scholarly journals Effects of Male Age and Female Presence on Male Associations in a Large, Polygynous Mammal in Southern India: The Asian Elephant

2021 ◽  
Vol 9 ◽  
Author(s):  
P. Keerthipriya ◽  
S. Nandini ◽  
T. N. C. Vidya
Keyword(s):  
Social Learning ◽  
Social Organization ◽  
Asian Elephant ◽  
Southern India ◽  
Older Individuals ◽  
Adult Males ◽  
Young Males ◽  
Male Age ◽  
Study Population ◽  
Female Presence

We present a detailed study of male associations in the Asian elephant, using 6 years of data on identified, non-musth males. Adult males spent greater proportions of their time solitarily than in mixed-sex or in all-male groups. Old (over 30 years) males were sighted more frequently with their age-peers and less frequently with young (15–30 years) males than expected at random in all-male groups. Young males were not sighted more frequently with old males than with young males, and did not disproportionately initiate associations with old males. These results suggest that male associations, in the absence of females, may allow for old non-musth males to test strengths against age-peers. Social learning from older individuals did not seem to be important in male associations, unlike that observed in the African savannah elephant. We also found a constraint on the sizes of all-male groups, similar to that seen in female groups in our study population, and all-male groups were rarer and smaller than those in African savannah elephant. Although male associations were weak, most males had a significant top associate, with whom their association was the strongest, in female absence. In mixed-sex groups, male associations occurred at random, suggesting that males were tracking female groups independently. Differences in male social organization from that of the related African savannah elephant that occupies a similar niche possibly arise from differences in ecology.

scholarly journals Effects of male age and female presence on male associations in a large, polygynous mammal in southern India

2018 ◽  
Author(s):  
P. Keerthipriya ◽  
S. Nandini ◽  
T.N.C. Vidya
Keyword(s):  
Social Learning ◽  
Ecological Factors ◽  
Social Organisation ◽  
Southern India ◽  
Older Individuals ◽  
Adult Males ◽  
Young Males ◽  
Male Group ◽  
Study Population ◽  
Female Presence

AbstractWe present a detailed study of male associations in a roving species, the Asian elephant, using six years of data on identified, nonmusth males. Adult males spent greater proportions of their time solitarily than in mixed-sex or in all-male groups. Old (over 30 years) males were sighted more frequently with their age-peers and less frequently with young (15-30 years) males than expected at random in all-male groups. Young males were not sighted more frequently with old males than with young males, and did not disproportionately initiate associations with old males. These results suggest that male associations, in the absence of females, primarily allow for old nonmusth males to test strengths against age-peers. Social learning from older individuals did not seem to be important in male associations, unlike that observed in African savannah elephants. We also found a constraint on the sizes of all-male groups, similar to that seen in female groups in our study population, and with male group sizes being smaller than that of African savannah elephants. However, most males had a significant top associate in female absence. In mixed-sex groups, male associations occurred at random, suggesting that males were tracking female groups independently. Thus, we find some differences in male social organisation compared to the phylogenetically related African savannah elephant that occupies a similar niche, and suggest that ecological factors might have shaped the differences in these male societies.

Musth and its effects on male–male and male–female associations in Asian elephants

2019 ◽  
Vol 101 (1) ◽  
pp. 259-270 ◽  
Author(s):  
P Keerthipriya ◽  
S Nandini ◽  
Hansraj Gautam ◽  
T Revathe ◽  
T N C Vidya
Keyword(s):  
Southern India ◽  
Adult Males ◽  
Age Classes ◽  
Asian Elephants ◽  
Young Males ◽  
Gain Access ◽  
Older Males ◽  
Term Data

Abstract Musth is an annual, asynchronous, rut-like phenomenon observed in male elephants. We examined whether musth is a roving strategy, and whether musth provides a temporary advantage to young males through increased access to female groups. We collected long-term data on the musth status, associations, and locations of male elephants in the Kabini population in southern India. We sighted older males more frequently in musth than younger males. We found a greater turnover of musth than non-musth males in the study area, suggesting that musth is a roving strategy, enabling males to travel widely and away from their non-musth range. Contrary to our expectation, young (15–30 years old) males spent a smaller proportion of their musth time than their non-musth time associating with females, and associated with similarly sized female groups irrespective of musth status. Old (> 30 years old) males spent only a slightly higher proportion of their musth time than non-musth time with female groups, but associated with larger female groups during musth. Although old males in musth associated with young non-musth males more often in the presence, than in the absence, of females, young males in musth were never sighted with old non-musth males in the presence of females. Therefore, the payoff from musth, as a strategy to gain access to females, was age-specific; musth in old males allowed for increased association with females, while musth in young males restricted their access to females. There was no spatial avoidance between musth and non-musth adult males at scales larger than immediate associations. Our results suggest that musth seems to be primarily a roving strategy for old males to find and associate with females and not a strategy for young males to gain a temporary advantage over old males, within the broad age-classes that we examined.

scholarly journals An experimental test to separate the effects of male age and mating history on female mate choice

2020 ◽  
Vol 31 (6) ◽  
pp. 1353-1360 ◽  
Author(s):  
Upama Aich ◽  
Timothee Bonnet ◽  
Rebecca J Fox ◽  
Michael D Jennions
Keyword(s):  
Female Choice ◽  
Female Mate Choice ◽  
Adult Males ◽  
Visual Contact ◽  
Young Males ◽  
Male Age ◽  
Offspring Fitness ◽  
Mating History ◽  
Association Time ◽  
Older Males

Abstract Should females prefer older males as mates? Male survival to old age might indicate the presence of fitness-enhancing genes that increase offspring fitness. However, many correlational studies show that mating with older males can lower female fecundity and even reduce offspring fitness due to epigenetic or germline mutation effects. One problem in quantifying female choice based on male age is that age is usually confounded with mating history. This begs a question: Do females choose males based on their age or their mating history? The answer requires an experimental approach, but few such studies exist. Here, we test if experimentally induced variation in the mating history of old and young males (12-week difference in postmaturity age) affects female choice in the eastern mosquitofish (Gambusia holbrooki). To vary mating history, adult males were either allowed to freely mate with females for 3 weeks or they only had visual contact with females. Immediately thereafter, we ran four-choice mating trials, using association time, to test the effects of male age and mating history (2 × 2 design) on male attractiveness. Females did not show a clear preference for males based on either characteristic. This was not due to a lack of female choice: females spent significantly more time with larger males. In addition, female choice was significantly repeatable across four trials: twice as a virgin and twice as a nonvirgin. Finally, female mating status (virgin or nonvirgin) did not affect her choice of mate, although virgin females spent significantly more time associating with test males.

scholarly journals Correlates and Treatment Outcome of Risky Sexual Behaviour in Young Males with ADHD and Comorbid Alcohol Use Disorder: A Prospective Study

2019 ◽  
Vol 1 (1) ◽  
pp. 62-69
Author(s):  
Shankar Kumar ◽  
Yamini Devendran ◽  
Madhumitha N. S. ◽  
Javagal Amith Thejas
Keyword(s):  
Sexual Behavior ◽  
Alcohol Use ◽  
Perceived Stress ◽  
Risky Sexual Behavior ◽  
Alcohol Use Disorder ◽  
Self Report ◽  
Adult Males ◽  
Young Males ◽  
Severity Scores ◽  
Inattention And Hyperactivity

Background: Attention-deficit/hyperactivity disorder (ADHD) is associated with risky sexual behavior (RSB). Alcohol use and high perceived stress in young adulthood contributes to this association. Previous studies have not found methylphenidate to reduce RSB in ADHD, as the population had comorbidities such as mood disorders and antisocial personality disorder. We aimed to study (a) the association of RSB with ADHD and severity of alcohol use among adolescents and young adult males with ADHD who had comorbid alcohol use disorder and (b) the effect of treatment of ADHD using methylphenidate on RSB in this population at 3- and 6-month follow-ups. Methodology: The study had 31 participants who were selected by screening for RSBs using the sexual behavior section of the HIV Risk-taking Behavior Scale (HRBS) manual among a cohort of individuals with ADHD and early onset alcohol use. These individuals were also administered WHO ADHD self-report scale (ASRS), alcohol-use disorders identification test (AUDIT), perceived stress scale (PSS), and HRBS-sexual behavior section. They were then treated with methylphenidate and these assessments were repeated at 3 and 6 months. Results: Those having ADHD with RSB had higher total ADHD score ( P = .007) and inattention score ( p = .0001) than those without RSB. There was a significant correlation between the ADHD total score with alcohol-use severity ( r = 0.47), with RSB ( r = 0.34), and ADHD hyperactivity scores with alcohol-use severity ( r = 0.49) and with RSB ( r = 0.34). There was also a significant reduction of ADHD total, inattention and hyperactivity scores, alcohol-use severity scores, RSB and perceived stress scores with use of methylphenidate at 3- and 6-month follow-ups. Multiple logistic regression predicted reduction in ADHD total scores to reduce RSB (odds ratio [OR] = 1.26, P = .01). Conclusion: RSB was associated with severity of ADHD and alcohol use. Methylphenidate not only reduced ADHD severity but also alcohol-use severity and RSB, whose reduction was predicted by reduction in ADHD severity.

scholarly journals Relating Reactive and Proactive Aggression to Trait Driving Anger in Young and Adult Males: A Pilot Study Using Explicit and Implicit Measures

2021 ◽  
Vol 13 (4) ◽  
pp. 1850
Author(s):  
Veerle Ross ◽  
Nora Reinolsmann ◽  
Jill Lobbestael ◽  
Chantal Timmermans ◽  
Tom Brijs ◽  
...  
Keyword(s):  
Pilot Study ◽  
Cognitive Biases ◽  
Young Male ◽  
Proactive Aggression ◽  
Implicit Measures ◽  
Adult Males ◽  
Young Males ◽  
Targeted Interventions ◽  
Driving Anger ◽  
Reactive And Proactive Aggression

Driving anger and aggressive driving are main contributors to crashes, especially among young males. Trait driving anger is context-specific and unique from other forms of anger. It is necessary to understand the mechanisms of trait driving anger to develop targeted interventions. Although literature conceptually distinguished reactive and proactive aggression, this distinction is uncommon in driving research. Similar, cognitive biases related to driving anger, measured by a combination of explicit and implicit measures, received little attention. This pilot study related explicit and implicit measures associated with reactive and proactive aggression to trait driving anger, while considering age. The sample consisted of 42 male drivers. The implicit measures included a self-aggression association (i.e., Single-Target Implicit Association Test) and an attentional aggression bias (i.e., Emotional Stroop Task). Reactive aggression related positively with trait driving anger. Moreover, a self-aggression association negatively related to trait driving anger. Finally, an interaction effect for age suggested that only in young male drivers, higher proactive aggression related to lower trait driving anger. These preliminary results motivate further attention to the combination of explicit and implicit measures related to reactive and proactive aggression in trait driving anger research.

Dispersal patterns in a regional koala population in south-east Queensland

2003 ◽  
Vol 30 (3) ◽  
pp. 281 ◽  
Author(s):  
David S. Dique ◽  
Jim Thompson ◽  
Harriet J. Preece ◽  
Deidré L. de Villiers ◽  
Frank N. Carrick
Keyword(s):  
Urban Areas ◽  
Home Ranges ◽  
Adult Males ◽  
Dispersal Patterns ◽  
Young Males ◽  
Straight Line ◽  
The Social ◽  
Straight Line Distance ◽  
Males And Females ◽  
Natal Home

Koala dispersal was investigated as part of a detailed ecological study of a nationally significant koala population located 20 km south-east of Brisbane, Queensland. From 1996 to 2000, 195 koalas from three sites were captured and fitted with radio-collars. A total of 40 koalas (23 males and 17 females) dispersed from these sites. Most (93%) dispersing individuals were 20–36 months of age. Three adult females (more than 36 months old) dispersed and no adult males dispersed during the study. A significantly higher proportion of young males dispersed than females. Dispersal occurred between June and December, with most dispersal of males commencing in July and August and that of females commencing between September and November prior to, and early in, the annual breeding season. The mean straight-line distance between the natal and breeding home ranges for males and females was similar and was measured at 3.5 km (range 1.1–9.7 km) and 3.4 km (range 0.3–10.6 km) respectively. Dispersing males and females tended to successfully disperse south and west of their natal home ranges and were generally unable to successfully disperse to urban areas within the study area, as a high proportion of the mortality of dispersing koalas was associated with attacks by domestic dogs and with collisions with vehicles on roads. Information from other studies indicates that most young koalas disperse from their natal areas. It is likely that the social behaviour and mating systems of koala populations provide mechanisms for young koalas to disperse. The potential role of dispersal in the dynamics of regional koala populations is discussed.

scholarly journals Male age, host effects and the weak expression or non-expression of cytoplasmic incompatibility in Drosophila strains infected by maternally transmitted Wolbachia

2002 ◽  
Vol 80 (2) ◽  
pp. 79-87 ◽  
Author(s):  
K. TRACY REYNOLDS ◽  
ARY A. HOFFMANN
Keyword(s):  
Drosophila Melanogaster ◽  
Host Species ◽  
Cytoplasmic Incompatibility ◽  
Strain Differences ◽  
Large Impact ◽  
Young Males ◽  
Male Age ◽  
Weak Expression ◽  
Host Effects

In Drosophila melanogaster, the maternally inherited endocellular microbe Wolbachia causes cytoplasmic incompatibility (CI) in crosses between infected males and uninfected females. CI results in a reduction in the number of eggs that hatch. The level of CI expression in this species has been reported as varying from partial (a few eggs fail to hatch) to nonexistent (all eggs hatch). We show that male age in this host species has a large impact on the level of CI exhibited and explains much of this variability. Strong CI is apparent when young males are used in crosses. CI declines rapidly with male age, particularly when males are repeatedly mated. Wolbachia from a Canton S line that was previously reported as not causing CI does in fact induce CI when young males are used in crosses, albeit at a weaker level than in other D. melanogaster strains. The strain differences in CI expression are due to host background effects rather than differences in Wolbachia strains. These results highlight the importance of undertaking crosses with a range of male ages and nuclear backgrounds before ascribing particular host phenotypes to Wolbachia strains.

scholarly journals Some Evidences on Effect of Intake Aguamiel (Agave sap)

2016 ◽  
Vol 5 (1) ◽  
pp. 49
Author(s):  
A. Carrillo-López ◽  
H. Silos-Espino ◽  
S. Flores-Benitez ◽  
E. A. Espinoza-Sánchez ◽  
J. R. Ornelas-Tavares ◽  
...  
Keyword(s):  
Blood Cell ◽  
Total Cholesterol ◽  
Cell Count ◽  
Adult Males ◽  
Blood Cell Count ◽  
Folk Belief ◽  
Young Males ◽  
Cholesterol Levels ◽  
Normal Ranges ◽  
Related Proteins

Honeywater or aguamiel (Agave sap) has been consumed by Mexican population since pre-columbian times. Although, it has been claimed by folk belief that aguamiel possesses some medicinal properties, scientific studies on its effect on human health have not been well documented. The behavior of blood components in nine volunteers (two young males, three adult females and four adult males) after aguamiel consumption (250 mL every three days during a period of 35 days) was analyzed. It was found that, serum red blood cell count, serum white blood cell count, platelet count, minerals (Zn, Mg and Fe) and iron-related proteins (ferritin and transferrin) levels were not negatively affected because of all of these blood indicators ranged within normal reference values. However, this study showed that aguamiel presented a specific functional effect since hypercholesterolemic adult males showed normal levels of serum total cholesterol after aguamiel consumption, whereas total cholesterol levels were kept in normal ranges after aguamiel consumption for normocholesterolemic subjects. Furthermore, aguamiel consumption did not cause hyperglycemia in any of the tested groups.

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