Maize and ancient Maya droughts

The ancient Maya culture of Mesoamerica shaped landscapes for centuries, in an area where maize (Zea mays) cultivation is considered a fundamental crop in the diet of present and ancient Mesoamerican cultures. Pollen records from sites with different environmental and climatic conditions of the Yucatán Peninsula (Mexico) and Peten (Guatemala) evidence a clear relationship between increased maize pollen and periods of reduced precipitation caused by El Niño Southern Oscillation (ENSO) while moist periods are characterized by low maize pollen presence. ENSO conditions were not evenly distributed across the Yucatán Peninsula, and regional droughts vary according to regional climate and geographical conditions. Our results indicate a strong relationship of increased maize and tropical forest decrease with dry periods, while the Late Preclassic Humid Period (ca. 500-200 BCE) is characterized by the absence of maize pollen. The dry Late Preclassic (300 BCE-250 CE) was a key period for increased maize production, suggesting a new conceptualization of maize. Maize changed from a basic diet crop to a pragmatic product to face adverse environmental conditions.

Scrutinizing the paleoecological record of the Maya forest

Human expansion into and occupation of the New World coincided with the great transition from the Pleistocene to the Holocene epoch, yet questions remain about how we detect human presence in the paleoecological record. In the Maya area of southern Mesoamerica, archeological evidence of the human imprint is largely invisible until ∼4,000 years ago. How do environmental changes after that time correspond and relate to human impacts? Are the archeological signatures of initial settlements in the Early Preclassic detected? Later, by ∼2,000 years ago when the Maya had fully settled the landscape, how does the evidence of forest compositional changes relate to human intervention? This paper evaluates published paleoecological data in light of the rise of the Maya civilization and reflects on interpretations of how swidden agriculture and the milpa cycle impacted the environment. Evaluating the contrast between the long archeological sequence of successful Maya development and paleoecological interpretations of destructive human-induced environmental impacts requires a concordance among pollen data, archeological evidence, ethnohistoric observations, ethnological studies of traditional Maya land use, and the historical ecology of the Maya forest today.

Ancient Lowland Maya neighborhoods: Average Nearest Neighbor analysis and kernel density models, environments, and urban scale

Many humans live in large, complex political centers, composed of multi-scalar communities including neighborhoods and districts. Both today and in the past, neighborhoods form a fundamental part of cities and are defined by their spatial, architectural, and material elements. Neighborhoods existed in ancient centers of various scales, and multiple methods have been employed to identify ancient neighborhoods in archaeological contexts. However, the use of different methods for neighborhood identification within the same spatiotemporal setting results in challenges for comparisons within and between ancient societies. Here, we focus on using a single method-combining Average Nearest Neighbor (ANN) and Kernel Density (KD) analyses of household groups-to identify potential neighborhoods based on clusters of households at 23 ancient centers across the Maya Lowlands. While a one-size-fits all model does not work for neighborhood identification everywhere, the ANN/KD method provides quantifiable data on the clustering of ancient households, which can be linked to environmental zones and urban scale. We found that centers in river valleys exhibited greater household clustering compared to centers in upland and escarpment environments. Settlement patterns on flat plains were more dispersed, with little discrete spatial clustering of households. Furthermore, we categorized the ancient Maya centers into discrete urban scales, finding that larger centers had greater variation in household spacing compared to medium-sized and smaller centers. Many larger political centers possess heterogeneity in household clustering between their civic-ceremonial cores, immediate hinterlands, and far peripheries. Smaller centers exhibit greater household clustering compared to larger ones. This paper quantitatively assesses household clustering among nearly two dozen centers across the Maya Lowlands, linking environment and urban scale to settlement patterns. The findings are applicable to ancient societies and modern cities alike; understanding how humans form multi-scalar social groupings, such as neighborhoods, is fundamental to human experience and social organization.

Effect of land use change on the phlebotomine sand fly assemblages in an emergent focus of cutaneous leishmaniasis in Yucatan, Mexico

As land use intensifies in tropical forests, it is expected that species assemblages will be modified and that key functions of these ecosystems will be affected. The latter scenario is important from a public health perspective, because the land use change has been linked the outbreaks of vector-borne diseases. In this study, we evaluated the response of Phlebotominae (Diptera: Psychodidae) assemblages and their pattern of co-occurrence in four sites with different land use in an emerging cutaneous leishmaniasis focus in Yucatan, Mexico. Our hypothesis is that the conservation status (as forest cover) will positively influence the structure and composition of sand flies' assemblages. Using three different traps over a period of five months, a sampling effort of 1, 440 night-traps was performed. A total of 7, 897 sand fly specimens belonging to six genera and 10 species were collected. Our hypothesis was partially achieved since sand fly diversity increased as forest cover increased and vice versa, however random patterns of co-occurrence in assemblages were detected among sites. Even though the high abundance of sand flies in the forest fragment suggests an amplification effect, our results show that different vector species directly dominate in each site. We discuss the potential implications of the nestedness of species dominance. We suggest that in this emerging focus and under the land use gradient, Lutzomyia cruciata and Psathyromyia cratifer could play a pivotal role in maintaining the transmission cycles of Leishmania. The apparent generalist or colonialist profile of Lu. cruciata in disturbed areas deserves attention, due to the potential risk of leishmaniasis "domiciliation". This information is essential to understand the eco-epidemiology of leishmaniasis and the factors associated with its emergence in Yucatan, Mexico.

Contributions of Agroforestry Systems to Food Provisioning of Peasant Households: Conflicts and Synergies in Chiapas, Mexico

Traditional agroforestry systems are widely recognized for their contributions to provisioning, support, regulation, and cultural services. However, because of the advancement of industrial agriculture and a corporative food system, peasants' food systems are rapidly undergoing transformation. We identify the contributions of four types of agroforestry systems (AFS)—shade cocoa agroforest, shade coffee agroforest, milpas and homegardens—to food provisioning in peasant families and discuss conflicts between traditional food systems and the contemporary industrial model of production and consumption confronted by peasants and semi-proletarian migrants. We carried out research in 17 peasant communities in Chiapas, Mexico, and conducted 97 semi-structured interviews and agroecological inventories with peasant families, and 15 interviews with semi-proletarian families laboring in shade-grown coffee plantations. Thirty-nine weekly food diaries were applied in two communities. We recorded 108 plant species belonging to 49 botanic families. These species play an important role as sources of carbohydrates, protein, vitamins, minerals, and fatty acids. Despite the extraordinary agrobiodiversity of peasant agroecosystems, peasant families (PF) are changing their AFS' structure, composition and functions due to the influence of agribusiness, global markets, and public policies that orient changes in production and marketing, which in turn devalue local food, agrobiodiversity, and knowledge. Changing perceptions regarding the value of “good food” vs. “food of the poor” and competition over land use between traditional and modern systems are driving changes in diet, food sources, and health of PF who are including industrialized foods in their diets, driving changes in consumption patterns and affecting human health. For semi-proletarian migrants laboring in coffee plantations, land access in and outside of the plantation and strengthening social networks could mean access to healthier and culturally appropriate foods. While peasants have historically responded to market and household needs, articulating both activities to satisfy family needs and provide income is limited. This work highlights the urgent need to acknowledge the non-monetary value of local foods, agrobiodiversity, local knowledge, community building, and the need to work towards securing land access for landless workers in Latin America.

Disentangling Domestication from Food Production Systems in the Neotropics

The Neolithic Revolution narrative associates early-mid Holocene domestications with the development of agriculture that fueled the rise of late Holocene civilizations. This narrative continues to be influential, even though it has been deconstructed by archaeologists and geneticists in its homeland. To further disentangle domestication from reliance on food production systems, such as agriculture, we revisit definitions of domestication and food production systems, review the late Pleistocene–early Holocene archaeobotanical record, and quantify the use, management and domestication of Neotropical plants to provide insights about the past. Neotropical plant domestication relies on common human behaviors (selection, accumulation and caring) within agroecological systems that focus on individual plants, rather than populations—as is typical of agriculture. The early archaeobotanical record includes numerous perennial and annual species, many of which later became domesticated. Some of this evidence identifies dispersal with probable cultivation, suggesting incipient domestication by 10,000 years ago. Since the Pleistocene, more than 6500, 1206 and 6261 native plant species have been used in Mesoamerica, the Central Andes and lowland South America, respectively. At least 1555, 428 and 742 are managed outside and inside food production systems, and at least 1148, 428 and 600 are cultivated, respectively, suggesting at least incipient domestication. Full native domesticates are more numerous in Mesoamerica (251) than the Andes (124) and the lowlands (45). This synthesis reveals that domestication is more common in the Neotropics than previously recognized and started much earlier than reliance on food production systems. Hundreds of ethnic groups had, and some still have, alternative strategies that do involve domestication, although they do not rely principally on food production systems, such as agriculture.

A Tale of Maize, Palm, and Pine: Changing Socio-Ecological Interactions from Pre-Classic Maya to the Present Day in Belize

The environmental impact of the ancient Maya, and subsequent ecological recovery following the Terminal Classic decline, have been the key foci of research into socio-ecological interactions in the Yucatán peninsula. These foci, however, belie the complex pattern of resource exploitation and agriculture associated with post-Classic Maya societies and European colonisation. We present a high-resolution, 1200-year record of pollen and charcoal data from a 52-cm short core extracted from New River Lagoon, near to the European settlement of Indian Church, northern Belize. This study complements and extends a previous 3500-year reconstruction of past environmental change, located 1-km north of the new record and adjacent to the ancient Maya site of Lamanai. This current study shows a mixed crop production and palm agroforestry management strategy of the ancient Maya, which corroborates previous evidence at Lamanai. Comparison of the two records suggests that core agricultural and agroforestry activities shifted southwards, away from the centre of Lamanai, beginning at the post-Classic period. The new record also demonstrates that significant changes in land-use were not associated with drought at the Terminal Classic (ca. CE 1000) or the European Encounter (ca. CE 1500), but instead resulted from social and cultural change in the post-Classic period (CE 1200) and new economies associated with the British timber trade (CE 1680). The changes in land-use documented in two adjacent records from the New River Lagoon underline the need to reconstruct human–environment interactions using multiple, spatially, and temporally diverse records.

Ecological, Cultural, and Geographical Implications of Brahea dulcis (Kunth) Mart. Insights for Sustainable Management in Mexico

Palm plants provide important benefits for rural communities around the world. Of the 95 native palm species in Mexico, Brahea dulcis (Soyate palm) has been tagged as an important resource for many Mesoamerican ethnical groups. Scientific and empirical knowledge concerning Soyate is thematically fragmented and disassociated, meaning that sound sustainable management is far from established. Research of over 20 years has permitted us to document ecological, cultural and geographical outcomes of B. dulcis; thus, the present paper aims at compiling all knowledge on Soyate to eventually guide its long-term management. It was conducted in two stages: firstly, it comprised a thorough review of previous studies on the management of B. dulcis in Mexico; secondly, we integrated unpublished outcomes obtained from fieldwork, including participatory ground-truth validation and semi-structured interviews obtained from local ethnic groups. Five factors guided our compilation effort: (i) biological and ecological information, (ii) cultural importance, (iii) economic triggers, (iv) traditional management, and (v) ecological and ecogeographical implications of Soyate palm management. The present paper confirms that B. dulcis is an important cultural resource whose utilization can be traced back over 10,000 years. The leaves of Soyate are the most useful part of the palm and were profusely used in the past for thatching roofs and weaving domestic and agricultural objects. Currently, however, palm-leaf weaving is primarily oriented toward satisfying economic needs. We depicted ten management practices aimed at favoring palm availability. Most of these management practices have enhanced sustainable palm leaf harvesting; however, these practices harbor spatial trends that turn highly diverse habitats into Soyate-dominated spaces. To conclude, we propose a framework to describe sound and sustainable Soyate management in the light of the current long-term Soyate–human relationship. It is here acknowledged that Soyate has played and continues to play a critical socioeconomic and cultural role for many ethnical groups in Central Mexico. Nonetheless, emerging challenges concerning the sustainability of the whole socioecological system at a landscape level are yet to be overcome.

Pontoscolex corethrurus: A homeless invasive tropical earthworm?

The presence of earthworm species in crop fields is as old as agriculture itself. The earthworms Pontoscolex corethrurus (invasive) and Balanteodrilus pearsei (native) are associated with the emergence of agriculture and sedentism in the region Amazon and Maya, respectively. Both species have shifted their preference from their natural habitat to the cropland niche. They contrast in terms of intensification of agricultural land use (anthropic impact to the symbiotic soil microbiome). P. corethrurus inhabits conventional agroecosystems, while B. pearsei thrives in traditional agroecosystems, i.e., P. corethrurus has not yet been recorded in soils where B. pearsei dwells. The demographic behavior of these two earthworm species was assessed in the laboratory over 100 days, according to their origin (OE; P. corethrurus and B. pearsei) food quality (FQ; soil only, maize stubble, Mucuna pruriens), and soil moisture (SM; 25, 33, 42%). The results showed that OE, FQ, SM, and the OE x FQ interaction were highly significant for the survival, growth, and reproduction of earthworms. P. corethrurus showed a lower survival rate (> mortality). P. corethrurus survivors fed a diet of low-to-intermediate nutritional quality (soil and stubble maize, respectively) showed a greater capacity to grow and reproduce; however, it was surpassed by the native earthworm when fed a high-quality diet (M. pruriens). Besides, P. corethrurus displayed a low cocoon hatching (emergence of juveniles). These results suggest that the presence of the invasive species was associated with a negative interaction with the soil microbiota where the native species dwells, and with the absence of natural mutualistic bacteria (gut, nephridia, and cocoons). These results are consistent with the absence of P. corethrurus in milpa and pasture-type agricultural niches managed by peasants (agroecologists) to grow food regularly through biological soil management. Results reported here suggest that P. corethrurus is an invasive species that is neither wild nor domesticated, that is, its eco-evolutionary phylogeny needs to be derived based on its symbionts.

The Apparent Resilience of the Dry Tropical Forests of the Nicaraguan Region of the Central American Dry Corridor to Variations in Climate Over the Last C. 1200 Years

The Central American Dry Corridor (CADC) is the most densely populated area of the Central American Isthmus and is subject to the greatest variability in precipitation between seasons. The vegetation of this region is composed of Dry Tropical Forests (DTF), which are suggested to be highly susceptible to variations in climate and anthropogenic development. This study examines the vulnerability of past DTF surrounding the Asese peninsula, Nicaragua to climatic and anthropogenic disturbances over the past c. 1200 years. Past vegetation, climate, burning, and animal abundance were reconstructed using proxy analysis of fossil pollen, diatoms, macroscopic charcoal, and Sporormiella. Results from this research suggest that DTF have been highly resilient to past climatic and anthropogenic perturbations. Changes in DTF structure and composition appear to be linked to the abundance and intensity of fire. Pre-Columbian anthropogenic impacts on DTF are not detected in the record; however, DTF taxa decline slightly after European contact (1522 C.E.). Overall the DTF for the Nicaraguan region of the CADC were found to be highly resilient to both climatic and anthropogenic disturbances, suggesting that this region will continue to be resilient in the face of future population expansion and climatic variation.

The legacy of 4,500 years of polyculture agroforestry in the eastern Amazon

The legacy of pre-Columbian land use in the Amazonian rainforest is one of the most controversial topics in the social1-10 and natural sciences11,12. Until now, the debate has been limited to discipline-specific studies, based purely on archaeological data8, modern vegetation13, modern ethnographic data3 or a limited integration of archaeological and palaeoecological data12. The lack of integrated studies to connect past land use with modern vegetation has left questions about the legacy of pre-Columbian land use on the modern vegetation composition in the Amazon, unanswered11. Here, we show that persistent anthropogenic landscapes for the past 4,500 years have had an enduring legacy on the hyperdominance of edible plants in modern forests in the eastern Amazon. We found an abrupt enrichment of edible plant species in fossil lake and terrestrial records associated with pre-Columbian occupation. Our results demonstrate that, through closed-canopy forest enrichment, limited clearing for crop cultivation and low-severity fire management, long-term food security was attained despite climate and social changes. Our results suggest that, in the eastern Amazon, the subsistence basis for the development of complex societies began ~4,500 years ago with the adoption of polyculture agroforestry, combining the cultivation of multiple annual crops with the progressive enrichment of edible forest species and the exploitation of aquatic resources. This subsistence strategy intensified with the later development of Amazonian dark earths, enabling the expansion of maize cultivation to the Belterra Plateau, providing a food production system that sustained growing human populations in the eastern Amazon. Furthermore, these millennial-scale polyculture agroforestry systems have an enduring legacy on the hyperdominance of edible plants in modern forests in the eastern Amazon. Together, our data provide a long-term example of past anthropogenic land use that can inform management and conservation efforts in modern Amazonian ecosystems.

Herding Ecologies and Ongoing Plant Domestication Processes in the Americas

Understanding both domestication processes and agricultural practices is an interdisciplinary endeavor. Ethnographic research is potentially helpful for reconstructing past events. Such knowledge is also crucial for documenting the links between biological and cultural diversity, as well as for future purposes such as innovation in food production and sustainability. Here, we review six ethnographic case studies in different pastoral socioecological systems of the American continent. The livestock species involved include the native South American camelids and Arctic reindeer, as well as some Old World species (mainly goats, sheep, and cattle). Starting with the Columbian exchange (15th-16th centuries) and continuing up to the present, Old World herbivores launched novel uses of the local flora which resulted in entirely new livelihoods and cultures, i.e., pastoralism with its variants. Three of these case studies approach specifically how herding ecologies (human-animal-plant relationships) stirred specific management practices (human-plant relationships) that in some instances have moved toward conscious human selection of plant phenotypes. The other examples correspond to three potential instances of similar ongoing processes that we propose on the basis of ethnobotanical and ethnozoological data that were produced separately by other authors. Based on the studies we have reviewed, along with additional information from other parts of the world, we are able to conclude that: (a) New World pastoralist societies are/have been continuously adding species to the humanity's portfolio of useful plants; (b) animals have been aiding in this processes in different ways; and, (c) how human-animal-plant relationships unfold in the present could have been similar in the past, thus analogies may be proposed for explaining prehistoric multispecies interactions and their outcomes. With our review, we intend to bring more attention to contemporary pastoralists as plant managers, animals as agents in human-plant interactions, and domestication as a behavioral complex and multispecies process that is as important in the present or future as it was in the past. Our understanding of food production practices is not only fundamental for improving our current frameworks of governance, conservation, and restoration of useful species populations, but also of biocultural diversity altogether.

'Multi-cropping', Intercropping and Adaptation to Variable Environments in Indus South Asia

Past human populations are known to have managed crops in a range of ways. Various methods can be used, singly or in conjunction, to reconstruct these strategies, a process which lends itself to the exploration of socio-economic and political themes. This paper endeavours to unpack the concept of 'multi-cropping' by considering diversity and variation in the cropping practices of the populations of South Asia's Indus Civilisation. It argues that nuanced interpretations of the evidence provided by the combinations of crop seeds and weeds present in specific contexts and phases of occupation can reveal much about Indus cropping strategies, which in turn enables consideration of issues related to adaptation, intensification and resilience in the face of changing social, political, economic and environmental climates.

Ecological consequences of human niche construction: Examining long-term anthropogenic shaping of global species distributions

The exhibition of increasingly intensive and complex niche construction behaviors through time is a key feature of human evolution, culminating in the advanced capacity for ecosystem engineering exhibited by Homo sapiens A crucial outcome of such behaviors has been the dramatic reshaping of the global biosphere, a transformation whose early origins are increasingly apparent from cumulative archaeological and paleoecological datasets. Such data suggest that, by the Late Pleistocene, humans had begun to engage in activities that have led to alterations in the distributions of a vast array of species across most, if not all, taxonomic groups. Changes to biodiversity have included extinctions, extirpations, and shifts in species composition, diversity, and community structure. We outline key examples of these changes, highlighting findings from the study of new datasets, like ancient DNA (aDNA), stable isotopes, and microfossils, as well as the application of new statistical and computational methods to datasets that have accumulated significantly in recent decades. We focus on four major phases that witnessed broad anthropogenic alterations to biodiversity-the Late Pleistocene global human expansion, the Neolithic spread of agriculture, the era of island colonization, and the emergence of early urbanized societies and commercial networks. Archaeological evidence documents millennia of anthropogenic transformations that have created novel ecosystems around the world. This record has implications for ecological and evolutionary research, conservation strategies, and the maintenance of ecosystem services, pointing to a significant need for broader cross-disciplinary engagement between archaeology and the biological and environmental sciences.

TEK and biodiversity management in agroforestry systems of different socio-ecological contexts of the Tehuacán Valley

Transformation of natural ecosystems into intensive agriculture is a main factor causing biodiversity loss worldwide. Agroforestry systems (AFS) may maintain biodiversity, ecosystem benefits and human wellbeing, they have therefore high potential for concealing production and conservation. However, promotion of intensive agriculture and disparagement of TEK endanger their permanence. A high diversity of AFS still exist in the world and their potentialities vary with the socio-ecological contexts. We analysed AFS in tropical, temperate, and arid environments, of the Tehuacan Valley, Mexico, to investigate how their capacity varies to conserve biodiversity and role of TEK influencing differences in those contexts. We hypothesized that biodiversity in AFS is related to that of forests types associated and the vigour of TEK and management. We conducted studies in a matrix of environments and human cultures in the Tehuacán Valley. In addition, we reviewed, systematized and compared information from other regions of Mexico and the world with comparable socio-ecological contexts in order to explore possible general patterns. Our study found from 26 % to nearly 90 % of wild plants species richness conserved in AFS, the decreasing proportion mainly associated to pressures for intensifying agricultural production and abandoning traditional techniques. Native species richness preserved in AFS is influenced by richness existing in the associated forests, but the main driver is how people preserve benefits of components and functions of ecosystems. Elements of modern agricultural production may coexist with traditional management patterns, but imposition of modern models may break possible balances. TEK influences decisions on what and how modern techniques may be advantageous for preserving biodiversity, ecosystem integrity in AFS and people's wellbeing. TEK, agroecology and other sciences may interact for maintaining and improving traditional AFS to increase biodiversity and ecosystem integrity while improving quality of life of people managing the AFS.

Current perspectives and the future of domestication studies

It is difficult to overstate the cultural and biological impacts that the domestication of plants and animals has had on our species. Fundamental questions regarding where, when, and how many times domestication took place have been of primary interest within a wide range of academic disciplines. Within the last two decades, the advent of new archaeological and genetic techniques has revolutionized our understanding of the pattern and process of domestication and agricultural origins that led to our modern way of life. In the spring of 2011, 25 scholars with a central interest in domestication representing the fields of genetics, archaeobotany, zooarchaeology, geoarchaeology, and archaeology met at the National Evolutionary Synthesis Center to discuss recent domestication research progress and identify challenges for the future. In this introduction to the resulting Special Feature, we present the state of the art in the field by discussing what is known about the spatial and temporal patterns of domestication, and controversies surrounding the speed, intentionality, and evolutionary aspects of the domestication process. We then highlight three key challenges for future research. We conclude by arguing that although recent progress has been impressive, the next decade will yield even more substantial insights not only into how domestication took place, but also when and where it did, and where and why it did not.

Phenotypic differentiation between wild and domesticated varieties of Crescentia cujete L. and culturally relevant uses of their fruits as bowls in the Yucatan Peninsula, Mexico

BACKGROUND

Selection criteria are important for analyzing domestication of perennial plant species, which experience a selection pressure throughout several human generations. We analyze the preferred morphological characteristics of Crescentia cujete fruits, which are used as bowls by the Maya of Yucatan, according to the uses they are given and the phenotypic consequences of artificial selection between one wild and three domesticated varieties.

METHODS

We performed 40 semi-structured interviews in seven communities. We calculated Sutrop's salience index (S) of five classes of ceremonial and daily life uses, and of each item from the two most salient classes. We sampled 238 bowls at homes of people interviewed and compared their shape, volume and thickness with 139 fruits collected in homegardens and 179 from the wild. Morphology of varieties was assessed in fruit (n = 114 trees) and vegetative characters (n = 136 trees). Differences between varieties were evaluated through linear discriminant analysis (LDA).

RESULTS

Use of bowls as containers for the Day of the Dead offerings was the most salient class (S = 0.489) with chocolate as its most salient beverage (S = 0.491), followed by consumption of daily beverages (S = 0.423), especially maize-based pozol (S = 0.412). The sacred saka' and balche' are offered in different sized bowls during agricultural and domestic rituals. Roundness was the most relevant character for these uses, as bowls from households showed a strong selection towards round shapes compared with wild and homegarden fruits. Larger fruits from domesticated varieties were also preferred over small wild fruits, although in the household different sizes of the domesticated varieties are useful. LDA separated wild from domesticated trees (p < 0.001) according to both fruit and vegetative variables, but domesticated varieties were not different among themselves.

CONCLUSIONS

The association between C. cujete bowls and traditional beverages in ritual and daily life situations has driven for centuries the selection of preferred fruit morphology in this tree. Selection of fruit roundness and volume has allowed for the differentiation between the wild variety and the three domesticated ones, counteracting gene flow among them. By choosing the best fruits from domesticated varieties propagated in homegardens, the Maya people model the domestication process of this important tree in their culture.