Phylogeography and demographic expansion in the widely distributed horned passalus beetle, Odontotaenius disjunctus (coleoptera: Passalidae)

2021 ◽  
pp. 1-14
Author(s):  
Megan Whitaker ◽  
Taylor Procter ◽  
Frank M. Fontanella
2019 ◽  
Vol 43 (4) ◽  
pp. 679-703
Author(s):  
Aaron Benanav

AbstractSince 1950, the world’s urban labor force has expanded dramatically, a process that has been accompanied by a large increase in informal employment. Accounts of these phenomena generally assume that urban workers without formal work are mostly recent migrants from the countryside. This article shows that outside of China, most of the growth of the world’s urban workforce has been the consequence of demographic expansion rather than rural-to-urban migration. A large portion of the world’s growing urban-born workforce has ended up in informal employment. I develop a concept of demographic dispossession to explain the relatively autonomous role demographic growth has played, first, in the proletarianization of the global population and, second, in the informalization of the urban workforce. I then explore the reasons why demographic growth in low- and medium-income countries tended to be more rapid and urban than demographic growth had been historically in the high-income countries.


2011 ◽  
Vol 102 (3) ◽  
pp. 333-343 ◽  
Author(s):  
K.C. Albernaz ◽  
K.L. Silva-Brandão ◽  
P. Fresia ◽  
F.L. Cônsoli ◽  
C. Omoto

AbstractIntra- and inter-population genetic variability and the demographic history of Heliothis virescens (F.) populations were evaluated by using mtDNA markers (coxI, coxII and nad6) with samples from the major cotton- and soybean-producing regions in Brazil in the growing seasons 2007/08, 2008/09 and 2009/10. AMOVA indicated low and non-significant genetic structure, regardless of geographical scale, growing season or crop, with most of genetic variation occurring within populations. Clustering analyzes also indicated low genetic differentiation. The haplotype network obtained with combined datasets resulted in 35 haplotypes, with 28 exclusive occurrences, four of them sampled only from soybean fields. The minimum spanning network showed star-shaped structures typical of populations that underwent a recent demographic expansion. The recent expansion was supported by other demographic analyzes, such as the Bayesian skyline plot, the unimodal distribution of paired differences among mitochondrial sequences, and negative and significant values of neutrality tests for the Tajima's D and Fu's FS parameters. In addition, high values of haplotype diversity (Ĥ) and low values of nucleotide diversity (π), combined with a high number of low frequency haplotypes and values of θπ<θW, suggested a recent demographic expansion of H. virescens populations in Brazil. This demographic event could be responsible for the low genetic structure currently found; however, haplotypes present uniquely at the same geographic regions and from one specific host plant suggest an initial differentiation among H. virescens populations within Brazil.


2018 ◽  
Vol 75 (3) ◽  
pp. 667-675
Author(s):  
Amandine S Juhel ◽  
Corentin M Barbu ◽  
Muriel Valantin-Morison ◽  
Bertrand Gauffre ◽  
Raphaël Leblois ◽  
...  

2018 ◽  
Vol 30 (2) ◽  
pp. 296-306
Author(s):  
Marilyn Mendoza-Ramírez ◽  
Jorge Gutiérrez-Rodríguez ◽  
Chantal Poteaux ◽  
Patricia Ornelas-García ◽  
Alejandro Zaldívar-Riverón

2007 ◽  
Vol 67 (4 suppl) ◽  
pp. 849-857 ◽  
Author(s):  
IF. Lopes ◽  
CI. Miño ◽  
SN. Del Lama

The present study determined nuclear and mitochondrial (mtDNA) levels of genetic variability and phylogeographic patterns in breeding populations of Roseate Spoonbill (N = 57), Wood Stork (N = 89), and Jabiru Stork (N = 30), sampled in the Brazilian Pantanal. These species were selected since they are bioindicators of wetlands’ health and are threatened in other parts of their distribution. As they are in close association with this ecosystem, they are appropriate for studying the effects of Pleistocene climatic changes on their demographic patterns. Levels of nuclear genetic diversity in Pantanal populations were not significantly different from those of other populations throughout the American continent, where they are considered threatened or of special concern. Reduced levels of mtDNA genetic diversity were observed in the Central American population of Jabiru Stork in comparison to the Pantanal population. Recent demographic expansion in the Pantanal was markedly evidenced by unimodal patterns of mismatch distribution and Fu’s Fs neutrality test in these three species. We hypothesize that the average time of population expansion (between 30,843 and 14,233 years before present) is associated to responses of these birds’ populations to paleoclimatic changes in these wetlands during the last glaciation period. We recommend special conservation efforts with the Jabiru Stork populations, a genetic monitoring program based on mtDNA, and an ecological characterization of these waterbirds species throughout their distribution range.


2019 ◽  
Vol 76 (4) ◽  
pp. 1209-1211 ◽  
Author(s):  
Massimiliano Cardinale ◽  
Stefano Mariani ◽  
Joakim Hjelm

Abstract Svedäng et al. (2018) concluded that “the occurrence of locally spawned cod eggs suggests that spawning on the Swedish Skagerrak coast takes place, which belong to either a coastal subpopulation that is a remnant stock of a once much larger cod population, or a newly formed subpopulation that is now successfully inhabiting the coastal ecosystems along the Swedish Skagerrak coast”. However, after carefully reviewing the results and the data presented by the authors, we were no longer convinced that the information presented provided enough evidence for a local, distinct, coastal cod population in the Swedish Skagerrak. Thus, we requested the original genotype data, which the authors kindly provided to us. This allowed us to explore the substructure of these samples further using STRUCTURE 2.3.2. Re-analysis of the data consistently rejects the existence of an independent coastal Swedish stock in contrast with Svedäng et al. (2018) conclusions. We acknowledge the observation of cod spawning in the area but, based on re-analysis of the original genetic data of Svedäng et al. (2018), we currently lack the scientific basis to assume the existence of established local stocks, and even less the demographic expansion of an older, relict population in the area.


2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Surapon Yodsiri ◽  
Komgrit Wongpakam ◽  
Adisak Ardharn ◽  
Chadaporn Senakun ◽  
Sutthira Khumkratok

The Mekong River and its tributaries possess the second highest diversity in fish species in the world. However, the fish biodiversity in this river is threatened by several human activities, such as hydropower plant construction. Understanding the genetic diversity and genetic structure of the species is important for natural resource management. Belodontichthys truncatus Kottelat & Ng is endemic to the Mekong River basin and is an important food source for people in this area. In this study, the genetic diversity, genetic structure, and demographic history of the twisted-jaw fish, B. truncatus, were investigated using mitochondrial cytochrome b gene sequences. A total of 124 fish specimens were collected from 10 locations in the Mekong and its tributaries. Relatively high genetic diversity was found in populations of B. truncatus compared to other catfish species in the Mekong River. The genetic structure analysis revealed that a population from the Chi River in Thailand was genetically significantly different from other populations, which is possibly due to the effect of genetic drift. Demographic history analysis indicated that B. truncatus has undergone recent demographic expansion dating back to the end of the Pleistocene glaciation.


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