Small-male advantage in the territorial tropical butterflyHeliconius sara(Nymphalidae): a paradoxical strategy?

1998 ◽  
Vol 56 (3) ◽  
pp. 533-540 ◽  
Author(s):  
MALVA I.M HERNÁNDEZ ◽  
WOODRUFF W BENSON
Keyword(s):  
Small Male ◽  
Male Advantage ◽  
Small Male Advantage

Does recent experience affect large male advantage in a sequentially-mating fish?

Behaviour ◽  
2021 ◽  
pp. 1-29
Author(s):  
Emily R. Allen ◽  
Laura K. Weir
Keyword(s):  
Body Size ◽  
Mating Success ◽  
Mating Systems ◽  
Interactive Effect ◽  
Large Male ◽  
Recent Experience ◽  
Small Male ◽  
Male Body ◽  
Mating Experience ◽  
Male Advantage

Abstract In many mating systems, large male body size is associated with dominance in direct contests with rivals and females may exhibit preference for larger males. As such, body size is often positively associated with mating success. However, mating experience can influence the potential advantage of large body size through alterations in behaviour and depletion of sperm reserves. In Japanese medaka (Oryzias latipes), males mate with many females each day, and larger males mate more frequently than smaller males. In an observational experiment, we tested the following alternate predictions: (1) recent mating experience may enhance mating success through a carry-over effect of prior mating, whereby small experienced males gain an advantage over large inexperienced rivals in mating contests; or (2) recent mating experience decreases mating success through a reduction in fertilization due to sperm limitation, effectively dampening the large-male advantage against a small inexperienced rival. We examined the interactive effect of size and recent experience on mating behaviour and success. While mating contests were monopolized by large males, recent experience enhanced mating success, especially in small male winners. Experienced males courted more readily than those without recent experience, suggesting that recent prior mating enhances this behaviour. Furthermore, males who had copulated recently did not exhibit sperm depletion when in the presence of a competitor, nor did female behaviour indicate a preference for inexperienced males. This suggests that males can use sexual experience to increase their reproductive success in future mating situations, which may influence the action of sexual selection and alternative tactics in shaping mating systems.

scholarly journals Alternative mating tactics in the yellow dung fly: resolving mechanisms of small-male advantage off pasture

2014 ◽  
Vol 281 (1774) ◽  
pp. 20132164 ◽  
Author(s):  
Brian E. Gress ◽  
Ryan J. Waltzer ◽  
Stefan Lüpold ◽  
Elizabeth M. Droge-Young ◽  
Mollie K. Manier ◽  
...  
Keyword(s):  
Mating Success ◽  
Small Male ◽  
Alternative Mating Tactics ◽  
Mating Tactics ◽  
Male And Female ◽  
Scathophaga Stercoraria ◽  
Mating Propensity ◽  
Gravid Females ◽  
Small Male Advantage ◽  
Behavioural Mechanism

Recent work suggests that the yellow dung fly mating system may include alternative patroller–competitor mating tactics in which large males compete for gravid females on dung, whereas small, non-competitive males search for females at foraging sites. Small males obtain most matings off pasture, yet the behavioural mechanism(s) giving rise to this pattern are unknown. We investigated the male and female behaviours that determine mating success in this environment by conducting field mating experiments and found small males to benefit from several attributes specific to the off-pasture mating environment. First, small males from foraging sites exhibited higher mating propensity, indicating that large males away from dung may be depleted of energy and/or sperm. Second, small males were more discriminating, being significantly less likely to attempt with non-gravid females, which are absent on dung but common off pasture. Third, non-gravid females were generally more likely to actively struggle and reject mating attempts; however, such behaviours occurred disproportionately more often with large males. Female Scathophaga stercoraria thus appear to preferentially mate with small males when off pasture. These findings challenge assumptions about male–female interactions in systems with alternative mating tactics and reveal hidden processes that may influence selection patterns in the field.

Functional Maturity in Small Male Snow Crabs (Chionoecetes opilio)

1988 ◽  
Vol 45 (12) ◽  
pp. 2106-2109 ◽  
Author(s):  
G. P. Ennis ◽  
R. G. Hooper ◽  
D. M. Taylor
Keyword(s):  
Rapid Development ◽  
Carapace Width ◽  
Reproductive Potential ◽  
Snow Crab ◽  
Small Male ◽  
Chionoecetes Opilio ◽  
In Captivity ◽  
Breeding Migration ◽  
High Level ◽  
Snow Crabs

The mean size of male snow crabs (Chionoecetes opilio) in sexual pairs during the annual spring breeding migration to shallow water in Bonne Bay, Newfoundland, decreased from 118.6 mm carapace width (CW) in 1983 to 100.3 mm in 1987. This decrease is due to an increase in males <95 mm CW participating from 1.5% in 1983 to 32.3% in 1987. This change appears to have resulted from a reduced abundance of commercial size [Formula: see text] males due to a rapid development of an illegal fishery on this previously unfished population and, as a consequence, less competition between males for possession of females. The percentages of spermathecae containing new spermatophores for females paired with males <95 mm CW (67%) and those with males [Formula: see text] (79%) were not significantly different. We assumed that each female with new spermatophores had recently mated with the male with which it was paired. Observations on selected pairs in captivity showed that males <95 mm CW are capable of mating with both primiparous and muitiparous females. Our results indicate that small mature males can replace large males in breeding activity in a snow crab population. We conclude that in the male-only snow crab fishery in Atlantic Canada with a minimum legal size of 95 mm CW, population reproductive potential is maintained at a high level despite high exploitation rates on males [Formula: see text].

Serum uric acid levels in optic neuritis

2004 ◽  
Vol 10 (3) ◽  
pp. 278-280 ◽  
Author(s):  
C M Knapp ◽  
C S Constantinescu ◽  
J HY Tan ◽  
R McLean ◽  
G R Cherryman ◽  
...  
Keyword(s):  
Uric Acid ◽  
Optic Neuritis ◽  
Serum Uric Acid ◽  
Future Research ◽  
Control Group ◽  
Female Group ◽  
Small Male ◽  
Recent Onset ◽  
Male Cohort ◽  
The Difference

Uric acid, an antioxidant, is reduced in multiple sclerosis (MS). Patients with gout have a reduced incidence of MS. O ptic neuritis (O N), often the first manifestation of MS, is not known to be associated with reduced uric acid. Patients with recent onset of O N were investigated to determine whether uric acid levels were reduced at presentatio n. Twenty-o ne patients with O N were included, 17 females and 4 males. The mean (SD) serum uric acid in the O N female group was 184.4 (±55.1) mmol/L (range, 116- 309 mmol/L), whilst in the control group it was 235.2 (±50.2) mmol/L (range, 172- 381 mmol/L). The difference was statistically significant (x2 = 8.93, P = 0.003). In the small male cohort, mean (SD) serum uric acid was 305 (±52.1) mmol/L, whilst in the control group it was 328 (±80.4) mmol/L. These differences were not statistically significant. Reduced antioxidant reserve is possibly an early patho genic mechanism in inflammatory demyelination, and raises the possibility that low uric acid levels could be an indicator of disease activity. Since optic neuropathies of other causes were not investigated, future research needs to determine whether low uric acid represents a unique feature of optic neuritis or is seen in other optic neuropathies.

scholarly journals Male advantage observed for in vitro fertilization mouse embryos exhibiting early cleavage

2020 ◽  
Author(s):  
Yosuke Kawase ◽  
Takanori Tachibe ◽  
Nobuo Kamada ◽  
Kou‐ichi Jishage ◽  
Hiroyuki Watanabe ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Mouse Embryos ◽  
Early Cleavage ◽  
Vitro Fertilization ◽  
Male Advantage

†Bittacopsocus—a new bizarre genus of †Permopsocida (Insecta) from Burmese Cretaceous amber

Zootaxa ◽  
2019 ◽  
Vol 4576 (2) ◽  
pp. 357
Author(s):  
ROLF GEORG BEUTEL ◽  
JAKUB PROKOP ◽  
PATRICK MÜLLER ◽  
HANS POHL
Keyword(s):  
Feeding Habits ◽  
Predatory Behavior ◽  
Unusual Feature ◽  
Insect Species ◽  
Wing Venation ◽  
Small Male ◽  
Burmese Amber ◽  
Extinct Group

A new insect species (†Bittacopsocus megacephalus Beutel, Prokop, Müller et Pohl gen. et sp. nov.) is described, based on a single small male (ca. 2.5 mm) embedded in mid Cretaceous Burmese amber. The species shows some resemblance with the mecopteran family Bittacidae, mainly due to strongly elongated and thin legs. However, the structural affinities are apparently due to convergency. Different features, but especially the mouthparts and the pattern of wing venation, indicate that the species belongs to the extinct order †Permopsocida (?Archipsyllidae). However, it differs markedly from all species previously described in this extinct group. The very thin and strongly elongated legs are probably autapomorphic. A very unusual feature is the antenna with only seven segments and extremely elongated flagellomeres. The two pairs of wings are unusually narrow. M and CuA are basally fused. Proximal rows of spines, two series of closed cells, and a distinctly increased number of terminal branches of M are present in the forewings, in contrast to other archipsyllid genera. It is conceivable that Bittacopsocus megacephalus used its long legs to rest suspended in the vegetation like Bittacus. The head structures tentatively suggest predatory behavior but the feeding habits are unclarified yet. 

scholarly journals Neuropsychiatric symptoms as the main determinant of caregiver burden in Alzheimer's disease

2011 ◽  
Vol 5 (3) ◽  
pp. 203-208 ◽  
Author(s):  
Renata Kochhann ◽  
Ericksen Borba ◽  
Maria Otília Cerveira ◽  
Diego Onyszko ◽  
Alyne de Jesus ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Caregiver Burden ◽  
Functional Capacity ◽  
Neuropsychiatric Symptoms ◽  
Primary Caregivers ◽  
Sociodemographic Characteristics ◽  
Small Male ◽  
Main Determinant ◽  
Severity Of Dementia

Abstract Caregiver burden is common in Alzheimer's disease (AD), decreasing the quality of life among caregivers and patients. Projections of aging and aging-related diseases such as AD in developing countries justify additional data about this issue because people living in these countries have shown similarly high levels of caregiver strain as in the developed world. Objective: The aim of this study was to analyze the association of AD caregivers' burden with patients' neuropsychiatric symptoms (NPS), cognitive status, severity of dementia, functional capacity, caregiver sociodemographic characteristics, and the characteristics of care provided by caregivers. Methods: A cross-sectional study was conducted in a sample of 39 consecutive AD patients and their primary caregivers. NPS were evaluated using the Neuropsychiatric Inventory (NPI). Severity of dementia was assessed with the Clinical Dementia Rating (CDR) scale. Functional capacity was assessed using the Katz and Lawton scales. The burden level was rated using the Burden Interview (BI). Sociodemographic characteristics of caregivers and the characteristics of care provided by them were evaluated. The Mann-Whitney U-test, Kruskal-Wallis test and Spearman's rho coefficient were performed. Results: The BI had a moderate correlation with NPI intensity (rho=0.563), p<001. Female caregivers reported a greater level of burden (p=0.031) than male caregivers. The other variables were not significantly associated to caregiver burden. Conclusion: NPS were the main determinant of burden in primary caregivers of AD patients. This result underscores the need for prevention and treatment of these symptoms. Sex also had an effect on caregiver burden, but the small male sample in this study precludes the generalization of this finding.

scholarly journals The relationship between fleas and small mammals in households of the Western Yunnan Province, China

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jia-Xiang Yin ◽  
Xiao-Ou Cheng ◽  
Yun-Yan Luo ◽  
Qiu-Fang Zhao ◽  
Zhao-Fei Wei ◽  
...  
Keyword(s):  
Small Mammals ◽  
Host Species ◽  
Yunnan Province ◽  
Negative Binomial ◽  
Negative Binomial Regression ◽  
Strong Relationship ◽  
Negative Binomial Regression Model ◽  
Small Male ◽  
Western Yunnan ◽  
The Relationship

Abstract The Yunnan province has one of the most serious outbreaks of the plague epidemic in China. Small mammals and fleas are risk factors for the occurrence of plague in commensal plague foci. Understanding the relationship between fleas and small mammals will help control fleas and prevent the onset of the plague. Four hundred and twenty-one small mammals, belonging to 9 species, were captured. Of these, 170 small mammals (40.4%) were found infested with fleas. A total of 992 parasitic fleas (including 5 species) were collected. The number of Leptopsylla segnis and Xenopsylla cheopis accounted for 91.03% (903/992). The final multiple hurdle negative binomial regression model showed that when compared with Rattus tanezumi, the probability of flea infestation with Mus musculus as well as other host species decreased by 58% and 99%, respectively, while the number of flea infestations of the other host species increased by 4.71 folds. The probability of flea prevalence in adult hosts increased by 74%, while the number of fleas decreased by 76%. The number of flea infestations in small male mammals increased by 62%. The number of fleas in small mammals weighing more than 59 g has been multiplied by about 4. R. tanezumi is the predominant species in households in the west Yunnan province, while L.segnis and X. cheopis were dominant parasitic fleas. There is a strong relationship between the abundance of fleas and the characteristics of small mammals (e.g. Species, age, sex, and body weight).

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