Non-reproductive Season Research Articles

Factors determining semen sample collection and semen quality parameters in African penguins Spheniscus demersus

Our research focuses on semen collection from 42 African penguin males, grouped by age, habituation levels, and reproductive season timing. We assess behavioral and physiological responses to dorso-abdominal massage, evaluating species-specific seminal traits using conventional and advanced methods. Positive behavioral responses corresponded with successful semen collection. Young and human-reared males exhibited more favorable behaviors, and samples containing spermatozoa were more likely collected during the reproductive season. Age did not influence sample collectability or spermatozoa presence, though mature males produced higher semen volumes. Young males exhibited more sperm morphological abnormalities, especially outside the breeding season. Sperm concentration and number per ejaculate showed no significant differences across age or seasonal groups. Young males had higher motile and progressive sperm percentages, while mature males had more static sperm. Additionally, percentages of live sperm and intact acrosomes were higher in mature males. Young males and samples from non-reproductive season presented more dead sperm with damaged acrosomes. Plasma membrane integrity positively correlated with age for live sperm and negatively for dying sperm. This research demonstrates the feasibility of semen collection from African penguins regardless of habituation level, fills the knowledge gap by describing sperm morphological abnormalities, and provides insights into using flow cytometry in Sphenisciformes.

Differential effect of melatonin on ram spermatozoa depending on the allelic variant of the RsaI polymorphism of the MTR1A gene, incubation medium and season.

Context The Rsa I polymorphism of the melatonin receptor MTNR1A gene affects seasonal reproduction in sheep, but its effect on ram spermatozoa and their response to melatonin is unknown. Aims This study aims to evaluate whether Rsa I polymorphism of the MTNR1A gene influences the response of ram spermatozoa to in vitro added melatonin. Methods Spermatozoa from rams carrying different Rsa I allelic variants were incubated with melatonin in a TALP medium or a capacitation-triggering medium during the reproductive and non-reproductive seasons. After incubation, sperm motility, membrane integrity, mitochondria activity, oxidative damage, apoptotic markers and capacitation status were assessed. Key results In the reproductive season, the T/T genotype was related to some adverse effects of melatonin when spermatozoa were incubated in TALP medium, whereas the C/C genotype was linked with adverse effects when the hormone was added in a capacitation-triggering medium. The decapacitating effect of melatonin on spermatozoa was also different depending on genotype. Conclusions The melatonin effect on spermatozoa from rams carrying different Rsa I genotypes differed depending on the season and the medium. Implications The knowledge of the Rsa I allelic variant of the MTNR1A gene of rams could be helpful when carrying out in vitro reproductive techniques in the ovine species.

Genotyping of rams based on melatonin receptor 1A gene polymorphisms: a tool in sire selection?

Context Several polymorphisms in the melatonin receptor 1A gene (MTNR1A ) have been related to reproductive performance in ovine. Aims To investigate the effect of the Rsa I and Mnl I polymorphisms on ram seminal quality. Methods Eighteen Rasa Aragonesa rams were genotyped for the Rsa I (C/C, C/T, T/T) and Mnl I (G/G, G/A, A/A) allelic variants of the MTNR1A gene. Individual ejaculates were analysed once a month throughout the whole year. Sperm motility, morphology, membrane integrity, levels of reactive oxygen species (ROS), phosphatidylserine (PS) inversion, DNA fragmentation and capacitation status were assessed. The effect of the season and polymorphisms on seminal quality was evaluated by mixed ANOVA. Key results Both polymorphisms had an effect on membrane integrity and viable spermatozoa with low levels of ROS and without PS translocation, and Rsa I also on motile and DNA-intact spermatozoa. An interaction between both polymorphisms was found, pointing to a negative effect on seminal quality of carrying the T or A allele in homozygosity. Differences were higher in the reproductive than in the non-reproductive season. Conclusions Mutations substituting C by T and G by A at Rsa I and Mnl I polymorphic sites, respectively, in the MTNR1A gene in rams could decrease the seminal quality. Implications Genotyping of rams based on melatonin receptor 1A could be a powerful tool in sire selection.

Impact of reproduction on roost selection of the Indian flying fox, Pteropus medius (Temminck, 1825)

A thorough knowledge of ecology and behaviour is a clear requirement for proper conservation and management of a species. The Indian flying fox, Pteropus medius (formerly P. giganteus Brünnich, 1782), lives gregariously in large trees and spends a considerable time at day roosts. The roost sites play vital roles in survival, reproduction and population persistence. This study describes changes in roost selection, colony size and behaviours of P. medius during reproductive and non-reproductive seasons in a large colony at Mohanlal Ganj, Lucknow (India). The colony size was significantly lower during the summer non-reproductive season (486.5 ± 121.1 SD) than during the spring (1942 ± 488.8 SD) and monsoon (2367.7 ± 277 SD) reproductive seasons. The number of roost trees utilised and roost site selection differed across the reproductive and non-reproductive seasons. The bats occupied the southern periphery of the sampled garden during the non-reproductive period (summer), whereas they shifted to the central and northern parts of the garden during the reproductive seasons and winter periods. The reproductively active individuals secluded themselves from the reproductively inactive colony members. The selection of secluded roost sites during the reproductive period demonstrates the need for social exclusion, less disturbance, and reduced mate competition. The higher population size during the reproductive period might be due to the immigration of bats, most probably male individuals, facilitating gene flow from nearby populations and thus increasing genetic diversity and species resilience.

Seasonal histological changes and aquaporin 5 immunoreactivity in the ductus deferens and prostate gland of Saudi Arabian dromedary camel

Objectives: The present study aims to investigate the seasonal histological structure changes and immunoreactivity of Aquaporin 5 (AQP-5) in the ductus deferens and prostate under the light microscope. Materials and Methods: For the present study, twelve mature male camels were employed. Following the animals breeding and non-breeding seasons of slaughter under official licensing and veterinary supervision, samples were obtained from various regions of the ductus deferens and prostate gland and processed using general histology and immunohistochemical methods. Results: The secretory end pieces of the vas deferens ampulla and prostate gland of the Saudi Arabian dromedary camel were well developed during reproductive and non-reproductive seasons. The spermatozoa were noticed in the lumen of the ductus deferens during the reproductive and non-reproductive seasons. The response of AQP-5 in the ductus deferens was particularly significant throughout the not-rutting season. Moreover, during the non-breeding season, the prostate gland showed a strong to moderate response. In the breeding season, the ampulla of the ductus deferens showed an insignificant reaction. Additionally, the body and disseminated portion of the prostate gland showed a mild to moderate response. Conclusion: The results suggested that Saudi Arabian dromedary camels might produce sperm during rutting and non-rutting seasons.

Hormone secretion in serum of bactrian camels during breeding and nonbreeding seasons: Insights into reproductive physiology

To enhance Bactrian camel population through reproductive technologies, 12 female camels (FC) aged 8-12 years underwent reproductive experiments involving synchronized estrus, superovulation, and artificial insemination. Using the enzyme-linked immunosorbent assay (ELISA), we examined the secretion patterns of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen (E2), and progesterone (PROG) in reproductive and non-reproductive seasons of FC. Exogenous hormones GnRH+GnRH, GnRH+PGF2α, and PMSG were given to synchronize estrus in FC. Comparing peak times and secretion levels of reproductive hormones determined the optimal protocol for synchronized estrus. The study found a positive correlation between FSH and LH secretion in FC, with LH higher. Female camels exhibited an increase in E2 secretion during the transition from non-reproductive to reproductive seasons. Conversely, the concentration of PROG in plasma was higher during the Non-reproductive season compared to the reproductive season. A positive correlation was observed between E2 and PROG levels in FC during reproductive and non-reproductive seasons. Exogenous hormones induce LH and E2 peaks in 2-4 hours and 2-8 hours, respectively, for synchronized estrus. The GnRH+PGF2α hormone superior for estrus synchronization. Our study reveals distinct hormone secretion patterns in female camels during reproductive and non-reproductive seasons. Our findings have significant implications for novel breeding technologies.

At home in the tropics: seasonal niche-tracking by the Yellow-green Vireo, Vireo flavoviridis, an intratropical migrant

Migratory birds move geographically by tracking specific climatic conditions through time. However, we lack information about the climatic conditions birds are tracking, especially in intratropical migrants, whose movements are contained inside the tropics. The Yellow-green Vireo Vireo flavoviridis is an intratropical migrant whose migration patterns remain only partially documented and understood. Using GBIF presence records and WorldClim monthly climatic layers, we reconstructed ecological niche for Yellow-green Vireo’ reproductive and non-reproductive seasons. Then, we used a niche overlap analysis, based on a PCA-env approach and similarity tests, to assess overlap in climatic niches between seasons. We also projected climatic niches onto their spring and fall migration to evaluate the climatic conditions tracked by the species in transitional months. Overall, models revealed significant geographic inter-prediction between seasons. Similarity analyses showed high niche overlap between seasons; however, they failed to reject the null hypothesis of niche similarity. As expected by the hypothesis of niche conservatism in the tropics, Yellow-green Vireo is a niche follower. This information will help to clarify evolution of intratropical migration and provide ecological information for future conservation plans.

Links between reproduction and immunity in two sympatric wild marine fishes

According to life-history theory, limited resources can result in trade-offs between costly physiological functions. Particularly, it can be expected that individuals present lower immune function, or an alternative immunological strategy, during their reproductive compared to their non-reproductive season. Here we investigate the link between reproduction and immunity in two sympatric marine fish species, the rockfish Sebastes oculatus and the sandperch Pinguipes brasilianus. The results showed lower values of total white blood cells and spleen index, but higher levels of natural antibodies (only in females) in reproductive rockfish compared to non-reproductive ones. On the other hand, reproductively active sandperch showed lower levels of natural antibodies and a higher neutrophil to lymphocyte ratio and spleen index (only in males), compared to non-reproductive ones. Also, negative correlations between reproductive and immune parameters were observed in female rockfish at the individual level, but not in sandperch. Our results are consistent with the presence of different immunological strategies in reproductive and non-reproductive periods, with patterns that appear to be species-specific. This specificity suggests that various aspects of immunity might respond differentially to resource limitation, which could be associated with the disparate life-history strategies of the studied species. Alternatively, though not exclusively, the observed patterns could be driven by abiotic factors that characterize the reproductive season of each species (i.e., winter for rockfish, summer for sandperch). Our study contributes to ecoimmunological knowledge on free-living fish and highlights that detection of trade-offs can depend on the combination of study species, season, sex, and specific immune components measured.

Expression of Testis-specific Serine/Threonine Kinases during the Reproductive and Nonreproductive Seasons and Their Localization in Mature Spermatozoa of Tree Shrews (Tupaia belangeri).

Tree shrews display obvious reproductive cycles, and sexually mature male tree shrews produce little or no sperm with extremely low motility during the nonreproductive season; the mechanism underlying this phenomenon remains unknown. Because testis-specific serine/threonine kinases (TSSK) are specifically expressed in the testis and male germ cells of mammals, we hypothesized that they may have an important role in spermatogenesis or sperm function regulation in tree shrews. In addition, the expression, distribution, subcellular localization, and dynamic changes of TSSK in tree shrew sperm are unclear. Here we show that during the reproductive season, the seminiferous tubules were significantly larger as compared with the nonreproductive season and contained mature sperm and other germ cells. The mRNA expression of Tssk genes in testis was significantly higher than that in other tissues, and the mRNA level in the testis during the reproductive season was significantly higher than that in nonreproductive season. In addition, the mRNA level of Tssk3 in the testis and sperm was significantly higher than that of other members. Specifically, Tssk1 mRNA was distributed in the acrosome and throughout the flagellum of tree shrew sperm, Tssk2 was present in the acrosome, Tssk3 was localized to postacrosomal region and relocated to the main part of the flagellum after capacitation, and Tssk6 was distributed in the acrosome and postacrosomal region. These results indicate that the TSSK are important regulating reproductive function in tree shrews.

Reproductive season-based plasticity in the size and strength of female crayfish (Faxonius obscurus) claws.

Animal weapons are morphological traits that improve the fighting ability of the wielder and are associated with competition. These traits are typically sexually dimorphic, with males possessing weaponry and females lacking weaponry. However, in some cases, like in many crustaceans, both males and females wield enlarged claws, which may function as weapons. Further, animal weapons may vary in their size, shape, and performance, with theory predicting that selection pressure for weaponry should be the highest when the importance of fights is the greatest, such as during a reproductive season. However, the degree and direction of selection may vary based on sex and season, with females potentially benefiting from wielding larger weapons during nonreproductive seasons. Crayfishes offer an ideal system to investigate how weapon phenotypes change across reproductive seasons since both males and females undergo a form alteration associated with reproduction. Thus, we investigated whether female Allegheny crayfish, Faxonius obscurus, claws change in size, shape, or pinching strength based on whether a female is in a reproductive or nonreproductive form. We found that female F. obscurus claws are larger and stronger during the reproductive season. These findings align with previous research on males of the same species. We discuss how predictions about the relationship between seasonality and weapon investment may differ based on sex.

Reproductive diapause influences spermatogenesis and testes’ size in the diplochronous wolf spider Allocosa senex (Lycosidae, Araneae) – A case study using a non-experimental approach

Seasonality considerably impacts on the life of organisms and leads to numerous evolutionary adaptations. Some species face seasonal changes by entering a diapause during different life stages. During adulthood, a diapause in the non-reproductive period can affect male gametogenesis as, for example, it occurs in insects. Spiders are distributed worldwide and show a variety of life cycles. However, data on spiders’ life cycles and seasonal adaptations are limited. Here, we explored the effect of reproductive diapause in a seasonal spider for the first time. We used the South American sand-dwelling spider Allocosa senex as a model as this species is diplochronous, meaning that individuals live two reproductive seasons, with juveniles and adults overwintering in burrows. It has been observed that individuals of this species reduce their metabolism during the non-reproductive season, diminishing prey consumption and locomotion to a minimum. This species is also well-known for exhibiting wandering and courting females and sedentary males. We analyzed spermatogenesis throughout the male's life cycle and described the male's reproductive system and spermiogenesis using light and transmission electron microscopy. We found that spermatogenesis in A. senex is asynchronous and continuous. However, when males face the non-reproductive season, the late spermatogenic stages and spermatozoa decline, causing an interruption but not a total arrest of this process. This seasonality is also reflected in smaller testes’ size in males from the non-reproductive season than in other periods. The mechanisms and constraints are unknown, but they could be related to the metabolic depression during this life cycle period. Since sex-role reversal apparently sets a low-intensity sperm competition scenario compared with other wolf spiders, surviving two reproductive seasons may balance mating opportunities by distributing them between both periods. Thus, the partial interruption of spermatogenesis during diapause could allow new mating encounters during the second reproductive season.

Sex and reproductive status affect sheltering and exploratory behaviours with high intra-individual variability in crayfish

Abstract The contexts in which individuals demonstrate behavioural consistency or variability have been the subject of research focus. We studied exploratory and sheltering behaviour in the crayfish F. virilis to understand how these behaviours vary by sex and reproductive readiness and to quantify the repeatability of these behaviours. Crayfish were tested in two sets of three rounds, one in the summer non-reproductive season and another in the autumn reproductive season. Reproductive crayfish spent more time outside the shelter and were more likely to accept a food item than non-reproductive crayfish. In the non-reproductive season, females spent more time outside the shelter than males, and over both seasons, females were more likely to seek and accept a food item. Repeatability estimates were low, indicating high intra-individual variability in these behaviours. Sheltering and exploratory behaviours were not correlated. This indicates sex or reproductive readiness have strong effects on both sheltering and exploratory behaviours.

Pampas fox spatial and temporal variation in Argentinean agroecosystems

Context Agricultural activities have reduced wildlife natural habitats and increased the spatial overlap between animals’ distribution and human activities. However, carnivores with a broad diet and flexible habitat requirements can tolerate human-induced environmental changes. Thus, identifying changes in their densities and spatial distribution are important factors to take into consideration when working towards minimising human–carnivore conflict. Aims Our aim was to identify the main environmental and human variables influencing Pampas fox density and to produce density maps in the reproductive and non-reproductive seasons. Methods We performed spotlight counts at night, following the line transect method in the non-reproductive and reproductive seasons during two consecutive years. We also obtained landscape, human-impact and environmental spatial variables using remote sensing data and Geographic Information Systems. We modelled and mapped the Pampas fox’s spatial density using Density Surface Models. Key results We found that disturbance by human activities and landscape configuration influenced the spatial variation of the Pampas fox density across time and space. We registered a positive association between the number of foxes and the proximity to urban areas and paved roads, and we also found higher densities near grasslands areas and less modified habitats varying with the season and year. A higher density of foxes was observed in the non-reproductive season compared with the reproductive season. Conclusions and Implications This study provides insight on the variation in Pampas fox densities across agroecosystems. It highlights the relevance of more naturalised and protected habitats to sustain the Pampas fox population in highly fragmented landscapes, but also shows a positive association with disturbed areas. The spatial information developed in this study is useful to identify areas where ecosystem services could be encouraged, helping to maintain the ecosystems’ equilibrium and biodiversity conservation, and develop new management programs creating human–wildlife coexistence.

Development of an efficient, noninvasive method for identifying gender year-round in the sea urchin Paracentrotus lividus

Identification of sex in the sea urchin, Paracentrotus lividus, has thus far been achieved through gamete analysis, often using lethal, stressful and generally invasive methods. In this study, we developed a noninvasive technique to identify the sex of P. lividus based on the secondary sexual characteristics of genital papillae. This method was evaluated with fully and nonfully sexually mature individuals that were collected during both reproductive and nonreproductive seasons. Each individual was examined under a stereomicroscope, and the genital papillae were classified according to morphological features such as male characteristics (conical protuberances) or female characteristics (flat papillae, sometimes sunk below the body surface). Subsequently, the reliability of the method was verified through gamete observation. Regardless of the season, the methodology resulted in reliable results for approximately 95% of fully mature individuals, while it was somewhat less reliable (approximately 73% accuracy) in nonfully sexually mature sea urchins. The observation of genital papillae morphology is thus a noninvasive, nonlethal (100% survival of animals), that is seasonally independent and inexpensive, and allows the number of animals used during experiments to be minimized, thus promoting animal welfare. This methodology is therefore expected to allow gender identification to be conducted year-round, with significant positive impacts in research and actual aquaculture operations.

RNA interference analysis of potential functions of cyclin A in the reproductive development of male oriental river prawns (Macrobrachium nipponense).

Cyclin A (CycA) plays essential roles in regulating multiple steps of the cell cycle, and it affects gonad development in mammals and invertebrates. Previous RNA interference (RNAi) analysis revealed that knocking-down the expression of CycA in female oriental river prawns (Macrobrachium nipponense) inhibited ovarian development. CycA was also predicted to have regulatory roles in reproductive development of male M. nipponense based on significant changes of Mn-CycA expression after eyestalk ablation. The goal of this study was to investigate the potential functions of CycA in the reproductive development of male M. nipponense using RNAi and histological observations. Quantitative real-time PCR analysis revealed that both single-side and double-side eyestalk ablation stimulated the expressions of Mn-CycA, and the expression was higher in prawns with double-side eyestalk ablation (p < 0.05). Mn-CycA expression was significantly higher in the testis and androgenic gland during the reproductive season than during the non-reproductive season (p < 0.05). In the RNAi analysis, Mn-CycA expression significantly decreased after prawns were injected with dsCycA, and the expression of insulin-like androgenic gland hormone (Mn-IAG) also decreased as Mn-CycA expression decreased. This result indicated that CycA positively regulated the expression of IAG in M. nipponense. Histological observations revealed that the number of sperm decreased dramatically to <5% of the total cells in the testis of the dsCycA-treated group compared to that of control group on day 14, indicating that knockdown of Mn-CycA expression inhibited testis development by affecting the expression of Mn-IAG in M. nipponense. These results highlighted the functions of CycA in male reproductive development of M. nipponense, which can be applied to future studies of male reproduction in other crustacean species.

RNA Interference Analysis of the Functions of Cyclin B in Male Reproductive Development of the Oriental River Prawn (Macrobrachium nipponense)

Cyclin B (CycB) plays essential roles in cell proliferation and promotes gonad development in many crustaceans. The goal of this study was to investigate the regulatory roles of this gene in the reproductive development of male oriental river prawns (Macrobrachium nipponense). A phylo-genetic tree analysis revealed that the protein sequence of Mn-CycB was most closely related to those of freshwater prawns, whereas the evolutionary distance from crabs was much longer. A quantitative PCR analysis showed that the expression of Mn-CycB was highest in the gonad of both male and female prawns compared to that in other tissues (p < 0.05), indicating that this gene may play essential roles in the regulation of both testis and ovary development in M. nipponense. In males, Mn-CycB expression in the testis and androgenic gland was higher during the reproductive season than during the non-reproductive season (p < 0.05), implying that CycB plays essential roles in the reproductive development of male M. nipponense. An RNA interference analysis revealed that the Mn-insulin-like androgenic gland hormone expression decreased as the Mn-CycB expression decreased, and that few sperm were detected 14 days after the dsCycB treatment, indicating that CycB positively affects testis development in M. nipponense. The results of this study highlight the functions of CycB in M. nipponense, and they can be applied to studies of male reproductive development in other crustacean species.

Histomorphological changes between short and long days in ovary guanacos (Lama guanicoe).

This is the first morpho-histological comparison of guanaco ovaries between reproductive (long-days) and non-reproductive (short-days) seasons, and oestrogen receptor-alpha (ERα) and beta (ERβ) detection. Different stages of follicle development were found in the cortical area, but no corpus luteum was detected. The size and frequency of antral follicles and large atretic follicles were higher in long-day ovaries than short-days, consistent with ovarian activity in this season. Differential expression of ERα and ERβ was observed in follicles at different stages of development between short and long days. These data reveal histological and molecular differences between reproductive and non-reproductive seasons of guanaco ovaries.

Seasonal Variations in the Lipid Profile of the Ovarian Follicle in Italian Mediterranean Buffaloes.

Simple SummaryReproductive seasonality is a major factor affecting buffalo breeding. The rationale of this work derives from the hypothesis that the reduced cleavage and blastocyst rates observed during the non-breeding season could be due to a suboptimal follicular environment. The present study aimed to evaluate the influence of season on the lipid profile of the ovarian follicle in the Italian Mediterranean buffalo. For this purpose, abattoir-derived ovaries were collected during the breeding and non-breeding seasons, and the apolar phase of follicular components was analyzed. To our knowledge, this is the first report of seasonal variations in lipid content of the buffalo ovarian follicle, including follicular fluid, follicular and cumulus cells, and oocytes. The results undoubtedly demonstrated significant seasonal variations in the lipid profile, including triglycerides, cholesterol, and phospholipids, in the different biological matrices analyzed. Interestingly, an increased amount in the total level of non-esterified fatty acids in the follicular fluid was also observed during the non-breeding season. The results allow a better understanding of the physiology of the ovarian follicle in buffalo and unveil some causes of reduced oocyte competence during the non-reproductive season, laying the groundwork for further studies and corrective strategies.The reduced oocyte competence recorded during the non-breading season (NBS) is one of the key factors affecting the profitability of buffalo farming and limits the IVEP efficiency. The purpose of this experiment was to evaluate whether season influences the lipid content within the ovarian follicle in the Italian Mediterranean buffalo. Abattoir-derived ovaries were collected during the breeding season (BS) and the NBS, and different matrices (follicular fluid, oocytes, cumulus and follicular cells) were recovered. After the extraction of the apolar fraction, all samples were analyzed by H1 nuclear magnetic resonance and FF samples by gas chromatography–mass spectrometry. Seasonal differences in lipid composition were observed in all matrices. In particular, during the NBS, the triglyceride content was higher in the follicular fluid and in the oocytes but reduced in the follicular cells. Both cholesterol and phospholipids were reduced in the follicular fluid and follicular cells during the NBS. Furthermore, the total amount of non-esterified fatty acids was significantly increased in the follicular fluid. The seasonal variation in lipid profile of the follicle may, in part, account for the reduced buffalo oocyte competence during the NBS, due to the critical role played by lipids in regulating ovarian functions.

Reproductive biology of the bullseye puffer Sphoeroides annulatus: Gonadosomatic index and its suitability for estimating length at maturity.

This study aimed to describe updated information on the basic reproductive biology of Sphoeroides annulatus females and potential use of the gonadosomatic index as input data to assess length at 50% maturity ( ) and identify the breeding season. From April 2014 to December 2015, 767 females were analysed along the north-west coast of the Mexican Pacific Ocean. Both immature and mature females were represented in the total length ( ), which ranged from 81 to 440 mm, and the smallest mature female was 92 mm (new record for the species). Gonadal maturity phases were assigned through histological analysis. A threshold value was established using the lower whisker value for maturity phase spawning capable (2.06%). The monthly variation of supported the annual spawning seasonality, and the presence of reproductively active mature females coincided with the observed periods with histological data and the peaks for both seasons 2014 and 2015. Also the presence of reproductively inactive mature females confirmed the nonreproductive season observed from January to April 2015. Estimates of were based on the cumulative proportion of reproductively active mature females: both datasets showed a 'bumpy trajectory'. Considering the functional form of data and models, a second objective was to verify if each dataset presented a simple or double sigmoid trajectory and select the most suitable model through the Akaike information criterion. For both datasets, the best fitted model was the double sigmoidal , while the single sigmoidal had low performance and did not have statistical support. The provided a value ca. 254 mm for both data sets. A trade-off between the model's correct fit and a reliable value was found, but this fact is not always considered when calculating the maturity, resulting in biased parameters. Correct data fitting may seem trivial, but the consequences for the conservation of immature individuals could be dramatic, affecting the population recruitment. In conclusion, the histologically calibrated was suitable for classifying females of S. annulatus into reproductively inactive or active types, with an agreement percentage of 99%. The =2.06% can be useful for subsequent studies for this species.

Differences in sex ratio, tail autotomy, body size and body condition between suburban and forest populations of the cuban endemic lizard Anolis homolechis

Although growing evidence suggests that natural and sexual selection pressures may differ between natural and urban habitats, their consequences in terms of morphological differentiation, extent of sexual dimorphism and sex ratio remain poorly studied. Anolis lizards are an ideal model to study the phenotypic effects of urbanization, as they are well known for the existence of ecomorphs adapted to particular microhabitats. However, so far most studies of urban populations of anoles have considered invasive species and largely focused on males. Here, we compared morphological differentiation, sexual dimorphism and sex ratio between suburban and forest populations of the native A. homolechis, in western Cuba, based on large sample size (n > 800) and a balanced nested design. Overall, both male and female individuals from suburban populations were larger and in better body condition than individuals from forest populations. In addition, evidence of caudal autotomy was more than twice more frequent in suburban populations compared to forest ones, with no sex effect. Habitat type and season of the year had additive effects on sex ratios, with a significant excess of males in suburban habitats and during the non-reproductive season. Accordingly, the extent of sexual dimorphism in size was more pronounced in suburban populations compared to forest ones. Our results suggest that the shape and direction of natural selection may differ between urban and natural populations of anoles.