Gonad Mass Research Articles

The Main Patterns of Transformation in Organs of Reproductive System During the Evolution of Vertebrates

The article presents an analysis of the main directions of transformations of the organs of the reproductive system during the evolution of vertebrates at various levels of the hierarchical organization of vertebrates - cellular, tissue, organ, organism, population. During the evolution of vertebrates, gonadal oligomerization occurred, a decrease in the number of hermaphrodite species, a decrease in the relative mass of gonads in the body, and a transition from isogamy to heterogamy (oogamy) was observed. In vertebrates, 4 types of structural and functional organization of male gonads have been formed: follicular type, follicular-cystic type, tubular-cystic type, tubular type. In representatives of different classes of vertebrates, the transformation of the ovaries proceeded in different directions. Large, grape-shaped ovaries have evolved in fish, amphibians, reptiles, birds, and cloacal mammals. These ovaries, just before the breeding season, can occupy almost the entire abdominal cavity. The ovaries of placental mammals are small in size, their shape is most often oval, the surface is smooth. One of the directions of the evolutionary transformation of the gonads was the compartmentalization of the structures of the male and female gonads, while there was a structural and topographic division into the actual gonads and the genital tract, which were formed on the basis of the structures of the primary kidney. Higher vertebrates have well-developed accessory sex glands. In the gonads, there was a clear topographical distinction between endocrine and germinal structures. Against the background of an increase in the number of species with internal fertilization, against the background of the formation of a complexly organized vagina and uterus in female mammals, the formation and complication of the copulatory organs of males occurred.

Energy channelling, food chain length and body condition in a northern lake predator

Abstract Identifying potential links between food web structure and animal body condition is fundamental for predicting the long‐term persistence of populations under rapidly changing environments. Northern lakes, and the cold‐water adapted species that inhabit them, are particularly vulnerable to a warming climate. We explored relationships among body condition and energy channel use in lake trout (Salvelinus namaycush) and seasonal variation in food‐chain length in the Lake of Two Rivers, Ontario, Canada. Bayesian mixing models using carbon isotope values (δ13C) of essential amino acids showed that individuals utilising multiple energy channels had higher gonad mass, suggesting that dietary diversity has reproductive fitness benefits. Amino acid nitrogen isotope (δ15N) analysis revealed seasonal variation in food chain length, with extension of the food web during winter and spring and truncation of the food web during summer. Although these findings illustrate increased omnivory of lake trout during summer, there was no clear evidence that seasonal changes in food chain length had an impact on trout condition. These findings provide new insight into potential relationships between food web structure, energy flow and consumer condition in freshwater ecosystems, thereby revealing potential responses of species to shifting ecosystem states under intensifying climate change at high latitudes.

Cloning, Expression Analysis and SNP Screening of the kiss1 Gene in Male Schizothorax biddulphi.

Schizothorax biddulphi is an endemic fish distributed only in southern Xinjiang, China. Due to overfishing, water conservancy facilities, and other factors, as well as inherent biological limitations, resource recovery is quite difficult. For endangered fish with slow growth, late sexual maturity, and insufficient natural population supplementation, large-scale artificial reproduction and breeding are important for restoring resources. Therefore, it is urgent to optimize the reproductive regulation methods of the fish. The kiss1 gene is a key regulator of the reproductive regulation cascade, and identifying and analyzing the role of kiss1 are important for further elucidating the reproductive mechanism of S. biddulphi. To understand the characteristics of the kiss1 of S. biddulphi, the full-length cDNA sequence of kiss1 was obtained in this study, and its tissue expression specificity and association with phenotypic traits were analyzed in male fish. The full-length cDNA sequence of kiss1 in S. biddulphi was 658 bp, with an ORF of 327 bp, and encoded a 108-amino acid, unstable protein. Homology results indicated that kiss1 was highly conserved. qPCR showed kiss1 expression in different tissues in male S. biddulphi, with the highest expression in the gonads, followed by muscle, and significantly lower expression in the swim bladder, pituitary gland, heart, hypothalamus, gill, fin, liver, eye, and mid-kidney. qPCR revealed three SNP loci in the exonic region of kiss1. The c.3G>T locus was significantly correlated (p < 0.05) with gonad mass and the maturation coefficient in S. biddulphi. These results will help uncover the reproductive endocrinology network of S. biddulphi, improve artificial breeding technology for fish, and unveil new directions for breeding excellent strains of S. biddulphi and molecular marker-assisted breeding.

Assessing the potential of the unexploited Atlantic purple sea urchin, Arbacia punctulata, for the edible market

The global demand for sea urchin as seafood is currently unmet. Despite exploitation of &amp;gt; 40 species across the world, there is a need to identify other candidate species, especially in regions where diversification in production is sought where species are considered native. The Eastern US presents an opportunity to determine the marketability of the currently unexploited Arbacia punctulata which is naturally distributed from Massachusetts and southwards into the Gulf of Mexico. To determine whether A. punctulata had market potential, it was fed one of the following diets to determine whether the gonad tissue (uni) could be manipulated to increase gonad mass and improve gonad color for the market: dried Ulva lactuca, Salmon pellets (Skretting), Tilapia pellets (Ziegler) or an Urchinomics diet designed for sea urchins either fed for 8 weeks or 12 weeks. All of the pelleted feeds (Salmon, Tilapia and Urchinomics) increased gonad mass and altered the color. The colors of the uni were generally darker than the colors that the market would typically prefer but some individuals did exhibit colors which have been classed as acceptable to the European market. This work highlights that further research is worthwhile to assess the market potential of A. punctulata.

1369-P: The Differential Effects of Estrogen on Determinants of Skeletal Muscle Bioenergetics with a High-Fat, High-Sucrose Diet in Rats

Estrogen is a powerful, beneficial regulator of skeletal muscle mitochondria. Premenopausal women with type 2 diabetes (T2D) have relatively greater complications associated with their T2D compared with the effect of the disease in men. We hypothesize that this impact of T2D in women is in part due to the impairment of estrogen-mediated regulation of skeletal muscle mitochondrial content and function. To explore the interaction between estrogen, diabetes and mitochondrial biogenesis in a rat model, 4-week-old, female Wistar Rats were fed a chow or a high fat/high sugar diet (HFHS) . At 8 weeks all mice underwent an ovariectomy (OVX) and randomized to estradiol (E2) replacement or none. One week prior to sacrifice, deuterium oxide was administered to determine skeletal muscle mitochondrial biogenesis. OVX +/- E2, animals were sacrificed 6 weeks post-randomization. Endpoints: body weight, gonadal fat mass, blood glucose and insulin levels, and gastrocnemius (mitochondrial biogenesis and function) . OVX+E2 rats had lower body mass compared with OVX (P = 0.0028) . HFHS fed rats had greater relative fat mass independent of E2 status (P = 0.0007) , and the OVX+E2 fed the HFHS diet were hyperglycemic (P = 0.00for the diet x E2 interaction) . State 3 mitochondrial respiration with carbohydrate-linked substrates was elevated in chow fed animals with E2, and this response was absent in HFHS animals (P = 0.0138 for the diet x E2 interaction) . Contrary to our hypothesis, there was no effect of diet or E2 on mitochondrial biogenesis measured with deuterium oxide (P &amp;gt; 0.4) . These data support the hypothesis that, in the context of a HFHS diet, the beneficial effect of E2 on skeletal muscle mitochondrial function is impaired. However, mitochondrial biogenesis does not appear to mediate this interaction of diet and E2. Future studies will focus on the E2-mediated regulation of mitochondrial quality to determine their role in the impairment of mitochondrial function. Disclosure N.A.Hulett: None. S.Hull: None. L.Knaub: None. G.Pott: None. B.F.Miller: None. J.Reusch: Advisory Panel; Medtronic. R.L.Scalzo: None. Funding Veterans Affairs (BX004533)

Switches, stability and reversals in the evolutionary history of sexual systems in fish

Sexual systems are highly diverse and have profound consequences for population dynamics and resilience. Yet, little is known about how they evolved. Using phylogenetic Bayesian modelling and a sample of 4614 species, we show that gonochorism is the likely ancestral condition in teleost fish. While all hermaphroditic forms revert quickly to gonochorism, protogyny and simultaneous hermaphroditism are evolutionarily more stable than protandry. In line with theoretical expectations, simultaneous hermaphroditism does not evolve directly from gonochorism but can evolve slowly from sequential hermaphroditism, particularly protandry. We find support for the predictions from life history theory that protogynous, but not protandrous, species live longer than gonochoristic species and invest the least in male gonad mass. The distribution of teleosts’ sexual systems on the tree of life does not seem to reflect just adaptive predictions, suggesting that adaptations alone may not fully explain why some sexual forms evolve in some taxa but not others (Williams’ paradox). We propose that future studies should incorporate mating systems, spawning behaviours, and the diversity of sex determining mechanisms. Some of the latter might constrain the evolution of hermaphroditism, while the non-duality of the embryological origin of teleost gonads might explain why protogyny predominates over protandry in teleosts.

Reproductive effort and terminal investment in a multispecies assemblage of Amazon electric fish

AbstractThe terminal investment hypothesis (TIH) predicts that individuals with favorable prospects for future reproduction (i.e., high residual reproductive value, RRV) should moderate current reproductive investment in favor of growth, survival, and future reproduction, whereas those with low RRV should “terminally invest” by diverting somatic resources towards current reproduction at the expense of future reproduction. However, support for the TIH in wild animal populations is fragmentary, and the ecological contexts of terminal investment remain poorly known. We report a remarkable case of simultaneous terminal investment involving five sympatric species of the electric knifefish genus Brachyhypopomus, from Amazonian floodplain and terra firme stream habitats. We found that terminal investment is synchronized by seasonal breeding, in response to circannual environmental variation in mortality risk. Four species exhibit a uniseasonal iteroparous (annual) life history with complete post‐reproductive mortality after a single breeding season. One species (Brachyhypopomus beebei) exhibits a 2‐year multiseasonal iteroparous life history with breeding in two seasons and post‐reproductive mortality after the second. In mature females and (most) males of the annual species, as well as in both mature female and male second‐year (but not first‐year) B. beebei, we documented an increase in two metrics of reproductive effort (size‐adjusted gonad mass and electric signal amplitude) and a concomitant reduction in somatic condition (size‐adjusted somatic mass), all in response to proximity to the end of the common breeding season, when RRV approximates zero. In mature first‐year B. beebei, we documented neither an increase in reproductive effort nor a decline in somatic condition, implying an alternative strategy of reproductive restraint. Our findings support Kirkwood's disposable soma theory, which posits that death by reproductive exhaustion can be delayed if terminal investment is replaced by reproductive restraint, allowing individuals to survive and breed in a subsequent season. Deferral of the terminal investment response in annual species, and the origin of a gonadal regression‐regeneration sequence, may open pathways for rapid evolutionary transitions to multiseasonal iteroparity. Excepting the age (year‐group) dependency of terminal investment in B. beebei, we were unable to identify intrinsic cues or extrinsic environmental cues for the terminal investment response in Brachyhypopomus.

Alterações endocrinológicas em crianças e adolescentes sobreviventes de linfoma de Hodgkin

INTRODUCTION: Hodgkins lymphoma (HL) is one of the main malignancies among adolescents and young adults, but with a high survival rate. Endocrinological disorders are frequent in post-treatment patients, affecting up to 44% of these individuals. OBJECTIVES: To evaluate the endocrinopathies existing in patients undergone HL treatment in childhood and adolescence, to correlate these changes with the treatment characteristics and to propose an evaluation and follow-up protocol. METHODS: Retrospective longitudinal study, performed through medical records analysis, that evaluated children and adolescents aged 0-18 years, HL survivors, with initial treatment and minimum 3 years follow-up in a pediatric oncology service from 1990 and 2015. RESULTS: The sample consisted of 75 individuals with a mean age at diagnosis of 9.2 years and follow-up time of 8.6 years. All had undergone chemotherapy and 85.3% radiotherapy, with an average dose of 25.7Gy. Twelve individuals were excluded due to treatment abandonment or death. At least one endocrinological disorder was present in 20.6% of the patients, and 100% of them had thyroid dysfunction, with hypothyroidism being the most frequent. It was not possible to assess gonadal function, bone mass, glucose metabolism or dyslipidemia in the sample due to lack of data and short follow-up. CONCLUSION: The elaboration of a protocol of evaluation and follow-up of these patients is necessary for standardization of management and early diagnosis of comorbidities. Knowledge of the repercussions of treatment is essential to provide better quality of life for the survivor.

The metabolic depression and revival of purple urchins (Strongylocentrotus purpuratus) in response to macroalgal availability

Organisms can reduce their metabolism and/or decrease energy allocation to reproduction in order to survive starvation during extended periods of food limitation. This is especially important for coastal rocky reefs where widespread kelp deforestation has become increasingly common in recent decades. This deforestation often results in the formation of urchin barrens that have high densities of herbivorous sea urchins and little macroalgae for them to consume. While it is known that these barrens can persist for years to decades, and it has been suggested that urchins can reduce their metabolisms and/or consume microalgae during these periods, the mechanisms that allow for such prolonged survival in adverse conditions, and if these are mechanisms are reversible are not entirely understood. Here, we provide experimental evidence to show that urchin metabolism and gonad mass both decrease significantly when the urchins are deprived of macroalgae, and that these urchins regain normal metabolic activity and gonad masses when access to this food resource is restored. Our results have important implications for consumers in other ecosystems where access to energetic resources is spatially or temporally variable and can point to new avenues of research to explain how organisms adjust their energetic needs to survive extended periods of starvation.

Does reproductive effort influence the metabolic rate of Tomodon dorsatus snakes?

AbstractIn Squamate reptiles, vitellogenesis in females is marked by an increase in the number and size of follicles, leading to an increase in aerobic metabolism to support the rising energy demand during reproductive activity. Male gametes are smaller than female gametes, and spermiogenesis requires less energy than vitellogenesis. This investigation compares the relationship between aerobic metabolism and reproductive effort in male and female viviparous Tomodon dorsatus snakes. We evaluated the influence of the males' and females' reproductive stages, along with the masses of follicles and testicles, on their aerobic metabolic rate. Our findings show that females have higher maintenance cost of pregnancy than metabolic costs of vitellogenesis. In males, we found no evidence of the reproductive effort influencing aerobic metabolic rates. In T. dorsatus, females have a long period of development and high fecundity. Therefore, the metabolic costs of vitellogenesis represent a critical component in the reproductive effort. On the other hand, males of T. dorsatus maintain a similar mass of gonads throughout the year with constant energy demand. These results reflect the difference in reproductive efforts between females and males of T. dorsatus.

Generation of Miniaturized Ovaries by In Vitro Culture from Mouse Gonads.

The incidence of infertility among individuals of reproductive age has been growing due to genetic and environmental factors, and considerable research efforts are focused on solving this issue. Ovarian development is an overly complex process in the body, involving the interaction between primordial germ cells and gonad somatic cells. However, follicles located in the center of the in vitro ovary are poorly formed owing to ovarian complexity, nutrient deficiency, and signaling deficiency. In the present study, we optimized methods for dissociating gonads and culture conditions for the in vitro generation of miniaturized ovaries. The gonads from embryos were dissociated into cell masses and cultured on a Transwell-COL membrane for 3-5 weeks. Approximately 12 follicles were present per in vitro ovary. We observed that miniaturized ovaries successfully matured to MII oocytes in vitro from 150 to 100 µm gonad masses. This method will be useful for investigating follicle development and oocyte production.

Running on empty? Freshwater feeding by spawning anadromous alewife Alosa pseudoharengus

Anadromous alewife Alosa pseudoharengus (n=202; mean ± s.d. fork length= 231 ± 14 mm) were captured from 10 May to 27 June 2018 in an upper watershed lake on the Isthmus of Chignecto, Canada (45°57'N, 64°14'W). Thirty individuals (mean ± s.d. fork length=250 ± 12 mm) were captured in an adjacent estuary downstream of a tide gate on 25 April 2018. Comparing estuarine to freshwater specimens, mean gonad mass and gonadosomatic indices in males and females decreased approximately 40% and 60%, and 31% and 50%, respectively. Individuals were characterized as pre-spawners in the estuary and spawners in the lake. Males maintained similar body condition throughout the spawning run whereas female condition decreased 9.4% between the estuary and lake. Stomach fullness decreased comparing estuarine and freshwater specimens, yet 93% of stomachs examined from individuals captured in the lake contained prey. Most males fed throughout all spawning stages (3%-17% empty stomachs), while all females fed during pre- and post-spawning stages and some fasted during spawning (11% empty stomachs). Cumulative prey curve never reached an asymptote, either weekly or for the entire sampling period, so freshwater diet may not have been completely described. Calanoid copepods (79.3%IA ) were a diet staple, with the secondary prey of mayfly nymphs (O. Ephemeroptera) consumed more by females (13.6%IA ) than males (6.2%IA ). PERMANOVA and PERMDISP analyses revealed significant dietary differences in freshwater were weekly and not due to dispersion effects, thus most likely due to feeding on various development stages of insect species. Our results challenge the long-held paradigm that anadromous A. pseudoharengus fast during the spawning migration.

Study of the pineapple peel vinegar potency in restoring the gonadosomatic index of the diabetic rats

The side effect of Diabetes mellitus is the decrease in the reproductive function which could be observed by the Gonadosomatic Index. Gonadosomatic index is a value that expresses the proportion of testis weight to body weight. Pineapple peel vinegar is a diabetic therapy that has been proved in decreasing the blood sugar levels in diabetic rats, but the effect in restoring GSI has not been evaluated yet. This study aimed to evaluate the effect of pineapple peel vinegar in GSI in diabetic rats. Eighteen male rats were divided into 6 groups, i.e., control (C); negative control (Cn), diabetic rats treated with water; positive control (Cp), diabetic rats treated with 0.4 ml apple vinegar; P1, P2, and P3 (diabetic rats s treated with 0,2 ml, 0,4 and 0,8 ml of pineapple peel vinegar). They were treated for 21 days. The day after the last treatment, rats were sacrificed, and testes were isolated and weighted. The GSI was determined by calculated the proportion of the gonad mass to the total body mass. The result showed there was a significant difference (p<0.05) in GSI between treated Cn (0,59 ± 0,05), P1 group (0,62 ± 0,06), P3 (0,70 ± 0,04) when compared to C (0,52 ± 0,03) and Cp (0,36 ± 0,24) groups. The P2 group (0,53 ± 0,08) showed has no significant difference (p>0.05) when compared to C (0,52 ± 0,03) and Cp (0,36 ± 0,24). It could be concluded that pineapple peel vinegar has high potency in restoring the GSI on diabetic rats.

Understanding the Dynamics of Kelp Forest Recovery from Fishing

Photo 1. Kelp forests provide numerous ecosystem services, including support for economically important fishery species. In southern California, USA, including the Channel Islands shown in the background above, kelp forests provide habitat for the spiny lobster Panulirus interruptus, which is the focus of a trap-based fishery. Photo credit: Robert Dunn. Photo 2. Herbivores can overgraze macroalgae on rocky reefs, leading to a transition from kelp forest to urchin barren. Here, a research diver surveys densities of purple and red sea urchins (Strongylocentrotus purpuratus and Mesocentrotus franciscanus, respectively) in a barren habitat at Santa Barbara Island, California, USA. In some cases, urchin barrens can form due to overharvest of kelp forest predators. Red urchins are themselves the focus of a targeted fishery, but urchins from barrens are typically not harvested due to their low gonad mass. Photo credit: Robert Dunn. Photo 3. When rocky reef fisheries are effectively managed, kelp forests can, in many instances, recover to their macroalgal-dominated state. Photo credit: Robert Dunn. These photographs illustrate the article “Transient dynamics during kelp forest recovery from fishing across multiple trophic levels” by Robert P. Dunn, Jameal F. Samhouri, and Marissa L. Baskett published in Ecological Applications. https://doi.org/10.1002/eap.2367.

Dysgerminoma in Pseudohermaphroditism: A Case Report

Female pseudohermaphroditism occurs when normal ovaries are present but the body is partially masculinized as individuals with congenital adrenal hyperplasia, also known as adrenogenital syndrome. This is an inherited disorder that accounts for about one-half of all cases of human intersexuality. We report a case of a 24-year-old male presenting with abdominal pain and increasing abdominal distension for one month. Computed tomography scan revealed large multiloculated heterogeneously enhancing solid –cystic lesion in the abdominopelvic cavity– malignant gonadal mass, gross ascites, and visualization of the poorly formed elongated uterus-like structure in the recto-uterine pouch and phallus-like structure with non-visualization of bilateral testes. Histopathology report suggested germ cell tumor and immunohistochemistry confirmed the diagnosis of dysgerminoma. Since dysgerminoma is sensitive to platinum-based chemotherapy patient was subjected to chemotherapy and the patient showed a good response. The patient underwent exploratory laparotomy with right salpingo-oophorectomy with omentectomy and appendectomy.

Spatial and environmental effects on Coho Salmon life history trait variation.

Adult size, egg size, fecundity, and mass of gonads are affected by trade‐offs between reproductive investment and environmental conditions shaping the evolution of life history traits among populations for widely distributed species. Coho salmon Oncorhynchus kisutch have a large geographic distribution, and different environmental conditions are experienced by populations throughout their range. We examined the effect of environmental variables on female size, egg size, fecundity, and reproductive investment of populations of Coho Salmon from across British Columbia using an information theoretic approach. Female size increased with latitude and decreased with migration distance from the ocean to spawning locations. Egg size was lowest for intermediate intragravel temperature during incubation, decreased with migration distance, but increased in rivers below lakes. Fecundity increased with latitude, warmer temperature during the spawning period, and river size, but decreased in rivers below lakes compared with rivers with tributary sources. Relative gonad size increased with latitude and decreased with migration distance. Latitude of spawning grounds, migratory distance, and temperatures experienced by a population, but also hydrologic features—river size and headwater source—are influential in shaping patterns of reproductive investment, particularly egg size. Although, relative gonad size varied with latitude and migration distance, how gonadal mass was partitioned gives insight into the trade‐off between egg size and fecundity. The lack of an effect of latitude on egg size suggests that local optima for egg size related to intragravel temperature may drive the variation in fecundity observed among years.

Traditional approaches to estimate length at first maturity (L50 ) retrieve better results than alternative ones in a Neotropical heptapterid.

Length at first maturity (L50 ) is an important tool for the management and conservation of fish populations. Traditional approaches based on macroscopic and microscopic maturity staging exhibit high accuracy and precision, while alternative approaches (e.g., Ig -based staging, stanza changing point) are less resource-demanding. Herein, we compare four approaches to estimate L50 in a population of the heptapterid Rhamdioglanis transfasciatus from Atlantic Forest streams. Fish were sampled monthly during a year by using electrofishing. We measured the length (cm), mass (g), and gonad mass (g) of each specimen, then classified their maturity status macroscopically and microscopically. Alternative approaches were strongly discordant from traditional ones. Logistic curves considering mature individuals as those displaying at least 1% of the maximum Ig in the sample greatly underestimated L50 for females and overestimated L50 for males. The stanza changing point derived from the polyphasic growth model underestimated L50 in both cases. Despite the increasing development of less onerous approaches, it seems that they are not suitable for all fish populations and the requirements to use such approaches demand further investigation.

The comparative toxicity of rainfall overflows and a municipal effluent plume in Elliptio complanata using a novel qPCR array approach

Municipal effluents have the potential to disrupt the endocrine system involved in reproduction in aquatic organisms. The purpose of this study was to develop a novel a quantitative polymerase chain reaction (qPCR) array for the freshwater mussel Elliptio complanata to compare the toxic properties of municipal effluents and rainfall overflows. Mussels were caged for 3 months at upstream and downstream sites of a municipal effluent discharge point and 2 rainfall overflow sites in the Saint-Lawrence River. The data revealed that exposure to municipal effluents and overflow sites lead to increased expression of vitellogenin (VTG) in male mussels, altered sexual differentiation in females, gene expression involved in oxidative stress (superoxide dismutase, glutathione S-transferase) and DNA damage (chromosome mismatch and repair of covalently-bound DNA adducts). Mussels at the downstream site accumulated also large amounts of heterotrophic bacteria but not at the overflow sites. However, mussels at the overflow sites had decreased expression in ABC transporter gene expression. Scaling analysis revealed that the following gene expression were related to effects at higher level of biological organization such as total RNA levels, gonad mass and gonad somatic index: DNA repair of covalent DNA adducts, mistmach chromosomal recombination during meiosis and undifferentiated cells in gonads. In conclusion, exposure to rainfall overflow sites have similar effects to municipal effluents based on VTG and oxidative stress responses at the transcriptomic levels only but the effects at the DNA integrity and sexual differentiation were involved in adverse outcome pathways of urban pollution in Elliptio complanata mussels.

Tradeoffs between dispersal and reproduction at an invasion front of cane toads in tropical Australia

Individuals at the leading edge of a biological invasion experience novel evolutionary pressures on mating systems, due to low population densities coupled with tradeoffs between reproduction and dispersal. Our dissections of >1,200 field-collected cane toads (Rhinella marina) at a site in tropical Australia reveal rapid changes in morphological and reproductive traits over a three-year period after the invaders first arrived. As predicted, individuals with dispersal-enhancing traits (longer legs, narrower heads) had reduced reproductive investment (lower gonad mass). Post-invasion, the population was increasingly dominated by individuals with less dispersive phenotypes and a higher investment into reproduction (including, increased expression of sexually dimorphic traits in males). These rapid shifts in morphology and reproductive biology emphasise the impacts of the invasion process on multiple, interlinked aspects of organismal biology.

The Reproductive Cycle of Holothuria Cucumaria frondosa of the Barents Sea

The study considers the morphological features of the gonad structure and the seasonal changes in the reproductive activity of the gonads of holothuria Cucumaria frondosa of the Barents Sea. The sex of individuals can be identified using morphometric analysis with the average mass of gonads of 1.63 g, with the average mass of the skin-muscle sac of 53.00 g and the length of 80.00-83.00 mm whereas the diameter of the genital tubes is not less than 0.50 mm. The spawning of cucumaria, producing plankton progeny, occurs from March to May, but the spawning period can be shifted, since the beginning of the spawning period is associated with the seasonal increase of the surface water temperature and the intensive phytoplankton blooming. The character of spawning is intermittent. Individual fertility is low, in individuals with the average mass of SMS 150.00-200.00 g ranged from 9 to 32 thousand cells.