Ultrasound imaging of reproductive organs and eggs in Galapagos tortoises,Geochelone elephantopus spp

This study demonstrates the efficacy of using ultrasound to determine the presence of ovarian developing, preovulatory, and atretic follicular structures and oviductal eggs in the Galapagos tortoise, Geochelone elephantopus spp. Ultrasound was effective in locating both right and left ovarian structures in 92% (n = 100 ovaries) of the trials. Developing and preovulatory follicles and oviductal eggs were echogenically visualized and had measurements ranging from 18 to 44 mm (n = 93) and 55 to 68 mm (n = 9), respectively. Atretic follicles ranged in size from 10 to 38 mm (n = 10). In one trial with four G. elephantopus, ultrasound observations were validated with the use of laparoscopy. All procedures were accomplished without general anesthesia on a specifically designed restraining table. Ultrasound provides an effective, safe modality for determining the reproductive status of adult female tortoises.     

Use of behavior to evaluate reproductive problems in captive mammals

Behavioral analyses constitute a logical starting point for discerning the causes of reproductive failure in captive mammals and should be completed before moving on to more invasive diagnostic procedures. Behavioral inadequacies affecting reproductive performance may be attributable to deficient early rearing environments, to the social milieux in which breeding-age animals are held on a long-term basis, or in the way pairings for mating are staged. Diagnoses may be focused on uncovering motivational, motoric, social, or communicative deficiencies. A biologically based approach which integrates species-typical behavior with concerns for genetics, physiology, and health in designing breeding programs will improve prospects for success. © 1994 Wiley-Liss, Inc.     

Mountain gorilla life histories,reproductive competition,and sociosexual behavior and some implications for captive husbandry

New data on modal patterns of, and variability in, mountain gorilla life history tactics and sociosexual behavior, collected during long-term fieldwork at the Karisoke Research Centre, are presented here. These data show that immature males and females develop sociosexual relationships with both peers and adults, and that these relationships—which contribute to more complex social relationships—often lead to mating between natal females and males who are “familiar” partners. They also show that within-group reproductive competition between males can reach considerable levels, but that immature males are sometimes able to copulate with both nulliparous and parous females; that unrelated silverbacked males can reside in the same all-male group but become intolerant of each other if females join the group; and that, whereas females sometimes compete with each other for opportunities of copulate, their probability of conceiving is probably not decreased by any inability to control the mating situation. This information may contribute to continued improvement in the husbandry of captive gorillas.     

Lineage identification of Galápagos tortoises in captivity worldwide

Ex situ conservation strategies may be substantially informed by genetic data, and yet only recently have such approaches been used to facilitate captive population management of endangered species. The Galápagos tortoise Geochelone nigra is an endangered species that has benefited greatly from the application of molecular and population genetic data, but remains vulnerable throughout its range. The geographic and evolutionary origins of 98 tortoises in private collections and zoos on three continents were identified using mitochondrial DNA (mtDNA) control region sequences and multi-locus microsatellite genotype data relative to a large database of representative samplings from all extant populations, including historical population allele frequency data for the Geochelone nigra abingdoni taxon on Pinta by way of museum specimens. All but six individuals had mtDNA haplotypes previously sampled, with the novel haplotypes identified as most closely related to robust populations on the islands of Santa Cruz and Isabela. Multi-locus genotypic assignments corroborated the results obtained from the mtDNA analyses, with 83.7% of individuals consistently assigned to the same locality by both datasets. Overall, the majority of captive unknowns sampled were assigned to the La Caseta Geochelone nigra porteri population, with no fewer than six individuals of hybrid origin detected. Although a purported Pinta individual was revealed to be of Pinzón ancestry, the two females currently housed with Lonesome George exhibited haplotypic and genotypic signatures that indicate that they are among the most appropriate matches for captive breeding. More generally, molecular approaches continue to represent important tools for assessing conservation value, minimizing hybridization and guiding management programs for preserving the distinctiveness of G. nigra taxa in captivity.     

The origin of Indian Star tortoises (Geochelone elegans) based on nuclear and mitochondrial DNA analysis: A story of rescue and repatriation

The Indian Star tortoise (Geochelone elegans) belongs to the family Testunidae and is distributed in southwest India and Sri Lanka. In addition to facing loss of its natural habitat, the species is also illegally traded as food and as an exotic pet internationally. Here we report DNA-based analyses for identification and repatriation of these tortoises into their natural habitat. We have attempted to establish the geographical origin of these tortoises rescued from smugglers, by comparing the microsatellite and mitochondrial markers of rescued animals with animals of known provenance. Star tortoises exhibited strong genetic structure in India. The populations from western India were genetically distinct at microsatellite and mitochondrial loci from southern populations. The rescued individuals had similar multilocus genotypes and mitochondrial DNA haplotypes as the reference individuals from south India. However, the precise geographic origin of many of the rescued samples remains unresolved, because we could not assign them to southern populations and the Neighbor-Joining cluster analysis indicated that some of rescued tortoises formed distinct clusters. These data strongly suggest that the rescued group of tortoises is composed of a mix of individuals from differentiated source populations that are probably located in southern India and possibly Sri Lanka. Our study provides valuable information based on molecular markers for the assessment of genetic diversity in Indian Star tortoises.     

Flexibility of digestive responses in two generalist herbivores,the tortoises Geochelone carbonaria and Geochelone denticulata

Summary To test the prediction that digestive responses digestibility, intake and passage time-of generalist herbivores vary with different diets, feeding trials were conducted in Venezuela with two sympatric tortoise species, Geochelone carbonaria and G. denticulata. Three single-species diets (two fruit, one foliage) were fed to both species. For a given diet, digestibility, mass-specific intake and passage time did not differ between the two tortoise species, nor did they vary by sex or body mass within each species. However, the digestive parameters varied for tortoises feeding on the different diets. The responses ranged from nearly abandoning cell wall fermentation and depending entirely on extraction of cell contents to relying heavily on cell wall fermentation. Therefore, these generalist herbivores have flexible digestive responses that are influenced by diet, not fixed digestive responses that limit the diet, as previously observed in other generalist herbivores. A three-part classification of herbivores (specialist, specialized mixed feeder and opportunistic mixed feeder) is suggested as an approach to understanding flexible and inflexible digestive strategies in herbivores.     

Observations on the behavior of captive sitatunga (Tragelaphus spekei)

Little is known about the behavior of the sitatunga. In order to learn more about their behavior, a group of sitatunga was studied at the Audubon Park and Zoological Garden. Courtship in the sitatunga begins with a male pursuing the female. The female occasionally stops, allowing the male to approach in the “low stretch” posture. If the female does not move away the male rests his chin on the female's rump and then mounts her. Males commonly horn branches, sticks, and turf. The possible functions of horning are discussed. Males also engage in sparring or “play-fighting.” Mutual grooming, vocalizations, and mother-young interactions of the sitatunga are described. The behavior of sitatunga is compared to that of other Tragelaphines.     

不同波长LED光源对韭菜迟眼蕈蚊生殖行为的影响

【目的】明确不同波长的LED光源对韭菜迟眼蕈蚊Bradysia odoriphaga Yang et Zhang求偶、交配及繁殖等生殖行为的影响。【方法】采用红(625~630 nm)、橙(600~605 nm)、黄(590~595nm)、绿(525~530 nm)、蓝(455~460 nm)和白(6 000~6 500 k)6种LED光源在韭菜迟眼蕈蚊成虫交配期进行照光处理,观察统计其求偶和交配行为以及单雌产卵量、卵孵化情况和有效后代数量。【结果】韭菜迟眼蕈蚊成虫求偶前期时长在橙光下最长,为28.48 min。求偶率在蓝光下最高,为86%;橙光下最低,为48%。交配期时长在蓝光下最长,为4.59 min;橙光下较短,为4.23 min。单雌产卵量在各波长光源下与对照均无显著差异。卵孵化率在蓝光下最低,仅为43.41%。有效后代数量在蓝光下最低,仅为27.00头;橙光下次之,为43.40头。【结论】LED光源的波长可影响韭菜迟眼蕈蚊的生殖行为,其中橙光(600~605 nm)不利于其求偶、交配和繁殖;蓝光(455~460nm)虽有利于其求偶和交配,但明显抑制其繁殖。     

Sexual dimorphism of body size and shell shape in European tortoises

Adult body size and shape were examined in almost 1400 individuals of the tortoises Testudo graeca , T. hermanni and T. marginata from Greece. The size at maturity was greater in females than in males in all three species. Maximum and mean adult sizes were also greater in females than in males in T. graeca and T. hermanni . Males grew to a larger size than females in T. marginata , and mean adult size was similar in the sexes in this species. Sexual dimorphism of shape (adjusted for size covariate) was shown in most of the characters examined, and the degree of this dimorphism differed significantly among the three species. Differences were related to their contrasting courtship behaviours: horizontal head movements and severe biting in T. marginata , vertical head bobs and carapace butting in T. graeca , and mounting and tail thrusting in T. hermanni . There was no difference in the frequency of observations of courtship or fighting among the three species, but courtship was about 10 times more common than combat in males. All species showed greatest courtship activity in autumn; copulation was rarely observed in T. hermanni (only 0.36% of courting males) and not seen in the other species in the field. Observations made throughout the activity season indicated that feeding was equally common in males and females in all three species. Differences in shape were more likely to be the result of sexual selection than of natural selection for fecundity. Detailed predictions are made for sexual dimorphism of other characters in these species.     

The lifetime costs of increased male reproductive effort: courtship,copulation and the Coolidge effect

The reproductive effort that a male directs to a familiar female declines over time, suggesting decreasing marginal returns. But is this diminishing returns a function of increasing reproductive costs or decreasing benefits of sustained effort? Here, we use the restoration of male reproductive effort with unfamiliar females to differentiate the role of diminishing returns and lifetime costs of increased reproductive effort of male guppies. We kept males with familiar or unfamiliar females throughout their lives and manipulated their ability to either court or mate with females. We found that increased male reproductive effort with novel mates lead to an immediate trade‐off in the form of reduced foraging effort. Further, males able to mate with a series of unfamiliar females had lower lifetime growth, indicating the primary cost of male reproductive effort in guppies arises from copulation rather than courtship. The lifetime growth trade‐offs were significant only when males mated with unfamiliar mates, suggesting that male reproductive effort with familiar females declines before it is restricted by physical exhaustion. These findings provide some of the first evidence of longitudinal costs of increased male reproductive effort in a vertebrate.     

Attachment sites of the tick Amblyomma marmoreum on its tortoise host,Geochelone pardalis

Leopard tortoises (n=162) were collected over a period of 19 months at the National Zoological gardens, Pretoria, South Africa and the attachment sites of larvae, nymphs and adults of A. marmoreum monitored. Most of the larvae (80%) and nymphs (87%) were found on the anterior parts of the tortoise while adults (90%) were found mainly on the posterior regions of the host body. The immature stages were predominant in soft skinned areas protected by the carapace especially the neck and upper leg areas. Male and female ticks were most commonly found on the posterior armpit. posterior legs and the areas surrounding the base of the tail. Interstadial competition as a major factor influencing attachment site segregation is doubtful. Anterior attachment site selection of the immature stages is believed to result largely from ticks lying passively in wait and then climbing onto the host as it moves through the vegetation and the requirement for soft skinned and protected areas to allow for blood feeding. Adult females usually attach posteriorly in areas that allow them to fully engorge without being dislodged by mechanical disturbance, while males prefer to attach at sites where they are protected but still remain in close proximity to female pheromone signals.     

Observations on the reproductive biology of Mastacembelus armatus (Lacèpede)

Some observations on the biology of Mastacembelus armatus (Lacepède) from Muzaffarnagar (U.P., India) have been made during the period July 1966 to June 1969. At a particular stage of maturity of the fish there is a close relationship between the gonad weight and the body weight which helps in determining the breeding period of the fish. Both male and female fishes mature simultaneously. The gonad weight influences the relative condition, while the visceral weight does not exert any significant effect on it. The development of the female gonads greatly affect the curve of relative condition, more than the development of male gonads, though the curve for male fish also shows a steady rise and fall in the seasonal variations of the relative condition. Seasonal fluctuations in relative condition correspond to its spawning season. In M. armatus , the presence of two peaks in the curve confirm two breeding seasons. The present studies have also elucidated to a certain extent the important aspect of the maturation and spawning habits of M. armatus in North India. The fish has two breeding seasons of short duration during June and July and again in November. The mature ovaries of each season contain slight maturing ova of next season along with mature ova of the present season. The entire stock of ova measuring 0.16 mm and above are shed during spawning.     

Adapting to the unpredictable: reproductive biology of vertebrates in the Australian wet-dry tropics

In the wet-dry tropics of northern Australia, temperatures are high and stable year-round but monsoonal rainfall is highly seasonal and variable both annually and spatially. Many features of reproduction in vertebrates of this region may be adaptations to dealing with this unpredictable variation in precipitation, notably by (i) using direct proximate (rainfall-affected) cues to synchronize the timing and extent of breeding with rainfall events, (ii) placing the eggs or offspring in conditions where they will be buffered from rainfall extremes, and (iii) evolving developmental plasticity, such that the timing and trajectory of embryonic differentiation flexibly respond to local conditions. For example, organisms as diverse as snakes (Liasis fuscus, Acrochordus arafurae), crocodiles (Crocodylus porosus), birds (Anseranas semipalmata) and wallabies (Macropus agilis) show extreme annual variation in reproductive rates, linked to stochastic variation in wet season rainfall. The seasonal timing of initiation and cessation of breeding in snakes (Tropidonophis mairii) and rats (Rattus colletti) also varies among years, depending upon precipitation. An alternative adaptive route is to buffer the effects of rainfall variability on offspring by parental care (including viviparity) or by judicious selection of nest sites in oviparous taxa without parental care. A third type of adaptive response involves flexible embryonic responses (including embryonic diapause, facultative hatching and temperature-dependent sex determination) to incubation conditions, as seen in squamates, crocodilians and turtles. Such flexibility fine-tunes developmental rates and trajectories to conditions--especially, rainfall patterns--that are not predictable at the time of oviposition.     

The mating and reproductive biology of the freshwater planktonic calanoid copepod Eudiaptomus gracilis

1. Quantitative aspects of the mating and reproductive biology of the freshwater planktonic calanoid copepod Eudiaptomus gracilis, including duration and frequency of mating, duration of various phases of the oviducal cycle, egg production rate and adult longevity were studied under laboratory conditions. One set of copepods was fed the alga Chlamydomonas reinhardtii whose density was adjusted to 2 × 10⁵ cells mL^?1 (about 10 mg C L^?1), another set was fed a mixed diet consisting of natural plankton (copepod nauplii, small rotifers and large algae) in the size range of 50–150 μm (dry mass approximately 90 mg L^?1). 2. The entire mating process, from the grasping of the female by the male’s right geniculate antennule to the separation of the pair, lasted about 2 min. Spermatophore placement started at about 30 s to 1 min after mating began and took approximately 1 min. Immediately after the spermatophore had been fixed in the female’s genital segment, the pair separated. 3. The total oviducal cycle, including the gravid phase where the female carried ripe oocytes and the non‐gravid phase where the female did not carry ripe oocytes, lasted about 5–6 days. The non‐gravid phase was particularly long; it was longer than the gravid phase and constituted 62–72% of the total cycle. 4. Mating and spermatophore placement usually occurred with gravid females although occasionally (in 30 of 200 observations) spermatophores were attached in the genital segment of non‐gravid females. Generally two to four, but up to seven, spermatophores were observed at a female’s genital segment at the same time. 5. Clutch size, rate of egg production and adult longevity depended on food. When fed on C. reinhardtii, females carried 7–8 eggs clutch^?1, produced a mean of 1.3 clutches and lived 14 days on average. When fed natural mixed food, females carried 10 eggs clutch^?1, produced 5.6 clutches and lived 37 days on average. 6. Removal of males after the first clutch resulted in no further egg production. Re‐mating is necessary in E. gracilis for continuous clutch production and the production of fertile eggs. 7. Mating duration is comparatively short and the non‐gravid phase comparatively long in E. gracilis. This could be an adaption to the life in the pelagic zone of the lake, where fish predators are present. Fish select ovigerous females, pairs in copula and, probably, females with ripe oocytes which make them conspicuous. Thus, a short mating duration and a prolonged period without conspicuous oocytes, can be advantageous.     

A comparison of the courtship and mating behavior of three species ofNasonia (Hymenoptera: Pteromalidae)

The parasitic waspNasonia vitripennis (Hymenoptera: Pteromalidae) is the subject of numerous genetic, evolutionary, ecological, and ethological studies, particularly relating to sex-ratio evolution, non-Mendelian inheritance, courtship behavior, and speciation. Here we describe the courtship behavior of two sibling species(N. longicornis andN. giraulti) and compare their courtship to that ofN. vitripennis. Courtship behavior ofNasonia males includes mounting of females, orientation to the female's head, and a repeated series of stereotypic movements, including head nods, mouthpart extrusions, antennal sweeps, and wing vibrations. Females signal receptivity by lowering their antennae in synchrony with opening their genital orifice. After copulation, males engage in brief postcopulatory displays. All three species have the basic components described above. However, although the three species are quite similar morphologically, there are distinct differences in courtship displays. Notable differences include the length of courtship cycles, the absence of a ritualized antennal sweep prior to the first cycle invitripennis, additional head nods and ritualized foreleg movements inlongicornis, and a dramatic increase in numbers of head nods ingiraulti. Results show that closely related species can often be distinguished based on courtship differences, although many of these differences may not contribute to a reproductive barrier.     

Use of behavioral measures to assess reproductive status in maned wolves (Chrysocyon brachyurus)

Captive breeding efforts of the threatened maned wolf (Chrysocyon brachyurus) have been plagued by a lack of reliable reproduction and a high rate of neonatal mortality. A particular problem for animal managers has been the ability to detect pregnancy in a noninvasive manner. Pseudopregnancies are common, and many staff hours are expended preparing for a birth that may not occur. The objectives of our study were to document changes in behavior during the breeding season in captive maned wolves in order to determine if behaviors other than sexual (i.e., copulation) could be used to distinguish nonbreeding from breeding pairs and, further, whether successful breeding pairs (young born) could be distinguished behaviorally from breeding pairs that did not produce young (pseudopregnant). Between 1988 and 1994, behavioral data were collected during the annual reproductive season from 52 maned wolf pairings (27 males, 26 females) housed at 17 North American institutions. Breeding animals showed significant increases in rates of affiliative behaviors (approach, friendly) and the amount of time spent in close association (social) during the estrous period, compared to pre- and post-estrous periods. In contrast, the behavior of nonbreeding pairs varied little throughout the breeding season. Discriminant function analysis (DFA) showed that several behavioral measurements during certain reproductive periods were useful in discriminating between nonbreeding and breeding animals (rates of friendly and social behavior for males, marking and social behavior for females). Unsuccessful (pseudopregnant) and successful breeding pairs could be further distinguished on the basis of agonistic and approach behavior frequencies (successful females showed higher rates of agonistic and lower rates of approach behavior during certain periods; successful males had higher rates of both behaviors). Discriminant equations for key behavioral measurements and examples of their practical application are presented. DFA provides animal managers with an effective, noninvasive technique for assessing the reproductive status of maned wolf pairs. © 1996 Wiley-Liss, Inc.     

Observations of social and reproductive biology of the bent-winged bat Miniopterus australis in northern Borneo

The small bent-winged bat Miniopterus australis was studied at low tropical latitudes north of the equator, principally in Subis cave, Niah, Sarawak, East Malaysia. During the course of field-work in 1957–58, most specimens were captured at roost in concavities in the cave ceiling, here termed cupolas. At all months of observation, roosting groups varied from one to seven bats. Solitary bats were predominantly males, and multiple groups rarely included more than one male. It is suggested that the sexes differ in their response to a potential or familiar roosting site, depending on the prior occupation by other bats. Roosting behaviour did not vary with the progress of the reproductive cycle and seemed to have no epigamic function.
Observations of reproductive biology in 1957–58, supported by specimens captured in 1959–60, demonstrated that the species is monoestrous, with a brief annually recurrent breeding season in November-December. Copulation was observed in early November and preceded ovulation. In unovulated females taken in early December the right uterine horn was distended with spermatozoa. The single embryo subsequently implanted in the right horn, although in the three females examined the fertilized ovum derived from the left ovary.
Parturition occurred in late April and early May after a gestation period of 4 1/2–5 months. This period is considerably longer than the presumed species-specific minimum, observed at latitude 15 S. The prolonged gestation period is regarded as an adaptation to perennially low and variable food resources in an otherwise favourable environment, and there is evidence that the months of gestation and birth coincide with a period of limited seasonal increase in abundance of insect prey.