Reproductive Activity Research Articles

Freshwater megafauna shape ecosystems and facilitate restoration.

Freshwater megafauna, such as sturgeons, giant catfishes, river dolphins, hippopotami, crocodylians, large turtles, and giant salamanders, have experienced severe population declines and range contractions worldwide. Although there is an increasing number of studies investigating the causes of megafauna losses in fresh waters, little attention has been paid to synthesising the impacts of megafauna on the abiotic environment and other organisms in freshwater ecosystems, and hence the consequences of losing these species. This limited understanding may impede the development of policies and actions for their conservation and restoration. In this review, we synthesise how megafauna shape ecological processes in freshwater ecosystems and discuss their potential for enhancing ecosystem restoration. Through activities such as movement, burrowing, and dam and nest building, megafauna have a profound influence on the extent of water bodies, flow dynamics, and the physical structure of shorelines and substrata, increasing habitat heterogeneity. They enhance nutrient cycling within fresh waters, and cross-ecosystem flows of material, through foraging and reproduction activities. Freshwater megafauna are highly connected to other freshwater organisms via direct consumption of species at different trophic levels, indirect trophic cascades, and through their influence on habitat structure. The literature documenting the ecological impacts of freshwater megafauna is not evenly distributed among species, regions, and types of ecological impacts, with a lack of quantitative evidence for large fish, crocodylians, and turtles in the Global South and their impacts on nutrient flows and food-web structure. In addition, population decline, range contraction, and the loss of large individuals have reduced the extent and magnitude of megafaunal impacts in freshwater ecosystems, rendering a posteriori evaluation more difficult. We propose that reinstating freshwater megafauna populations holds the potential for restoring key ecological processes such as disturbances, trophic cascades, and species dispersal, which will, in turn, promote overall biodiversity and enhance nature's contributions to people. Challenges for restoration actions include the shifting baseline syndrome, potential human-megafauna competition for habitats and resources, damage to property, and risk to human life. The current lack of historical baselines for natural distributions and population sizes of freshwater megafauna, their life history, trophic interactions with other freshwater species, and interactions with humans necessitates further investigation. Addressing these knowledge gaps will improve our understanding of the ecological roles of freshwater megafauna and support their full potential for facilitating the development of effective conservation and restoration strategies to achieve the coexistence of humans and megafauna.

Gender Livelihood Strategies among Farmers’ Household in Kano State, Nigeria

Gender-based livelihood continues to be one of the most prevalent issues facing Nigerian households, with implications in virtually every industry. This study accessed the gender-based livelihood strategies of farmers’ households in Kano State, Nigeria. The research was conducted in Kano state, four Local Government Areas (LGAs) in Kano State were selected using a multi-stage sampling procedure, and 215 farmers were randomly selected from 717 households in the LGAs. In addition, 80 households, of which 20 were randomly selected from each LGA, were interviewed about their means of subsistence. A combination of quantitative and qualitative techniques was used to gather information for the study. Both descriptive statistics and the Harvard Analytical Framework were used to analyse the collected data. The results revealed that the average age of farmers in Kano State was 35 years, the majority (89.3%) were married, with an average household size of 9 people, and 55.8% had informal education. The majority of productive activities were carried out by men and boys; both men and women carried out activities that generated income; and more than 70 percent of reproductive activities were carried out by women, as revealed by the household's livelihood strategies. It further revealed that women had limited access to resources and that the majority of resources were under the control of males in the study area. Men dominated access to and control over the resources that were available. It is recommended that women be encouraged to devise legal means for accessing and controlling resources in order to improve their livelihood status.

Strengthening organizational capacity in Kenya, Malawi, and South Sudan

This reports on a US-AID-funded project which engages faith-based organizations to strengthen their organizational capacity as they implement reproductive, maternal, newborn, and child health grant activities. Implementing partners in Kenya, Malawi, and South Sudan completed the self-administered Organization Capacity Assessment and created corresponding action plans based on the assessment results. Each organization completed the priority activities that they identified in their action plans; strengthening staff capacity, sharpening monitoring and evaluation systems; and improving information systems. We conclude that grantmakers’ investment in strengthening the organizational capacity of their implementing partners results in the grantees having improved internal systems and being better positioned to obtain and execute future grant opportunities.

No sign of reproductive cessation in the old workers of a queenless ponerine ant

In many social hymenopterans, workers of different ages engage in different tasks; younger workers remain inside the nest as intranidal workers, while older workers go outside the nest as extranidal workers (i.e., age polyethism). Previous studies have shown that ovarian activity is diminished in old, extranidal workers, but it remains unclear whether workers’ reproductive ability persists for life or whether they exhibit post-reproductive lifespans. In this study, we investigated the age-dependence of worker reproductive ability in a monomorphic ponerine ant Diacamma cf. indicum. In Diacamma ants, all females in a colony have reproductive ability, but effective reproduction is limited to one or a few dominant females, and the remaining females act as sterile helpers. Using long-term laboratory rearing, we investigated whether worker reproductive ability lasts throughout a worker’s lifetime. The ages of workers were accurately tracked, and the reproductive ability of young and old workers was examined by creating several gamergate-less sub-colonies. Results showed that at least one individual in each sub-colony developed ovaries, even in the sub-colonies that solely consisted of very old workers (> 252 days old). Interestingly, in the presence of younger workers, old workers rarely showed ovarian development. Besides age, we found a positive correlation between the amount of fat (i.e., nutritional condition) and ovarian development in old workers. Our data suggest that reproductive activity of old workers is low but maintained throughout their life in Diacamma.Significance statementFemales of social animals, such as cetaceans, are known to stop reproducing before the end of their lifespan. It is suggested that the reproductive ability of ant queens does not decline and is maintained throughout their lives; however, it is unclear whether this is also true in ant workers. We maintained ant colonies for more than 500 days and then tested whether the reproductive ability of ant workers is maintained throughout their lifespan. Even in small groups composed of only very old workers (> 252 days old), at least one individual in each group always reproduced actively. Interestingly, the presence of young workers seemed to suppress the reproduction of old workers. In addition, fat content was positively associated with the individual’s reproductive potential.

Characterizing the seasonal abundance and reproductive activity of overwintering Anopheles (Diptera: Culicidae) mosquitoes.

In temperate regions of the United States, female Anopheles mosquitoes respond to low temperatures and short photoperiods by entering an overwintering dormancy or diapause. Diapause in Anopheles results in reduced frequency of blood-feeding and reproductive arrest, indicating a period when pathogen transmission by these mosquitoes is unlikely. However, it is unclear precisely how late into the fall and how early in the spring these mosquitoes are biting, reproducing, and potentially transmitting pathogens. This is further complicated by the lack of clear markers of diapause in Anopheles (e.g., changes in egg follicle length). Our goal was to characterize the seasonal reproductive activity of female Anopheles in central Ohio, United States and evaluate egg follicle length as an indicator of Anopheles diapause. We used traditional mosquito traps and aspirators to collect Anopheles from urban woodlots and culverts, respectively, from late September 2021 through mid-May 2022 in central Ohio. By measuring their egg follicle length, reproductive status, and blood-feeding status, we found that egg follicle length is not a reliable indicator of Anopheles diapause. We also found that a small proportion of An. punctipennis (Say), An. perplexens (Ludlow), and An. quadrimaculatus (Say) continued to bite and reproduce into early November 2021 and that females of these species terminated reproductive dormancy and began biting by mid-March 2022. This period of reproductive activity extends beyond current mosquito surveillance and control in Ohio. Our findings suggest that within temperate regions of North America, Anopheles have the capacity to transmit pathogens throughout the spring, summer, and fall.

No- or Low-Content Copper Compounds for Controlling Venturia oleaginea, the Causal Agent of Olive Leaf Spot Disease.

The efficacy of using a synthetic (azoxystrobin + difenoconazole), copper-based (copper oxychloride) and low-content copper compound (copper complexed with gluconate and lignosulphonate) fungicides for controlling Venturia oleaginea, the causal agent of olive spot disease, was evaluated in an olive (cv. Nabali) orchard located in the Kafr Qud area (Palestine) in 2017-2018. Treatments were applied at three different times (February, April, and August). In January 2017, at the beginning of the experiment, about 90% of the leaves grown in 2016 were infected. Defoliation was determined by counting the leaves on the labeled branches initially and then periodically. It increased gradually in both the control and treated trees, but those treated with azoxystrobin + difenoconazole or with copper complexed with gluconate and lignosulphonate showed a slower defoliation rate. During 2017, new shoots grew and new leaves developed. All treatments reduced the drop of new leaves with respect to the control, with positive effects on the reproductive activity (inflorescence growth and yield). Overall, all treatments significantly reduced the disease, thus indicating the possibility of greatly reducing infections if treatments are regularly applied each year, also with traditional (copper-based) fungicides. Due to their capability of penetrating inside the vegetative tissue, azoxystrobin + difenoconazole or copper complexed with gluconate and lignosulphonate reduced/slowed down the drop of infected leaves. The use of these fungicides is therefore particularly recommended when olive leaf spot disease is severe. The use of low-content copper compounds allows the amount of metallic copper used for the treatments against V. oleaginea to be greatly reduced.

Male Reproductive Hormonal Activity of Synergistic Ingestion of Aqueous Extract of Cyperus esculentus, Phoenix dactylifera and Cocos nucifera in Male Rat Model

Male Reproductive Hormonal Activity of Synergistic Ingestion of Aqueous Extract of Cyperus esculentus, Phoenix dactylifera and Cocos nucifera in Male Rat Model

Adolescent-Parent Communication About Reproductive Health Among Junior High School Students

Adolescent-parent communication about reproductive health is still considered taboo. This view prevents students from telling their parents about their health problems. This study aimed to analyze the relationship between factors related to adolescent-parent communication about reproductive health. This research method is analytically observational with a cross-sectional approach. Respondents involved were students of classes VII and VIII, totaling 117 people. The results showed no relationship between gender (p-value= 0.182, OR (95%CI)= 0.846-3.686), information access (p-value= 0.561, OR (95%CI)= 0.603-3.314), gender compatibility (p-value= 0.302, OR (95%CI)= 0.707-5.020), and parental credibility (p-value= 0.100, OR (95%CI)= 0.950-4.370) with adolescent-parent communication about reproductive health. Adolescent-parent communication about reproductive health, which is low and high, has almost the same percentage—of recommendations to parents to improve communication with adolescents regarding reproductive health further. The school also needs to add reproductive health education activities.

A social reproduction analysis of digital care platform work

ABSTRACT Digital platforms are becoming an important factor in the process of reconfiguration and commodification of social reproduction during the neoliberal phase of capitalism. Developing a theoretical framework merging social reproduction theory and migrant labour regimes, this article argues that the introduction of digital platforms in the care sector is facilitating the expansion of precarised commodification of reproductive activities in a context of social care crisis. Through a mixed-method analysis, combining desk-based research with in-depth interviews of digital care platform work in Spain, the study examines the migrant labour regime of digital care platforms and how they take advantage of the international division of labour and global care chains to further exploit a highly precarious, informalised, feminised and racialised workforce. Our findings reveal that platforms use technology to rapidly access a reserve labour army, thus extracting more surplus value by restricting access to information, controlling the intermediation process and further fragmenting the workforce in reproductive activities.

Is the Pyrenean newt (<em>Calotriton asper</em>) a thermoconformer? Cloacal and water temperature in two different thermal periods in a Pre-Pyrenean stream population

In ectothermic animals, heat seems to be a determining factor because it influences many vital activities such as locomotion, the ability to escape, feeding, and reproduction, among others. In aquatic environments, physical characteristics of water prevent small ectotherms from thermoregulating and therefore it is expected that their body temperature remains similar to water temperature. Throughout its distribution and annual cycle, the Pyrenean newt (Calotriton asper) is exposed to a wide range of water temperatures that affect its biological and ecological traits like the standard metabolic rate, oxygen consumption, activity period and growth pattern. This study analyses the relationship between the cloacal and water temperatures in a Pre-Pyrenean population of C. asper in two periods with well differentiated water temperatures (July and September). The aims are to establish if there are differences between sexes in cloacal temperature, whether reproductive activity modifies cloacal temperature, and to analyse the degree of thermoconformity of the species. The results indicate that cloacal temperature depends on the water temperature, corroborating the idea that C. asper is mainly a thermoconformer, as it corresponds to an aquatic ectotherm. However, the cloacal temperature of newts was slightly higher than water temperature. In individuals in amplexus, cloacal temperature was significantly higher than in specimens that are not in this mating position, and in July, females showed much greater dispersion in cloacal temperature than males, which is probably related to spawning behaviour.

Reproductive Activity and Diet of an Urban Population of Pallas' Free-Tailed Bats Molossus molossus (Molossidae)

Reproductive Activity and Diet of an Urban Population of Pallas' Free-Tailed Bats Molossus molossus (Molossidae)

Expression and localization of HPG axis-related genes in Carassius auratus with different ploidy.

In the Dongting water system, the Carassius auratus (Crucian carp) complex is characterized by the coexistence of diploid forms (2n=100, 2nCC) and polyploidy forms. The diploid (2nCC) and triploid C.auratus (3n=150, 3nCC) had the same fertility levels, reaching sexual maturity at one year. The nucleotide sequence, gene expression, methylation, and immunofluorescence of the gonadotropin releasing hormone 2(Gnrh2), Gonadotropin hormone beta(Gthβ), and Gonadotropin-releasing hormone receptor(Gthr) genes pivotal genes of the hypothalamic-pituitary-gonadal (HPG) axis were analyzed. The analysis results indicated that Gnrh2, follicle-stimulating hormone receptor(Fshr), and Lethal hybrid rescue(Lhr) genes increased the copy number and distinct structural differentiation in 3nCC compared to that in 2nCC. The transcript levels of HPG axis genes in 3nCC were higher than 2nCC (P<0.05), which could promote the production and secretion of sex steroid hormones conducive to the gonadal development of 3nCC. Meanwhile, the DNA methylation levels in the promoter regions of the HPG axis genes were lower in 3nCC than in 2nCC. These results suggested that methylation of the promoter region had a potential regulatory effect on gene expression after triploidization. Immunofluorescence showed that the localization of the Fshβ, Lhβ, and Fshr genes between 3nCC and 2nCC remained unchanged, ensuring the normal expression of these genes at the corresponding sites after triploidization. Relevant research results provide cell and molecular biology evidence for normal reproductive activities such as gonad development and gamete maturation in triploid C. auratus, and contribute to further understanding of the genetic basis for fertility restoration in triploid C. auratus.

Effect of immunization against OPN5 on the reproductive performance in Shan Partridge ducks under different photoperiods

Photoperiod is an important environmental factor that influences seasonal reproduction behavior in birds. Birds translate photoperiodic information into neuroendocrine signals through deep brain photoreceptors (DBPs). OPN5 has been considered candidate DBPs involved in regulating seasonal reproduction in birds. We found that OPN5 could mediate light to regulate the follicle development in ducks. In this study, we further verified the effect of OPN5 on follicular development in Shan Partridge ducks by immunizing against the extracellular domain (ECD) of OPN5. We investigated the specific regulatory mechanism of photoperiod mediated by OPN5 on the reproductive activity of ducks. The trial randomly divided 120 Shan Partridge ducks into 3 groups with different treatments: the immunization of OPN5 group was done at d0, d15, d30, and d40 with 1 mL of vaccine containing OPN5 protein (thus containing 1, 1, 0.5, and 0.5 mg of OPN5-KLH protein), and the control group (CS and CL groups) was injected at the same time with the same dose of OPN5-uncontained blank vaccine. The group of CS (900 lux), OPN5 (600 lux), and CL (600 lux) lasted for 40 d in 12 L:12 D photoperiods, respectively. Then, the groups of CS, OPN5, and CL subsequently received 12 L:12 D, 12 L:12 D, and 17 L:7 D light treatments for 33 d, respectively. The ducks were caged in 3 constant rooms with the same feeding conditions for each group, free water, and limited feeding (150 g per duck each day). Duck serum and tissue samples were collected at d 40, d 62, and d 73 (n = 12). It was found that before prolonged light, the group of immunization (group OPN5) and the group of strong light intensity (group CS) were higher than the group of CL in egg production. Subsequent to prolonged light, the group CL in egg production rose about the same as the group immunization, while the strong light group (group CS) was lower. Group OPN5 increased the ovarian index of ducks, and both the immunization of group OPN5 and group CL (extended light) increased the thickness of the granular layer and promoted the secretion of E2, P4, LH, and PRL hormones. Compared with group CS, group CL and OPN5 increased the mRNA level and protein expression of OPN5 in the hypothalamus on d 62 and d 73 (P < 0.05). The gene or protein expression patterns of GnRH, TRH, TSHβ, DIO2, THRβ, VIP, and PRL were positively correlated with OPN5, whereas the gene expression patterns of GnIH and DIO3 were negatively correlated with OPN5. The results showed that immunization against OPN5 could activate the corresponding transmembrane receptors to promote the expression of OPN5, up-regulate the expression of TSHβ and DIO2, and then regulate the HPG axis-related genes to facilitate the follicular development of Shan Partridge ducks. In addition, in this experiment, prolonging the photoperiod or enhancing the light intensity could also enhance follicle development, but the effect was not as significant as immunizing against OPN5. Our results will offer beneficial data and more supportive shreds of evidence in favor of elucidating the role of OPN5 in relation to photoperiods and reproduction.

The reproductive biology of Ellochelon vaigiensis from the Vietnamese Mekong Delta.

The Squaretail mullet, Ellochelon vaigiensis, is a commercial fish species distributed throughout the Indo-Pacific region. This species tolerates wide variations in salinity, having been reported from both freshwater and marine habitats. Although economically significant, there is little information on its reproduction, especially in the Vietnamese Mekong Delta (VMD), where it is heavily extracted. Our study elucidates the breeding pattern, seasonality, first length at maturity, as well as potential and relative fecundity of this species. Fish specimens were collected by trawl nets from November 2020 to October 2021 at four estuarine sites within the VMD. We found this species to be a synchronous spawner, with peaks in reproductive activity from June to September. In the populations we surveyed, there was significant dominance of males (1.26:1.00) based on 942 fish samples (526 males and 416 females). The length at 50% maturity for females was significantly higher than for males at all sites and ranged from 10.6 to 19.3 cm. The diameter of the eggs examined for this species exhibited slight variation, from 0.43 to 0.54 mm. The potential fecundity ranged from 246,254 ± 35,878 to 411,970 ± 54,370 eggs, corresponding to female length and weight of 26.7-32.6 cm and 102.97-234.19 g, respectively. Relative fecundity values were highest at Thanh Phu, Ben Tre (6388 ± 605 eggs), and Dong Hai, Bac Lieu (6461 ± 637 eggs), followed by Tran De, Soc Trang (4729 ± 408), and were found to be lowest at Duyen Hai, Tra Vinh (3117 ± 223 eggs). Information on reproductive behavior in this species has far-reaching impacts on sustainable extractions, stock conservation, and aquaculture.

Influence of environmental factors on reproduction of the invasive Gulf toadfish Opsanus beta (Teleostei: Batrachoididae) in a subtropical estuary

A hallmark of biological invasion is the rapid reproduction of invasive species. However, we still do not have an adequate understanding of how fluctuations in environmental factors affect the reproduction of invasive species, particularly in estuarine habitats. In this study, we evaluated the reproduction of the Gulf toadfish Opsanus beta and its relationships with temperature and rainfall in the Paranaguá estuary, a subtropical region in southern Brazil. This species was likely introduced into the Brazilian ecosystems through the discharge of ballast water. Since invasion, which was first reported in port areas, the species has rapidly spread along the Brazilian coast line. We collected specimens monthly from October 2011 to September 2012 and from October 2019 to September 2020, to give us insight into the seasonal and temporal changes in the reproduction of this species. We found that O. beta population uses the estuary throughout its life cycle, including during spawning. Females and males spawned throughout almost the entire sampling period and spawning was specified as partially. Peak reproductive activity occurred in periods of lower temperature and was also related to rain. The length of first maturation in females (10cm) was considered early, indicating reproductive activity in smaller individuals. Our results demonstrate that the reproductive strategy used by the invasive species supports its ability to successfully colonize new environments.

Impact of Fear and Group Defense on the Dynamics of a Predator–Prey System

To reduce the chance of predation, many prey species adopt group defense mechanisms. While it is commonly believed that such defense mechanisms lead to positive feedback on prey density, a closer observation reveals that it may impact the growth rate of species. This is because individuals invest more time and effort in defense rather than reproductive activities. In this study, we delve into a predator–prey system where predator-induced fear influences the birth rate of prey, and the prey species exhibit group defense mechanism. We adopt a nonmonotonic functional response to govern the predator–prey interaction, which effectively captures the group defense mechanism. We present a detailed mathematical analysis, encompassing the determination of feasible equilibria and their stability conditions. Through the analytical approach, we demonstrate the occurrence of Hopf and Bogdanov–Takens (BT) bifurcations. We observe two distinct types of bistabilities in the system: one between interior and predator-free equilibria, and another between limit cycle and predator-free equilibrium. Our findings reveal that the parameters associated with group defense and predator-induced fear play significant roles in the survival and extinction of populations.

Tubercidin inhibits PRRSV replication via RIG-I/NF-κB pathways and interrupting viral nsp2 synthesis.

Porcine reproductive and respiratory syndrome (PRRS) is one of the most important swine diseases, which causes huge economic loss worldwide. However, there is no effective therapeutic method for PRRS prevention and control. Here, we found that tubercidin, a naturally extracted adenosine analog, exhibited strong anti-porcine reproductive and respiratory syndrome virus (PRRSV) activity. Mechanically, tubercidin inhibited viral binding, replication, and release. Tubercidin suppressed PRRSV non-structural protein 2 expression, which is important for the formation of replication and transcription complex, leading to the block of viral RNA synthesis and PRRSV replication. Moreover, tubercidin could activate retinoic acid-inducible gene I/nuclear factor kappa-light-chain-enhancer of activated B cell innate immune signaling pathway and increased the expression of interferons and proinflammatory cytokines, which was the other way to inhibit PRRSV replication. Our work evaluated the potential value of tubercidin as an antiviral agent on PRRSV replication and provided a new way to prevent PRRSV replication in vitro.

Dietary 25 Hydroxyvitamin D3 Improved Serum Concentration Level and Alkaline Phosphatase Activity during Lactation but Had Meager Impact on Post-Farrowing Reproductive Performance in Sows

Dietary 25 hydroxyvitamin D3 (25(OH)D3) promotes serum 25(OH)D3 concentration and alkaline phosphatase activity (ALP); however, post-farrowing reproductive performance of lactating sows fed with 14-epimer of 25(OH)D3 is uncertain. This study investigated post-farrowing reproductive performance, serum ALP activity, and serum 25(OH)D3 concentration in sows fed VD3, 25(OH)D3, or 14-epi 25(OH)D3. Weaned sows (n = 203) in parities 2 and 3 were blocked weekly and treated with 2000 IU/kg VD3 (T1), 25 μg/kg 25(OH)D3:14-epi 25(OH)D3 (T2), or 50 μg/kg 25(OH)D3 (T3) diets, all equilibrated to 2000 IU/kg as fed. Sow performance, treatment, and sampling period effects were analyzed. Environmental conditions were analyzed as covariates. The number of piglets weaned (p = 0.029), pre-weaning mortality (p = 0.029), sampling period (p &lt; 0.001), and treatment and period interaction (p = 0.028) differed significantly. There was an increase in 25(OH)D3 during lactation due to physiological demands for milk calcium and milk production. Supplementing twice the concentration of 25(OH)D3 compared to its epimer, 25(OH)D3:14-epi 25(OH)D3, had no significant effect on the post-farrowing reproductive performance of lactating sows. The effect of 25(OH)D3 on post-farrowing reproductive performance and ALP activity in sows was influenced by metabolic demand for calcium due to physiological changes during lactation as well as epimer conformation.

The Relationship of Gametes and Somatic Cells of Male Gonads of Vertebrates: Evolutionary, Age and Seasonal Aspects, Adaptive and Reactive Transformations Under the Action of Destabilizing Factors

The aim of the study is a comparative analysis of the morphofunctional interactions of germ and somatic cells in the organs of the male reproductive system of vertebrates during ontogenesis, under conditions of changes in reproductive activity and under the influence of destabilizing factors. Material and methods. Using light and electron microscopy, immunohistochemistry and morphometry, the testes of representatives of various classes of vertebrates (amphibians, reptiles, birds and mammals) were studied. The collection of material was carried out in environmentally safe ecosystems and in ecosystems with high anthropogenic load in the Orenburg region of Russia and in the Aktobe region of the Republic of Kazakhstan. Results. Based on the material of our own studies of the gonads, as well as on the basis of information from modern domestic and foreign literature, the patterns of relationships between germ cells and somatic cells of their microenvironment in the testes of vertebrates are shown. The features of the structural organization of the germinal and endocrine components of the male gonads are considered. The features of the structural organization of intertitial endocrinocytes (Leydig cells) are shown, and their high resistance to the action of various destabilizing factors compared to spermatogenic epithelium is established. Pubertal generation of endocrinocytes in vertebrate testes during reproductive age is characterized by stability in cell numbers and belongs to cell populations of a stable type. The role and significance of the structures of the blood-testis barrier are shown and the morphological equivalents of changes in the permeability of this barrier are established; it is revealed that in the studied animals, under the influence of negative anthropogenic factors, the integrity of the blood-testis barrier in the testes is violated. The action of destabilizing factors leads to a decrease in the number of developing germ cells in the lumen of the epididymal tubules (up to their complete disappearance in individual individuals), which is probably due to the deterioration of the trophic influences on them from the structures of the epididymis. Conclusion. The principle of organization of the main compartments of the testes, the convoluted seminiferous tubules and the interstitium of the organ, formed during evolution, probably turned out to be evolutionarily advantageous, since it is represented in the testes of all amniotes - reptiles, birds and mammals. In the process of evolutionary development, several types of structural organization of convoluted seminiferous tubules and interstitium were formed in the testes of vertebrates. The need to protect developing germ cells from the effects of immunocytes, which led to the formation of a blood-testis barrier in the testes.

Correction to: Reproductive system and activity patterns of Philornis downsi (Diptera: Muscidae)

Correction to: Reproductive system and activity patterns of <i>Philornis downsi</i> (Diptera: Muscidae)