Species limits and phylogeography of North American cricket frogs (Acris: Hylidae)

Cricket frogs are widely distributed across the eastern United States and two species, the northern cricket frog (Acris crepitans) and the southern cricket frog (A. gryllus) are currently recognized. We generated a phylogenetic hypothesis for Acris using fragments of nuclear and mitochondrial genes in separate and combined phylogenetic analyses. We also used distance methods and fixation indices to evaluate species limits within the genus and the validity of currently recognized subspecies of A. crepitans. The distributions of existing A. crepitans subspecies, defined by morphology and call types, do not match the distributions of evolutionary lineages recovered using our genetic data. We discuss a scenario of call evolution to explain this disparity. We also recovered distinct phylogeographic groups within A. crepitans and A. gryllus that are congruent with other codistributed taxa. Under a lineage-based species concept, we recognize Acris blanchardi as a distinct species. The importance of this revised taxonomy is discussed in light of the dramatic declines in A. blanchardi across the northern and western portions of its range.     

Comparative energy allocation in two sympatric, closely related gobies: the black goby Gobius niger and the grass goby Zosterisessor ophiocephalus

Seasonal energy allocation of lipid reserves into different body tissues was analysed comparatively in two sympatric, closely related gobies: the grass goby Zosterisessor ophiocephalus and the black goby Gobius niger . Lipid reserves were measured in liver, muscle and ovary and compared between the two species within a given sex and seasonal period (reproductive v . non-reproductive). Furthermore, temporal patterns of lipid reserves were investigated in the two species in relation to gonado-somatic and liver-somatic indices, as well as the relationship between size and lipid content. Results showed that the grass goby allocated more lipid reserves in reproduction while the black goby accumulated more reserves in liver and muscle, at a given size, although the temporal patterns of lipid accumulation and depletion were basically similar. Results are discussed in the light of life-history theories, taking into account both adaptation and evolutionary constraints.     

Reproduction of the Atlantic bobtail squid Sepiola atlantica (Cephalopoda: Sepiolidae) in northwest Spain

Atlantic bobtail squid (Sepiola atlantica) in northwest Spain show seasonal variation in population structure, with juvenile abundance peaking during summer and autumn. However, whether similar patterns exist for reproduction is unknown. Therefore, we describe the reproductive biology of 505 specimens of S. atlantica collected monthly during two consecutive years at two different sites off of Areamilla beach in the Ría de Vigo. Mature males displayed a type of sexual dimorphism previously unknown in members of this species, developing a muscular nodule in the base of each of the ventral arms over ontogeny. Reproductive output of both sexes was similar to that of other bobtail squids. Relative oocyte size (~10% mantle length) appeared to be similar to those of other bobtail squids. Females did not show evidence of having mated before complete maturity. Females of S. atlantica have group‐synchronous ovary maturation, with a positive correlation between female mantle length and ripe oocyte mass, suggesting a terminal investment strategy. Atlantic bobtail squids displayed the same seasonal patterns of reproductive traits at both sampling sites, with significant differences in reproductive activity between males and females. We consider reproductive traits in these small animals as adaptations to the coastal shelf lifestyle.     

Oogenesis and ovarian histology in two populations of the viviparous lizard Sceloporus grammicus (Squamata: Phrynosomatidae) from the central Mexican Plateau

The annual histological changes in ovarian morphology (oogenesis, follicular atresia, and corpus luteum) are described for the Mexican lizard Sceloporus grammicus, in two populations that inhabit contrasting environments (vegetation categories, climate, precipitation, and temperature) from Hidalgo State, Mexico. Two germinal beds were situated on the dorsal surface of each ovary of this species. In both the populations, oogenesis involves two major processes: previtellogenesis and vitellogenesis. The histological changes during previtellogenesis are similar to those for other reptilian sauropsids, whereas vitellogenesis differs and the features of this last process are described for the first time. In early previtellogenesis, primary oocytes have fibrillar chromosomes and the ooplasm stains slightly. The primordial follicles are surrounded by a granulosa composed of cuboidal follicular cells. During late previtellogenesis, the oocyte had an eccentric nucleus with lamp‐brush chromosomes and multiple nucleoli. The granulosa becomes multilayered and polymorphic, containing three cell types: small, intermediate, and pyriform. The zona pellucida was homogeneous and clearly observed. In early vitellogenesis, the oocyte showed several small acidophilic granules distributed in the center and the periphery of the oocyte. As vitellogenesis progresses, the yolk platelets move toward the central area of the oocyte and they fuse to form acidophilic and homogeneous yolk. Lipid droplets were distributed irregularly in the ooplasm of the oocyte. In Zacualtipán, the results revealed a strong seasonal reproductive activity. Females had vitellogenic follicles from July to September, and pregnant females were founded from September to March. In Tizayuca, the results showed an unusual pattern of reproductive activity. Females with vitellogenic follicles and pregnant females were found throughout the year, indicating continuous reproduction. We suggest that the observed differences in reproductive activity from these populations indicate adaptative fine tuning in response to local environmental conditions. These results contribute to the knowledge of variation in vitellogenesis and reproductive strategies of this species and among spiny lizards overall. J. Morphol. 275:949–960, 2014. © 2014 Wiley Periodicals, Inc.     

Characterization,multiplex conditions,and cross‐species utility of tetranucleotide microsatellite loci for Blanchard's cricket frog (Acris crepitans blanchardi)

We have isolated and characterized 17 tetranucleotide microsatellite loci for Blanchard's cricket frog (Acris crepitans blanchardi), an anuran common in the central USA. Sixteen loci were organized into four multiplex amplification reactions. These loci were highly polymorphic when screened in 55 individuals from two distant populations, with 11–48 alleles per locus (average = 24.8). Observed and expected heterozygosities ranged from 0.18 to 0.97 and from 0.17 to 0.96, respectively. Nine loci were also polymorphic in Acris crepitans crepitans, with seven polymorphic in Acris gryllus. Five loci amplified in all three taxa. These loci will be useful for population‐ and species‐level investigations of this widespread group.     

Seasonality, body condition, and timing of reproduction in Propithecus verreauxi verreauxi in the Kirindy Forest

Mammals that live in seasonal environments may adjust their reproductive cycles to cope with fluctuations in food availability. Because lemurs in Madagascar experience highly seasonal variation in food availability, we examined the effects of fluctuating food availability on body condition and reproduction in one of the larger living species, Verreaux's sifaka (Propithecus verreauxi verreauxi), in the Kirindy Forest of western Madagascar. Seven years of demographic data were combined with an intensive study of 25 individuals over the course of 18 months. In contrast to other populations of Verreaux's sifaka, females were found to have greater body mass than males. Both male and female sifaka exhibited significant losses of body mass and fat during the dry season. Females were more likely to give birth and successfully wean an infant when they had higher body mass during the mating season. They mated during the periods of high and declining food availability, gave birth during the lean season, and then timed mid/late lactation with the period of increasing food availability. Thus, we conclude that sifaka follow the "classic" reproductive strategy (sensu van Schaik and van Noordwijk [Journal of Zoology (London) 206:533-549, 1985]).     

Reproductive characteristics of Bufo bankorensis at two elevations in Taiwan

We compared the reproductive characteristics of two populations of Bufo bankorensis in central Taiwan, one inhabiting a temperate climate (Meifong, 2100 m), the other inhabiting a subtropical climate (Wushe, 1100 m). We determined ovary status, spermatogenetic activity, fat body and liver mass cycles, and plasma 17-betaestradiol and androgen levels over a 14 month period. B. bankorensis from both populations are prolonged breeders but the temperate population exhibits breeding activity throughout the year, while the subtropical population only breeds from September to March. Their spermatogenic cycles are continuous, and their spermatogenetic activities are invariably at stage 6, in which spermatozoa are predominant in the seminiferous tubule. Both populations show monthly variations in plasma androgen and 17-betaestradiol levels, but follow different patterns. Ovary mass is larger in the temperate than in the subtropical population. The reproduction differences of two elevation toads could be reflected by adaptations to the local environmental regimes of its habitat. The reproductive patterns of these populations of Bufo bankorensis are also compared to those of sympatric and allopatric populations of five anurans studied from sites throughout Taiwan.     

树鼩(Tupaia belangeri chinensis)卵巢的显微结构及不同季节的卵巢活动

本文报道不同季节的野外成体树鼩卵巢结构的观察和卵泡发育测定的结果。树鼩卵巢的间质腺组织稀少,但普遍有“睾丸索”型的髓质索结构。卵泡发育过程类似于大多数哺乳类和灵长类。近成熟卵泡的腔极大,内膜较窄并有插入的膜腺细胞层。孕期成熟黄体较大,中间有小腔,多角形的黄体细胞具圆形的核和富含脂滴的胞质。带退化透明带残体的付黄林结构偶尔可见,有的与孕期黄体同时出现。次级卵泡和中等囊状卵泡的发育未见有明显的季节性差别。但是,具生长活性的大囊状卵泡和近成熟卵泡的发育,在1、4月份更为明显,为卵泡前期和卵泡期的卵巢周期形态者较多。孕期黄体和付黄体结构见于7月份。10月份未见孕期卵巢结构,多数卵巢缺乏生长活性的大囊状卵泡的发育。这些结果表明,树鼩的卵巢活动同睾丸的精子发生一样,有季节性变化。     

Activity of glutathione related enzymes and ovarian steroid hormones in different sizes of follicles from goat and sheep ovary of different reproductive stages

The investigations on enzymes related to glutathione like glutathione-S-transferase (GST) and glutathione peroxidase (GSH-Px) have been carried out mostly in human and rat ovaries, however the studies on these enzymes in ruminants are relatively absent. In the present study the changes in the activity of these enzymes, in different sizes of follicles from goat and sheep ovaries of different reproductive stages, were investigated. The results demonstrated that the activity of the enzyme GST increased with the increase in size of the follicles from small to large follicles of follicular phase ovary and from small to medium follicles of luteal phase ovary in both the species, thereafter it decreased in large follicles of luteal phase ovary. There was increasing pattern in the activity of GSH-Px in the follicular phase follicles and a decreasing pattern in the luteal phase follicles from both the species. Thus the changes in the activity of glutathione related enzymes namely GST and GSH-Px in different size follicles from both the species during different reproductive phases are evident from the results. It is reasonable, therefore, to assume that these enzymes may have functional role in the steroid hormone metabolism in ruminant ovary as reported in human ovary.     

Biochemical composition of ovary, embryo, and hepatopancreas in the grapsoid crabs Armases cinereum and Sesarma nr. reticulatum (Crustacea, Decapoda)

Biochemical composition of ovary, embryo, and hepatopancreas tissues in wild populations of Armases cinereum and Sesarma nr. reticulatum were monitored during the reproductive season. Total lipid, carbon, nitrogen, C:N ratio, and water concentration of the ovary, hepatopancreas and embryos were quantified over the course of ovarian maturation. Ovary nitrogen concentration decreased as ovaries matured. Ovary lipid and carbon concentration differed significantly over the course of ovarian maturation for both species, but there was no relationship between the concentration or total content of hepatopancreas lipid and the stage of ovarian development in females. Neither species showed a relationship between measures of hepatopancreas lipid and the gonadosomatic index. There was also no simultaneously measurable net decrease in mass of the females' hepatopancreas. Lipid demands of ovarian maturation thus appear to be met in large part by increased dietary intake rather than by substantial draw down of pre-existing lipid stores from the hepatopancreas. While these temperate grapsoid crabs live with putatively fluctuating quality and quantity of food resources, no evidence could be found to demonstrate depletion of lipid concentrations in the hepatopancreas concomitant with ovarian maturation.     

Ovarian morphology and folliculogenesis and ovulation process in the flat-faced fruit-eating bat Artibeus planirostris and the Argentine brown bat Eptesicus furinalis: A comparative analysis

The Neotropical bat species Artibeus planirostris and Eptesicus furinalis present a different morphology of the female reproductive organs: the first presents a simplex uterus, while the second presents a bicornuate uterus, but there is no information about their ovaries. Our aim was to compare the general ovary morphology and the folliculogenesis process in these species to increase the knowledge about the reproductive diversity of tropical bats. We observed a morphological distinction between the ovaries of both species: A. planirostris presents the primordial follicles located in a cranial portion of the ovary and the interstitial gland cells are not distinctive, while in E. furinalis, the primordial follicles are located throughout the cortex, and there is an abundance of interstitial gland cells. Both species present binovular or triovular follicles. Artibeus planirostris is a monovular species, with a preferential ovulation in the left side. Some females of E. furinalis exhibited two corpora lutea in the same ovary, and others presented a corpus luteum in both right and left ovaries at the same time; thus, E. furinalis is a polyovular species. Our results express the variation between two Neotropical species, reflecting the great variation in the reproductive aspects in Chiroptera.     

Seasonal variation in ovarian histology of the viviparous lizard Sceloporus torquatus torquatus

Changes in ovarian histology during the reproductive cycle of the viviparous lizard Sceloporus torquatus torquatus are described. In general, the variation in follicular histology observed during the seasonal cycle is similar to that of other lizards. Sceloporus t. torquatus exhibits a cycle in which small, previtellogenic follicles exist in the ovary from December to August. Vitellogenesis occurs between September and November, followed by ovulation from late November to early December. Parturition occurs the following spring. After ovulation, the remaining follicular cells form the corpus luteum and luteolysis did not occur until April-May. Follicular atresia is commonly observed in previtellogenic follicles with polymorphic granulosa, but occurs less frequently in follicles during late vitellogenesis. There are two germinal beds in each ovary. The yolk nucleus is evident in young oocytes as is a vacuolated ooplasma prior to vitellogenesis. Extensive polymorphism is observed in yolk platelets. Mast cells and secretory cells are observed in the thecal layer of the follicular wall as are melanocytes in the ovarian stroma. © 1995 Wiley-Liss, Inc.     

Unilateral ovariectomy increases egg size and reduces follicular atresia in the semelparous coho salmon, Oncorhynchus kisutch

Unilateral ovariectomy (ULO, removal of one ovary) is a powerful technique for studying aspects of reproductive physiology, including follicular recruitment and growth. To examine effects of ULO for the first time in a semelparous species, coho salmon (Oncorhynchus kisutch) were unilaterally ovariectomized during mid-vitellogenesis approximately 3 months before spawning. At termination of the study (79 days post-surgery), single ovaries of ULO fish were gravimetrically equivalent to paired ovaries of sham surgery, control fish. There was no evidence of recruitment of new vitellogenic follicles. Instead, the dramatic increase in ovary mass was attributable to hypertrophy of existing vitellogenic follicles (33% increase in volume) and increased fecundity achieved through a greater than two-fold reduction in follicular atresia. The composition of whole ovaries on a dry weight basis from ULO fish was greater in protein, but lower in lipid than that of control fish. Expressing the data on a per follicle basis, however, showed that follicles of ULO fish contained more protein, ash, water, and lipid. The results indicate that ULO of coho salmon induces compensatory hypertrophy of existing vitellogenic follicles, while maximizing fecundity through reduction of atresia. Thus, 3 months before spawning, coho salmon exhibit the ability to adjust final egg size and number when faced with significant depletion of ovarian follicles. This in vivo system provides a platform for further study of physiological mechanisms regulating follicular growth and atresia, and the trade-off between egg size and egg number. J. Exp. Zool. 309A:468-476, 2008. (c) 2008 Wiley-Liss, Inc.     

山地麻蜥的雌性繁殖和孵出幼体特征

山地麻蜥年产多窝卵。窝卵数、窝卵重和卵重与雌体体长呈正相关,卵重与窝卵数无关。窝卵数、窝卵重和卵重不存在明显的季节变化。卵长径与卵短径呈正相关,卵长径、卵短径与窝卵数无关。雌体通过增加窝卵数和卵大小增加繁殖输出。孵出幼体的体重、体长、尾长、躯干干重、刺余卵黄不存在季节差异,但5月份孵出幼体的脂肪体高于4月份。     

Viewing chelonian reproductive ecology through acoustic windows: cranial and inguinal perspectives

Ultrasonography is a powerful new tool in reproductive physiology and ecology but quantitative evaluations of acoustic window efficacies are necessary to assess methodological accuracy. We evaluated the efficacy of the left inguinal, right inguinal and cranial acoustic windows for detecting ovarian follicles and oviducal eggs in three tortoise species. Incorporating cranial results improved upon inguinal efficacies for detecting follicles in the three species, and for detecting eggs in Chersina angulata, which had small inguinal apertures for its body size. The cranial window provided the best follicle results (highest numbers detected) but the left inguinal window provided the best egg results. This asymmetry was probably due to the primarily posterior position of the oviducts (eggs) and the pliable ovarian sheets allowing follicles to move cranially. The left-right asymmetry may result from intestinal asymmetry (i.e., between the cecum and descending colon) in obscuring ultrasound transmission or displacing follicles and eggs. Seasonal influences upon efficacies varied with species, partially due to species differences in a) reproductive cycles and b) size and number of follicles and eggs. We attributed other efficacy differences among species to differences in body size and shell morphology, especially the inguinal apertures. Correlation analyses revealed strong individual influences upon window efficacy, suggesting that individuals varied in the position of follicles and eggs and the degree of obfuscation by nonreproductive structures. The paucity of correlations between efficacies and body size reflects the complex interactions of body size, shell morphology, reproductive structures and reproductive cycles on efficacies.     

A morphological study on the reproductive organs as a possible cause of developmental abnormalities in diabetic NOD mice

The reproductive organs in non-obese diabetic (NOD) mice were histopathologically studied, in order to elucidate the relationships between developmental abnormalities, such as diminished rates of implantation and viable embryos, and structural changes in the reproductive organs. NOD mice with (NOD-DM) and without (NOD-N) diabetes mellitus and ICR mice were compared. The severity of histopathological changes in the pancreas and in the liver were used as parameters which indicated the severity of diabetes itself and of the secondary metabolic disorder. NOD-DM mice exhibited uterine weight loss, accumulation of lipids in luminal and glandular epithelium, atrophies of the endometrium and myometrium and a decrease in the number of muscle cell layers. They also showed a high concentration of lipid droplets in ovarian granulosa cells, atretic follicles and atrophy and lack of lipids in ovarian stroma cells. The severity of these structural changes in the reproductive organs corresponded to those of the changes in the pancreas and the liver. The structural alterations in the ovary suggested disorder in oocyte maturation. The structural changes in the uterus appeared to be related to the decrease in the ratios of implantation and of viable embryos at post-implantation stage. The present studies suggest that the impaired structural environment together with the metabolic environment caused the abnormal development seen, for example, in the oocyte maturation, and at the implantation and post-implantation stage of diabetic mice. It also caused alterations in their hormonal environment.     

Isolation,characterization and molecular cloning of cathepsin D from lizard ovary: Changes in enzyme activity and mRNA expression throughout ovarian cycle

During vitellogenesis, the oocytes of oviparous species accumulate in the cytoplasm a large amount of proteic nutrients synthetized in the liver. Once incorporated into the oocytes, these nutrients, especially represented by vitellogenin (VTG) and very low‐density lipoprotein (VLDL), are cleaved into a characteristic set of polypeptides forming yolk platelets. We have studied the molecular mechanisms involved in yolk formation in a reptilian species Podarcis sicula, a lizard characterized by a seasonal reproductive cycle. Our results demonstrate the existence in the lizard ovary of an aspartic proteinase having a maximal activity at acidic pH and a molecular mass of 40 kDa. The full‐length aspartic proteinase cDNA produced from total RNA by RT‐PCR is 1,442 base pairs long and encodes a protein of 403 amino acids. A comparison of the proteic sequence with aspartic proteinases from various sources demonstrates that the lizard enzyme is a cathepsin D. Lizard ovarian cathepsin D activity is maximal in June, in coincidence with vitellogenesis and ovulation, and is especially abundant in vitellogenic follicles and in eggs. Ovarian cathepsin D activity can be enhanced during the resting period by treatment with FSH in vivo. Northern blot analysis shows that cathepsin D mRNA is exceedingly abundant during the reproductive period, and accumulates preferentially in previtellogenic oocytes. Mol. Reprod. Dev. 52:126–134, 1999. © 1999 Wiley‐Liss, Inc.     

Systemic Compensatory Response to Neonatal Estradiol Exposure Does Not Prevent Depletion of the Oocyte Pool in the Rat

The formation of ovarian follicles is a finely tuned process that takes place within a narrow time-window in rodents. Multiple factors and pathways have been proposed to contribute to the mechanisms triggering this process but the role of endocrine factors, especially estrogens, remains elusive. It is currently hypothesized that removal from the maternal hormonal environment permits follicle formation at birth. However, experimentally-induced maintenance of high 17β-estradiol (E2) levels leads to subtle, distinct, immediate effects on follicle formation and oocyte survival depending on the species and dose. In this study, we examined the immediate effects of neonatal E2 exposure from post-natal day (PND) 0 to PND2 on the whole organism and on ovarian follicle formation in rats. Measurements of plasma E2, estrone and their sulfate conjugates after E2 exposure showed that neonatal female rats rapidly acquire the capability to metabolize and clear excessive E2 levels. Concomitant modifications to the mRNA content of genes encoding selected E2 metabolism enzymes in the liver and the ovary in response to E2 exposure indicate that E2 may modify the neonatal maturation of these organs. In the liver, E2 treatment was associated with lower acquisition of the capability to metabolize E2. In the ovary, E2 depleted the oocyte pool in a dose dependent manner by PND3. In 10 µg/day E2-treated ovaries, apoptotic oocytes were observed in newly formed follicles in addition to areas of ovarian cord remodeling. At PND6, follicles without any visible oocyte were present and multi-oocyte follicles were not observed. Our study reveals a major species-difference. Indeed, neonatal exposure to E2 depletes the oocyte pool in the rat ovary, whereas in the mouse it is well known to increase oocyte survival.