Yanomami Mobility and Its Effects on the Forest Landscape

The Yanomami are a hunter-gatherer and gardener people with high mobility, which influences the regeneration of forest in agricultural clearings. Increasing contact with the wider Brazilian and Venezuelan societies may lead to sedentarization. Population groups and clearings were mapped in the Yanomami Land in Brazil using four mosaics of Landsat images from within a two-year period. The mosaics were separated by intervals of 7 years. Few groups were sedentary, and most of these maintained alternative residences. The Yanomami cleared 16,856 ha (0.17% of the Yanomami territory in Brazil) over the 21 years covered by this study. Individuals in mobile groups deforested more than those in sedentary groups, but secondary-forest regeneration occurs mainly in clearings made by mobile groups. Permanent settlements had impeded regeneration of 48% (2,025 ha) of the area cleared prior to 1988. Access to health care has led to population growth but has not increased sedentarization.     

Evolutionary demography of agricultural expansion in preindustrial northern Finland

A shift from nomadic foraging to sedentary agriculture was a major turning point in human evolutionary history, increasing our population size and eventually leading to the development of modern societies. We however lack understanding of the changes in life histories that contributed to the increased population growth rate of agriculturalists, because comparable individual-based reproductive records of sympatric populations of agriculturalists and foragers are rarely found. Here, we compared key life-history traits and population growth rate using comprehensive data from the seventieth to nineteenth century Northern Finland: indigenous Sami were nomadic hunter-fishers and reindeer herders, whereas sympatric agricultural Finns relied predominantly on animal husbandry. We found that agriculture-based families had higher lifetime fecundity, faster birth spacing and lower maternal mortality. Furthermore, agricultural Finns had 6.2% higher annual population growth rate than traditional Sami, which was accounted by differences between the subsistence modes in age-specific fecundity but not in mortality. Our results provide, to our knowledge, the most detailed demonstration yet of the demographic changes and evolutionary benefits that resulted from agricultural revolution.     

Means,variances, and ranges in reproductive success: comparative evidence

Data on reproductive success in traditional cultures suggest that for men, but not for women, range and variance rise as subsistence intensifies. For hunter–gatherers, ranges and variances tend to cluster in single digits: they reach 15 or 16, at the high end. For herder-gardeners, ranges and variances are more consistently in double digits: they get as high as 80 or 85. And for full-time agriculturalists in the first civilizations, ranges consistently ran to triple digits: emperors from Mesopotamia to Peru were the fathers of hundreds of children. In human societies, as in other animal societies, reproductive skew goes up with a more sedentary life.     

On interacting populations that disperse to avoid crowding: The effect of a sedentary colony

An analysis is given of a model for two interacting species, one mobile and the other sedentary, in which the mobile one disperses to avoid crowding. The spatial distribution of the mobile species over the habitat, as it evolves with time, is studied. In particular it is shown that a colony of the sedentary species can form an effective barrier against the spreading mobile species, and prevent it from entering certain parts of the habitat.     

Exploring the thrifty genotype's food-shortage assumptions: a cross-cultural comparison of ethnographic accounts of food security among foraging and agricultural societies

The "thrifty genotype hypothesis" has become firmly entrenched as one of the orienting concepts in biomedical anthropology, since first being proposed by Neel (1962 Am. J. Hum. Genet. 14:353-362) over 40 years ago. Its influence on inquiries into the evolutionary origins of diabetes, lactose tolerance, and other metabolic disorders can hardly be underestimated, as evidenced by its continued citation in many top scientific and medical journals. However, its fundamental assumption, that foragers are more likely to experience regular and severe food shortages than sedentary agriculturalists, remains largely untested. The present report tests this assumption by making a cross-cultural statistical comparison of the quantity of available food and the frequency and extent of food shortages among 94 foraging and agricultural societies as reported in the ethnographic record. Our results indicate that there is no statistical difference (P < 0.05) in the quantity of available food, or the frequency or extent of food shortages in these reports between preindustrial foragers, recent foragers, and agriculturalists. The findings presented here add to a growing literature that calls into question assumptions about forager food insecurity and nutritional status in general, and ultimately, the very foundation of the thrifty genotype hypothesis: the presumed food shortages that selected for a "thrifty" metabolism in past foraging populations.     

Degenerative joint disease in hunter-gatherers and agriculturalists from the Southeastern United States

This study examines degenerative joint disease of the major appendicular joints in hunter-gatherers and agriculturalists from northwestern Alabama. Arthritis is highest at the shoulder, elbow, and knee and lower at the hip and ankle. There are virtually no sex differences in the hunter-gatherer group, but in the agriculturalists, males have more severe osteoarthritis than females. The hunters-gatherers have a somewhat greater prevalence of arthritis than the agriculturalists, but the differences are rarely significant. The similarity in osteoarthritis levels over time conflicts with biomechanical evidence, which indicates an increase in usual activities in the agricultural period. Several possible reasons for this are explored, including the suggestion that arthritis is a response to intensive or infrequent activities. Whatever the cause, it is clear that biomechanical data and osteoarthritis are responding to different factors and do not equally represent the level of usual activities.     

Agriculturalists and pastoralists: Bronze Age economy of the Murghab alluvial fan,southern Central Asia

Archaeological investigations of pastoral economies often emphasize exchange relations with agricultural populations, though for Bronze Age Eurasia the notion of a ubiquitous ‘pastoral realm’ has masked various forms of mixed subsistence economies. In Central Asia, there are few attempts to specifically identify the domestic crops utilized by mobile pastoralists or what they may suggest about the role of agriculture in mobile pastoral production or subsistence strategies. This study reports the macrobotanical remains from two Late/Final Bronze Age (ca. 1950–1300 bc) mobile pastoralist habitation sites in the Murghab alluvial fan region of southern Turkmenistan. We compare our results with published macrobotanical data from contemporary agricultural settlements in the Murghab region, as well as with other sites in broader prehistoric Eurasia. We find that mobile pastoralists in the Murghab utilized some of the same domestic crops as their sedentary neighbors. While the data presented here do not preclude the possibility that mobile pastoralists may have practiced some low-investment cultivation (particularly of millet), we hypothesize an economic model that places mobile pastoralists in direct contact with nearby sedentary farming communities through exchange for pre-processed grains. These results highlight one of the possible strategies of mobile pastoral subsistence in Central Asia, and are a further step toward identifying the various degrees of agricultural involvement in the conceptually outdated pastoral realm of Eurasia.     

Dental caries prevalence as evidence for agriculture and subsistence variation during the Yayoi period in prehistoric Japan: biocultural interpretations of an economy in transition

The Yayoi period represents the earliest point of agricultural dependence in Japan, dating from approximately 2500 BP to AD 300. Yayoi period people consumed wet-rice as a primary subsistence base. This article uses dental caries prevalence to interpret the biocultural implications of agriculture among these people by testing the following hypotheses: 1) Yayoi period agriculturalists had greater frequencies of carious teeth than Jomon period foragers, 2) regional variation in carious tooth frequencies will be observed among Yayoi period agriculturalists, while 3) variation in carious tooth frequencies will be observed between male and female agriculturalists. Statistically significant differences in carious teeth were observed between the agriculturalists from Southern Honshu and all other samples. These differences suggest greater reliance on cariogenic plants among farmers from Southern Honshu and are consistent with an agricultural economy. The people of the Yayoi period from Tanegashima Island and Northern Kyushu did not have significantly different carious tooth frequencies compared to Jomon period foragers. This suggests that rice alone was not a more cariogenic dietary substance than those consumed by Jomon period foragers but a cariogenic food nonetheless. Dietary heterogeneity between the prehistoric people of the Yayoi period from Southern Honshu and those from Northern Kyushu and Tanegashima Island is also inferred from these differences. Significantly greater frequencies of carious teeth among older aged Yayoi period females compared with males suggest dietary differences between the sexes.     

Trade-off between mobility and fitness in Cydia pomonella L. (Lepidoptera: Tortricidae)

Abstract.  1. The codling moth Cydia pomonella , one of the most important pest insects of apple fruit orchards worldwide, is regarded as a 'sedentary' insect, but the natural populations consist of both mobile and sedentary genotypes that display different dispersal capacity in the field. The current study investigated whether there is a fitness consequence of being mobile in this species by comparing two strains with contrasting levels of mobility obtained through bi-directional selection.
2. Female moths of the sedentary strain were significantly larger, laid more eggs during their lifespan, and both male and female moths of this strain lived longer, when compared with the mobile strain.
3. The age-specific fecundity of female moths from the sedentary strain was significantly greater, in particular between 3 and 5 days after emergence when the peaks of both oviposition and flight capacity occur, relative to the mobile moths, thereby leading to a greater reproductive function.
4. These differences resulted in different demographic parameters between the two strains. The sedentary strain had a significantly greater net reproductive rate ( R _o ) and a higher intrinsic rate of natural increase ( r _m ), although the generation time ( T ) was similar, hence requiring a shorter time to double the population size, in comparison to the mobile strain.
5. This study provides empirical evidence for the cost of being mobile in C. pomonella . Trade-offs between mobility and fitness might have contributed to the existence of genetic variance for dispersal behaviour in the natural populations and the maintenance of relative sedentariness in the species.     

One Leg or Two? Food Security and Pastoralism in the Northern Sahel

Should pastoralists in dryland Africa diversify or specialize in their productive activities? To investigate this question, we analyze data from a consumption survey and two surveys of the nutritional status of children in addition to qualitative interviews comparing nomadic and sedentary population groups in the Gourma area in northern Mali. We show how the children of pastoralists seem to be better nourished than children of sedentary farmers and that the children of the sedentarized nomads seem to be the worst off. Based on these findings, we first argue that sedentary farming appears to be a poorer adaptation than nomadic pastoralism in arid environments such as the northern Sahel. Secondly, we argue that the diversification argument (better to stand on two legs than one) is flawed for mobile pastoralists in the northern Sahel because the logistical and organizational costs of combining different modes of livelihood are large and easily become insurmountable for a single household.     

Complexity in a prey-predator model with prey refuge and diffusion

Prey-predator interaction is one of the most commonly observed relationships in ecosystem. In the study of prey-predator models, it is frequently assumed that the changes in population densities are only time-dependent and the dynamics is generally represented by coupled nonlinear ordinary differential equations. In natural system, however, either prey or predator or both move from one place to another for various reasons. In such a case, their dynamic interaction depends both on time and space and requires coupled nonlinear partial differential equations for its dynamic representation. It is also well documented that prey refuges affect the interaction between prey and predator significantly. In this paper, we studied the dynamics of a diffusive prey-predator interaction with prey refuge and type III response function. We have considered both one and two dimensional diffusivity in the model system and presented different stability results under the assumptions that one or both species may be mobile or sedentary. Our results showed that the system may exhibit different spatiotemporal (non-Turing) patterns, like spiral waves, patchy structures, spot pattern, or even spatiotemporal chaos depending on the refuge availability and diffusion rate of species. Another interesting finding was that the dynamic complexity in a prey-predator model increases in case of mobile predator and sedentary prey compare to mobile prey and sedentary predator while refuge availability is varied.     

农业区游牧民族饮食文化的滞后性——基于大同东信广场北魏墓群人骨的稳定同位素研究

不同地域的人群具有不同的饮食传统和饮食文化。然而,当人们持续不断的直接或间接接触时,一方或双方原有的饮食文化将会产生变化,如拓跋鲜卑的饮食文化就经历了从游牧向农业的转变。本文对山西大同东信广场北魏墓群26例人骨进行了C、N稳定同位素分析,结果 (δ~(13)C值为-11.5±2.7‰,n=26;δ~(15)N值为9.8±1.2‰,n=26)显示,先民的食物类型差异较大,并包含大量的肉食资源。研究表明,以C_3类食物为主的先民主要放牧或狩猎,以C_4类食物为主的先民主要以种植粟、黍等C_4型农作物喂养家畜。大同东信广场北魏墓群人群中两种不同饮食传统的存在,显示游牧民族新的饮食习惯(以粟作农业产品为食)的形成滞后性于北魏政权的建立,这可能与气候变冷及他们的排斥有关。     

The association between amount of red muscle and mobility in fishes: A statistical evaluation

Synopsis It is commonly accepted that more active fishes have a greater proportion of red muscle in their trunk musculature than do less active fishes. Further, the proportion of red muscle has been used to classify fish species into functional groups reflecting different activity patterns. Nevertheless, existing measures of both red muscle and mobility have several limitations, and the relationship between these parameters has never been evaluated quantitatively. Using data from the literature, we demonstrate a positive, statistical association between the proportion of red muscle in the caudal peduncle of marine fishes and a qualitative measure of mobility (categorization as sedentary vs. mobile based on natural-history accounts). Analyses of the frequency distribution of the proportion of red muscle also provide evidence for two subdistributions. However, this bimodality does not correspond with sedentary vs. mobile or sit-and-wait vs. active search dichotomies.     

Dental indicators of health and stress in early Egyptian and Nubian agriculturalists: a difficult transition and gradual recovery

Although agriculture is now the globally predominant mode of food production, studies of the skeletal remains of early agriculturalists have indicated high levels of physiological stress and poor health relative to hunter-gatherers in similar environments. Previous studies identifying this trend in different regions prompt further research of the causes and effects of subsistence transitions in human societies. Here, 242 dentitions from five ancient Egyptian and Nubian populations are examined: 38 individuals from Jebel Sahaba (Upper Paleolithic), 56 from Badari (Predynastic), 54 from Naqada (Predynastic), 47 from Tarkhan (Dynastic), and 47 from Kerma (Dynastic). These populations span the early period of agricultural intensification along the Nile valley. Skeletal remains were scored for the presence of linear enamel hypoplasia (LEH) of the dentition, an established indicator of physiological stress and growth interruption. The prevalence of LEH was highest in the "proto-agricultural" (pastoralist) Badari population, with a gradual decline throughout the late Predynastic and early Dynastic periods of state formation. This suggests that the period surrounding the emergence of early agriculture in the Nile valley was associated with high stress and poor health, but that the health of agriculturalists improved substantially with the increasing urbanization and trade that accompanied the formation of the Egyptian state. This evidence for poor health among proto- and early agriculturalists in the Nile valley supports theories that agricultural intensification occurred as a response to ecological or demographic pressure rather than simply as an innovation over an existing stable subsistence strategy.     

Guild mobility affects spider diversity: Links between foraging behavior and sensitivity to adjacent vegetation structure

The movement patterns of species may affect their susceptibility to modified habitat structure. It is likely that sedentary species perceive habitat features at smaller spatial extents compared to mobile species, but there is a lack of experimental research on the effects of fine-scale habitat characteristics on organisms of differing mobility. Spiders display two basic mobility levels based on foraging behavior: web-building species are restricted to specific sites whereas active hunters are mobile. We collected spiders inhabiting sagebrush shrubs with a structurally enhanced, unmodified, or removed understory, to examine (1) whether habitat structure in the immediate vicinity of shrubs affected cursorial and web spiders differently in terms of abundance and species richness and (2) which genera most contributed to changes in community composition. Shrubs without understory had reduced cursorial spider densities and species richness compared to shrubs with added and unmodified understories, whereas web spiders lacked significant responses to treatments. Community-level differences based on relative abundance of genera were detected in cursorial spiders but not in web spiders, despite a strong contribution of the web-building genus Theridion to community dissimilarities. Our results support the hypothesis that sedentary organisms may be sensitive to contiguous habitat at finer spatial scales than cursorial organisms, and highlight the risks associated with only collecting local habitat information when studying mobile species.     

Some problems of regressive evolution

The concept of morphophysiological regress as one of the main ways to biological progress, as well as its major factors (the sedentary and parasitic modes of life), are discussed. Some notions of regressive evolution are critically reviewed. Special attention is paid to evolutionary transformations of the nervous system, one of the main integrating factors in the body. All theories of evolutionary progress based on sedentary organisms are demonstrated to be untenable. The entire progressive evolution of Metazoa has been related to mobile life. Since regressive trends are common in the evolution, the phylogenetic tree of Metazoa requires serious revision.     

Investigating children's physical activity and sedentary behavior using ecological momentary assessment with mobile phones

The risk of obesity during childhood can be significantly reduced through increased physical activity and decreased sedentary behavior. Recent technological advances have created opportunities for the real-time measurement of these behaviors. Mobile phones are ubiquitous and easy to use, and thus have the capacity to collect data from large numbers of people. The present study tested the feasibility, acceptability, and validity of an electronic ecological momentary assessment (EMA) protocol using electronic surveys administered on the display screen of mobile phones to assess children's physical activity and sedentary behaviors. A total of 121 children (ages 9-13, 51% male, 38% at risk for overweight/overweight) participated in EMA monitoring from Friday afternoon to Monday evening during children's nonschool time, with 3-7 surveys/day. Items assessed current activity (e.g., watching TV/movies, playing video games, active play/sports/exercising). Children simultaneously wore an Actigraph GT2M accelerometer. EMA survey responses were time-matched to total step counts and minutes of moderate-to-vigorous physical activity (MVPA) occurring in the 30 min before each EMA survey prompt. No significant differences between answered and unanswered EMA surveys were found for total steps or MVPA. Step counts and the likelihood of 5+ min of MVPA were significantly higher during EMA-reported physical activity (active play/sports/exercising) vs. sedentary behaviors (reading/computer/homework, watching TV/movies, playing video games, riding in a car) (P < 0.001). Findings generally support the acceptability and validity of a 4-day EMA protocol using mobile phones to measure physical activity and sedentary behavior in children during leisure time.     

A ‘WATCH’ census of common British butterflies

In summer 1981, members of WATCH made a quantitative survey of common butterflies throughout Britain. Adult numbers were recorded along standardized transects on 670 sites, covering most commonplace biotopes. Butterflies were identified into families, except for five conspicuous species.

Ten common biotopes were sufficiently well sampled for general conclusions to be made about their value. Although garden flowers attracted the few species of butterfly that are very mobile, sedentary species were virtually absent from gardens especially in urban areas. Improved pasture also contained few sedentary species, but road verges and woods held moderate densities. Abandoned railway tracks and wasteland supported large numbers of common butterflies, but the highest counts were made in unimproved pasture. Numbers along hedges differed little from the open fields that they bordered.

The method was modified in 1982 so that sponsored counts could be made in the richest biotopes. These raised about £4000 for conservation.     

The Impact of Subsistence Change on Mobility and Settlement Pattern in a Tropical Forest Foraging Economy: Some Implications for Archeology

I critically examine archeological presumptions that a continuum from "mobility" to "sedentism" underlies the evolutionary transition from hunting-gathering to agriculture. An ethnographic case from the Philippines shows that some foraging societies undergoing subsistence change may become more mobile as they near or cross the threshold to sedentary life. A distinction between residential and logistical mobility does not account for this finding, because the increased mobility in question has both residential and logistical demensions.