Communal nursing in mexican free-tailed bat maternity colonies

Examination of genotypes of female-pup nursing pairs taken from large maternity colonies of the Mexican free-tailed bat in Texas demonstrates that nursing is nonrandom and selective along genetic (kinship) lines. This is contrary to previous reports that nursing in these colonies is indiscriminate. Although nursing is nonrandom, an estimated 17 percent of the females sampled were nursing pups that could not be their offspring. This "nonparental" nursing is an apparent result of the difficulties females face in consistently relocating and selectively nursing their own pups within these enormous colonies.     

Evidence for mate fidelity in the gray seal

Colonially breeding gray seals are polygynous. Males are larger than females, compete with each other for position among aggregated females, and contribute no parental care. Genetic analysis of pups born on the island of North Rona, Scotland, reveals large numbers of full siblings, although dominant males father disproportionately few of these. This result cannot be explained by mating patterns based solely on male dominance and the spatio-temporal organization of the breeding colony. Instead, many full siblings must result from choices favoring previous parental combinations. Thus, polygyny and partner fidelity appear to operate simultaneously in this breeding colony.     

Infantile experience with suckling odors determines adult sexual behavior in male rats

Because infant rats learn about odors that elicit suckling, and because certain chemosensory cues that help elicit mating behavior in adults are similar to those that elicit suckling, an experiment was undertaken to assess the influence of suckling-associated odors experienced during infancy on adult sexual behavior. Rat pups lived with and suckled dams whose nipple and vaginal odors were altered with citral, a lemon scent. The rats were weaned and never exposed again, until testing, to citral or females. At about 100 days of age, the males were paired in mating tests with a normal sexually receptive female or with a sexually receptive female that had been treated perivaginally with citral immediately before testing. The males ejaculated readily when paired with citral-treated females but were slow to achieve ejaculation when paired with normal females. These findings implicate an infantile experience as a determinant of adult sexual behavior in a mammal.     

Demography of northern elephant seals, 1911-1982

Northern elephant seals (Mirounga angustirostris) were hunted to near extinction in the 19th century. Protection has allowed them to recolonize former habitat on islands off California, where the population is increasing more than 14 percent per year. Immigration of young pregnant females from Baja California initiated the California rookeries but is responsible for only a small part of recent population growth. Almost 25,000 northern elephant seal pups were born in the species' range in Mexico and the United States in 1982 in comparison with only six known births in 1911.     

Nonhormonal basis of maternal behavior in the rat

Rats were tested for induction of maternal behavior by exposing them to young pups continously for 10 to 15 days. Nonpregnant intact, ovariecto-mized. and hypophysectomized females were studied, as well as intact and castrated males. Nearly all the animals exhibited the four main items of maternal behavior and there were only minor differences in the latencies for the onset of maternal behavior among the various groups. It is concluded that all rats have a basic level of maternal responsiveness which is independent of hormonal stimulation.     

Rapid expulsion of Trichinella spiralis in suckling rats

Orally administered Trichinella spiralis muscle larvae were rapidly expelled by rat pups suckling an immune dam. The immunity was delivered in the milk; substantial resistance was conferred on normal rat pups suckled for only 24 hours by a Trichinella-immune foster mother. The pups were protected by oral or systemic administration of specific serum antibodies. When infused into a normal lactating dam, these antibodies accumulated in the serum of her suckling pups.     

Effects of helpers on juvenile development and survival in meerkats

Although breeding success is known to increase with group size in several cooperative mammals, the mechanisms underlying these relationships are uncertain. We show that in wild groups of cooperative meerkats, Suricata suricatta, reductions in the ratio of helpers to pups depress the daily weight gain and growth of pups and the daily weight gain of helpers. Increases in the daily weight gain of pups are associated with heavier weights at independence and at 1 year of age, as well as with improved foraging success as juveniles and higher survival rates through the first year of life. These results suggest that the effects of helpers on the fitness of pups extend beyond weaning and that helpers may gain direct as well as indirect benefits by feeding pups.     

Evolution and development of sex differences in cooperative behavior in meerkats

In cooperatively breeding birds, where helpers of both sexes assist with the provisioning and upbringing of offspring who are not their own, males tend to contribute more than females to rearing young. This sex difference has been attributed to paternity uncertainty, but could also occur because males contribute more where they are likely to remain and breed in their group of origin. In contrast to most birds, female meerkats (Suricata suricatta) are more likely to breed in their natal group than males. We show that female meerkat helpers contribute more to rearing young than males and that female helpers feed female pups more frequently than males. Our results suggest that sex differences in cooperative behavior are generated by sex differences in philopatry and occur because females derive greater direct benefits than males from raising recruits to their natal group. These findings support the view that direct, mutualistic benefits are important in the evolution of specialized cooperative behavior.     

Early maternal separation increases gastric ulcer risk in rats by producing a latent thermoregulatory disturbance

Rat pups that are separated early from their mothers, at postnatal day 15, become hypothermic when subjected to physical restraint on postnatal day 30. Restraint of separated pups also elicits an unusually high incidence of gastric erosions, as well as insomnia and an increase in quiet wakefulness. If hypothermia during restraint is prevented, neither the erosions nor the behavioral responses occur. Rat pups separated at the customary age (postnatal day 22) do not become hypothermic during restraint, and the restraint of such pups is not associated with either gastric erosion or insomnia.     

南海鸢乌贼微型群肌肉和性腺组织能量积累及其分配

利用组织能量密度测定技术和残差指标分析方法,分析了南海鸢乌贼微型群个体肌肉组织和性腺组织的能量积累及其分配规律的变化过程。结果显示,微型群个体的肌肉、性腺组织之间的能量密度存在显著性差异;除缠卵腺之外,其它组织的能量密度均随性腺发育变化显著。肌肉组织和性腺组织的组织能量积累均随性腺发育增加显著。同一性腺成熟度等级,肌肉组织的相对组织能量积累较高,性腺组织的相对组织能量积累相对较低。雌性个体性腺组织相对组织能量积累随着性腺发育增长显著,雄性个体性腺组织相对组织能量积累在Ⅰ期~Ⅴ期增长较快,在Ⅵ期~Ⅶ期趋于稳定。肌肉和性腺组织在性腺发育后期的质量特征较发育前期均显著改善,并且肌肉组织能量积累-胴长残差与性腺组织能量积累-胴长残差呈显著的正相关关系,表明性腺发育过程中的肌肉组织与性腺组织之间不存在能量交流。研究表明,南海鸢乌贼微型群个体的生殖能量倾向于外源性投入,肌肉和性腺组织的组织能量密度、组织能量积累和相对组织能量积累存在雌雄差异性。     

Drosophila males contribute to oogenesis in a multiple mating species

Two species of Drosophila that differ in their ecology and mating systems have been compared with respect to male contribution to the somatic tissues and developing oocytes of females. In the species Drosophila mojavensis females remate daily, exhibit a copulatory plug, and have been shown to obtain a contribution from the male ejaculate. In contrast, Drosophila melanogaster males do not contribute to females. Female Drosophila melanogaster do not remate as frequently as Drosophila mojavensis females nor is a copulatory plug formed.     

Major urinary protein complex of normal mice: origin

Mouse serum contains protein having the same charge density and molecular size as the major urinary protein complex of mice. Mouse liver (but not eight other tissues examined) incorporated amino acids labeled with carbon-14 into the complex in vitro. The degree of incorporation was greater in livers from males than from females, and was internmediate in livers from females treated with testosterone.     

BEHAVIOR OF ADULT RATS IS MODIFIED BY THE EXPERIENCES THEIR MOTHERS HAD AS INFANTS

Some rat pups were handled for 20 days in infancy, while others were not. When the rats reached adulthood the females were bred. Some of the offspring were left with their natural mothers, others were fostered to mothers of the same background (handled/nonhandled) as that of their natural mothers, while still others were fostered to mothers with a different background from that of their natural mothers. The offspring were weaned and weighed at 21 days; at 50 days, activity and defecation scores were obtained in the open field. The weights at weaning and the defecation scores at 50 days were significantly influenced by the experience in infancy of the "postnatal" mother, whether she was the natural mother or a foster mother. The natural mother and the foster mother jointly affected the open-field activity of the offspring.     

Zinc deficiency in murine milk underlies expression of the lethal milk (lm) mutation

The inability of nursing pups to survive on milk of mice homozygous for the recessive mutation, lethal milk (lm), is correlated with a reduction in zinc levels of both milk and pup carcass. Administration of zinc to pups nursing on lmlm dams reduces the observed mortality and morbidity. It is suggested that lm alters zinc transport from maternal blood to milk and that its study may provide useful information for understanding the rare human disease, acrodermatitis enteropathica.     

Rabbit: frequency of suckling in the pup

Rabbit does were given free access to their young, access once a day, and access twice a day. In all three groups the young were nursed only once every 24 hours. Growth curves for the pups from day 2 of age to day 30 were identical for all three groups. The restriction of suckling to once a day appears to depend on the mother and not the pups.     

Comparative Studies of Substrate and Inhibitor Specificity of Glutathione S-Transferases in Six Tissues of Oxya chinensis (Thunberg) (Orthoptera: Acrididae)

Specific activity, substrate specificity, and kinetic parameters (Km and Vmax) of glutathione S-transferases (GSTs) towards three substrates, 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), and p-nitrobenzene chloride (pNBC) were investigated in six tissues (foregut, midgut, hindgut, fat body, hemolymph, and muscle) of Oxya chinensis. In addition, the inhibition in vitro (ethacrynic acid, and Cibacron Blue 3GA) of Oxya chinensis in the six tissues was also investigated. Glutathione S-transferase activity was detected in all the six tissues examined. The rank order of GST activities towards CDNB was fat body > midgut > hindgut > muscle > foregut > hemolymph both in females and males. Glutathione 5-transferase activities in the fat body in females and males were 1.3- to 10.4-fold and 1.1- to 10.0-fold higher than those in the other tissues. The rank order of GST activities towards the other substrates changed slightly. From these results, it was inferred that GSTs in the fat body and midgut played important roles in detoxifying xenobiotics including insecticides and plant allelochemicals in O. chinensis. In the three substrates examined, CDNB seemed to be the best substrate, followed by pNBC and DCNB. The kinetic parameters of GSTs were different among the six tissues. This suggested that GSTs in different tissues have various affinities and catalytic efficiency to substrates. In vitro inhibition study showed that the median inhibition concentration (IC50) values of the two inhibitors to GSTs from the six tissues were different. The results suggested that the two inhibitors have different inhibition potency to GSTs from the different tissues. The observed changes in kinetic parameters and inhibition in vitro among the six tissues of the insect might suggest that the number and structure of isoenzymes and their rate of expression varied for the different tissues.     

Change in the fatty acid composition of black pied cows’ colostrum and milk during parturient paresis

Substantial changes are found in the fatty acid (FA) composition of colostrum and milk of cows during parturient paresis: the content of saturated FAs was 10–14% higher than in healthy animals and that of mono- and polyunsaturated FAs was respectively 5.5 and 1.6% lower.     

东营池塘养殖中华绒螯蟹生长性能、性腺发育及营养品质

为了解不同地理纬度中华绒螯蟹(Eriocheir sinensis)的养殖性能和常规营养成分差异,通过连续采样和生化分析研究山东东营池塘养殖中华绒螯蟹的生长性能、生殖蜕壳率、肝胰腺指数(HSI)、性腺指数(GSI),并进一步比较出肉率(MY)、总可食率(TEY)、肥满度(CF)和可食组织的常规营养成分。结果表明:(1)无论是雌体还是雄体,中华绒螯蟹体质量与头胸甲长和头胸甲宽均呈幂函数相关性,头胸甲长和头胸甲宽则呈线性函数相关。雌体平均体质量始终小于雄体,且7—9月差异显著(P0.05);雌雄蟹增重率(WGR)和特定生长率(SGR)均无显著性差异(P0.05)。(2)雌体生殖蜕壳略早于雄体,生殖蜕壳高峰出现在8—9月,9月中旬成蟹全部完成生殖蜕壳。8—10月,雌雄蟹GSI显著增加,HSI则为下降趋势(P0.05)。9月上市成蟹雌体平均体质量集中于60.00～99.99 g,而雄体则集中于100.00～139.99 g。(3)10月上市成蟹雌体GSI和TEY显著高于雄体(P0.05),而MY和CF则以雄体为高(P0.05)。成蟹雌体可食组织中粗蛋白和总脂含量均高于雄体,而水分含量则以雄体为高,灰分含量两者差异不大。综上,山东东营池塘养殖中华绒螯蟹生殖蜕壳高峰集中于8—9月,雌雄成蟹总可食率均较高,分别为46.47%和44.81%,可食组织具有较高的营养价值。     

孕期心理干预对改善孕产妇心理状况的研究

目的：探讨孕期心理干预对改善孕产妇心理状况的可行措施。方法：随机将孕妇分为2组并随访至产后2周（非心理干预组402人，随访至产后2周者356人；心理干预组323人，随访至产后2周者287人），心理干预组孕妇分孕早期、孕中期和孕晚期进行三阶段的心理干预，孕期调查用医院焦虑和抑郁量表（HAD），产后2周调查用艾迪产后抑郁量表（EPDS）并增加本次有关妊娠、分娩前后的生活事件等内容并进行比较。结果：心理干预组孕妇临产前焦虑和抑郁情绪均分值明显低于非心理干预组，其焦虑和抑郁情绪发生率也明显低于心理干预组，差异非常显著（P＜0．01）；产后抑郁症发生率明显低于非心理干预组（P＜0．01）。对其潜在心理背景分析表明：心理干预组的孕产妇在妊娠心境、产后育儿、与社会家人关系等得到明显改善（P＜0．01）；而对来自分娩周围环境、分娩疼痛等压力无明显改善，与非心理干预组比较差异不显著（P＞0．05）。结论：孕期心理干预可明显改善孕产妇的心理状况和降低产后抑郁症的发生率。     

Intersexes and sex determination in chickens

Chickens sexed as females in commercial flocks show a low frequency of intersex individuals. Gross anatomical examination of the intersexes revealed malformed gonads. Histological examination proved that these gonads were not ovotestes but were composed of testicular tissues. Karyotype analysis of 15 intersex individuals showed 13 of them to be 3A-ZZW triploids (normal females are 2A-ZW) while the other 2 were mosaic for male and female karyotypes. Red blood cell volume accurately reflects the ploidy level and is suggested for use in screening for polyploids. Intersex triploids may develop parthenogenetically or from fertilization between reduced and unreduced gametes.