Carry-over effect of captive breeding reduces reproductive fitness of wild-born descendants in the wild

Supplementation of wild populations with captive-bred organisms is a common practice for conservation of threatened wild populations. Yet it is largely unknown whether such programmes actually help population size recovery. While a negative genetic effect of captive breeding that decreases fitness of captive-bred organisms has been detected, there is no direct evidence for a carry-over effect of captive breeding in their wild-born descendants, which would drag down the fitness of the wild population in subsequent generations. In this study, we use genetic parentage assignments to reconstruct a pedigree and estimate reproductive fitness of the wild-born descendants of captive-bred parents in a supplemented population of steelhead trout (Oncorhynchus mykiss). The estimated fitness varied among years, but overall relative reproductive fitness was only 37 per cent in wild-born fish from two captive-bred parents and 87 per cent in those from one captive-bred and one wild parent (relative to those from two wild parents). Our results suggest a significant carry-over effect of captive breeding, which has negative influence on the size of the wild population in the generation after supplementation. In this population, the population fitness could have been 8 per cent higher if there was no carry-over effect during the study period.     

Captive breeding of pangolins: current status,problems and future prospects

Pangolins are unique placental mammals with eight species existing in the world, which have adapted to a highly specialized diet of ants and termites, and are of significance in the control of forest termite disaster. Besides their ecological value, pangolins are extremely important economic animals with the value as medicine and food. At present, illegal hunting and habitat destruction have drastically decreased the wild population of pangolins, pushing them to the edge of extinction. Captive breeding is an important way to protect these species, but because of pangolin’s specialized behaviors and high dependence on natural ecosystem, there still exist many technical barriers to successful captive breeding programs. In this paper, based on the literatures and our practical experience, we reviewed the status and existing problems in captive breeding of pangolins, including four aspects, the naturalistic habitat, dietary husbandry, reproduction and disease control. Some recommendations are presented for effective captive breeding and protection of pangolins.     

Introducing mother's curse: low male fertility associated with an imported mtDNA haplotype in a captive colony of brown hares

Mitochondrial DNA mutations create variation in the efficiency of the oxidative phosphorylation pathway and therefore cellular energy production. Mildly deleterious mutations may reduce the performance of sperm cells in particular, due to their high energy requirements and low number of mitochondria, yet have little or no effect on the viability of somatic cells or ova. Mutations will be maintained in the population, despite the fitness cost for males, because mtDNA is passed down the female line. We looked for this so-called mother's curse effect in our captive colony of European brown hares. Significantly reduced male reproductive success was detected for a divergent haplotype that could be traced back to hares imported from a remote population. Median reproductive success for these hares was 0.17 compared to 0.49 for the indigenous haplotypes (Wilcoxon rank-sum, P  = 0.002). No difference was detected for female reproductive success, nor were we able to find a nuclear DNA component to variation in male fertility. Our data are strong evidence for a mother's curse effect persisting despite multiple crossings over seven generations. These data raise important issues relating to the reproductive fitness of small or intermixing populations and have particular implications for the management of populations for conservation.     

Assortative mating among animals of captive and wild origin following experimental conservation releases

Captive breeding is a high profile management tool used for conserving threatened species. However, the inevitable consequence of generations in captivity is broad scale and often-rapid phenotypic divergence between captive and wild individuals, through environmental differences and genetic processes. Although poorly understood, mate choice preference is one of the changes that may occur in captivity that could have important implications for the reintroduction success of captive-bred animals. We bred wild-caught house mice for three generations to examine mating patterns and reproductive outcomes when these animals were simultaneously released into multiple outdoor enclosures with wild conspecifics. At release, there were significant differences in phenotypic (e.g. body mass) and genetic measures (e.g. G_st and F) between captive-bred and wild adult mice. Furthermore, 83% of offspring produced post-release were of same source parentage, inferring pronounced assortative mating. Our findings suggest that captive breeding may affect mating preferences, with potentially adverse implications for the success of threatened species reintroduction programmes.     

Effective population size,reproductive success and sperm precedence in the butterfly,Bicyclus anynana,in captivity

A pedigree approach is used to estimate the effective population size yn two population cages of the butterfly, Bicyclus anynana. Each cage was founded with 54 individually marked adults of each sex. Matings were recorded over a 3‐day period. Eggs were then collected from each female over a similar period before the numbers of hatching larvae were counted to assess progeny number. The males showed a higher variance in reproductive success than the females. Since about one‐quarter of all females mated more than once, we also examined the pattern of sperm precedence using molecular markers or, in separate crossing experiments, wing pattern mutants. Both instances of complete first and last male sperm precedence, as well as of sperm mixing, were found. In some crosses a ‘leakiness’ was found in which some of the early eggs laid by a female were fertilized by a male partner which was subsequently completely unsuccessful. However, the estimates of effective population size were largely unaffected by the pattern of sperm precedence. Estimates for N_e : N in each cage were close to 0.60. The possibility of obtaining comparable estimates in selected natural populations of butterflies is discussed.     

Reduced reproductive success of hatchery coho salmon in the wild: insights into most likely mechanisms

Supplementation of wild salmonids with captive-bred fish is a common practice for both commercial and conservation purposes. However, evidence for lower fitness of captive-reared fish relative to wild fish has accumulated in recent years, diminishing the apparent effectiveness of supplementation as a management tool. To date, the mechanism(s) responsible for these fitness declines remain unknown. In this study, we showed with molecular parentage analysis that hatchery coho salmon (Oncorhynchus kisutch) had lower reproductive success than wild fish once they reproduced in the wild. This effect was more pronounced in males than in same-aged females. Hatchery spawned fish that were released as unfed fry (age 0), as well as hatchery fish raised for one year in the hatchery (released as smolts, age 1), both experienced lower lifetime reproductive success (RS) than wild fish. However, the subset of hatchery males that returned as 2-year olds (jacks) did not exhibit the same fitness decrease as males that returned as 3-year olds. Thus, we report three lines of evidence pointing to the absence of sexual selection in the hatchery as a contributing mechanism for fitness declines of hatchery fish in the wild: (i) hatchery fish released as unfed fry that survived to adulthood still had low RS relative to wild fish, (ii) age-3 male hatchery fish consistently showed a lower relative RS than female hatchery fish (suggesting a role for sexual selection), and (iii) age-2 jacks, which use a sneaker mating strategy, did not show the same declines as 3-year olds, which compete differently for females (again, implicating sexual selection).     

家庭饲养金头闭壳龟15年的体会

金头闭壳龟Ｃｕｏｒａａｕｒｏｃａｐｉｔａｔａ是我国特产的一种珍稀龟类 ,目前仅知分布于安徽省的少数地区。该龟体色艳丽 ,性格温和 ,很受龟类爱好者青睐。由于分布面窄 ,数量稀少 ,长期的盗捕和走私使其濒于灭绝。笔者自 1 987年起对其进行家庭饲养至今。现将自己饲养中的体会加以总结 ,以供爱好者参考。1　关于性成熟的判定1 988年购得雌龟 1只重约 4 0 0ｇ。根据雌龟体重和背甲量度确定年龄在 1 0岁左右。该龟 1 992年体重约 60 0 ｇ时首次产卵 2枚 ,可惜都被咬碎。 1 993～ 2 0 0 1年该雌龟每年都正常产卵 3～ 7枚 (年均 4 6枚 ) ,…     

Can proboscis monkeys be successfully maintained in captivity? A case of swings and roundabouts

Although most western zoos have experienced difficulties in maintaining proboscis monkeys, the Singapore Zoo has managed to sustain a social group of proboscis monkeys housed in a large naturalistic exhibit since 1998. Within 3 years after the monkeys were brought to the zoo, five offspring were produced, all of which survived. Natural forest vegetation from 20 plant species was provided along with a staple diet of about seven different species on a daily basis. The calcium and sodium contents of the plant items consumed by monkeys in the Singapore Zoo were similar to those in the diet of wild proboscis monkeys in Borneo. However, the levels of other minerals, such as iron, magnesium, manganese, potassium, zinc, and phosphorus, were significantly lower in the natural vegetation consumed by the monkeys compared to the wild diet. Food supplements such as primate biscuits, cod liver oil, boiled egg, multivitamins, and mineral syrup further ensured a more balanced diet for the captive monkeys. The data presented here show that zoos can maintain these rare Colobine monkeys successfully by provide them with a natural diet, along with appropriate husbandry and hygiene practices, minimal human interference, and applied nutritional science. The husbandry and nutritional management model presented in this paper could be of use to other institutions around the world. Zoo Biol 23:533–544, 2004. © 2004 Wiley-Liss, Inc.     

Common ringtail possum (Pseudocheirus peregrinus) as a management model for the Pseudocheiridae: Reproductive scope,behavior, and biomedical values on a browse-free diet

The purposes of this study were to determine 1) the life history characteristics of a captive colony of the arboreal folivore Pseudocheirus peregrinus maintained on a browse free diet under enhanced laboratory conditions, 2) the direction and magnitude of life history differences from wild population values, and 3) the feasibility of developing captive colonies of this and related species for conservation and research programs. Rates of reproduction, growth, and development; demographic trends; behavioral patterns pertinent to exhibition; and management and medical techniques are reported. Fecundity was 67% greater than that of wild populations and there was an approximate four-fold increase in the rate of offspring survival to sexual maturity. These trends were due largely to reduced post-pouch emergence mortality and the decay of reproductive seasonality. The results indicate that a properly designed “artificial” diet can support significantly enhanced reproduction in a trophic specialist. Other demographic, developmental, and behavioral measures found to be consistent with those reported from wild populations indicate that there was no significant life history distortion caused by the management regime. Empirical data are presented showing that the common ringtail is nocturnal, has low rates of activity, and has specific space and substrate preferences. These results suggest ways in which the animals' physical environment can be manipulated to improve exhibition. We conclude that the reproductive rates of other ringtail possum species might also be enhanced under comparable management conditions.     

Habitat use,foraging behavior,and activity patterns in reproducing western tarsiers,Tarsius bancanus,in captivity: A managment synthesis

As the only obligatorily predatory primates, tarsiers are notoriously difficult to keep successfully in captivity. Here we report empirical and experimental results from a 5-year study of behavior and life history in captive Tarsius bancanus. Four reproducing adult tarsiers used space nonrandomly, preferring small-diameter vertical or near-vertical locomotor substrates at midlevel enclosure heights (1.2–2.1 m) for sleeping, scanning, and prey capture. The tarsiers were completely nocturnal, and spent 78% of the scotophase scanning, 13% sleeping, and 9% in prey capture and other activities. Only live crickets were eaten; prey capture rates were highest in the first hour after waking, but overall activity rates were highest later in the scotophase. Adult males and nonpregnant or lactating females ingested approximately 44.7–49.7 kJ/day. Growing and lactating individuals ingested approximately 84.4–94.1 KJ/day. An energetically conservative, sit-and-wait predatory strategy was employed, in which 88% of capture attempts were successful. Most successful prey captures involved reaching for, or leaping from, 90° or 60° supports in a horizontal or downward direction onto prey less than 0.6 m away. Virtually all prey captures were in arboreal locations, despite much higher densities of crickets on enclosure floors. Prey capture rates during the first hour of the nocturnal activity period were positively correlated with arboreal cricket densities. At constant arboreal cricket densities, capture rates were negatively correlated with ambient light intensity, with optimum levels for prey capture ranging from 0.1 to 2.0 Lux. In terms of social behavior, these T. bancanus were nongregarious. Females enforced interindividual spacing by chasing and displacing males. Chase/displacement rates increased significantly during late pregnancy and lactation, apparently in an attempt to keep males from harassing infants. There was no direct male parental care. Infants were precocial at birth, and grew at a rate of 0.35–0.5 g/day, until nutritional weaning at approximately 60 days of age. The implications of specialized predatory morphology and behavior for management are discussed. © 1993 Wiley-Liss, Inc.