孕期接触四氯联苯对大鼠母性行为的影响

为评价多氯联苯对人体发育的影响,本研究以大鼠为模型,研究多氯联苯（PCB）对母性行为的影响。将50只同期怀孕的Long-Evans大鼠随机分为5组,在怀孕第7－18天,每天给大鼠肌注四氯联苯或芝麻油。1组、2组,按每kg体重分别注射1mg、20mg2,2′,4,4′－四氯联苯（PCB47）;3组、4组,按每kg体重分别注射0.25mg、1mg3,3′,4,4′－四氯联苯（PCB77）;5组（对照组）注射芝麻油。产仔后的第0、3、6、12、15天分别观察母鼠的筑窝、舔仔、自发叼仔和诱发叼仔、蹲伏和在窝内的时间。结果表明：对照组母鼠在30min的观察中,其窝内时间与幼仔出生后天娄和负相关,而接触PCB的母鼠的窝内时间与幼仔出生天数无相关关系。接触PCB47的母鼠的筑巢、蹲伏、舔仔、自发叼仔行为在幼仔出生后的第0天和6天与对照组有显著差异,而接触PCB77的母鼠仅在第15天与对照组大鼠有区别。在诱导叼仔的实验中,接触PCB77的母鼠的叼仔时间在幼仔出生后的第12天增加。     

杂色山雀亲代喂食与子代乞食间的行为

在育雏期,晚成鸟的子代一般都是由双亲共同来抚育,子代为了更好地存活,会用自己的方式竞争获得更多的食物和更好的生存空间,同时亲代也会根据子代的乞食信号来分配食物。2011年3～7月采用针孔摄像技术录制了杂色山雀(Parus varius)育雏期巢内亲代与子代间的行为,统计了亲鸟站位、雏鸟站位、雏鸟乞食强度及亲鸟的喂食情况等数据。分析结果表明:(1)雌雄亲鸟在巢中的站位各有特点,雄鸟在整个育雏期都喜欢站在距离巢口较近的位置;雌鸟站位不太固定,前期离巢口相对较远,中期和后期离巢口相对较近;(2)雏鸟离亲鸟越近,乞食强度越大,获得食物的机会就越多;离亲鸟越远的雏鸟越不爱乞食,所以站位对雏鸟的食物获得影响最大;(3)雌鸟承担主要的育雏任务,喂食频率远大于雄鸟;(4)育雏期的不同阶段雏鸟乞食强度、亲鸟喂食频率变化很大:中期雏鸟乞食强度最大,亲鸟喂食频率最高,后期雏鸟乞食强度最弱;(5)整个育雏期雌性亲本没有表现出明显的偏爱行为,但雄性亲本在中、后期更偏爱体型大的雏鸟。可见杂色山雀子代的行为和体型大小影响着亲代的食物分配,亲代也会根据雏鸟日龄调整站位和喂食行为。     

Maternal Care by the Earwig Doru lineare Eschs. (Dermaptera: Forficulidae)

We performed laboratory experiments to study maternal care in Doru lineare Eschs. (Dermaptera: Forficulidae), a predator of the maize pest Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae). Females laid 29.7?±?8.43 (SD) eggs which took 7–10 days to hatch. Mothers searched for an appropriate nest, where they cleaned and defended eggs and nymphs. Females did not recognize eggs from other females as foreign and adopted them. Other evidence of maternal behavior was also observed, such as egg-cleaning, nest-cleaning, and a lower viability of eggs not cared for by females.     

Variations in maternal behavior in the rat as a function of sex and gonadal state

Performance of major components of maternal care was evaluated quantitatively in several test situations for various groups of rats. Maternal behavior of concaveated ovaríectomized virgin females and castrated males was inferior on a variety of measures to that of concaveated intact virgin females. However, concaveated intact virgin females were markedly inferior to natural mothers on measures of nest building and responsiveness to an intruder. Thus, it was found that test situations other than the standard homecage test revealed previously undetected group differences and that the occurrence of pup retrieval is not a valid predictor of the performance of some major components of maternal care. In addition, it was concluded that gonadal hormones partially determine the quality of maternal responsiveness displayed by virgin females, but that gonadal hormones characteristic of the cycling female are not sufficient to increase maternal responsiveness to the level seen with natural mothers. Possible relationships between pup-induced maternal behavior and that of natural mothers are discussed.     

Ontogeny of social behavior of pups of laboratory rats genetically selected for activity level

In pups of Wistar laboratory rats genetically selected for high (+A) and low (-A) locomotor activity in an open field social behavior was tested in a situation of paired interactions in a novel environment. Tests were performed on postnatal Days 16, 19, 23, and 27. They consisted of four five-minute trials with 50 min, intertrial intervals. Duration of active contacts, passive contacts, mutual grooming, following (chasing), and playful fighting was recorded. In pups of the +A line total duration of all social interactions increased between Days 16 and 23, while in the -A pairs preweaning maximum in most types of social activities was achieved already on Day 16, after this day the time spent in mutual contacts decreased. Analysis of dynamics of social behavior over trials in the -A line showed the tendency to habituate, maximum duration of paired interactions appeared in the first trial contrary to +A groups, in which duration of social contacts tended to increase with repeated trials. In both lines, duration of following responses increased from Day 16 to Day 27. In +A pairs following often led to playful fighting, while in -A pairs fighting was practically absent. The experiment demonstrated that differences between lines +A and -A appeared in those social contacts which required higher energy expenditure and which realized themselves in the larger space of the testing box.     

Attraction of the sexes inFormica lugubris Zett (Hymenoptera: Formicidae)

Summary Sexuals ofFormica lugubris fly to mating places, where females attract males by using a sex pheromone. Females collected on the nest surface before departing on a mating flight are much less attractive than those collected on the mating place after the mating flight, suggesting that the mating flight triggers the release of the sex pheromone. Olfactory cues are essential for males to locate females while they patrol. Males probably use visual cues to locate females once they have alighted nearby them. Males are also attracted by aggregations of other males on the ground, probably because one or several females are likely to be close to male aggregations.     

Estrogen implants in the lateral habenular nucleus do not stimulate the onset of maternal behavior in female rats

The natural onset of maternal behavior in the rat is hormonally mediated. Estrogen, progesterone, and prolactin administered to ovariectomized females in amounts and sequences that produce circulating levels similar to those found during pregnancy stimulate the onset of maternal behavior. In fact, maternal behavior can be stimulated by estrogen alone, administered either peripherally or by implant in the central nervous system. The lateral habenula (Lhb), which is a necessary component in the neural circuit that supports maternal behavior, contains a subset of neurons with estrogen receptors. The present study investigated whether estradiol implants directly in the Lhb are sufficient to stimulate maternal behavior. Female rats, hysterectomized and ovariectomized on day 16 of pregnancy, received estrogen implants in the Lhb or, as a positive control, in the medial preoptic area (MPOA). An additional control group received cholesterol implants in the Lhb. All females were tested for pup retrieval, nest building, crouching behavior, locomotor activity, and carrying behavior. Estradiol implants into the Lhb did not stimulate the onset of maternal behavior. Females with estrogen implants in the Lhb scored significantly lower in pup retrieval and crouching behavior compared to females with implants in the MPOA and were not significantly different from females with cholesterol implants in the Lhb. There were also no significant differences in overall activity or carrying behavior among the groups.     

Role of early experience in social behaviour of laboratory-bred female rats

Social relationships among female laboratory-bred rats in a community are influenced by their early life history. When the rats were born and kept until adulthood under conventional breeding conditions, i.e. in single cages, and then used to form a community in which they gave birth, one female assumed the dominant role, with all others subordinate. The dominant female herded all young rats born in the community, irrespective of their age, in a single litter and suckled them. She accumulated food and wood shavings from other parts of the community near the nest and prevented access to the nest to all other community members including other females that had given birth. Subordinate females ceased to show maternal behaviour, including lactation, within 24 h (occasionally within 48 h). The mortality of the young until 15 days of age was high. This type of behaviour in a community was observed both with randomly chosen female rats and with rats selected as dominant and subordinate types in preceding experiments. Female rats born and reared in a community and rats living in a community from 15 to 30 days of age did not differentiate into dominant and subordinate types. All females retained their maternal behaviour, including lactation. Mortality of young rats was minimal. In most cases the females built one common nest; sometimes each female built her own nest. The results point to the decisive role of early experience in the development of maternal behaviour and in the occurrence of communal rearing of the young.     

Do Laboratory Mouse Females that Lose Their Litters Behave Differently around Parturition?

Efficiency in laboratory mouse breeding is hampered by poor reproductive performance, including the loss of entire litters shortly after birth. However, the underlying mechanisms are not yet fully understood and establishing the cause of death in laboratory mouse pups can be complicated. Newborn mouse pups are generally hidden in nests, dead pups are often eaten by the female, and the widespread practice of leaving periparturient females undisturbed complicates inspection, which may delay the discovery of pup loss. In order to efficiently prevent problems with litter loss, it is important to find key factors for survival. We investigated differences in periparturient behavior between female laboratory mice whose pups survived until weaning and females whose entire litters were lost. Video recordings of 82 primiparous females of the C57BL/6 strain or knockouts with C57BL/6 background were used. The mice were observed from 24 h before until 24 h after parturition and female behaviors coded using a pre-established ethogram. The relationship between behavior and survival was analyzed using logistic models, where litter survival was regressed on the proportion of 30-s observations with at least one occurrence of the behavior. We found that females with surviving litters performed more nest building behavior during the last 24 h before parturition (p = 0.004) and spent less time outside the nest during the entire observation period (p = 0.001). Increased litter survival was also associated with more passive maternal behaviors and the female ignoring still pups less. Females that lost their litters performed more parturition-related behaviors, suggesting prolonged labor. The results indicate that maternal behavior plays a significant role in laboratory mouse pup survival. Complications at parturition also contribute to litter mortality.     

Motherhood and the hormones of pregnancy modify concentrations of hippocampal neuronal dendritic spines

Short-term fluctuations in steroid hormones such as estradiol (E2) and progesterone (P) can affect the concentration of hippocampal dendritic spines in adult, cycling nulliparous female rats. Pregnancy is characterized by a significantly longer duration of substantially elevated E2 and P compared to the estrous cycle. Thus, even greater changes than those reported during estrus may be evident. In two experiments, we examined the extent to which reproductive and hormonal state altered the concentration of apical neuronal dendritic spines of the CA1 region of the hippocampus in the following age-matched groups (N's = 7-10/group) of rats: in Exp. 1., CA1 dendritic spine density was examined in nulliparous diestrus (DES), proestrus (PRO), and estrus (ES) females, and late-pregnant (LP) (day 21) and lactating (day 5-6; LACT) females. In Exp. 2, the effects on spine density of a regimen mimicking pregnancy (and that stimulates maternal behavior) were examined, using ovariectomized, no hormone-exposed (OVX-minus) vs. sequential P&E(2)-treated (OVX + P&E2) groups. For both experiments, brains were removed, Golgi-Cox-stained and the most lateral tertiary branches of the apical dendrite of completely-stained hippocampal CA1 pyramidal neurons were traced with oil-immersion at x 1600 and dendritic spine density (# spines/10 micro dendritic segment) recorded. In Exp. 1, spine density was increased in LP and LACT females (which were not different) compared to the other virgin groups, including PRO females, who had more spines than DES and ES. In Exp. 2, OVX + P&E2 displayed significantly more dendritic spines per 10 micro than OVX-minus females (and had numbers that were similar to those of LP and LACT from Exp. 1). Pregnancy and its attendant hormonal fluctuations, therefore, may alter hippocampal neurons that regulate some non-pup-directed components of maternal behavior (e.g., nest building) or behaviors that support maternal behavior (e.g., foraging, associative memory).     

Fighting and mating behaviors of dimorphic males in the ant

Colony composition inCardiocondyla wroughtoni and the fighting and mating behaviors of 2 types of males, alates and ergatoids, are described. This species is polygynous, with a mean of 7.0 queens per nest, and forms polycalic colonies. Within nests, ergatoid males fight with each other, leading to the death of all but one in single nests. On the other hand, alate males exhibit no aggressive behavior towards any of their colony members. Both types of males conduct intranidal mating with their sisters, though the alate males also conduct nuptial flights. Many alate females leave their maternal nest even if they have already been inseminated by intranidal mating.     

Patterns of maternal behavior of rats genetically selected for opposite coping styles

Maternal behavior of Koltushi High- and Low-avoidance (KHA and KLA) rats strains was assessed over the prewealing period (days 6-21). Ten litters of each strain were observed during the light phase of the light/dark cycle. In a series of experiments, rat pups were taken from the maternal nest and placed into the opposite corner of the cage. The following parameters of the maternal behavior were recorded: the latency of the first contact with the pups, pup licking, latency of carrying/retrieval of the first pup back to the nest, time of returning to the nest of the whole litter, and mother's spontaneous behavior (grooming and locomotion time) over the course of 10 min of observation. KLA mothers stayed with their pups and took care of them more frequently than KHA mothers during the light phase of the circadian cycle. Time of self-grooming was significantly higher in KHA rats. The highest levels of self-grooming of mothers was registered on the first day of testing. The latency of the first coming to pups after their removal from the nest was lower in KHA rats, but they needed more time to returned all pups to the nest. The experimental evidence suggests that the KHA but not KLA rats with the active coping style and higher stress reactivity display disorders in maternal behavior in a novel situation.     

Female-Directed Aggression in Free-Ranging Ateles geoffroyi

In a study of the reproductive biology and behavior of black-handed spider monkeys (Ateles geoffroyi) on Barro Colorado Island, Panama, 107 instances of female directed male aggression (male attacks) occurred during >1,000 h of observation. Two hypotheses might explain this behavior. First, males may attack to induce defecation/urination by target females, from which they can gain reproductive information. Rates of defecation and urination did not increase subsequent to attacks; however, there was an association between attacks and investigative behaviors such as place sniffing. Alternatively, the attacks might be a form of sexual coercion. My results indicate that female reproductive state, as determined by fecal steroid metabolites (E1C and PdG), had an inconsistent effect on the frequency of attacks received. In addition, when females were in the peri-ovulatory period of the ovarian cycle they did not receive more attacks than at other times. Nor were attacks associated with observed copulations, suggesting that sexual coercion does not sufficiently explain the behavior. Some support is provided for the notion that the attacks allow males to dominate equally-sized females.     

Foraging and nesting behavior of Osmia lignaria (Hymenoptera: Megachilidae) in the presence of fungicides: cage studies

During orchard pollination studies in California, we observed dramatic changes in nesting and foraging behavior of Osmia lignaria Say (Hymenoptera: Megachilidae) after sprays with tank mixtures containing fungicides. A characteristic pattern of postspray events observed includes erratic behavior and interrupted foraging and nesting activity for several days. In an effort to determine whether fungicidal sprays were disruptive to bee foraging and thus to pollination, we exposed O. lignaria females nesting in field cages planted with lacy scorpionweed, Phacelia tanacetifolia Benth (Hydrophyllaceae), to selected spray mixtures normally encountered in California orchard production systems: iprodione (Rovral), propiconazole (Orbit), benomyl (Benlate), and captan (Captan 50 WP); the surfactant Dyne-Amic, alone and mixed with Rovral; and the tank mixture IDB (Rovral + Dyne-Amic + the foliar fertilizer Bayfolan Plus). An additional cage sprayed with an equal volume of water acted as control, and a cage sprayed with the insecticide dimethoate as a toxic standard. For each female O. lignaria, we recorded time spent inside the nest depositing pollen-nectar loads, foraging time, cell production rate, and survival. All females in the dimethoate treatment died postspray + 1 d. Before death, some of these females behaved similarly to our previous orchard observations. A high proportion of females in the IDB cage were inactive for a few hours before resuming normal foraging and nesting activity. No lethal or behavioral effects were found for any of the other compounds or mixtures tested. Our results indicate that the fungicide applications that we tested are compatible with the use of O. lignaria as an orchard pollinator.     

Do female degus communally nest and nurse their pups?

We examined the nesting and nursing behavior of females of the caviomorph rodent Octodon degus. We recorded the behavior of two, three-female groups of lactating degus kept in captivity and compared it with that of singly housed lactating females. Grouped females spontaneously nested communally. Five of six lactating females had non-offspring pups hanging from their teats, which suggests that some non-offspring nursing took place. Non-mothers increased their maternal behavior after the delivery of their own pups. Although time allocated to parental care by each communally nesting dam did not differ from that of solitary lactating females, young of communal litters spent less time alone and enjoyed more time cared for by a lactating female than young of single dams. Electronic Publication     

The role of sex steroids in courtship, pairing and pairing behaviors in the socially monogamous zebra finch

The purpose of this study was to test whether sex steroid actions are necessary for courtship and pairing in socially monogamous birds. We examined the effects of an aromatase inhibitor, 1,4,6-androstatriene-3,17-dione (ATD), combined with an anti-androgen, flutamide (F), on the behavior and pairing status of initially unpaired male and female zebra finches (Taeniopygia guttata). In the first experiment, 24 adult males were implanted with either a combination of ATD and flutamide or empty implants. Two weeks after implantation, birds were housed in aviaries containing 3 ATD + F males, 3 control males, and 3 females and allowed 2 weeks to pair, with observations 7 times during the 2-week period. A second experiment tested the effects of these same treatments in females. During the first 4 days of testing, ATD + F males were less likely to attack conspecifics than were control males. ATD + F males were also less likely to "greet," or approach, females than were control males, but other courtship behaviors, including directed singing, were unaffected. ATD + F females did not differ from control females on any courtship behavior measured. Furthermore, these treatments did not affect pairing behaviors (time spent clumping or in a nest box together) or the likelihood of pairing with a partner of the opposite sex. ATD + F treatments in females did, however, increase the likelihood of same-sex pairing. This suggests that, although sex steroids may regulate some courtship behaviors in males, they do not regulate pairing behaviors and have little effect on the likelihood that a male or female will be chosen as a mate by a bird of the opposite sex.     

The α-fetoprotein knock-out mouse model suggests that parental behavior is sexually differentiated under the influence of prenatal estradiol

In rodent species, sexual differentiation of the brain for many reproductive processes depends largely on estradiol. This was recently confirmed again by using the α-fetoprotein knockout (AFP-KO) mouse model, which lacks the protective actions of α-fetoprotein against maternal estradiol and as a result represents a good model to determine the contribution of prenatal estradiol to the sexual differentiation of the brain and behavior. Female AFP-KO mice were defeminized and masculinized with regard to their neuroendocrine responses as well as sexual behavior. Since parental behavior is also strongly sexually differentiated in mice, we used the AFP-KO mouse model here to ask whether parental responses are differentiated prenatally under the influence of estradiol. It was found that AFP-KO females showed longer latencies to retrieve pups to the nest and also exhibited lower levels of crouching over the pups in the nest in comparison to WT females. In fact, they resembled males (WT and AFP-KO). Other measures of maternal behavior, for example the incidence of infanticide, tended to be higher in AFP-KO females than in WT females but this increase failed to reach statistical significance. The deficits observed in parental behavior of AFP-KO females could not be explained by any changes in olfactory function, novelty recognition or anxiety. Thus our results suggest that prenatal estradiol defeminizes the parental brain in mice.     

Mating system and kin relationship between adults and young in the shell-brooding cichlid fish <Emphasis Type="Italic">Neolamprologus meeli</Emphasis> in Lake Tanganyika

Mating system and parental behavior of ten monogamous pairs and two polygynous groups of the Tanganyikan cichlid Neolamprologus meeli were observed in their natural habitat. The home ranges of males and females overlapped with each other. Most groups included one to six young. Paternal and maternal relationships were determined for 22 young from DNA microsatellite markers. Three types of kinship were found: (I) kinship to both the male and female; (II) kinship to females only; and (III) non-kinship to both sexes. In the groups with type II young, step-fathering or sneaking may have occurred. Type III young were larger than type I, suggesting that the former were of sufficient size to leave their birth nest and settle in the territories of foster parents. Both males and females drove out potential predators of young (including three species of Lepidiolamprologus) as a parental behavior. Adults with type III young attacked approaching predators with as much frequency as those with type I young only, indicating that they provided alloparental care. Adults and young swam together, but, a significant difference existed in the frequencies of interactions between adults versus kin young and adults versus non-kin young. The results suggest that both adults and young recognized kin. Electronic Publication     

The influence of maternal experience on the formation of species-specific offspring behavior in early ontogenesis

The influence of maternal experience on the formation of early behavioral responses and species-specific defensive behavior (dark preference response) was investigated in Wistar rat offspring. Maternal behavior of primiparous rats was found to differ from that of the same females parturiated for the second time. The behavior of maternally experienced females is distinguished by creating more comfort in the nest and taking more care of their offspring. A study of the behavioral dynamics in the primiparous females’ offspring revealed a disappearance of correlative links between eye opening times and the appearance of first behavioral responses, which is a negative factor for the formation of adaptive behavior in ontogenesis. Disturbed development of the speciesspecific defensive behavior (dark preference response) was found in the offspring of naïve females. The obtained results indicate a positive influence of the maternal experience on the formation of functions in offspring.     

Plural Breeding in the Splendid Fairy-wren,Malurus splendens (Aves: Maluridae), a Cooperative Breeder

Groups of the cooperatively breeding splendid fairy-wren Malurus splendens may include more than one female. Previously this species has been described as singular breeding (only one female breeds). This paper describes the occurrence of plural breeding (PB) groups in 10% of group years, in which two females had separate nests. In all cases, the secondary female (Y) was related to the primary breeding female (X) and was generally a 2-year old female which had helped in the group during the previous breeding season. Plural breeding was correlated with an increase in population density and in the number of female helpers; PB groups were larger than singular-breeding groups. In most cases, the X female was occupied with her own nest or offspring when the Y female began to nest, and there was no aggression between them. Which birds helped the Y female to feed at her nest depended on the time between the hatching of the two nests. If the interval was small, some group members helped at each nest; with longer intervals, the group members began to feed at the earlier nest, and the other female was left to raise her brood alone. Female helpers were very active in feeding at single nestings, and the cost to an X female of a Y female breeding was mainly a loss of this assistance. The success of individual X nests was not affected. Effects on productivity were slight, but fewer X females in PB groups raised second broods than did experienced singular breeding females. Y females were less productive than X females, but no less productive than singular breeding novice females without helpers. It is not known whether Y females copulated with primary or secondary males within their group, or with males from outside the group. Certainly, they did not form an observable pairing with any male in the group. Plural breeding occurred in a minority of group years in response to extrinsic conditions and the current demographic situation, and shows the extreme plasticity of the mating system in M. splendens.