Male-biased adult sex ratios and their significance for cooperative breeding in dhole, Cuon alpinus, packs

Two free-ranging packs of dholes (Asiatic wild dog, Cuon alpinus) were monitored for a period of 6 yr (Sep. 1990-Sep. 1996) in the Mudumalai sanctuary, southern India. Demographic data on age structure, litter-size, sex ratio and age and sex specific dispersal were collected. Behavioural data on social interactions and reproductive behaviour among pack members were obtained to determine the frequencies of dominant and subordinate behaviours shown by malt: and female pack members and a measure of each male's reproductive access to females. Behaviours displayed by pack members at dens were recorded to determine whether any age- or sex-specific role specialization existed during pup care. Tenures for dominant males and females within the pack were calculated to ascertain the rate of breeding vacancies occurring within packs. Approximate levels of genetic relatedness within packs were determined by studying pedigrees. In most years one study pack had a male-biased adult sex ratio. This was caused by almost twofold higher dispersal of adult females over adult males. A considerable variance existed in the percentage of sub-adults dispersing from the two packs. Differences existed in the frequencies of dominant and subordinate behaviours shown by males. For males, dominance ranks and ranks based on submissive behaviours were not correlated with frequencies of reproductive behaviours. Subordinate males also displayed reproductive behaviours. In packs, dominant males had lower tenures than dominant females indicating that among males breeding vacancies arose more quickly. The litter size was found to be negatively correlated with the age of the breeding female. There were no significant differences across individuals of varying age or sex classes in the display of pup care behaviours. Significant differences did exist among individual adults. Genetic relatedness among packs tended to vary temporally as a consequence of possible mating by subordinate animals and immigration of new males into the pack. In conclusion, it appears that males delay dispersal and cooperate within their natal packs because of the variety of reproductive strategies they could pursue within. A combination of ecological constraints and the difficulties of achieving breeding status within non-natal packs may make early dispersal and independent breeding less beneficial.

Spray characterization of straight vegetable oils at high injection pressures

We present results of high pressure spray characterization of Straight Vegetable Oils (SVOs) which are potential diesel fuel substitutes. SVO sprays are visualized at high injection pressures (up to 1600 bar) to study their atomization characteristics. Spray structure studies are reported for the first time for Jatropha and Pongamia vegetable oils, under atmospheric conditions. Jatropha and Pongamia SVO sprays are found to be poorly atomized and intact liquid cores are observed even at an injection pressure of 1600 bar. Non-Newtonian behavior of Jatropha and Pongamia oil is shown to be the reason for observed spray structure. (C) 2012 Elsevier Ltd. All rights reserved.

Mud-packing frog: A novel breeding behaviour and parental care in a stream dwelling new species of Nyctibatrachus (Amphibia, Anura, Nyctibatrachidae)

Reproductive modes are diverse and unique in anurans. Selective pressures of evolution, ecology and environment are attributed to such diverse reproductive modes. Globally forty different reproductive modes in anurans have been described to date. The genus Nyctibatrachus has been recently revised and belongs to an ancient lineage of frog families in the Western Ghats of India. Species of this genus are known to exhibit mountain associated clade endemism and novel breeding behaviours. The purpose of this study is to present unique reproductive behaviour, oviposition and parental care in a new species Nyctibatrachus kumbara sp. nov. which is described in the paper. Nyctibatrachus kumbara sp. nov. is a medium sized stream dwelling frog. It is distinct from the congeners based on a suite of morphological characters and substantially divergent in DNA sequences of the mitochondrial 16S rRNA gene. Males exhibit parental care by mud packing the egg clutch. Such parental care has so far not been described from any other frog species worldwide. Besides this, we emphasize that three co-occurring congeneric species of Nyctibatrachus, namely N. jog, N. kempholeyensis and Nyctibatrachus kumbara sp. nov. from the study site differ in breeding behaviour, which could represent a case of reproductive character displacement. These three species are distinct in their size, call pattern, reproductive behaviour, maximum number of eggs in a clutch, oviposition and parental care, which was evident from the statistical analysis. The study throws light on the reproductive behaviour of Nyctibatrachus kumbara sp. nov. and associated species to understand the evolution and adaptation of reproductive modes of anurans in general, and Nyctibatrachus in particular from the Western Ghats.

Breeding in bamboo: a novel anuran reproductive strategy discovered in Rhacophorid frogs of the Western Ghats, India

Amphibians exhibit extraordinarily diverse sets of reproductive strategies among vertebrates. Understanding life history strategies in an evolutionary framework is lacking for many amphibian species in the tropics. Here, we report a novel reproductive mode where adult frogs enter hollow internodes of bamboo via a small opening, deposit direct developing eggs, and provide parental care. This behaviour is observed in two species of the frog genus Raorchestes. The first description of this unique life history and details of nest site characteristics and embryo development are provided along with ecological comparisons. Evolution of novel reproductive modes and parental care are discussed in context of natural selection. Dearth of natural history information on amphibians in the Western Ghats and much of the South-East Asian region is highlighted with suggestions for further studies.(c) 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 114, 1-11.

Evaluación de técnicas de defensa y de la densidad en el cultivo de una nueva hortaliza : Cucúrbita pepo var. vegetable spaghetti

El zapallo Spaghetti, cultivo vigoroso de clima templado, constituye una alternativa productiva interesante y novedosa para nuestro país. El objetivo de este estudio fue evaluar el efecto del mulching y de la densidad sobre el rendimiento total, el peso medio y el calibre de los frutos. El estudio se llevó a cabo en Azul sobre un suelo Argiudol típico en camellones de 0,80 m de ancho con diferentes densidades de siembra. Se realizó una fertilización profunda en bandas de 0,80 m con fosfato diamónico, controlando las malezas en forma química, manual y mecánicamente, y las plagas haciendo aplicaciones preventivas de insecticidas y fungicidas. La siembra manual se efectuó el 2 de noviembre y los tratamientos fueron: densidades de siembra de 20, 15, 10 y 5 mil pl/ha (D1, D2, D3 y D4), con y sin mulching. Se trabajó con 32 parcelas y cada una tenía tres surcos de seis metros de longitud separados entre si por 2m. Se realizaron cuatro cosechas al llegar a la madurez completa (15/2, 29/2, 7/3 y 3/4). Los calibres evaluados fueron: (1) 2,2 kg, (2) 1,7 kg; (3) 1,3 kg y (4) 0,8 kg / fruto. Para el análisis de los datos se utilizó un modelo de bloques completamente aleatorizados con parcelas sub-divididas. En la parcela principal se evaluó el efecto del mulching, en la subparcela la densidad y la interacción de mulching por densidad, y en la subsubparcelas las diferentes cosechas. La cosecha total mostró diferencias significativas para el efecto del mulching, obteniéndose 71,90 t/ha (a) (con mulching) y 62,02 t/ha (b) (sin mulching); para cada densidad se detectaron diferencias significativas para el efecto mulching: D1: 84,45 t/ha (a), D2: 76,47 t/ha (ab); D3: 65,14 t/ha (b) y D4: 61,55 t/ha (b). Se observaron diferencias significativas en el número de frutos cosechados: con mulching (51.667 frutos/ha) y sin mulching (44.167 frutos/ha), y para las diferentes densidades: D1: 54.167 (a); D2: 50.000 (ab); D3: 47.700 (ab) y D4: 40.833 (b) t/ha. La composición de calibres de frutos cosechados fue el mismo para todos los tratamientos y cosechas.

Lessons from established breeding programs: terrestrial and aquatic animals

Some relevant components of selection program theory and implementation are reviewed. This includes pedigree recording, genetic evaluation, balancing genetic gains and genetic diversity and tactical integration of key issues. Lessons learned are briefly described – illustrating how existing method and tools can be useful when launching a program in a novel species, and yet highlighting the importance of proper understanding and custom application according to the biology and environments of that species.

Potential applications of reproductive and molecular genetic technologies in the selective breeding of aquaculture species

The use of reproductive and genetic technologies can increase the efficiency of selective breeding programs for aquaculture species. Four technologies are considered, namely: marker-assisted selection, DNA fingerprinting, in-vitro fertilization, and cryopreservation. Marker-assisted selection can result in greater genetic gain, particularly for traits difficult or expensive to measure, than conventional selection methods, but its application is currently limited by lack of high density linkage maps and by the high cost of genotyping. DNA fingerprinting is most useful for genetic tagging and parentage verification. Both in-vitro fertilization and cryopreservation techniques can increase the accuracy of selection while controlling accumulation of inbreeding in long-term selection programs. Currently, the cost associated with the utilization of reproductive and genetic techniques is possibly the most important factor limiting their use in genetic improvement programs for aquatic species.