scholarly journals Acceptance threshold theory can explain occurrence of homosexual behaviour

2015 ◽  
Vol 11 (1) ◽  
pp. 20140603 ◽  
Author(s):  
Katharina C. Engel ◽  
Lisa Männer ◽  
Manfred Ayasse ◽  
Sandra Steiger

Same-sex sexual behaviour (SSB) has been documented in a wide range of animals, but its evolutionary causes are not well understood. Here, we investigated SSB in the light of Reeve's acceptance threshold theory. When recognition is not error-proof, the acceptance threshold used by males to recognize potential mating partners should be flexibly adjusted to maximize the fitness pay-off between the costs of erroneously accepting males and the benefits of accepting females. By manipulating male burying beetles' search time for females and their reproductive potential, we influenced their perceived costs of making an acceptance or rejection error. As predicted, when the costs of rejecting females increased, males exhibited more permissive discrimination decisions and showed high levels of SSB; when the costs of accepting males increased, males were more restrictive and showed low levels of SSB. Our results support the idea that in animal species, in which the recognition cues of females and males overlap to a certain degree, SSB is a consequence of an adaptive discrimination strategy to avoid the costs of making rejection errors.

2020 ◽  
pp. 3-4
Author(s):  
Oleg Yu. Chernykh ◽  
◽  
Vadim A. Bobrov ◽  
Sergey N. Zabashta ◽  
Roman A. Krivonos ◽  
...  

Rabies remains a constant threat to humanity in many parts of the world. At the same time, scientifically grounded antiepizootic measures should be based on the peculiarities of the regional epizootology of this zooanthroponosis. The authors studied the epizootological and statistical reporting data of the Kropotkin Regional Veterinary Laboratory, presented an analysis of the registration of rabies in animals in Krasnodar region. From the obtained data, it should be noted that despite the wide range of animals involved in the epizootic process of rabies infection in Krasnodar region, dogs, cats and foxes play a major role in the reservation and spread of infection, which account for 78.6. Of the total number of registered cases, 15.5% falls on foxes, that indicates the natural focus of the disease, along with the manifestation of the disease in an urban form. At the same time, stray and neglected dogs and cats, which occupy a significant place among the total number of sick animals, are also sources and spread of the infection. Thus farm animals (8.3% of the total number of infected animals) are a biological dead end for the infection. Isolated cases of the disease were noted in muskrat, donkey, raccoon, raccoon dog, marten, ferret and jackal. The authors also established the specific morbidity of various animal species with rabies infection, that is an important aspect in the development and implementation of antiepizootic measures complex


1976 ◽  
Vol 231 (5) ◽  
pp. 1415-1420 ◽  
Author(s):  
P Posner ◽  
EL Farrar ◽  
CR Lambert

The effect of catecholamines over a wide range of concentrations was studied on 42K uptake and efflux, as well as on spontaneous rate in canine cardiac Purkinje fibers. Low levels of catecholamines (less than 10(-10) M epinephrine; less than 10(-9) M norepinephrine) decreased automaticity. This negative chronotropic effect was blocked by phentolamine and mimicked by phenylephrine. These low levels of epinephrine and norepinephrine also inhibited 42K uptake by Purkinje fibers but had no effect on 42K efflux. The inhibition of 42K uptake was blocked by phentolamine and verapamil and mimicked by phenylephrine. The data indicate an alpha-receptor-mediated negative response of rate and 42K uptake to low levels of catecholamine. The end result is discussed in terms of a competitive increase in the influx of Ca2+ rather than Na+ and an indirect inhibition of the Na+-K+ pump.


1998 ◽  
Vol 46 (4) ◽  
pp. 421 ◽  
Author(s):  
Ross L. Goldingay ◽  
Susan M. Carthew

There has been a significant increase in the number of studies investigating plant breeding and mating systems over the past 10 years. The family Proteaceae, in particular, has dominated such research conducted in Australia. Thus it is now timely to present a critical review of the breeding and mating systems of the Australian Proteaceae. It is hoped that this will stimulate further research. The review covers key events between pollen deposition on stigmas through to fruit set. The genus Banksia, although not the most diverse of the family, has received a disproportionate amount of attention. It has featured in nine published studies of self-compatibility compared to 13 studies spanning the other 45 genera and has featured in eight genetic studies of the mating system compared to just two on other genera. Few studies have assessed the timing of stigma receptivity despite the intriguing situation in most Proteaceae of auto-deposition of self-pollen on or near stigmas at anthesis. Studies suggest that stigmas are not receptive until 0.5–4 days after anthesis. Banksia species appear to show low levels of self-compatibility although one subspecies shows high levels of selfing and evidence of selective fruit development. Self-compatibility may be more common in other genera, although a dearth of studies precludes generalisation. Assessment of mating systems indicates almost complete outcrossing for most species, lending support to the idea of selective fruit development. It is clear that many further studies of all topics are required but particularly across a wide range of genera because many have not been studied at all.


2021 ◽  
Vol 12 ◽  
Author(s):  
◽  
Aline Fugeray-Scarbel ◽  
Catherine Bastien ◽  
Mathilde Dupont-Nivet ◽  
Stéphane Lemarié

The present study is a transversal analysis of the interest in genomic selection for plant and animal species. It focuses on the arguments that may convince breeders to switch to genomic selection. The arguments are classified into three different “bricks.” The first brick considers the addition of genotyping to improve the accuracy of the prediction of breeding values. The second consists of saving costs and/or shortening the breeding cycle by replacing all or a portion of the phenotyping effort with genotyping. The third concerns population management to improve the choice of parents to either optimize crossbreeding or maintain genetic diversity. We analyse the relevance of these different bricks for a wide range of animal and plant species and sought to explain the differences between species according to their biological specificities and the organization of breeding programs.


2018 ◽  
Vol 17 (3) ◽  
pp. 395-413 ◽  
Author(s):  
Fayadh Hamed Alanazi

The purpose of this research was to explore and compare the ideas of Saudi boys and girls on animal species. Eighty-four children (comprising 42 boys and 42 girls), aged nine years, from four primary schools, participated in structured interviews to determine their ideas pertaining to taxonomic labels, namely ‘animal’, ‘fish’, ‘amphibian’, ‘reptile’, ‘bird’, ‘mammal’, and ‘insect’. The results demonstrated that Saudi children of both genders display a wide range of alternative conceptions; more specifically, the effect of gender was significant for all taxonomic vertebrate labels, suggesting that Saudi boys have better knowledge relating to animals than girls. However, generally, children did not have adequate forms of reasoning for biological classification. It was also found that none of the fourth graders thought of humans as animals due to the Islamic science worldview. Based on these findings, it is argued that science education, notably in an international context, should strive to incorporate an understanding of local values and beliefs. Keywords: early year's science, animal taxonomy, socio-cultural perspective, Islamic science worldview


2019 ◽  
Vol 7 (1) ◽  
pp. 62-67
Author(s):  
E. O. Ogumo ◽  
W. M. Muiru ◽  
J. W. Kimenju ◽  
D. M. Mukunya

Root-knot nematodes (RKN) (Meloidogyne spp) are a serious pest causing heavy economic losses in a wide range of agricultural crops. A trial was carried out to evaluate the effectiveness of various eco-friendly nematicides in the management of RKN affecting French bean. The field trial was carried out in two seasons with the following treatments; Rigel-G (salicylic acid), Phyto Protect (Sesame oil extract), Mytech (Paecilomyces lilacinus), Neemraj 0.3% (Azadirachtin), Vydate® (Oxamyl) as a positive control and an untreated control. Various rates; Rigel –G (2.5 ml/l), Phyto Protect (10 l/ha), Mytech (125 g/ha) Neemraj 0.3% (3L/ha) and Vydate® (6 l/ha) of treatments were administered and damage on plants was assessed based on galling indices, crop biomass and yield whereas nematode reproductive potential was assessed based on the J2 counts. There was no significant difference (P ≥ 0.05) in the nematode population densities and galling indices observed among the eco-friendly nematicides and the conventional nematicide (Vydate®). Eco-friendly nematicides had a significant (P ≤ 0.05) reduction of RKN J2 population densities compared to the negative control. The negative control had the highest mean of root-knot nematode densities (240 RKN/200 cc soil) and a galling index of 3.77 while Vydate and Neemraj had the lowest mean density (40 RKN/200 cc soil) in the first season. Similar results were observed in the second season with control having the highest RKN J2 population densities (285 RKN/200 cc soil) and a galling index of 3.89 and Vydate had the lowest (23 RKN/200 cc soil). The results of this study clearly indicate that eco-friendly nematicides can be fully adopted to suppress RKN in French beans as alternatives to conventional nematicides.


1989 ◽  
Vol 69 (4) ◽  
pp. 867-874 ◽  
Author(s):  
J. M. CAREFOOT ◽  
T. ENTZ ◽  
J. B. BOLE

Soft white wheat was grown on a clay loam soil for 2 yr with a wide range of soil nitrate (SN) (70–280 kg ha−1) and fertilizer nitrogen (FN) (0–400 kg ha−1) treatments The field experiment was designed to determine the slopes of the yield response curves to FN (δy/δFN) and to SN (δy/δSN), to determine how the ratio of (δy/δSN)/(δy/δFN), or marginal rate of substitution, is affected by FN, SN, and depth of SN and to determine if refinements to the current FN recommendations for irrigated soft white wheat are required. The δy/δFN values in both years were high at low levels of FN and SN but declined as FN and SN increased. The δy/δSN in 1985 when most SN was situated in the 0- to 30-cm soil layer was initially high (26.0) at low levels of SN but rapidly declined as SN increased. The δy/δSN in 1986, when most SN was situated in the 30- to 120-cm soil layer, was intially low (6.0) but increased as SN increased. Since the δy/δFN and δy/δSN values were sensitive to changes in FN and SN as well as the depth of SN the MRS values were variable in both years. The δy/δSN increased as SN increased when SN was situated in the 30- to 120-cm soil layer so there was only a small effect of depth of SN on FN recommendations. The FN at maximum profit occurred at a greater combined amount of SN and FN for the higher SN levels in both years. This preliminary field study suggested that fertilizer N recommendations could be improved by using an equation for predicting FN that considers a variable yield response to FN and SN, an interactive effect of FN and SN on yield, and an effect of depth of SN on yield. Key words: Soil nitrate, fertilizer nitrogen, soft white wheat, soil test N


2016 ◽  
Vol 60 (4) ◽  
pp. 417-421
Author(s):  
Muhammad Luqman Sohail ◽  
Muhammad Sarwar Khan ◽  
Muhammad Avais ◽  
Muhammad Yasir Zahoor ◽  
Irfan Khattak ◽  
...  

Abstract Introduction: Leptospirosis affects a wide range of mammals, humans, and even a few poikilothermic animal species. In Pakistan, serological studies of equine leptospirosis have reported a prevalence of over 40%, but no study has ever been conducted towards molecular detection of Leptospira in horses. Material and Methods: Blood samples from 128 horses were screened using ELISA and 41 positive samples were examined for the presence of leptospiral DNA using specific primers for 16S rRNA gene. Results: Out of 41 tested samples, 20 samples were found to be PCR-positive, revealing a fragment of 306 bp after gel electrophoresis. Sequencing and phylogenetic analysis of positive samples revealed circulation of pathogenic Leptospira spp. in Pakistani horses. No evidence of circulation of intermediate species was found in this study. Conclusion: This study reports the first molecular evidence of equine leptospirosis in Pakistan and lays ground for further research in this area. It also confirms the efficiency of 16S rRNA for the diagnosis of equine leptospirosis.


2008 ◽  
Vol 13 (1) ◽  
pp. 174-187 ◽  
Author(s):  
Melanie McCarry ◽  
Marianne Hester ◽  
Catherine Donovan

The article discusses the issues and problems that need to be addressed in the development of a comprehensive survey approach to explore same sex domestic violence in relationships involving individuals identifying as lesbian, gay male, bisexual, transgender or queer (LGBT&Q). It draws on the most detailed study to date in the UK comparing love and domestic violence in same-sex and heterosexual relationships. The survey methodology built on previous research, attempting in particular to overcome the limitations of earlier studies; and to produce data that could be compared with existing data on domestic violence in both heterosexual and LGBT&Q communities. The result was a questionnaire that reflected a wide range of abusive behaviours; examined impact of the violence alongside a quantification of particular acts; took into account experience of violence from a partner, as well as use of violence against that partner; and incorporated issues related to equality/inequality and dependency. The questionnaire was successfully distributed across the UK to provide a national ‘same sex community’ survey of problems in relationships and domestic violence.


1999 ◽  
Vol 29 (2) ◽  
pp. 299-308 ◽  
Author(s):  
K. S. KENDLER ◽  
M. C. NEALE ◽  
P. SULLIVAN ◽  
L. A. COREY ◽  
C. O. GARDNER ◽  
...  

Background. The development of drug dependence requires prior initiation. What is the relationship between the risk factors for initiation and dependence?Methods. Using smoking as a model addiction, we assessed smoking initiation (SI) and nicotine dependence (ND) by personal interview in 1898 female twins from the population-based Virginia Twin Registry. We developed a twin structural equation model that estimates the correlation between the liability to SI and the liability to ND, given SI.Results. The liabilities to SI and ND were substantially correlated but not identical. Heritable factors played an important aetiological role in SI and in ND. While the majority of genetic risk factors for ND were shared with SI, a distinct set of familial factors, which were probably partly genetic, solely influenced the risk for ND. SI was associated with low levels of education and religiosity, high levels of neuroticism and extroversion and a history of a wide range of psychiatric disorders. ND was associated with low levels of education, extroversion, mastery, and self-esteem, high levels of neuroticism and dependency and a history of mood and alcohol use disorders.Conclusions. The aetiological factors that influence SI and ND, while overlapping, are not perfectly correlated. One set of genetic factors plays a significant aetiological role in both SI and ND, while another set of familial factors, probably in part genetic, solely influences ND. Some risk factors for SI and ND impact similarly on both stages, some act at only one stage and others impact differently and even in opposite directions at the two stages. The pathway to substance dependence is complex and involves multiple genetic and environmental risk factors.


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