Behavior and maintenance of the woolly opossum (Caluromys) in captivity

Circadian activity, general behavior, dietary requirements, and reproductive activity were recorded in a small laboratory colony (four females, six males) of two species of the woolly opossum (Caluromys lanatus and C derbianus) over a period of 3 years. The two species were indiscernable in all aspects of their behavior. Both were completely nocturnal and rarely active during daylight hours. General behavior was apparently related to many variables, particularly individual temperament and cage size. Even docile individuals were more excitable when housed in small cages. Although the woolly opossum is reported to prefer a meat diet, the opossums in this study remained healthy on a meat-egg-fruit diet, and showed a special liking for fruit, especially bananas. Vaginal smears indicated that females of the colony were cyclic, but all attempts to breed them were unsuccessful. Sexual behavior included pre-mount, pelvic-thrust displays on the part of the male, with complete repulsion by all females.     

Establishment of an outbred strain (Jic: SUN) in the house musk shrew, Suncus murinus]

Planned reproduction of the house musk shrew, Suncus murinus was investigated using 3,016 females for mating. The birth rate and the weaning rate attained were 77.2% and 82.3%, respectively. The average litter size was 3.4. The mean value of the productive index (number of weaned individuals/number of females mated) was estimated as 2.2. The highest value of the productive index, 2.6, was recorded when the fourth litter was used for reproduction. No seasonal fluctuation in the reproductive ability was observed through the course of the present breeding. In the present study, we have maintained the closed colony of the house musk shrew for six years. This colony is established as a outbred strain, and is designated as Jic: SUN.     

Colony size and individual fitness in the social spider Anelosimus eximius

ABSTRACT The effects of colony size on individual fitness and its components were investigated in artificially established and natural colonies of the social spider Anelosimus eximius (Araneae: Theridiidae). In the tropical rain forest understory at a site in eastern Ecuador, females in colonies containing between 23-107 females had india significantly higher lifetime reproductive success than females in smaller colonies. Among larger colonies, this trend apparently reversed. This overall fitness function was a result of the conflicting effects of colony size on different components of fitness. In particular, the probability of offspring survival to maturity increased with colony size while the probability of a female reproducing within the colonies decreased with colony size. Average clutch size increased with colony size when few or no wasp parasitoids were present in the egg sacs. With a high incidence of egg sac parasitoids, this effect disappeared because larger colonies were more likely to be infected. The product of the three fitness components measured-probability of female reproduction, average clutch size, and offspring survival-produced a function that is consistent with direct estimates of the average female lifetime reproductive success obtained by dividing the total number of offspring maturing in a colony by the number of females in the parental generation. Selection, therefore, should favor group living and itermediate colony sizes in this social spider.     

Establishing a free-ranging breeding colony of rhesus monkeys. Part I.

The Caribbean Primate Research Center recently contracted with the Food and Drug Administration to establish a free-ranging island breeding colony of rhesus monkeys. The goal of the program is to produce 600 to 800 offspring yearly from 1,000 breeding age females. The initial colony stock will consist of approximately 360 animals from an existing colony that was established on an island off the southwestern coast of Puerto Rico in 1961. Expansion of the colony will be accomplished by the purchase and introduction of rhesus females obtained from the wild. The colony site, reproductive history, composition, and the methodology of our expansion plans are discussed. In addition, anticipated problems are identified and analyzed.     

Comparison of colony foundation success between sexual pairs and female asexual units in the termite Reticulitermes speratus (Isoptera: Rhinotermitidae)

In termites, a male and a female usually found a colony cooperatively. However, pairing efficiency tends to be low in Reticulitermes speratus because of a limited mate-searching range, the female-biased sex ratio, and a relatively low calling ability. Females that fail to pair with males found colonies either in female–female pairs or even alone. In the laboratory, we examined colony foundation by single females (F), female–female pairs (FF), and normal male–female pairs (FM). The time until colony foundation (when termites began excavating wood baits) differed significantly among the unit types. Time until excavation was much longer for single females than for FF and FM units, which reflects the relative success of colony foundation. The survival rate of single females was also significantly lower than that of FF- and FM-unit females, although there was no difference between FF and FM units. This result demonstrates that cooperation, even female–female, promotes female survivorship. Nevertheless, the number of progeny per female was significantly lower in FF units than in FM units, possibly because females of FF units must share reproductive output. These results lead us to the conclusion that a normal monogamous pair is the best unit for colony foundation. Nevertheless, females alone can establish colonies by parthenogenesis, and even female–female cooperation promotes colony foundation success if pairing with males is not possible. Considering the functional decision for females in F and FF units of how much time to spend searching for a male mate, we believe that these facultative pathways of colony foundation by parthenogenesis have adaptive significance. Received: November 30, 2000 / Accepted: March 6, 2001     

Cellular responsiveness to stimulation in vitro: increased responsiveness to colony stimulating factor of bone marrow colony-forming cells treated with surface-active agents and cyclic 3'5' AMP.

Addition of low concentrations (10 ng/ml) of saponin or Tween 80 to stimulated cultures of normal mouse bone marrow in agar increased the number of granulocyte-macrophage colonies which developed. Addition of cyclic AMP or dibutyryl cyclic AMP in low concentration (10(-8) to 10(-10) M) also enhanced colony numbers although concentrations above 10(-5) M were inhibitory. enhancement was found when marrow cells were pre-treated with these agents and cultured in their absence. The agents did not stimulate colony development in the absence of colony-stimulating factor and enhancement of colony number occurred only in cultures containing a concentration of colony-stimulating factor which was sub-optimal in terms of maximum colony development. There was no indication of increased colony-stimulating factor production by treated marrow cells under the experimental conditions used to show colony enhancement. It was concluded that the agents caused an increased responsiveness of colony-forming cells to colony-stimulating factor.     

Effects of weather on the cyclic patterns of colony attendance in the Cape petrelDaption capense

 Colony attendance of Cape petrels on Nelson Island, South Shetland Islands, Antarctica, fluctuated in a non-random pattern. In the pre-breeding period a relatively weak cycle of about 6 days was observed. Low attendance was associated with brief periods of either SE wind or strong wind, the effects of which lasted 2 days. During breeding, regular attendance cycles were approximately twice as long (8 days) as the average incubation shift (3.8 days), which may have resulted from synchronization of unemployed birds not engaged in incubation. Breeding attendance was lowered on 2 days after strong wind and on days with SE wind, but only wind speed showed a significant effect when both variables were considered. Post-breeding colony attendance showed a continuation of the rhythm established during breeding, but with the majority of birds participating. Correlations found between wind factors and colony attendance suggest that some weather characteristics, which themselves were not truly cyclic, could act to synchronize the endogenous rhythms of individual birds. Seasonal changes of wind effects on colony attendance could be interpreted in terms of foraging behaviour, i.e. as a consequence of the feeding grounds in summer being not restricted by sea ice to one particular direction from the colony. Received: 2 May 1995/Accepted: 4 September 1995     

Behaviour of one-year-old rhesus monkeys in a strange situation

When one-year old rhesus monkeys and their mothers were removed from the colony to a strange situation, infants' activity was initially low compared with behaviour six days later. Although absolute values did not differ between males and females, correlations did. That is, three days after return to the colony, correlations with baseline colony behaviour were significantly positive for females, while males had one significantly negative correlation. On the other hand, males had more significant correlations than females when behaviour in the strange situation was correlated with colony scores. Of the six individuals that had adverse early experience, five showed extreme behaviour. The exception was CT, son of a female with a very low ‘excitable’ score. In fact for all males, mothers' colony scores were significantly correlated with sons' behaviour in the strange situation.     

Fertility of the post-partum bank vole (Clethrionomys glareolus)

Analysis of records of a bank vole breeding colony suggests that fertility is high immediately post partum, declines during established lactation and rises after weaning of young. Mating tests with lactating females and females whose young had been removed at birth showed that receptivity is reduced during lactation, although amongst the females which did mate there was no difference between lactating and non-lactating animals in the proportion which produced litters. However, average size of litters at birth was significantly larger for the lactating than for the non-lactating females. There is some evidence suggesting that this difference may arise after ovulation has occurred. Virgin females were no more receptive or fertile than lactating females.     

Contraception in the chimpanzee: 12-year experience at the CIRMF Primate Centre, Gabon

The Primate Centre of the International Center for Medical Research in Franceville, Gabon (CIRMF) has had a chimpanzee (Pan troglodytes) colony for more than 20 years. A contraceptive policy was started in 1990, following a rapid increase in the number of individuals in the 1980s. Intrauterine devices were first used in 24 females; 10 failures occurred over a period of about 4 years. Depo-provera was then used in 28 chimpanzees for between 4 months and 4 years; 10 failures occurred, the animals gained weight, and cyclic swelling of the external genitalia was markedly modified. Starting in late 2000, 25 females received progestin implants; only one failure has so far occurred, and the main side effect is a complete abrogation of cyclic sexual swelling.     

Domestication-related changes in sexual performance of Queensland fruit fly

In Sterile Insect Technique (SIT) programs, massive numbers of insects are reared, sterilized, and released in the field to impede reproduction of pest populations. The domestication and rearing processes used to produce insects for SIT programs may have significant evolutionary impacts on life history and reproductive biology. We assessed the effects of domestication on sexual performance of laboratory reared Queensland fruit fly, Bactrocera tryoni, by comparing an old (49 generations) and a young colony (5 generations). We evaluated mating propensity, mating latency, copula duration, sperm transfer, and ability to induce sexual inhibition in mates. Overall, both males and females from the old colony had greater mating propensity than those from the young colony. Copula duration was longer when females were from the old colony. There was no evidence of sexual isolation between the colonies as males and females from the two colonies had similar propensity to mate with flies from either colony. Males from the old colony transferred more sperm regardless of which colony their mate was from. Finally, males from both colonies were similarly able to induce sexual inhibition in their mates and were also similarly able to secure copulations with already-mated females. Positive effects of domestication on sperm transfer, coupled with maintained ability to induce sexual inhibition in mates and to secure copulations with previously mated females, highlights that domestication may have little effect, or even positive effects, on some aspects of sexual performance that may advantage mass-reared B. tryoni in SIT programs.     

Rhodnius prolixus vitellogenesis: Dependence upon the blood source

The haemolymph-protein patterns of a Rhodnius prolixus colony, fed on human blood and of a colony fed on sheep blood, were compared by SDS-PAGE analysis. The vitellogenin-polypeptide patterns of larvae and females of both colonies were similar. However, males of the human-blood-fed colony had levels of circulating vitellogenin comparable to those of females, while males of the colony fed on sheep blood had only residual vitellogenin levels. The effect of human blood on different instars of a colony fed on sheep blood was examined. Autogeny occurs in the colony fed on human blood but not on that fed on sheep blood. When 5th-instar females from the sheep-blood-fed colony were fed on human blood, the phenomenon of autogeny was not displayed after moulting to the adult stage. Fourth-instar larvae from the colony fed on sheep blood however showed autogeny in the adult stage when fed on human blood from the 4th-instar on or in this stage only. Furthermore, first-cycle oviposition and the percentage moulting to the adult stage were increased in these groups.     

Identification of Y chromosomal PCR marker and production of a selected strain for molecular sexing in the brown planthopper, Nilaparvata lugens

A laboratory colony was established in order to enable molecular sexing in premature stages in the brown planthopper, Nilaparvata lugens. We found four male-specific amplified fragment length polymorphisms (AFLPs) in the planthopper, and sequenced one of the AFLPs along with its 5' flanking region (1,423 bp in total). PCR primers were designed based on the nucleotide sequence information so that the PCR product was present in male planthoppers and absent in female planthoppers. However, we could not completely distinguish males from females, because the PCR amplification product was absent in some of the males screened. We, therefore, established a laboratory colony, in which all males carried this sequence. We can directly sex pre-adult stages in this colony using our PCR primers, making this strain of considerable value for studies that require sex separation in egg and nymphal stages.     

Establishment of a Self-Mating Mosquito Colony of Anopheles sinensis From Korea

ABSTRACT Many Korean entomologists have attempted to colonize Anopheles sinensis Korean strain, a primary malaria vector in Korea, previous efforts, however, were unsuccessful. Only a study that a successful colonization of An. sinensis Korean strain over 5 generations was recently reported. Recently we obtained a self-mating colony from this mosquito strain. The original colony was established from progenies obtained from females collected from So-Rae District, Incheon, Republic of Korea (ROK), and was maintained for 23 successive generations. While the adult females of first five generations were fed on humans as a source of blood, those of the subsequent 18 generations were fed on white rats as a source of blood. A self-mating colony was initiated from the 9th generation by rearing 200 and 300 newly emerged females and males, respectively, in a 30x30x30 cm cage. The insemination rates increased from approximately 40% to 81% by the 20^th generation. Comparisons of biological aspects between artificial mating and self-mating colonies are reported.     

Reproductive schedule and factors affecting soldier production in the eusocial bamboo aphid Pseudoregma bambucicola (Homoptera, Aphididae)

Summary: The reproductive characteristics of the soldier-producing aphid Pseudoregma bambucicola were studied in Kagoshima, Southern Japan, to know the factors affecting soldier production of eusocial aphids. The soldier proportion in aphid colonies was highest from October to November. In some large colonies, soldiers were observed in all seasons except in July when colony size was relatively small. Multiple regression analysis showed that the colony size was a principal factor affecting soldier proportion throughout a year. Other social or environmental factors such as aphid composition, host plant conditions and predator abundance were not always significant. Rearing experiments revealed that large colonies (̿,000 individuals) produced soldiers in almost all seasons while small colonies (<1,000) never produced any soldiers. The caste-production schedule of adult females was examined in the field. When solitary females produced both castes, they usually produced normal nymphs first and then soldiers. Females from large colonies tended to produce more soldiers in the earlier period of their lifetime, whereas females from newly established small colonies produced no or only a few soldiers at later times. The average number of soldiers and normal nymphs produced consecutively by a single female was >10 and >20, respectively. Because they have a small number of ovarioles (<15 on average), females should alter caste production within the same ovarioles according to changes in environmental conditions. Artificial removal or introduction of predators and reduction of colony size did not affect soldier production over two successive generations, revealing maternal effects on soldier production. Females cannot shift caste production quickly in response to changes in predator abundance and colony size. This is probably due to early developmental determination of castes within the mother's body.     

How to put all your eggs in one basket: empirical patterns of offspring provisioning throughout a mother's lifetime

Maternal effects arise when a mother's phenotype or the environment she experiences influences the phenotype of her progeny. Most studies of adaptive maternal effects are a "snapshot" of a mother's lifetime offspring provisioning and do not generally consider the effects of earlier siblings on those produced later. Here we show that in soil mites, offspring provisioning strategies are dynamic, changing from an emphasis on egg number in young females to egg size in older females. This pattern may be adaptive if it increases the survival of younger offspring that must compete with older, larger siblings. The dynamic shift in egg provisioning was greater in high-food environments in which females lived longer, creating increasing asymmetry in offspring competitive abilities. Females reared in isolation and in the presence of a high-density colony had identical provisioning strategies, suggesting that, unlike males in this species, females do not use pheromones to assess colony size. Our findings suggest that the adaptive significance of maternal effects may be misinterpreted when studies consider only a snapshot of a female's offspring provisioning strategy or when components of the offspring provisioning strategy are studied in isolation.     

Cooperative colony foundation by termite female pairs: altruism for survivorship in incipient colonies

To determine the costs and benefits of queen association in termites we examined for the first time female-female interactions in colonies founded by two unmated females. In the termite Reticulitermes speratus, females that fail to pair with males found colonies cooperatively with partner females and reproduce by parthenogenesis. We analysed the relationship between queen dominance and initial size ranking in two-queen colonies from the viewpoint of first worker brood production and weight gain. To assign parentage to offspring of two-queen colonies we used mtDNA restriction fragment length polymorphism (RFLP); the results suggested that the two queens produced first worker brood equally throughout colony foundation. Furthermore, initially smaller females gained significantly more weight than initially larger females. This may have resulted from altruistic behaviour of the larger females towards the smaller ones. A simple mathematical model, which considered resource allocation and survivorship, could explain why the larger females behave altruistically towards the smaller females. We also examined the responses of females when more than two females were placed in a petri dish in the presence or absence of a male. If a partner male was present, only one female survived in the colony. In the absence of a partner male, two females, but never more than two, founded a colony cooperatively. These results show that females need a partner to found, and retain, a colony.Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved .     

Conspecific reproductive success affects age of recruitment in a great cormorant, Phalacrocorax carbo sinensis, colony.

Few studies have addressed the proximate factors affecting the age at which individuals of long-lived bird species are recruited into the breeding population. We use capture-recapture analysis of resightings of 16 birth cohorts of colour-ringed great cormorants, Phalacrocorax carbo sinensis, in a Danish colony to assess the evidence for two hypotheses: conspecific attraction (earlier recruitment when the colony is large) and conspecific reproductive success (earlier recruitment following years of high breeding success). For both males and females, conspecific reproductive success was the most important covariate explaining the interannual variation in age of recruitment; colony size was also important for females. These covariates explained nearly 60% of the year-to-year variation for both sexes. The age of recruitment increased for cohorts born after 1990, and this increase was correlated with a decline in breeding success in the colony; we interpret this as an indirect and delayed density-dependent effect. Females were recruited earlier than males (mean age of recruitment for cohorts born before 1990: 2.98 years versus 3.53 years); the most plausible reason for this is a skewed sex ratio in favour of males in the adult population. Recruitment of males may thus, to some extent, be constrained by the availability of females. This study provides the first evidence that conspecific reproductive success can affect the age at which individual birds start to breed.     

Changes in female reproductive condition following male take-overs in a colony of hamadryas and hybrid baboons

This paper describes and discusses events observed in the Madrid colony of hamadryas and hybrid baboons, when a novel group of 3 adult males, 3 adult females and 1 unweaned infant was introduced to the resident colony comprising 12 adult females, 11 juveniles and 6 unweaned infants. Novel males took over resident adult females in any reproductive condition, and all acyclic females (i.e. lactating, pregnant and immature) exhibited a dramatic enhancement of sexual activity. Lactating females shortened their postpartum amenorrhoea periods and resumed oestrous cycles around day 14 following the introduction of the novel males, without infanticide occurring. Their return to breeding condition was not affected by the age of their current infant or the day they were taken over by the males. A female in an early stage of pregnancy aborted spontaneously and resumed oestrus on day 26. The other pregnant female significantly shortened her gestation time, delivered a viable infant on day 13, and resumed breeding activity 39 days post-partum (on day 52), while suckling her infant. A cycling female adopted and suckled a 74-day-old infant, continued showing oestrous cycles and conceived. Immature females reached menarche significantly earlier than expected and only then joined one of the newly established harem units. It is argued that the observed enhancement of sexual activity was not imposed by the males' aggressive behaviour but rather was a spontaneous female response to male novelty. This single causal factor was potent enough to override the role that nutrition and lactation normally play in the control of the females' reproductive activity. Differences in latency until the appearance of the response were probably due to the different constraints imposed by the female's current reproductive state. It was also hypothesized that when (a) sexual swellings are attractive to males, (b) novel males are especially active in the process of bonding with new females, and (c) males are important sources of coalitionary support, females might by developing sexual swellings compete more successfully against other females and attain a higher position in the female hierarchy of the newly established unit. This would have the ultimate effect of increasing their potential reproductive success. In several cases females did gain socially by coming into oestrus, but attained no immediate reproductive advantage.     

Sex, age, experience and condition as factors affecting arrival date in prospecting common terns, Sterna hirundo

Several studies have shown that seabird colonies consist to a large extent of young nonbreeders (prospectors). These individuals appear at the colony later in the season than established breeders. The reasons for this late arrival have remained unclear in most cases, mainly because of technical difficulties in collecting sufficient data from nonbreeding individuals. We used a novel transponder system to identify remotely the members of a common tern colony, including nonbreeders, during eight breeding seasons and we combined the system with automatic balances. Ninety-two per cent of prospectors returned for the first time when 2 years old and 88.9% of recruits to the breeding population had spent at least one previous season at the colony as prospectors. In both sexes, most individuals prospected for one season, but more males than females prospected for more than one season, although a higher proportion of females started breeding without a previous prospecting phase. Terns arrived earlier in the season the older they were and the more experience of the colony they had, but experience proved to be more important than age. Prospectors gained about 3 weeks with a previous prospecting season whereas an additional year of age allowed birds to arrive only about 6 days earlier. Prospectors returning later in the season arrived with lower body masses. Males on average arrived earlier at the colony than females. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.