Adult stature and age at menarche in Zapotec-speaking communities in the Valley of Oaxaca,Mexico, in a secular perspective

Adult stature and the age at menarche among individuals from Zapotec-speaking communities in the Valley of Oaxaca in southern Mexico are considered in a secular perspective. Four sets of observations are utilized: (1) adult stature in males and females from five rural communities; (2) age at menarche in adult women and school girls from a single rural community; (3) earlier studies of adult stature in the Valley of Oaxaca; and (4) estimated stature from long bones excavated in various archaeological sites in the Valley of Oaxaca. There were no significant differences among the five communities for stature; hence, the data were pooled for analysis and comparison. Results of linear regression of stature and stature adjusted for the estimated effects of aging after 30 years of age on year of birth indicate negligible secular changes in either sex. Comparisons with statures from earlier surveys, the earliest dates to 1899, also indicate negligible changes. When adult women are grouped according to age, there are no differences in mean ages at menarche between the older and younger women. Mean age at menarche for the total adult sample is 14.53 ± 0.08 years, which compares favorably with the probit estimate for school girls, 14.70 ± 0.32 years. These results thus suggest virtually no secular change in adult size and maturity of the Zapotec-speaking population in the Valley of Oaxaca over the past 80 years. Differences in stature between contemporary populations and estimated statures from long bones from several archaeological sites in Oaxaca are small, and thus suggests little secular change over the past one to two–thousand years.     

Scale and the Explanation of Demographic Change: 3,500 Years in the Valley of Oaxaca

Explicit attention to scale provides ways to relate the long run of archaeology to the shorter moments of ethnography and history, and ways to link biology and ecology to political economy. In the Valley of Oaxaca, in southern Mexico, the long–term history of the aggregate, regional population was constrained by relatively stable factors of human biology and ecology. However, significant, patterned variation in shorter–term, disaggregated, local demographic change was caused by shifts in political economy, both in the past and in recent times. Such conclusions are made possible by an unusual datasetthat combines recent, historical, and archaeological population estimates for a whole region covering a 3,500–year period, from initial settled villages to the present, for every place ever inhabited. [Keywords: population, demography, political economy, Oaxaca, Mexico]     

Growth of rural and urban children in the Valley of Oaxaca,Mexico

Weight, stature, arm circumference, and the triceps skinfold were measured in 1,410 school children, 6 through 14 years of age, from two urban colonias in the city of Oaxaca de Juarez (n = 479), and from two rural Ladino (n = 467) and two rural Zapotec (n = 464) communities in the Valley of Oaxaca in southern Mexico. Children from rural Ladino communities and urban colonias are significantly taller, heavier, and more muscular than children in rural Zapotec communities. The differences between rural Ladino and urban colonia children favor the former, particularly for weight and stature. These observations thus suggest (1) that children in the rural, indigenous communities in the Valley of Oaxaca are relatively undernourished compared to children in Ladinoized and urban communities, and (2) that rural-to-urban migration does not necessarily result in improved growth status.     

Growth of rural and urban children in the valley of Oaxaca,Mexico

Weight, stature, arm circumference, and the triceps skinfold were measured in 1,410 school children, 6 through 14 years of age, from two urban colonias in the city of Oaxaca de Juarez (n = 479), and from two rural Ladino (n = 467) and two rural Zapotec (n = 464) communities in the Valley of Oaxaca in southern Mexico. Children from rural Ladino communities and urban colonias are significantly taller, heavier, and more muscular than children in rural Zapotec communities. The differences between rural Ladino and urban colonia children favor the former, particularly for weight and stature. These observations thus suggest (1) that children in the rural, indigenous communities in the Valley of Oaxaca are relatively undernourished compared to children in Ladinoized and urban communities, and (2) that rural-to-urban migration does not necessarily result in improved growth status.     

Health and agricultural intensification in the prehistoric Valley of Oaxaca, Mexico

The effects of agricultural intensification on health are examined in prehistoric populations of the Valley of Oaxaca, Mexico. Agriculture was practiced in the Valley of Oaxaca by the beginning of the Early Formative period (ca. 1400 B.C.), and had intensified by the Late Formative (ca. 500 B.C.). Skeletal remains from 14 archaeological sites in the Valley are pooled by temporal affiliation into a nonintensive agriculture group (1400-500 B.C.) and an intensive agriculture group (500 B.C.-1400 A.D.). The health effects of agricultural intensification are assessed by comparing the frequency of periosteal reactions, cribra orbitalia, and enamel hypoplasia between the intensive and nonintensive agricultural groups. Overall, no significant differences (alpha = 0.05) are found between the nonintensive and intensive groups. Power analyses of the chi-square tests indicate that the tests have a high probability of rejecting a false null hypothesis. The intensification of agriculture does not appear to have had a deleterious effect on the health of the prehistoric population of the Valley. The differences between this study and previous studies of health and agricultural development may be explained by differences between the processes of intensification and development or by differences between primary and secondary centers of agricultural development.     

Genetic drift and natural selection in an isolated Zapotec-speaking community in the Valley of Oaxaca, southern Mexico

Genetic drift and natural selection were analyzed in a genetically isolated Zapotec-speaking community in the Valley of Oaxaca, southern Mexico. Moderately intense genetic drift and selection potentials were found. Potential for drift was related to (1) the small effective size of the population, and (2) the exceptionally low number of migrants into the population. Potential for selection was due to (1) an unusually high variance in fertility, and (2) a high contribution of prereproductive mortality. Significant potential for genetic evolution was found due to genetic drift and natural selection.     

Elevation gradients of diversity for rodents and bats in Oaxaca, Mexico

1  This study documents patterns of rodent and bat diversity related to abiotic and biotic factors along elevational gradients in the Sierra Mazateca (640–2600 m a.s.l.) and Sierra Mixteca (700–3000 m a.s.l.) in Oaxaca, Mexico.
2  The two transects share similar faunas: 17 and 23 rodent species were captured in the sierras Mazateca and Mixteca, respectively, 14 of which occurred on both transects. Rodent species richness was similar in the wet season and the dry season along both transects. Rodent species richness peaked at 1025–1050 m in tropical semi-deciduous forest on both transects. Endemic species were restricted to high-elevation habitats.
3  Sixteen and 17 bat species were captured in the sierras Mazateca and Mixteca, respectively; 11 occurred on both transects. Bat species richness was higher in the wet season than in the dry season in the Sierra Mazateca. Bat species richness peaked at 1850 m in pine–oak forest in the Sierra Mazateca, and at 750 m and 1050 m in tropical semi-deciduous forest in the Sierra Mixteca, decreasing abruptly at higher elevations on both transects.
4  Patterns of trophic diversity of rodents and bats coincided with those of species richness on each transect. Species richness increased with increasing habitat diversity; increased with increasing rainfall and productivity; increased with increasing resource diversity; and increased in areas with high rates of speciation (rodents only).
5  The need for conservation action in Oaxaca is urgent and proponents should promote establishment of protected areas linking lowland habitats with high species richness to high-elevation habitats harbouring large numbers of endemic forms.     

Transnational Migration in Rural Oaxaca, Mexico: Dependency, Development, and the Household

Contradictory models of dependency and development have dominated the discussion of migration between Mexico and the United States. Transnational models of migration resolve these contradictions by defining a series of interdependencies (economy and society, for example). Using data collected in a rural Zapotec community in Oaxaca, Mexico, this article focuses on three areas: the stage-specific development of transnational movement; the domestic cycle, household decision making, and migration/remittance outcomes; and the changing nature of community participation. Rooting the discussion in household decision making captures the important role local social variability and economic dynamism play in understanding transnational processes and advancing migration studies. [ households, migration, transnationalism, dependency and development, Oaxaca, Mexico ]     

Diversity of Alticinae in Oaxaca,Mexico: A preliminary study (Coleoptera,Chrysomelidae)

This is a preliminary study of the diversity of the Flea Beetles (Alticinae) of the Mexican state of Oaxaca based on fieldwork by the author in 1991, 1997, and 2010, the literature, and specimens in several institutional collections. The number of genera and species for Mexico as well as for Oaxaca increased significantly from previous studies. There are now 625 species in 90 genera recorded from Mexico with 275 species in 68 genera recorded from Oaxaca. There are 113 species known only from the state of Oaxaca and another 38 species known only from Oaxaca and the surrounding states. Oaxaca has a relatively high diversity as well as a high percentage of endemism. This study also demonstrates the effects of how even a small amount of fieldwork together with extracting specimen data from institutional collections can significantly increase the total faunistic and diversity knowledge of an area. A complete list of the genera and species known from Oaxaca is included.     

New Mexican species of Byttneria (Sterculiaceae), Bakeridesia (Malvaceae), and Triumfetta (Tiliaceae)

Recent collections have brought to light the following new species from the states of Tabasco and Oaxaca, Mexico:Byttneria fluvialis (Sterculiaceae) from Tabasco;Bakeridesia amoena (Malvaceae), andTriumfetta calzadae (Tiliaceae) from Oaxaca.     

Craniofacial dimensions in children in rural Oaxaca, southern Mexico: secular change, 1968-2000

The objective of this investigation was to analyze the underlying cause(s) of secular changes in craniofacial dimensions among indigenous children in an isolated community in Oaxaca, southern Mexico, between 1968-2000. Subjects were schoolchildren resident in a rural, agrarian, Zapotec-speaking community in the Valley of Oaxaca, previously characterized as mildly-to-moderately undernourished with growth-stunting in 1968 and 1978. In 2000, children had experienced a secular increase in height compared with two prior growth surveys. Four craniofacial dimensions (head length, head breadth, and bizygomatic and bigonial breadths) were measured during anthropometric surveys of schoolchildren aged 6-13 years in 1968, 1978, and 2000. Cephalic and zygomandibular indices were calculated. Samples by survey were: 1968, 151 males and 157 females; 1978, 179 males and 184 females; and 2000, 180 males and 186 females. The analysis was based on a total of 1,037 children. Multivariate analysis of covariance was used to assess secular trend effects, with height, age, and age2 as covariates by sex. Over the interval of 32 years, significant secular changes occurred in craniofacial dimensions and one index: 1) head length was shorter in boys and girls; 2) bizygomatic breadth was narrower in boys and girls; 3) head breadth increased over time only among girls; 4) brachycephalization increased significantly in a linear manner among both sexes; and 5) the zygomandibular index decreased significantly only in boys. Thus, the cranial complex remodeled to a shorter head length, both relatively (brachycephalization) and absolutely. Remodeling over time also resulted in a narrower face, with the midface changing at about the same rate as the lower face (i.e., mandible). Secular changes are generally recognized as multifactorial. Changes in the cephalic index and cranium over time in schoolchildren in an isolated rural agrarian Zapotec-speaking community in the Valley of Oaxaca suggest that the underlying forces for the secular change are associated: 1) decreased food (maize) coarseness or grit content (masticatory stress), and 2) relaxed natural selection, resulting in 3) a greater role for developmental plasticity.     

The archaeological remains of leucaena (Fabaceae) revised

Archaeological specimens of Leucaena (Fabaceae; Mimosoideae) previously published (Tamaulipas, Tehuacan Valley, and Oaxaca Valley) which are housed at the Departmento de Prehistoria, Instituto Nacional de Antropología e Historia, Mexico City, were reexamined. Selected remains from Tehuacan were observed with scanning electron microscopy and ultrastructural features were compared to material from herbarium specimens. External epidermis near margins of legume valves provided identification characteristics (stomata abundance and morphology, texture, pubescence). In Tehuacan, L. leucocephala subsp. glabrata was found in addition to two previously reported taxa—L. esculenta and L. diversifolia subsp. stenocarpa (L. pueblana). Acacia sericea, a wild tree with edible legumes, was frequently misidentified as Leucaena. In Guilá Naquitz, Oaxaca, all samples reported as L. esculenta were identified as another edible, wild legume tree, Conzatia multiflora. Chronology was assigned following published reports and, also for Tehuacan, the field catalogue. Possible use was assigned based upon evidence of chewing and insect damage, indicating ripeness of legumes. No direct evidence of cultivation was found. However, the presence of L. esculenta in Tehuacan (since ca. 4000-1000 B.C.) and of L. I. glabrata (since ca. 300 B.C.-A.D. 780) suggests their introduction there as a cultivated plant.     

Prehispanic colonization of the Valley of Oaxaca,Mexico

A decade ago in a seminal monograph, Anne Kirkby proposed a model of colonization for the prehispanic Valley of Oaxaca, Mexico, in which settlement location was determined by the distribution of prime agricultural land. The model was tested against the corpus of known prehispanic settlements and tentative support was found. In the years since this study, a systematic archeological settlement pattern project was completed, making a more adequate test of the model possible. Reexamination of the colonization process suggests that, although agricultural considerations were important, they were less determinant of settlement location than had been implied previously. The adoption of a broader perspective toward regional colonization is suggested.     

Maternal fetal transmission of Trypanosoma cruzi: a problem of public health little studied in Mexico

The first case of neonatal Chagas was reported in Mexico in 1998, but there have been no studies since then. Therefore, we investigated the rates of congenital infection of Trypanosoma cruzi by examining the seroprevalence among 1448 pregnant women in Oaxaca, Jalisco and Mexico City. We performed ELISAs to screen for recombinant and total antigens in mothers, and examined the frequency of congenital T. cruzi transmission by PCR with cord blood and antibody testing in children when they reached two years old. Our results showed that the prevalence of infection in pregnant women was 7.32% (106/1448) overall, and 4.4% (35/794) in Oaxaca, 12.02% (67/557) in Jalisco and 4.12% (4/97) in the Mexico City. In Oaxaca, T. cruzi infection was detected by PCR in 20% (7/35) of infants born to seroreactive mothers and 11.9% (8/67) in Jalisco. No infections were identified in infants from the Mexico City. From these only eleven serological follow up their children are agree to take blood. Therefore, the maternal-fetal overall transmission rate was 4.08% (4/98) in Oaxaca and 9.1% (3/33) in Jalisco 1.5% (1/65) children with positive serology were given specific treatment Chagas. In conclusion, these are the first reports of the rates of congenital Chagas disease in Mexico. The seroprevalence was higher in mothers from Jalisco, and could be related to that there is not the periodic fumigation of the transmitting vector performed in that state. The high rates of maternal-fetal transmission found in Oaxaca could be related to the differences of pathogenicity of trypanosome. No association between both the rate of congenital transmission and the gynecologic anthropometric data was observed.     

Distribution of domestic triatominae and stratification of Chagas Disease transmission in Oaxaca, Mexico

Mexico has 18 species of Triatomine bugs (Hemiptera: Reduviidae) reported to be vectors of Trypanosoma cruzi. Chagas Disease is widespread in Mexico, with up to 3.5% seropositivity of human transfusion blood. The State of Oaxaca has the longest history of endemic Chagas Disease, based on acute and chronic case reports, and of entomological surveys in the country. However, the State health care services need more information on current risks of vector transmission. In order to identify and characterize areas of transmission in Oaxaca and to stratify the vector potential, the distribution of domestic Triatominae was surveyed during 1996-98 in collaboration with the primary health care services and local communities. Villages were studied in 11% of 570 municipalities in Oaxaca. Eight triatomine species were found in domestic and peri-domestic habitats: Triatoma barberi Usinger, T. bolivari Carcavallo et al., T. dimidiata (Latreille), T. mazzottii Usinger, T. nitida Usinger, T. pallidipennis (Stal), T. phyllosoma (Burmeister) and Rhodnius prolixus Stal. For each triatomine species in Oaxaca, the range of distribution and habitat characteristics are described. Habitat partitioning, principally based on altitude and mean annual precipitation, limited the overlap of distribution between species. Relatively consistent altitude of human settlements facilitates the dispersion of individual species within microregions. Entomological indices of house infestation were used to estimate that approximately 50% of the human population (1,874,320 inhabitants) would be at risk of vector transmission, with a minimum of 134,320 infected people and 40,280 chronic cases of Chagas Disease currently in Oaxaca.     

Epidemiologic transition in an isolated indigenous community in the Valley of Oaxaca, Mexico

The objective of the present study is to analyze age-specific mortality in a rural indigenous community in the throes of a secular increase in size in the Valley of Oaxaca, southern Mexico, over 30 years, 1970-1999. Variation in mortality by age group was analyzed over time for evidence of an epidemiological transition. The seasonal rain pattern in the Valley of Oaxaca (83% from May through September) was evaluated for its relationship with mortality in wet and dry months. Mortality and causes of death changed markedly over the 30-year interval. Infant and preschool mortality, overall mortality, and causes of death changed from the 1970s through the 1990s. Prereproductive deaths (<15 years) predominated in the 1970s and were largely due to gastrointestinal and respiratory diseases, with periodic outbreaks of measles. Deaths of adults 65+ years predominated in the 1990s and were largely due to degenerative diseases usually associated with aging. The marked changes in age and causes of death over the three decades (epidemiologic transition from Stage I to Stage II) occurred concurrently with significant secular increases in body size in children, adolescents, and young adults, highlighting improved health and nutritional conditions in the community which is in early Stage II of the demographic transition. The demographic transition to Stage II is a leading indicator (15-25 years lag) for the onset of the secular trend, while the epidemiologic transition to Stage II is a predictor that the secular increase is in process in the study community.     

Phaseolus (Fabaceae) in Archaeology: AMS

Beans of several species were domesticated in tropical America thousands of years ago, to be combined with maize and other crops in highly successful New World agricultural systems. Radiocarbon dates on charcoal associated with Phaseolus in archaeological sites, in Mexico and Peru indicated the presence of domesticated beans as early as 10 000 years ago. However, direct dates on the beans and pods themselves by accelerator mass spectrometry (AMS) do not provide evidence for the cultivation in Mexico of common beans, P. vulgaris, and teparies, P. acutifolius, before about 2500 B.P. in the Tehuacán Valley, and of common beans about 1300 years ago in Tamaulipas and 2100 years ago in the Valley of Oaxaca. AMS dates support the presence in the Peruvian Andes of domesticated common beans by about 4400 B.P. and lima beans by about 3500 B. P. and lima beans by about 5600 B.P. in the coastal valleys of Peru. The late appearance of common and lima beans in the Central Highlands of Mesoamerica supports the importance of missing evidence that may be obtained from prehistoric agricultural sites in western Mexico and in Central America which are located within the range of the wild populations of these species. Additionally, biochemical studies of subsamples of the dated specimens should be carried out in order to extend the molecular evidence for the independent domestication of North and South American common beans.     

Una nueva especie de Weltrichia (Bennettitales) del Jurásico Medio de la Formación Tecomazuchil (Oaxaca, México)

A new species of Weltrichia (Williamsoniaceae: Bennettitales) is described from the Middle Jurassic of Oaxaca. The specimens come from the Tecomazuchil Formation in the Ayuquila region, at the border between the Oaxaca and Puebla states. Fossils are preserved as impressions and compressions, in a fine-grained sublitharenite sequence deposited in a fluvial environment. Preserved diagnostic characters include: large size; a cup-shaped receptacle showing seven radially arranged and basically fused microsporophylls bearing synangia. Microsporophylls are ornamented with longitudinal striations and fine brittled hairs on the edge of their wide base, and taper into a narrow distal tip. In the adaxial part of the microsporophylls seven to nine synangia are observed. These characters differentiate the new species Weltrichia mixtequensis from all previously recorded species from Mexico or elsewhere. The presence of this new species in the Middle Jurassic strata of the Ayuquila region add to the scarce fossil record of microsporangiate structures in the Jurassic flora of Mexico.     

Adaptive significance of small body size: strength and motor performance of school children in Mexico and Papua New Guinea

The postulated superior functional efficiency in association with reduced body size under conditions of chronic protein-energy undernutrition was considered in school children from rural Mexico and coastal Papua New Guinea. Grip strength and three measures of motor performance were measured in cross-sectional samples of children 6-16 years of age from a rural agricultural community in Oaxaca, Mexico, and from the coastal community Pere on Manus Island, Papua New Guinea. The strength and performance of a mixed-longitudinal sample of well nourished children from Philadelphia was used as a reference. The Oaxaca and Pere children are significantly shorter and lighter and are not as strong as the well nourished children. Motor performances of Pere children compare favorably to those of the better-nourished Philadelphia children, whereas those of the Oaxaca children are poorer. Throwing performance is more variable. When expressed relative to body size, strength is similar in the three samples, but the running and jumping performances of Pere children per unit body size are better than the relative performances of Oaxaca and Philadelphia children. Throwing performance per unit body size is better in the undernourished children. The influence of age, stature, and weight on the performance of Oaxaca and Pere children is generally similar to that for well nourished children. These results suggest that the hypothesized adaptive significance of small body size for the functional efficiency of populations living under conditions of chronic undernutrition varies between populations and with performance tasks.     

Socioeconomic variation in estimated growth velocity of schoolchildren from a rural, subsistence agricultural community in southern Mexico

Socioeconomic variation in estimated growth velocities (annual growth increments) of several anthropometric dimensions was considered in schoolchildren from a rural, subsistence agricultural community in the Valley of Oaxaca in southern Mexico. The children (114 males, 99 females), 6-13 years of age, were measured twice, approximately one year apart. Annual growth increments were computed by subtracting measurements taken in the fall of 1978 from those taken in the fall of 1979. Information on household land holdings and appliances and parental occupation was used to compute an index of socioeconomic status (SES). Analysis of annual increments among upper SES (65 males, 45 females) and lower (49 males, 54 females) children indicated negligible differences. The results suggest that growth deficits evident in the children at school age occurred in infancy and early childhood so that there was little, if any, SES variation in growth rate at the school ages.