scholarly journals Phenotypic ranking experiments in identifying breeding objective traits of smallholder farmers in northwestern Ethiopia

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248779
Author(s):  
Oumer Sheriff ◽  
Kefyalew Alemayehu ◽  
Aynalem Haile

We executed two live animal ranking experiments, own-flock and group-animal ranking, to identify the breeding objectives of Arab and Oromo goat keepers in northwestern Ethiopia as a preliminary step towards designing sustainable breeding programs for two goat populations. In the own-flock ranking experiment, a total of 147 households, out of which 46 were Arab and 101 were Oromo goat keepers that live in semi-arid and sub-humid agroecologies respectively, were visited at their homesteads and were asked to choose their first best, second best, third best and the most inferior does from their own flock. The reasons of ranking and life history of the does (age, previous production and reproduction information) were inquired and recorded; live body weight and some linear body measurements were taken. In the group-animal ranking experiment, 12 breeding does and 12 breeding bucks from Arab goats and the same number of animals from Oromo goats were randomly selected. Life history of selected does and bucks (age, birth type, libido and temperament) were inquired from the owners. The selected animals were randomly grouped into four in Arab goats (three animals per group) and the same was applied in Oromo goats. Twelve farmers for Arab goats and the same number of farmers for Oromo goats who have not known the experimental animals were invited to do the ranking. Each person ranked the three animals in each group as 1st, 2nd and 3rd, giving reasons of ranking. After a first round of ranking, s/he was then provided with the history of each individual animal and asked whether s/he would consider re-ranking them. This procedure was continued eight times until a person covered all groups of does and bucks. It was found out that in own-flock ranking experiment, keepers focus on productive, reproductive and behavioral traits (such as body size, mothering ability, twinning rate, kidding interval and temperament) while in group-animal ranking experiment, there was a general tendency to focus on observable physical traits like coat color, body size and body conformation. Simultaneous use of both own-flock and group-animal ranking experiments is advisable to identify breeding objective traits in production systems where record keeping is absent.

2008 ◽  
Vol 29 (2) ◽  
pp. 161-170 ◽  
Author(s):  
Carlo Utzeri ◽  
Claudio Angelini ◽  
Damiano Antonelli

Abstract We studied nine populations of Salamandrina perspicillata for two to nine years and described the life history variation among these population. Despite experiencing similar climatic conditions, populations differed in mean body size: populations using still water bodies for oviposition were larger body-sized than those using brooks. One semi-natural pond was used by particularly small individuals and was probably recently colonised. The mean body size of ovipositing females varied from year to year. Measurements of individuals in successive years showed that the tail grew more than the trunk and this differential growth increased with age. Females did not oviposit every year and, within a given population, the number of ovipositing females varied widely from year to year.


2010 ◽  
Vol 37 (1) ◽  
pp. 74-90 ◽  
Author(s):  
S. Pfennigwerth

Nicolas Baudin's 1800–1804 voyage was the only scientific expedition to collect specimens of the dwarf emu (Dromaius ater) endemic to King Island, Bass Strait, Australia. The expedition's naturalist, François Péron, documented the only detailed, contemporaneous description of the life history of the bird, and the artist Charles-Alexandre Lesueur made the only visual record of a living specimen. Hunted to extinction by 1805, the King Island emu remains relatively unfamiliar. It is ironic that a bird collected as part of one of the most ambitious ordering enterprises in early nineteenth-century science – a quest for intellectual empire – has been more or less forgotten. This paper discusses how human error, assumption, imagination and circumstance hampered recognition and understanding of the King Island emu. Poor record-keeping led to the confusion of this species with other taxa, including the Australian emu and a dwarf species restricted to Kangaroo Island, contributing to the epistemological loss of the species. The expedition's agenda was equally influential in the perception and documentation of the species, with consequences for its conservation in the wild. The paper also argues that as a symbolic rather than a scientific record, Lesueur's illustration fostered inaccuracies in later descriptions of the King Island emu, especially when the image was taken out of context, subjected to the vagaries of nineteenth-century printing techniques and reproduced in more recent ornithological literature. Rather than increasing knowledge about this species, the Baudin expedition and its literature contributed, albeit unwittingly, to the King Island emu's textual and literal extinction.


Author(s):  
Kenji Yoshino ◽  
Manato Nagayoshi ◽  
Masanori Sato ◽  
Toshiya Katano ◽  
Yuji Ito ◽  
...  

The life history of the Japanese sternaspid polychaeteSternaspis costatavon Marenzeller, 1879 was investigated in the inner part of Ariake Bay from May 2010 to May 2011, with additional sampling in July and September 2011. All the worms were measured by the width of the ventral shield (WS) as an indicator of body size, and their coelomic contents were also examined. Ovigerous females occurred throughout the year, except during October and March, with the highest ovigerous rate (number of ovigerous females/number of adults with a WS larger than that of the smallest ovigerous female, i.e. 1.8 mm) noted in September (43.8% in 2010, 34.7% in 2011). The ovigerous rate was less than 10% in the other months, except in April 2011 (30%). Although the coelomic oocytes ranged from 90 to 160 μm in diameter, the diameters of most of the oocytes were 140–160 μm in September. The number of adults drastically decreased from September to October, suggesting that most of the adults died after spawning in the major reproductive period, although a small fraction of adults seemed to reproduce earlier or later. A cohort of recruits with an approximately 1.2 mm WS was identified in March and April. Most of the recruits grew to adult size in July–September, when many ovigerous females occurred. These results indicated that this species is fundamentally semelparous, with longevity around 1 year, and they mostly reproduce in September, with a few adults reproducing almost throughout the year.


Fossil Record ◽  
1999 ◽  
Vol 2 (1) ◽  
pp. 103-112 ◽  
Author(s):  
P. M. Sander

Abstract. Sauropod dinosaurs present exceptional challenges in understanding their biology because of their exceptional body size. One of these, life history, can be inferred from the histology of their bones. For this purpose, the diverse sauropod assemblage of the Upper Jurassic Tendaguru beds was sampled with a new coring method which provided unprecented access to and insights into sauropod bone histology. Growth series of humeri and femora as well as long growth records from single bones suggest that all four sauropod taxa are characterized by continued growth after sexual maturity but that growth was determinate. Fibrolamellär bone is dominant in the samples, indicating that the bones of the Tendaguru sauropods grew at rates comparable to those of modern large mammals. The growth pattern of these sauropods thus combines typically reptilian traits with typically mammalian traits. In the details of their bone histology, the Tendaguru sauropod taxa show considerable variation which reflects life history. In addition, Barosaurus exhibits probable sexual dimorphism in bone histology. Das Verständnis der Biologie der sauropoden Dinosaurier wird durch ihre enorme Körpergröße außerordentlich erschwert. Allerdings kann ein Aspekt, die Lebensgeschichte, anhand der Histologie ihrer Knochen untersucht werden. Zu diesem Zweck wurde die diverse Sauropoden-Vergesellschaftung der oberjurassischen Tendaguru-Schichten beprobt, und zwar mit einer neuartigen Kernbohrmethode, die einen herausragenden Zugang und Einblick in die Knochenhistologie der Sauropoden ermöglichte. Wachstumsserien von Humeri und Femora sowie umfassende Überlieferungen des Wachstums von Individuen anhand einzelner Knochen machen es wahrscheinlich, daß alle vier Sauropoden-Taxa der Tendaguru-Schichten durch ein auch nach der Geschlechtsreife anhaltendes Wachstum gekennzeichnet waren. Allerdings ging das Wachstum nicht bis zum Tode des Tieres weiter, sondern kam bei einer etwas variablen Maximalgröße zum Stillstand. Fibrolamellärer Knochen ist der vorherrschende Knochentyp in den Proben, was anzeigt, daß die Tendaguru-Sauropoden mit für Säugetieren typische Raten wuchsen. Die Tendaguru-Sauropoden kombinerten also ein für Reptilien typisches Muster des Wachstums, nämlich nach der Geschlechtsreife anhaltendes Wachstum, mit für Säuger typischen Raten des Wachstums. Die verschiedenen Sauropoden-Taxa zeigen erstaunliche Unterschiede in den Details ihrer Knochenhistologie, die Unterschiede in der Lebensgeschichte belegen. Bei Barosaurus scheint außerdem ein Geschlechtsdimorphismus in der Histologie der Langknochen vorzukommen. doi:1002/mmng.1999.4860020107


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3004 ◽  
Author(s):  
J. Antonio Baeza ◽  
Donald C. Behringer

Management of the few regulated ornamental fisheries relies on inadequate information about the life history of the target species. Herein, we investigated the reproductive biology of the most heavily traded marine invertebrate in the western Atlantic; the blue-legged hermit crabClibanarius tricolor. We report on density, individual-level, and population-level reproductive parameters in 14 populations spanning the Florida Keys. In C. tricolor, abundance, population-level, and individual-level reproductive parameters exhibited substantial small-scale spatial variation in the Florida Keys. For instance, the proportion of brooding females varied between 10–94% across localities. In females, average (±SD) fecundity varied between 184 (±54) and 614 (±301) embryos crab-1 across populations. Fecundity usually increases with female body size in hermit crabs. However, we found no effect of female body size on fecundity in three of the populations. Altogether, our observations suggest that C. tricolor may fit a source-sink metapopulation dynamic in the Florida Keys with low reproductive intensity and absence of a parental body size—fecundity relationship resulting in net reproductive loses at some localities. We argue in favor of additional studies describing population dynamics and other aspects of the natural history of C. tricolor (e.g., development type, larval duration) to reveal ‘source’ populations, capable of exporting larvae to nearby populations. Our observations imply that future studies aimed at assessing standing stocks or describing other aspects of the life history of this hermit crab need to focus on multiple localities simultaneously. This and future studies on the reproductive biology of this species will form the baseline for models aimed at assessing the stock condition and sustainability of this heavily harvested crustacean.


1992 ◽  
Vol 70 (10) ◽  
pp. 1995-2006 ◽  
Author(s):  
Laurie J. Vitt ◽  
Celso Morato de Carvalho

The ecology and life history of the tropical teiid lizard Kentropyx striatus were studied in a grassland of northern Brazil, the lavrado area. The area, located nearly at the equator, experiences a prolonged dry season with a wet season extending from May to September. Total annual rainfall averages 1750 mm. Lizards were nonrandomly distributed among habitat patches and microhabitats. Most individuals were in trees and shrubs surrounding temporary and permanent water. Most individuals were observed active during late morning, the time period during which feeding and social interactions were observed. Lizards bask to achieve active body temperatures averaging 35.7 ± 0.23 °C. Body temperature is correlated with both substrate and air temperatures; foraging lizards maintained higher temperatures than basking lizards regardless of whether they were in sun, and lizards sampled when there was cloud cover had lower body temperatures than those sampled when sun was available. Females reach sexual maturity at 74 mm snout–vent length (SVL), produce 3–9 eggs per clutch, reproduce more than once per season, and commence reproduction during the wet season. Lizards hatch from eggs at 31 mm SVL. Maturity appears to be reached in 1 year or less. Overall, female reproductive characteristics are similar to those of other tropical teiid lizards that have been studied, with body size explaining much of the variance in reproductive characteristics across species. There is pronounced sexual dimorphism, with males larger in body size as well as certain other characteristics independent of body size. Sexual dimorphism appears to be a consequence of sexual selection. The diet is varied, but is dominated volumetrically by frogs, eruciform larvae, and spiders. Lizard body size accounted for only 5.5% of the variance in prey size and there was no difference in prey size due to sex. The occurrence of frogs and lizards in K. striatus stomachs suggests that teiid lizards may influence the structure of lizard and frog assemblages. The similarity of K. striatus to other studied tropical teiids in reproductive characteristics, morphology, activity period, activity temperatures, and diet underscore the conservative nature of the ecology of teiid lizards, presumably a consequence of their mode of prey acquisition.


2018 ◽  
Vol 28 ◽  
pp. 29-38
Author(s):  
Nicholas S. Gladstone ◽  
Evin T. Carter ◽  
K. Denise Kendall Niemiller ◽  
Lindsey E. Hayter ◽  
Matthew L. Niemiller

Lungless salamanders in the family Plethodontidae exhibit an impressive array of life history strategies and occur in a diversity of habitats, including caves. However, relationships between life history, habitat, and body size remain largely unresolved. During an ongoing study on the demography and life history of the paedomorphic, cave-obligate Berry Cave Salamander (Gyrinophilusgulolineatus, Brandon 1965), we discovered an exceptionally large individual from the type locality, Berry Cave, Roane County, Tennessee, USA. This salamander measured 145 mm in body length and represents not only the largest G.gulolineatus and Gyrinophilus ever reported, but also the largest plethodontid salamander in the United States. We discuss large body size in G.gulolineatus and compare body size in other large plethodontid salamanders in relation to life history and habitat.


2015 ◽  
pp. 206-234 ◽  
Author(s):  
James H. Brown ◽  
Astrid Kodric-Brown ◽  
Richard M. Sibly
Keyword(s):  

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