Evidence of polygamy in the socially monogamous Amazonian fish Arapaima gigas (Schinz, 1822) (Osteoglossiformes, Arapaimidae)

Arapaima gigas is one of the largest freshwater fishes of the world. It is socially monogamous, forming pairs, constructing a nest and providing parental care. We performed a paternity analysis under three scenarios in captive, semi-natural and natural areas using 10 microsatellite markers. As a positive control, we analyzed three pairs and their offspring isolated individually in artificial breeding ponds (a priori very high probability of monogamy). We then analyzed two samples of offspring from large artificial ponds with multiple adults but only one reproductive pair (a priori high probability of monogamy), two samples from semi-natural breeding station with multiple adults but only one reproductive pair (a priori high probability of monogamy), and a sample from a natural lake with multiple adults, some potentially breeding (a priori medium probability of monogamy). Analysis of patterns of Mendelian heredity suggested an extra-pair contribution for all broods except the positive controls. Similarly, results based on multilocus analysis estimated at least two sib-groups per nest. These results reject monogamy as a system of breeding in Arapaima gigas. From a management perspective, this behavior may be exploited to maintain genetic diversity in captive and as well in wild populations of Arapaima gigas.

O pirarucu Arapaima gigas é um dos maiores peixes de água doce do mundo. É socialmente monogâmico, forma casais, constrói ninhos e fornece cuidado parental. Com o objetivo de acessar o sistema de acasalamento do pirarucu, analisamos três cenários: em áreas de cativeiro, semi-naturais e naturais, utilizando 10 marcadores microssatélites. Como controle positivo, analisamos três casais e suas ninhadas isolados em açudes individuais (probabilidade a priori muito alta de monogamia). A seguir, analisamos duas amostras de ninhadas de um açude com vários adultos, mas somente um casal reprodutivo (probabilidade a priori alta de monogamia), duas amostras de estação de criação semi-natural com vários adultos mas somente um casal reprodutivo (probabilidade a priori alta de monogamia), e uma amostra de lago natural com vários adultos alguns potencialmente em fase de reprodução (probabilidade a priori média de monogamia). Análises de padrões mendelianos de hereditariedade sugerem contribuição extra-par para todas as ninhadas, exceto as do controle positivo. Similarmente, resultados baseados em análises multilocus realizadas no programa KINALYZER estimaram pelo menos dois grupos-irmãos por ninhada. Nossos resultados rejeitam a monogamia como sistema de acasalamento em Arapaima gigas. Da perspectiva de manejo, esse comportamento pode ser explorado para manter a diversidade genética em cativeiro assim como em populações naturais de Arapaima gigas.

Polyandry Practiced among Jaunsari of Uttarakhand: Scope for Futuristic Study.

Man learns his behaviour and behaviour that is learnt denotes his culture. Thus culture is a system of learned behaviour shared by and transmitted among the members of a group and every group have tried to maintain their cultural heritage / uniqueness by the effort to make their culture distant from the others. The most significant task for the students of anthropology is to observe the different cultural systems and to find out the cultural units of distinctive pattern of a culture or group that mark them unique from the rest of the world. Marriage is such a prime cultural unit and at the same time may be viewed as a reference point to locate the diversity and uniqueness of each culture at intra and inter analytical level. In this paper researchers have tried to share their observations regarding polygamous marriage especially polyandrous marriage practiced among the Jaunsari people living at the village of Lakhamandal, state of Uttrakhand.

Origin and occurrence of sexual and mating systems in Crustacea: A progression towards communal living and eusociality.

Crustaceans are known for their unrivalled diversity of sexual systems, as well as peculiar mating associations to achieve maximum mating success and fertilization accomplishment. Although sexes are separate in most species, various types of hermaphroditism characterize these predominantly aquatic arthropods. A low operational sex ratio between female and male, together with temporally limited receptivity of females towards males, imposes restrictions on the structuring of mating systems in crustaceans. The basic mating systems consist of monogamy, polygamy, mate guarding and pure searching. Understandably, ecological influences may also play a determinative role in the evolution of such sexual and mating systems in crustaceans. An important outcome of the crustacean sexual biology is the development of complex social structures in many aquatic species, in much the same way insects have established them in terrestrial conditions. In addition, groups like isopods and certain families of brachyuran crabs have shown terrestrial adaptation, exhibiting peculiar reproductive modes, sometimes reminiscent of their terrestrial counterparts, insects. Many caridean shrimps, living in symbiotic relationship with other marine invertebrates in the coral reef habitats, have reached pinnacle of complexity in sexuality and peculiar mating behaviours, resulting in communal living and establishing advanced social systems, such as eusociality.