Male behavior in colonies of the social wasp Polistes lanio (Hymenoptera, Vespidae)

Sixteen post-emergent colonies of Polistes lanio were studied while producing males in the course of the colonial cycle. Individually, they remained in the nest only 10.5 days (5-31, n=165). Twelve different male behaviors were observed: remaining immobile on the nest (82,8%), giving alarm (4,8%), flying out from the nest (2,4%), copulating on the nest (2,4%), being dominated (1,6%), self-grooming (1,2%), checking cells (1,2%), adult-adult trophallaxis (receiving food) (0,8%), larva-adult trophallaxis (0,8%), chewing prey and giving it to the larvae (0,8%), returning to the nest without food (0,8%), and fanning the nest (0,4%). In comparison to the behavioral repertory of females (28 items), they performed fewer tasks and remained immobile most of the time on the nest. Their behavior was largely related to self maintenance, but also included giving chewed prey to the larvae, giving alarm signals and fanning the nest.

Morphotypes in male Amazon River Prawns, Macrobrachium amazonicum

The occurrence of morphotypes in Macrobrachium amazonicum males was investigated. Prawns aged 4 to 24 months were taken from 10 aquaculture earthen ponds. Color and spination of right second cheliped were analyzed under a stereomicroscope. Post-orbital and carapace length were measured as well as the length of the cheliped and all limb joints on the right second pereiopods. Four distinct morphotypes were identified: Translucent Claw (TC), Cinnamon Claw (CC), Green Claw 1 (GC1) and Green Claw 2 (GC2). They differed in cheliped morphology and some morphometric relationships. Chelipeds were translucent in TC prawns while in CC they were generally cinnamon-color. Both showed a few spines and some low prominences similar to very small tubercles. GC1 and GC2 showed long moss green chelipeds provided with long and robust spines. However, in GC2, cheliped length was always greater than post-orbital length and the angles of spines on the carpus and propodus were more open, ranging from 51°to 92°, while, in GC1 it varies from 34°to 65°. Cheliped length, the cheliped length/post-orbital length ratio and the spine angle were significantly different among the four morphotypes. A description for the identification of each group is provided and the development of M. amazonicum males is discussed. Each morphotype may play a different role in the population and in the environment in which it lives. Therefore, the identification of morphotypes is advisable for future researches on the biology and culture of M. amazonicum. © 2004 Elsevier B.V. All rights reserved.

Bone mineralization among male adolescents: Critical years for bone mass gain

Objective: To verify the behavior of the mineral bone content and density in male adolescents according to age and secondary sexual characters. Methods: 47 healthy adolescents between 10 and 19 years old were assessed according to weight, height, body mass index, puberty stage, calcium intake, bone mineral density and content in the lumbar spine and in the proximal femur. The bone mass was measured through bone densitometries. The intake of calcium was calculated through a 3-day diet. The BMI (body mass index) was calculated with the Quetelet Index and the puberty stage was defined according to Tanner's criteria. The analysis used descriptive statistics such as average and standard deviation, and variance estimates to compare the different age groups. Moreover, the Tukey test was used to determine the significant differences. Results: It was evident that the calcium intake in the different ages assessed has not reached the minimum value of 800 mg. The bone mineral density and content showed an increase after the age of 14, as well as when the teenagers reached the sexual maturation stage G4. The mineralization parameters showed a high level when the teenagers were in the G3 stage, however, without statistical significance. Conclusion: The results indicate an important level of bone mineralization during adolescence. Maturation levels superior to G3 have shown more mineralization. This study proves that the critical years for bone mass gain start after the 14-15 years old or older. Copyright © 2004 by Sociedade Brasileira de Pediatria.

Chronic renal failure in male and female rats

Gender influences the progression of chronic renal failure (CRF). We studied male (M) and female (F) Wistar rats for 90 days: castrated (CMc, n=7; CFc, n=6) and non castrated controls (CM, n=9; CF, n=6); castrated (CRFMc, n=8; CRFFc, n=6) and non castrated animals submitted to 5/6 nephrectomy (CRFM, n=13; CRFF, n=6). Data are expressed as mean ± SEM. Proteinuria (PTN) was higher in CRFM (554 ± 69mg/24h) compared to CRFMc (277 ± 85 mg/24h), but not in females (CRFF=193 ± 20mg/24h, CRFFc=164 ± 71mg/24h). Mesangial fractional volume increased in all CRF animals. CRF animals showed an increase of glomerular sclerosis index (GSI) and tubulointerstitial damage (TID) but in a smaller proportion in male castrated animals; the opposite occurred with females: castration induced an increase of these parameters. CRF animals showed increased cortical and glomerular fibronectin (FN) rates. Castration decreased glomerular and cortical FN rates in CRFM but not in females. In conclusion, proteinuria was higher in CRFM and probably led to glomerular and interstitial damage, as well as to FN accumulation, castration seems to protect against development of PTN, TID and FN accumulation in males. Castrated female rats presented mesangial expansion, with no changes in PTN, TID and FN rates. It seems that female sex hormones do not protect against renal disease progression, instead, we suggest that male sex hormones lead to acceleration of CRF.

Male behavior of Mischocyttarus cerberus (Hymenoptera, Vespidae) during attacks on the nest by ants

The objectives of the present study were to verify if the males of the wasp Mischocyttarus cerberus participate in defense of the nest as they react to attack by ants, and to observe if they use chemical defense. First, wasps were stimulated with an empty pair of tweezers and a second stimulation was done with a pair of tweezers containing an ant, Camponotus crassus. The behaviors of the wasps were recorded and analyzed. The males can participate in defense of the nest, presenting some aggressive behaviors, even so, most of the time they ignore the stimulation, hide behind the nest and stay immobile.

Brood care and male behavior in queenless Acromyrmex subterraneus brunneus (Hymenoptera: Formicidae) colonies under laboratory conditions

In this study we describe and quantify the brood care performed by workers in queenless colonies of the leaf-cutting ant Acromyrmex subterraneus brunneus. Fifteen behavioral acts were recorded in the three colonies studied. The behavioral repertoire of males was more limited, with only four behavioral acts being observed: feeding through workers, collecting staphylae and self-feeding, mutual grooming between adults (worker-males), and self-grooming. Males were also found to be able to collect food (staphylae or fungal hyphae) from the fungus garden and to feed themselves, not requiring workers for this activity. This study contributes to a better understanding of the basic biology of leaf-cutting ant colonies, with the description and quantification of the activities performed by the members of a colony in a situation of the loss of the fertile caste.

The effects of male age on sperm DNA damage in an infertile population

The objective was to investigate the influence of age on sperm DNA damage. Semen samples were collected from 508 men in an unselected group of couples attending infertility investigation and treatment. DNA fragmentation in spermatozoa was measured by TdT (terminal deoxynucleotidyl transferase)-mediated dUTP nick-end labelling (TUNEL) assay; at least 200 spermatozoa in randomly selected areas of microscope slides were evaluated using a fluorescent microscope and the percentage of TUNEL positive spermatozoa was determined. The number of cells with red fluorescence (TUNEL positive) was expressed as a percentage of the total sample [DNA fragmentation index (DFI)]. Age was treated as a continuous variable for regression and correlation analysis. The following male age groups were used: Group I: ≤35 years, Group II: 36-39 years, and Group III: ≥40 years. DFI was significantly lower in Group I than in Group II (P = 0.034) or III (P = 0.022). There was no difference in DFI between Groups II and III. In addition, regression analysis demonstrated a significant increase in sperm DFI with age (P = 0.02). TUNEL assay clearly demonstrates an increase in sperm DNA damage with age. © 2007 Published by Reproductive Healthcare Ltd.

Hindlimb unloading producing effects on bone biomechanical properties in mature male rats

Aging is associated with decline in muscle mass and strength and reduced bone density. Age-related bone loss is a primary factor in osteoporosis and all individuals are potential candidates for osteoporosis because bone loss with aging occurs in men and women, but less studied in men. To examine the appropriateness of hindlimb elevation, by tail suspension as a model for diminished mechanical loading, and to determine the influence of age on bone responsiveness to skeletal unloading, we use dual X ray absorptiometry (DXA) and digital radiographic images to analyze the response of the femur from mature rats to biomechanical loads. Femurs from male Wistar rats (9-mo-old) were scanned using DXA and DIGORA and measures obtained in ephipyseal and diaphyseal regions of interest. The mechanical testing was divided into compression load to fracture the head and a three-point bending load to fracture the femur middiaphysis. In femoral epiphysis from hindlimb unload (HU), animals presented significant differences between mineral bone content and density assessed by DXA. Detailed regions of femoral epiphysis (head, throcanteric fossa, throcanter and metaphysis) presented significant lower values from radiographic density. Only compressive load necessary to fracture the femoral head neck was also significantly diminished in HU animals. Disuse induced, as in elderly patients, deterioration of the trabecular bone architecture with critical effect on bone fragility. Rats with 21 days of hindlimb unloading can simulate disuse, suggesting that certain sub-regions of their aging bones are more susceptible to fracture, while other, i.e. diaphyses, are not.

Low caloric value of ethanol itself increases alveolar bone loss in ligature-induced periodontitis in male rats

This study aimed at morphometrically evaluating the influence of variable caloric values of ethanol consumption on alveolar bone loss in periodontitis in male rats. Thirty-six male rats were randomized into four groups of nine rats each, as follows: Test group A (low) - rats were fed an ethanol-containing liquid diet (ethanol representing 22% of total caloric value); Control group A - rats were fed a pair-fed control diet (ethanol replaced by isocaloric amounts of carbohydrate); Test group B (high) - rats were fed an ethanol-containing liquid diet (ethanol representing 36% of total caloric value); Control group B - rats were fed a pair-fed control diet for Test B. Following anesthesia, cotton ligatures were placed around the cervix of the right upper second molar. At eight weeks, the maxillary bones were removed and alveolar bone loss was analyzed by measuring the distance between the cementoenamel junction and the alveolar bone crest at buccal and palatal sites of the upper second molar. The unligated groups showed no significant differences between the bone loss values observed for the low and high caloric values of ethanol (p > 0.05). In the ligated groups, the rats receiving low caloric values of ethanol showed significantly greater bone loss compared to the isocaloric rats (p < 0.05); however, the rats receiving high caloric values of ethanol showed no significant differences compared to the controls. Analysis of the results demonstrated that, in male rats, ethanol itself affected ligature-induced bone loss when representing a low value in the total caloric value.

Perinatal exposure to parasiticide ivermectin: Long-term effects on reproductive parameters of adult male rats

Ivermectin is one of the most widely used antiparasitic drugs globally. The aim of this study was to evaluate the chronic effects of perinatal exposure to ivermectin on male reproductive parameters in rats. Pregnant rats were treated daily by oral gavage with 0.4 or 1.6 mg kg -1 of ivermectin or vehicle, from gestational day 6 until post-natal day 10. In the adulthood stage, there were significant reductions in the relative testicular weight of rats exposed to the low dose and in relative prostate weight of male rats exposed to the high dose of ivermectin. Furthermore, the animals exposed to the low dose also presented an increased seminal vesicle weight compared to controls. However, neither of the ivermectin doses interfered in daily sperm production, sperm number in testis, or sexual behavior of exposed males. In conclusion, perinatal exposure to ivermectin neither altered the male reproductive system development markedly, nor produced any adverse effects on the parameters evaluated. © 2011 Taylor & Francis.

MMP-2 and TIMP-2 in the prostates of male and female mongolian gerbils: Effects of hormonal manipulation

TIMPs in the prostates of male and female gerbils and evaluated the effects of testosterone on the expression of these enzymes. Ventral prostates from male gerbils that were either intact or had been castrated for 7 or 21 days, along with prostates from female gerbils that were either intact or had been treated with testosterone for 7 or 21 days, were submitted to histological, stereological and immunohistochemical analyses. Stereology of prostatic components showed significant alterations of tissue compartments in the ventral male prostate after castration, especially after 21 days, with a significant increase in stroma. Administration of testosterone led to disorganization in the female prostate, with a significant increase in collagen fibers and smooth muscle cells after 21 days, along with the development of epithelial lesions such as PINs. MMP-2 increased after 21 days of castration in males; however, the TIMP-2 immunoreaction for this group was weak or absent. In females, the expression of MMP-2 appeared to decrease after 7 days of treatment with testosterone, but after 21 days, both epithelium and stroma showed a stronger reaction for MMP-2 than the controls. The expression of TIMP-2 in the treated females was similar to its expression in the castrated males. We conclude that the distribution of MMPs and TIMPs in both male and female prostates is altered by androgen manipulation, but the mechanism of stromal regulation appears to be distinct between genders because both the lack of T in castrated males and the excess levels of T in treated females lead to the same effect.

High-sucrose effect on bone structure, hardness and biomechanics in an obesity model using Wistar male rats

Introduction: Excessive consumption of sugar-sweetened beverage is positively related to overweight. Despite the epidemic of childhood obesity, body mass can have a positive or negative effect on bone health. Material and methods: Wistar rats 8 weeks olds were randomly assigned to consume water (Control group, n = 10), sucrose 30% (HS group, n = 10) and water + sucrose 30% (WHS group, n = 14) for 8 weeks. All animals received standard laboratory chow ad libitum. Femur measurements included microhardness, bone mineral density (BMD) by DXA, mechanical compression test and microcomputed tomography (microCT) analysis. Results: We observed significant difference in final body weight in HS and WHS groups, significant increase in triacylglycerol/fructosamine in HS and WHS groups, significantly high BMD in WHS group, increased periosteal/endosteal cortical microhardness in WHS group. Compared with control, microCT parameters evidenced lower amount of connected trabecular bone, decreased bone volume, lower trabecular number with high trabecular separation in distal epiphysis in WHS animals. Conclusion: High-sucrose consumption causes obesity induced by a liquid diet with negative effects on cancellous bone.

Estrogen receptors alpha and beta in male and female gerbil prostates

The Mongolian gerbil (Meriones unguiculatus, Gerbilinae: Muridae) is useful for prostate studies, because both males and females spontaneously develop prostatic disorders with age. Estrogens regulate prostate homeostasis via two estrogen receptors, ER alpha (ESR1) and ER beta (ESR2), but the cellular distribution and regulation of these receptors in the gerbil prostate has not been described. Both receptors were localized by immunohistochemistry in the ventral prostate of intact male and female gerbils, in males 7 and 21 days after castration, and in females treated with testosterone for 7 and 21 days. In male and female adult gerbils, ER alpha was detected mainly in prostatic stromal cells, whereas ER beta was present mostly in secretory and basal cells. More ER alpha-positive stromal cells were found in females than in males, as was a reduction toward the male value in females treated with testosterone. Castration did not alter ER alpha expression. Testosterone was necessary for maintenance of ER beta in the male prostate epithelium: ER beta expression declined markedly in prostates of males older than 1 yr, and castration of 4-mo-old males caused a reduction in ER beta to levels seen in 1-yr-old males. Because ER beta is an antiproliferative receptor, its loss with age may predispose the aging gerbil to proliferative diseases of the prostate. © 2013 by the Society for the Study of Reproduction, Inc.

The reproductive cycle of the male sleep snake Sibynomorphus mikanii (Schlegel, 1837) from southeastern brazil

This study describes the male reproductive cycle of Sibynomorphus mikanii from southeastern Brazil considering macroscopic and microscopic variables. Spermatogenesis occurs during spring-summer (September-December) and spermiogenesis or maturation occurs in summer (December-February). The length and width of the kidney, the tubular diameter, and the epithelium height of the sexual segment of the kidney (SSK) are larger in summer-autumn (December-May). Histochemical reaction of the SSK [periodic acid-Schiff (PAS) and bromophenol blue (BB)] shows stronger results during summer-autumn, indicating an increase in the secretory activity of the granules. Testicular regression is observed in autumn and early winter (March-June) when a peak in the width of the ductus deferens occurs. The distal ductus deferens as well as the ampulla ductus deferentis exhibit secretory activities with positive reaction for PAS and BB. These results suggest that this secretion may nourish the spermatozoa while they are being stored in the ductus deferens. The increase in the Leydig cell nuclear diameter in association with SSK hypertrophy and the presence of sperm in the female indicate that the mating season occurs in autumn when testes begin to decrease their activity. The peak activity of Leydig cells and SSK exhibits an associated pattern with the mating season. However, spermatogenesis is dissociated of the copulation characterizing a complex reproductive cycle. At the individual level, S. mikanii males present a continuous cyclical reproductive pattern in the testes and kidneys (SSK), whereas at the populational level the reproductive pattern may be classified as seasonal semisynchronous. © 2012 Wiley Periodicals, Inc.