (3 weeks) of cold conditions, and this was accompanied by a decrease in viability of the offspring.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 90 , 735–746.     

Maternal serum progesterone concentration during pregnancy and lamb birth weight at parturition in Javanese Thin-Tail ewes with different litter sizes

Pregnant ewes, (N=38), with similar body weight and age (19, 13 and 6 carrying 1, 2 and 3 fetuses, respectively) were used to study the relationship between maternal serum progesterone concentration during pregnancy and lamb birth weight at parturition. Average maternal serum progesterone concentration in the ewes carrying 1, 2, and 3 fetuses was: 5.3±0.3, 6.2±0.7 and 6.6±0.5 ng/ml, during weeks 0 to 7 of gestation; 16.9±1.4, 25.3±1.5, and 26.8±2.5 ng/ml, during weeks 8 to 20; and 13.2±1.0, 18.7±1.0, and 19.8±1.7 ng/ml, during the entire gestation period respectively. Total lamb birth weight in ewes carrying 1, 2, and 3 fetuses was 1.9±0.1, 3.2±0.2, and 4.2±0.4 kg, respectively. In the respective litter sizes, ewes with higher mean serum progesterone concentration during the whole pregnancy gave birth to lambs with higher birth weight (r²=0.76, 0.42 and 0.46, for ewes carrying 1, 2 and 3 fetuses, respectively). The results of the study indicated that prenatal growth could probably be improved by increasing endogenous secretion of maternal progesterone during pregnancy.     

Regression analysis of four physical characteristics—stature,length of thigh,length of leg and length of foot of the male population in Sichuan Province

Using four physical characteristics of 394 adult male individuals in the Sichuan Province of China — stature, length of thigh, length of leg and length of foot, a series of linear regression equations and ternary regression equations have been established. Meanwhile three stepwise regression equations also have been established including a quarternary regression equation. Generally speaking, the established multiple equations in this study should be applied as much as possible, where there are two or three independent variables, because they predict more effectively in the individual identification of forensic practice.     

Sexual dimorphism and reproductive behavior in the Brazilian scorpion Tityus pusillus (Scorpiones,Buthidae)

We studied sexual dimorphism (SD) and reproductive behavior in the litter‐dwelling scorpion, Tityus pusillus. SD was determined by measuring seven body structure attributes (prosoma, mesosoma, and metasoma lengths, and pedipalp chelae and metasomal segment V lengths and widths) in 634 individuals (211 males and 423 females) from the Arachnological Collection of the Universidade Federal de Pernambuco. Reproductive behavior was observed in 55 couples during nocturnal activity observations conducted in the laboratory. In addition, we evaluated gestation time, hemispermatophore replacement, and sequential courtship. Individuals of T. pusillus exhibited typical reproductive behavior, with a short courtship time (averaging 10±5 min). Males only accepted new partners at least 48 h after first mating, suggesting that this period may be necessary for hemispermatophore production. Females did not accept new partners for 24–48 h after their first mating. The average gestation period was 85±12 d, ranging 60–100 d. Our results showed a more complex picture of SD than previously described for this species, including features characteristic of both sexual size dimorphism (SSD) and sexual body component dimorphism in scorpions. In general, considering the relatively large size of the prosoma and mesosoma in T. pusillus, it seems reasonable to conclude that female‐biased SSD exists in the species, and that male‐biased sexual body component dimorphism is evident in the metasoma and chelae.     

Natural environmental conditions and collaborative efforts provide the secret to success for sand tiger shark Carcharias taurus reproduction in aquaria

Sand tiger sharks are an iconic large shark species held in aquaria worldwide. They rarely reproduce under managed care, with only seven aquaria reporting limited and sporadic success. For the first time in the Americas, a full-term young was born in an aquarium. The young was the result of breeding among a group of sharks purposefully brought together in 2016 for reproduction. Sharks were maintained in natural seawater and exposed to natural light and seasonal temperature fluctuations similar to their in situ counterparts. Decreased food consumption associated with breeding season and gestation was observed. Gestation time estimated from breeding observations and parturition was 321 days. Although the neonate was stillborn, this was a significant achievement. The husbandry details described within will be useful for other aquaria striving to support the reproduction of sand tiger sharks.     

Prevalence of flea infestation in dogs and cats in Hungary combined with a survey of owner awareness

A survey was conducted in order to gain current information on flea species (Siphonaptera: Pulicidae) infesting dogs and cats living in urban and rural areas of Hungary, along with data on the factors that affect the presence, distribution and seasonality of infestation. In addition, owner awareness of flea infestation was evaluated. Practitioners in 13 veterinary clinics were asked to examine all dogs and cats attending the clinic and to collect fleas, when present, on 2 days in each month from December 2005 to November 2006. They also completed a questionnaire for each animal examined. A total of 319 dogs (14.1%) were found to be infested; the highest prevalence (27.1%) of infestation on dogs occurred in August and the lowest (5.4%) in May. Prevalence of fleas on cats was higher (22.9%); the highest (35.0%) and lowest (8.1%) prevalences occurred in July and April, respectively. Fleas were more prevalent in rural (387/1924 animals, 20.2%) than in urban (161/1343 animals, 12.0%) areas. Three species, Ctenocephalides felis (Bouché), Ctenocephalides canis (Curtis) and Pulex irritans L., were found. On dogs, the prevalence of C. canis alone was 53.0%, whereas that of C. felis alone was 36.0%. Only 19 specimens of P. irritans were found on 14 dogs from rural habitats only. Prevalence of C. felis only on cats was 94.3%; the remaining cats were infested with either C. canis or with mixed infestations of C. felis and C. canis. More than half (51.4%) of the owners of infested dogs and cats had not used flea control products in the past year or more, and five times as many owners in rural than urban areas had not used flea control products in the same period. Very few owners reported having attempted to kill fleas in their animals' environment; instead, they believed that fleas were acquired from other cats or dogs.     

Relationship of queen number and queen relatedness in multiple-queen colonies of the fire ant Solenopsis invicta

1. The relationship between the number of queens per nest and their relatedness was examined in the polygyne (multiple queens per nest) social form of the fire ant Solenopsis invicta .
2. No significant relationship between these two variables was found. Moreover, the overall average relatedness among nestmate queens was not significantly different from zero.
3. These findings indicate that polygyne nests of S. invicta do not represent closed societies. Furthermore, they are consistent with continual acceptance of non-nestmate queens throughout a colony's lifetime. This strategy differs from the expectation of kin selection theory that only related queens should be accepted as new reproductives within polygyne colonies.
4. The postulated acceptance of non-nestmate queens is associated with a decrease in the number of parasites, predators and diseases and a concomitant increase in the density of nests in introduced populations, suggesting that the permissive environment experienced by introduced fire ants may have decreased the relative importance of kinship as a stabilizing factor in the evolution of polygyny.     

The evolution of queen control over worker reproduction in the social Hymenoptera

A trademark of eusocial insect species is reproductive division of labor, in which workers forego their own reproduction while the queen produces almost all offspring. The presence of the queen is key for maintaining social harmony, but the specific role of the queen in the evolution of eusociality remains unclear. A long‐discussed scenario is that a queen either behaviorally or chemically sterilizes her workers. However, the demographic and ecological conditions that enable such manipulation are still debated. We study a simple model of evolutionary dynamics based on haplodiploid genetics. Our model is set in the commonly observed case where workers have lost the ability to lay female (diploid) eggs by mating, but retain the ability to lay male (haploid) eggs. We consider a mutation that acts in a queen, causing her to control the reproductive behavior of her workers. Our mathematical analysis yields precise conditions for the evolutionary emergence and stability of queen‐induced worker sterility. These conditions do not depend on the queen's mating frequency. We find that queen control is always established if it increases colony reproductive efficiency, but can evolve even if it decreases colony efficiency. We further derive the conditions under which queen control is evolutionarily stable against invasion by mutant workers who have recovered the ability to lay male eggs.     

A survey of genetic diversity and reproductive biology of Puya raimondii (Bromeliaceae), the endangered queen of the Andes

Abstract: Puya raimondii Harms is an outstanding giant rosette bromeliad found solely around 4000 m above sea level in the Andes. It flowers at the end of an 80 - 100-year or even longer life cycle and yields an enormous (4 - 6 m tall) spike composed of from 15 000 to 20 000 flowers. It is endemic and currently endangered, with populations distributed from Peru to the north of Bolivia. A genomic DNA marker-based analysis of the genetic structure of eight populations representative of the whole distribution of P. raimondii in Peru is reported in this paper. As few as 14 genotypes out of 160 plants were detected. Only 5 and 18 of the 217 AFLP marker loci screened were polymorphic within and among these populations, respectively. Four populations were completely monomorphic, each of the others displayed only one to three polymorphic loci. Less than 4 % of the total genomic variation was within populations and genetic similarity among populations was as high as 98.3 %. Results for seven cpSSR marker loci were in agreement with the existence of a single progenitor. Flow cytometry of seed nuclear DNA content and RAPD marker segregation analysis of progeny plantlets demonstrated that the extremely uniform genome of P. raimondii populations is not compatible with agamospermy (apomixis), but consistent with an inbreeding reproductive strategy. There is an urgent need for a protection programme to save not only this precious, isolated species, but also the unique ecosystem depending on it.     

蜂王幼虫与工蜂幼虫发育期食物消耗量的研究

以意大利蜜蜂Apis mellifera ligustica雌性幼虫为试验材料,用鲜王浆、葡萄糖、果糖和酵母抽提物分别配制不同日龄的蜂王幼虫食物和工蜂幼虫食物,采用室内人工饲养蜜蜂幼虫技术饲养12h以内的蜂王幼虫和工蜂幼虫,直到幼虫出现排便和吐丝行为,记录幼虫生长发育期间消耗的总食物量。结果表明:1只蜂王幼虫在生长发育期平均消耗196.8mg蜂王幼虫食物,而1只工蜂幼虫在生长发育期平均消耗139.4mg工蜂幼虫食物。     

The red queen coupled with directional selection favours the evolution of sex

Why sexual reproduction has evolved to be such a widespread mode of reproduction remains a major question in evolutionary biology. Although previous studies have shown that increased sex and recombination can evolve in the presence of host-parasite interactions (the 'Red Queen hypothesis' for sex), many of these studies have assumed that multiple loci mediate infection vs. resistance. Data suggest, however, that a major locus is typically involved in antigen presentation and recognition. Here, we explore a model where only one locus mediates host-parasite interactions, but a second locus is subject to directional selection. Even though the effects of these genes on fitness are independent, we show that increased rates of sex and recombination are favoured at a modifier gene that alters the rate of genetic mixing. This result occurs because of selective interference in finite populations (the 'Hill-Robertson effect'), which also favours sex. These results suggest that the Red Queen hypothesis may help to explain the evolution of sex by contributing a form of persistent selection, which interferes with directional selection at other loci and thereby favours sex and recombination.     

Growth and reproduction in the Icelandic common seal (Phoca vitulina L., 1758)

Length, weight and maturity were studied in relation to age in the common seal (Phoca vitulina vitulina L., 1758), collected during the periods 1979-1983 and 1990-2000 in Icelandic waters. The maximum age of common seal observed was 36 years for females and 30 years for males. For common seal females and males, asymptotic length and weight were 161 cm and 93 kg and 174 cm and 97 kg, respectively, showing slight sexual dimorphism in size. The condition of adult females, measured as fat thickness at the lower end of the sternum, was lower in the period 1979-1983 than in 1990-2000 during June-September, the breeding and mating time of the Icelandic common seal. Males reached sexual maturity between 5 and 7 years, whereas 50% of females did so at age 4 years. Including the length and age interaction term in the logistic regression model for the maturity of females significantly improved it. Thus, body size matters in the onset of maturity. The mean birthing date for the Icelandic common seal was found to be in early June. A comparison of animals collected in the two periods 1979-1983 and 1990-2000 did not show significant differences in growth and the average age of sexual maturity for either males or females. The observed decline of the Icelandic common seal population is most probably caused by increased mortality, due to exploitation and accidental by-catch in gill-nets, rather than a decrease in fecundity.     

Facultative use of thelytokous parthenogenesis for queen production in the polyandrous ant Cataglyphis cursor

The evolutionary paradox of sex remains one of the major debates in evolutionary biology. The study of species capable of both sexual and asexual reproduction can elucidate factors important in the evolution of sex. One such species is the ant Cataglyphis cursor, where the queen maximizes the transmission of her genes by producing new queens (gynes) asexually while simultaneously maintaining a genetically diverse workforce via the sexual production of workers. We show that the queen can also produce gynes sexually and may do so to offset the costs of asexual reproduction. We genotyped 235 gynes from 18 colonies and found that half were sexually produced. A few colonies contained both sexually and asexually produced gynes. Although workers in this species can also use thelytoky, we found no evidence of worker production of gynes based on genotypes of 471 workers from the six colonies producing sexual gynes. Gynes are thus mainly, and potentially exclusively, produced by the queen. Simulations of gynes inbreeding level following one to ten generations of automictic thelytoky suggest that the queen switches between or combines thelytoky and sex, which may reduce the costs of inbreeding. This is supported by the relatively small size of inbred gynes in one colony, although we found no relationship between the level of inbreeding and immune parameters. Such facultative use of sex and thelytoky by individual queens contrasts with other known forms of parthenogenesis in ants, which are typically characterized by distinct lineages specializing in one strategy or the other.     

Progesterone receptors in the human uterus and their possible role in parturition

An overview is given on the role of progesterone in parturition in the human. Progesterone withdrawal is considered to be a major event for the beginning of parturition. However, in the human, no evidence exists in favour of a decline in placental progesterone production prior to labour. Progesterone actions are mediated by two functionally different but structurally highly related intranuclear proteins, progesterone receptor (PR) A and PRB. In the human, functional progesterone withdrawal is thought to play a role. This may be mediated by a change in the expression of the two isoforms of the PR, with an increase in the PRA:PRB ratio, and this is accompanied by an increase in the expression of the estrogen receptor. These mechanisms are considered to be critical for the endocrine control of parturition.