Dominance at a Fungus Mating Type Locus

THE action of the two alleles which control mating type in fungi with bipolar heterothallism is uncertain. A diffusible oligopeptide, produced by the α mating type of Saccharomyces cerevisiae, blocks division and induces copulatory processes in cells of a mating type^2,3 and in some yeasts the mating type locus may be induced to mutate by other genes in the same cell^4,5. These observations in yeast, however, may not be representative of the other fungi with bipolar heterothallism².     

Assortative Mating

Abstract

Theories of mate selection and the effects of assortative mating are reviewed, including differences in the basic theoretical orientations of the social and biological sciences with respect to human evolution and assortative mating. Topics discussed include evolution in parallel and interaction, terminology of nonrandom mate selection, theories of mate choice, social stratification and class endogamy, and suggestions for future research.     

Dominance and Mating in a Communal Polygynandrous Bird: Cooperation or Indifference towards Mating Competitors?

The effect of dominance on the mating behaviour of both females and males was investigated for the communally breeding pukeko (Porphyrio porphyrio melanotus). Pukeko are polygynandrous with most groups consisting of three to 7 breeding males and one or two breeding females that lay eggs in a single nest. Linear dominance hierarchies are well established within breeding groups. Alpha females were involved in more copulations than beta females, but this difference did not appear to be a result of dominance status. There was also no evidence of egg tossing or egg destruction by breeding females. There was no positive correspondence between dominance rank of males and their frequency of sexual activity or copulations during the prelaying or laying periods. Dominants did interrupt matings by subordinates, but both qualitative and quantitative analyses of behaviour found no evidence of mate guarding. Furthermore dominants were no more likely to interrupt a copulation involving a subordinate male than they were to passively observe it or not react at all. This led us to suggest that males tended to behave indifferently toward mating competitors. As a result, multiple paternity is predicted to be high in pukeko groups. We also question the standard interpretation that males are behaving cooperatively in communal groups rather than coactively.     

Mating duration and Frequency in a Pine Sawfly

Newly emerged females of the European pine sawfly, Neodiprion sertifer Geoffroy (Hymenoptera: Diprionidae), were placed on pine twigs in the field and their behavior was recorded. Twenty to 25% of the females attracted wild males and mated on the day of release. One-third to one-half of these females remained and oviposited, while the rest disappeared from their twigs after mating. The mating frequency peaked at noon, and on average the mating lasted for 19 ± 13 (SD) min. Eleven to 30% of the females that remained on their twigs after mating remated, occasionally up to five times. Most released females disappeared from their twigs on the first day. Disappearances included both predation and dispersal. Only a few dispersals >5 m were recorded, because the sawflies were difficult to follow during flight. By color marking, dispersal up to 20 m was recorded.     

Mating systems among European passerines: a review

A review of the mating systems of 122 relatively well-studied European passerines (out of 172 species) is given. Of all species, 39% are polygynous and 25 of the 47 polygynous species are regular polygynists exceeding the limit of 5% polygyny in a population. Of 46 polygynous species, 63% are monoterritorial (having a maximum of one territory), the rest being polyterritorial (having a maximum of more than one territory). Regular polygyny is more common among polyterritorial passerines. Polygyny is frequently found among species breeding in open habitats (marshes, meadows, pastures and low shrubs). Polyterritorial species tend to have tropical winter quarters more frequently than monoterritorial species do. Colonial breeding is absent from the polyterritorial group. Monogamous male passerines participate more frequently in feeding nestlings than their polygynous counterparts do. Regular polygynists tend to be sexually dimorphic in plumage more often than infrequent polygynous passerines, and polyterritorial passerines similarly tend to be plumage dimorphic more often than monoterritorial species. Sexual size dimorphism was more pronounced in monoterritorial than in polyterritorial passerines.     

Mating system as a barrier to gene flow

Understanding mating system as one of reproductive isolating barriers remains important although this barrier is classified in a different sense from behavioral, ecological, and mechanical isolating barriers. Selfing enhances incipient speciation while outcrossing facilitates species integrity. Here, I study how mating system affects gene exchanges between genetically diverging species in a hybrid zone. Results show that a predominant selfing species has a greater barrier to selective gene flow than does a predominant outcrossing species. Barrier to neutral gene flow convexly changes with the selfing rate due to linkage disequilibrium, with a maximum at around intermediate selfing rate. Asymmetric transient or steady‐state barriers to neutral gene flow occur between two sides of a hybrid zone when the neutral gene is affected by its linked selective gene whose alternative alleles are adaptive to heterogeneous habitats. Selfing interacts with both a physical barrier and a density‐dependent ecological regulation (a logarithmic model) to strengthen the barriers to neutral and selective gene flow. This theory helps to interpret incipient speciation driven by selfing or to explain the asymmetric gene flow or unequal genomic mixtures between closely related species caused by their asymmetric mating systems in natural hybrid zones.     

Territory Area as a Determinant of Mating Systems

Territoriality is an integral part of breeding behavior in manyanimals. Because the reproductive success of territorial malesis often limited by access to females, breeding males shouldbehave as "area maximizers" when the basis of female choiceis either the abundance of resources within the territory orterritory area per se. Being reproductively more limited byenergy, territorial females should be "energy maximizers." Aseries of simple analytical models of territory area for suchforagers is developed to explore how changes in local food productionand/or local competitor density affect both the probabilityof a territorial male securing more than one mate (polygyny)and the probability of his and his mates' reproductive successincreasing. Two cases are modeled (only males territorial vs.both sexes territorial), each for various sets of assumptionsregarding interactions between food production, feeding efficiency,and competitor density. Concurrent responses in territory area,territory food reserves, net energy gain, and time budgetingprovide testable sets of predictions for each scenario. Whereonly males are territorial (Case I), changes in food productioncan have different (indeed, opposite) effects upon an individualmale's probability of becoming polygynous, depending upon whetherthe basis of female choice is the abundance of food within theterritory or another factor positively correlated with territoryarea. Increases in competitor density usually decrease the probabilityof polygyny regardless of the basis of female choice. Whereboth sexes are territorial and territories overlap intersexually(Case II), the mating system becomes a function of the numberof female territories within each male's territory, which varieswith the ratio of male to female territory areas. In this case,the probability of polygyny occurring will increase if foodproduction for both sexes increases without concurrent increasesin competitor density, and will decrease if competitor densityfor both sexes increases without concurrent increases in feedingefficiency. Few data are presently available to test eitherthese general predictions or numerous sets of secondary predictionstabulated in the text. Available evidence is largely consistentwith the models, but mostly circumstantial. This is becausethe predictions of these and other models of territory areaare strongly assumption dependent, and few published studieshave investigated these assumptions. These analyses demonstratethat to accurately assess the mechanisms by which environmentalfactors affect territory area, and thus mating systems, testsof the underlying assumptions of models are essential.     

Mating system shifts a species’ range

Understanding the ecological and evolutionary mechanisms that shape a species’ range is an important goal in evolutionary biology. Evidence indicates that mating system is an effective predictor of the global range of native species or naturalized alien plants, but the mechanisms underlying this predictability are not elaborated. Here, we develop a theoretical model to account for the ranges of plants under different mating systems based on migration‐selection processes (an idea proposed by Haldane). The model includes alternation of gametophyte and sporophyte generations in one life cycle and the dispersal of haploid pollen and diploid seeds as vectors for gene flow. We show that the interaction between selfing rates and gametophytic selection determines the role of mating system in shaping a species’ range. Selfing restricts the species’ range under gametophytic selection in nonrandom mating systems, but expands the species’ range under the absence of gametophytic selection in any mating system. Gametophytic selection slightly restricts the species’ range in random mating. Both logarithmic and logistic models of population demography yield similar conclusions in the case of fixed or evolving genetic variance. The theory also helps to explain a broader relationship between mating system and range size following biological invasion or plant naturalization.     

Mating success in lekking males: a meta-analysis

Traits that are correlated with mating success are likely tobe subject to sexual selection. In lekking species, a male'smating success can be estimated as the number of females thathe copulates with. Earlier reviews of sexual selection in lekkingspecies have been inconclusive, suggesting that different traitsmay be important in different species. To obtain a more completeunderstanding of the outcome of sexual selection in this matingsystem, we performed a meta-analysis in which we combined theresults from different studies across a wide variety of taxa.Our aim was to synthesize available information about correlatesof male mating success in lekking species. We found that behavioraltraits such as male display activit aggression rate, and lekattendance were positively correlated with male mating success.Further, territory position was negatively correlated with malemating success, such that males with territories close to thegeometric center of the leks had higher mating success thanother males. The size of "extravagant" traits, such as birdstails and ungulate antlers, and age were positively correlatedwith male mating success. Male morphology (measure of body size)and territory size showed small effects on male mating success.Our results confirm some of the suggestions put forward by earlierreviews but add more rigor to the condusions drawn. Part ofthe variation across studies still remain unaccounted for. Furtherstudies are needed to perform proper meta-analyses that cantake factors like phylogeny and sexual dimorphism into account.     

子囊菌交配型位点与交配型基因研究进展

有性生殖是真菌的生殖方式之一,是真菌遗传重组的重要驱动力。交配型(mating-type,MAT)位点控制真菌性别,在有性生殖过程中起决定性作用。不同类型真菌MAT位点的基因组成、排列方式和编码蛋白不尽相同。近年来,MAT位点和MAT基因的功能与调控网络研究进展较快。本文对子囊菌交配型位点的基因组成及分布、MAT基因的功能、MAT位点与有性生殖调控通路的关系等进行了综述。     

Female Fitness Optimum at Intermediate Mating Rates under Traumatic Mating

Traumatic mating behaviors often bear signatures of sexual conflict and are then typically considered a male strategy to circumvent female choice mechanisms. In an extravagant mating ritual, the hermaphroditic sea slug Siphopteron quadrispinosum pierces the integument of their mating partners with a syringe-like penile stylet that injects prostate fluids. Traumatic injection is followed by the insertion of a spiny penis into the partner's gonopore to transfer sperm. Despite traumatic mating, field mating rates exceed those required for female fertilization insurance, possibly because costs imposed on females are balanced by direct or indirect benefits of multiple sperm receipt. To test this idea, we exposed animals to a relevant range of mating opportunity regimes and assessed the effects on mating behavior and proxies of female fitness. We find penis intromission duration to decrease with mating rates, and a female fecundity maximum at intermediate mating rates. The latter finding indicates that benefits beyond fertilization insurance can make higher mating rates also beneficial from a female perspective in this traumatically mating species.     

动物的婚配制度

婚配制度是动物种群个体为获得配偶普遍采取的一种行为策略。一般分为单配制、一雄多雌制、一雌多雄制和混交制。作为动物的一种进化稳定对策,婚配制度又具有一定的可塑性,有时可以逆转,有时又是兼性的。配偶外交配主要存在于单配制物种中特别是单配制鸟类中。其发现表明通过观察个体间联系来确定的“社会性婚配制度”和通过个体实际上的交配对象来描述的“遗传性婚配制度”有可能存在差异。婚配制度影响有害动物的不育控制,在存在繁殖性竞争的情况下,对单配制和一雄多雌制而言,不育效果最佳。     

Mating Type Interaction in Closterium peracerosum-strigosum-littorale: Mating Induced Protoplast Release

Mating type interaction between heterothallic strains of Closteriumperacerosum-strigosum- littorale was studied during the conjugationprocess. When vegetative cells of opposite mating types weremixed under the nitrogen depleted mating conditions, the formationof conjugation-papilla and the release of the protoplast withinthe distended papilla from the gametangial cell were shown inboth the paired and unpaired cells. The protoplasts of pairedcells fused to form zygotes, while those of unpaired cells broke.When cells were mixed at a ratio of around 5 to 3 (mating typeplus to mating type minus), sexual activation occurred at thehighest frequency. Mixing at a ratio of 1 to 3, however, inducedthe highest frequency of disrupted cells. Mating type plus cellswere found to be broken specifically when direct contact withmating type minus cells was prevented. This disruption seemedto be mediated by a factor secreted from mating type minus cells. (Received March 20, 1981; Accepted August 18, 1981)     

Altered Oceanic pH Impairs Mating Propensity in a Pipefish

Anthropogenic disturbance is currently altering the environment of terrestrial as well as aquatic organisms. Those changes affect a variety of animal behaviours, which in turn may cause changes in species interactions, population dynamics and evolutionary processes. In marine ecosystems, nutrient enrichment may elevate pH, while it is reduced by carbon dioxide‐induced ocean acidification. These two processes are not expected to balance one another but rather to affect the environment at different times and scales. We here show experimentally that an increase in water pH has a negative effect on mating propensity in the broad‐nosed pipefish Syngnathus typhle, whereas lowered pH did not elicit the same detrimental effect. This study provides, to our knowledge, the first evidence that mating propensity is impaired by an increase in pH, suggesting that anthropogenic nutrient enrichment in aquatic ecosystems may change the processes of sexual selection and population dynamics solely on the basis of altered water pH.     

Non-Random Mating in a Wild Radish, Raphanus sativus

Abstract When mating is non-random among several, compatible donors, the fitness of pollen donors, maternal plants, and offspring may be affected. Although this process may be important, it is much less studied than other forms of non-random mating such as incompatibility and avoidance of inbreeding. Therefore, the amount and consequences of non-random mating were investigated in greenhouse studies with wild radish, Raphanus sativus . Six compatible donors differed in the number, position, and weight of seeds sired, so mating was non-random at the level of mate identity. Mate number also affected mating patterns; fruits with more fathers were allocated more resources. This keeps mate number per fruit high. In contrast, other processes appear to keep mate number below the maximum so that mate number per fruit is regulated at an intermediate level. Mate identity had clear consequences as offspring with different fathers were of different sizes after 11 weeks. The effects of mate number on offspring success were less clear. These and other data suggest that non-random mating among compatible donors is a relatively common process in wild radish. It may occur through mechanisms controlled by the pollen tubes, the maternal plants or the embryos. While this non-random mating is the raw maternal for sexual selection in plants, whether sexual selection actually occurs and how important it may be is still nuclear.     

Mating Ethogram of a Video-aided Study of Mating and Parturition in Captive Chinese Crocodile Lizards (Shinisaurus crocodilurus)

Mating behavior and parturition are important components in the life history of any species. The endangered Chinese crocodile lizard(Shinisaurus crocodilurus) is suffering dramatic population decreases in the wild. Successful captive breeding can provide individuals to be reintroduced into their natural habitat and help to restore the wild populations. Studying the mating behavior and parturition of these lizards in captivity will enable us understand how is this ancient species reproduction and optimize artificial reproduction protocol. We studied the mating behavior and parturition of Chinese crocodile lizards in captivity using video recordings at the Daguishan National Nature Reserve, China, from 2015 to 2017. We analyzed pre-copulation and copulation, which occurred in mid-March to late May from all studied years. Pre-copulation and copulation lasted on average 7.51(n = 11) and 27.45(n = 11) minutes, respectively. We found that large-bodied male lizards have longer copulation periods, a pattern seen in other lizard species. In the mating event, males always initiated sex, while the females were passive. The duration of parturition lasted 153.8 ± 26.8(n = 46) minutes, and larger females had heavier clutches. In addition, even though Chinese crocodile lizards represent an ancient lizard clade with primitive characteristics, they still abide by the reproduction patterns seen in most other lizard species.