Overall, the gene pool of cultivated fig analyzed possesses substantial genetic polymorphism and exhibits narrow differentiation. It is evident that fig accessions from Turkmenistan are somewhat genetically different from the rest of the Mediterranean and the Caucasus figs. A long history of domestication and cultivation with extensive dispersal of cultivars has often resulted in a great deal of confusion in the identification and classification of cultivars.Coffee, a highly demanded commodity supporting the livelihoods of more than 20 million families , has been traditionally cultivated under the shade of trees within tropical and subtropical biodiversity hotspots, making it relevant for conservation, food provisioning for rural families and the delivery of ecosystem services, meaning the processes and conditions provided by natural ecosystems with the potential to sustain and fulfill human welfare . Important ecosystem services in coffee plantations are pest control and pollination . However, coffee agroecosystems continue to experience a dramatic change in their management, characterized by the reduction of shade trees and increased use of chemical inputs . This intensification has had severe ecological implications, including the decline of ecosystem services ; and social consequences like food insecurity and seasonal hunger for farming families . Much research on the benefits of biodiversity in coffee agroecosystems – has pointed out that highly bio-diverse habitats have the potential to sustain a number of species and interactions that support ecosystem services . However, less is known about the specific ecological mechanisms supporting more biodiversity and higher abundance of natural enemies of coffee pests in complex agroecosystems . Previous studies have suggested that resource heterogeneity, large pots plastic meaning the variability of available resources through space and time and accessible refuges provided by surrounding vegetation could be important factors for arthropod communities . Yet, this is still an ongoing scientific exploration in coffee systems .

A second area of attention in coffee studies comprises the benefits that humans perceive from the planned and associated biodiversity in coffee agroecosystems. Most of these studies have highlighted the importance of bio-diverse coffee smallholdings in delivering food security and contribute to livelihoods of peasant households . However, research has suggested that established and temporary farm workers are a highly marginalized sector of the coffee production chain , which indicates that further attention needs to be put in terms of the overall lived experience– and specifically food-related experiences– of this sector. Ecological theory provides foundations for explaining higher abundance and diversity of natural enemies in complex habitats. Two complementary hypothesis have been developed and are useful in this sense: the first one suggests that different habitat types– meaning a variety of plants, strata, microhabitats, the spatial arrangement and temporal overlap of the plants –can support greater biodiversity of predators and reduce crop damage . This hypothesis considers that an increase in resources such as floral and extrafloral nectar and provisioning of shelter through improving non-crop vegetation, favors generalist and specialist predators and parasitoids through the delivery of alternative food . A second hypothesis suggests that niche complementarity, which occurs when higher diversity in the system allows for a grater range of functional traits to be represented, favors a more efficient use of resources and promotes diversity at higher trophic levels . Following these hypotheses communities of natural enemies could potentially thrive in coffee agroecosystems to the extent that these systems provide the necessary resources to survive when the main prey are not available. My dissertation departs from two socio-ecological understandings: 1) Resource heterogeneity– expressed in temporal variation of a particular resource, differences in quality and nutritional variation of resources, or differences in microhabitats – is considered an important factor influencing communities.

More complex habitats provide diversity of niches and ways to exploit resources in a particular environment , which in turn supports more biodiversity , influences the distribution and interactions of species and may favor niche partitioning and species coexistence in a given environment . 2) Ecological diversity exists along a gradient of social complexity, allowing the co-creation of spaces. The subsistence value of bio-diverse coffee systems draws upon the potential of growing and using a variety of resources other than coffee within the agroecosystem and adjacent plots . There is an increase interest and awareness that biodiversity conservation can have positive effects on food production and livelihoods . Such is the case of traditional coffee polycultures and indigenous agroforestry systems . Despite benefits of highly bio-diverse coffee plantations, coffee farmers frequently experience seasonal hunger and food shortages . Food related challenges are mostly reported from smallholdings; however a smaller but important sector of coffee production happens in large plantations, which represent a historically and currently important sector of the coffee production in Central America and issues of food security have not been explored enough. Under this framework, this dissertation evaluates three intertwined areas. First – I examine the influence of the availability of three resources on ant community dynamics such as colonization, reproduction, and two species interactions: predator-prey and parasitoid-host interactions. Ants and parasitoids are important natural enemies of coffee pests and are model systems to understand the mechanisms that favor diversity in complex habitats. Second, I examine the influence of local habitat factors on community dynamics. Third, I explore the every-day lived experiences of farm workers in coffee plantations, a scantily explored area that requires attention in coffee growing regions in Mexico. Community assembly is the process that leads to particular patterns of colonization of interacting species, that may share a particular resource , and a process that reflects survival of species in a particular habitat . The study of communities and their assemblage processes is important for explaining community dynamics, but also because it can provide important insights into spatiotemporal factors that maintain ecosystem services in face of global change, destruction of natural biomes, and intensification of managed systems .

Ants are a diverse and an interesting group of insects to use for studies of community assembly and drivers of coexistence because they are found almost everywhere and in the tropics they can represent up to 80% of the animal biomass . Understanding drivers of ant diversity and co-occurrence is of relevance, as ants participate in competitive, mutualistic and predatory interactions, as well as trait mediated interactions that often result in ecosystem services . Ants are important pollinators , predators of pests in agricultural systems , square planter pots seed dispersers and protectors of plants that provide resources useful for ants . Local and regional factors influence ant assemblages, however there is no single cause or dynamic that explains nest colonization patterns of entire communities of ants. Thus, recognizing that community assemblages can be structured through multiple ecological and evolutionary processes interacting synergistically is essential in community studies . By examining the community of arboreal ants that nest in hollow twigs in a coffee plantation, we investigated how availability of resources, such as diversity of nests with different sized entrances, and the vegetation strata in which nests are located influence colonization and nesting patterns for a community of twig-nesting ants. The role of cavity entrance diversity on Neotropical arboreal ants has been previously shown to strongly influence cavity colonization in a natural ecosystem . Although the present study shares a number of similarities with the previous study in terms of the experimental design, the novelty of our study lies in the examination of the assembly process of the arboreal ant community in an agroecosystem considering the vegetative strata as a potentially significant local factor influencing ant assembly. Other studies have also made important contributions to the understanding of the influence of resource availability, interspecific competition from dominant ants, and changes in environmental conditions on ant colonization, survival and community assembly ; similarly, studies have reported that niche differentiation and interspecific competition for similar resources structure ant communities . In the litter environment, factors such as patchiness in nest site availability can influence ground ants . For other communities, however, nesting sites might not be a limiting factor, although nest-site limitation may increase with agricultural habitat intensification or disturbance . Moreover, increases in diversity of nesting sites can influence species richness and composition . Only few studies examine factors that influence ant communities at the colonization stage, despite the importance of priority effects for community assembly . Recruitment limitation can affect colony density and incidence of less competitive species, thus examining initial phases of colonization may be important for understanding species coexistence . Moreover, the dispersal stage of colony formation maybe strongly influenced by community assembly mechanisms such as habitat filtering because ants must find suitable habitats .

The present study asked the following questions: 1) Does nest strata or diversity of nest entrance sizes influence the percent of nests colonized by arboreal twig-nesting ants, 2) Does nest strata or diversity of nest entrance sizes influence the species richness of arboreal twig-nesting ants colonizing nests? 3) Does nest strata or diversity of nest entrance sizes influence the community composition of twig-nesting ants colonizing nests? 4) Are nests with certain nest entrance sizes more frequently occupied, or have a higher species richness of ants? 5) Do individual ant species more frequently occupy nests in a certain strata or nests of a certain entrance size?We conducted field research in a 300-ha shaded coffee farm in the Soconusco region of Chiapas, Mexico between March and June 2012. The farm is located between 900-1100 m a.s.l. Between 2006-2011, annual rainfall at the farm was between 4000-5000 mm. During the time of the research, the production style of the farm could be classified as a mix of commercial polyculture and shaded monoculture according to the system of Moguel & Toledo . The farm has ~50 species of shade trees that provide 30-75% canopy cover to the coffee buses in the understory. We studied ant occupation of nests in 44 locations on the farm. Each study site was separated by a minimum of 100 m, and consisted of two neighboring Inga micheliana trees of approximately the same size and two coffee plants directly underneath the trees. In order to characterize the vegetation of each study site, we measured trees, canopy cover, and coffee density. For all measurements, we used the midway point between the two Inga micheliana trees as the center point. In a 25 m radius circle around the center, we identified and counted each tree and measured the circumference and height of all tress. We sampled canopy cover at the circle center, and 10 m to the N, S, E, and W of the circle center with a convex spherical densitometer. We counted the number of coffee plants within 5 m of each focal Inga tree in each site. With the vegetation data, we calculated a vegetation complexity index . To calculate the index, we divided values for each vegetation variable by the highest observed value for each variable. For the number of coffee plants and the percent of trees in the genus Inga, we subtracted the product from 1 as these two factors generally negatively correlate with vegetation complexity. Then, we took the average of all values for each site to obtain a single value between 0 and 1 .Treatments were randomly assigned to plants in each site. We attached nests to plants with twist ties and plastic string between 0.5 to 1.5 m above ground on coffee plants, and between 4 to 6 m above ground for Inga trees. We placed nests flush with coffee or tree branches. We placed nests between 5-7 March and harvested all nests 14 weeks later . The period of the study encompassed part of the rainy season. Rain and moisture have a significant effect on colony phenology because they regulate alate’s flights in the absence of temperature variation . Although nests were placed long enough to be colonized by ants, longer time periods may have allowed us to capture colonization dynamics across time. To determine effects of nest entrance size, entrance size diversity, and nest vegetation strata on colonization, we collected artificial nests, placed them in bags, froze them, and then cut open all nests to remove the contents. We noted whether each nest was occupied or not. We stored ants in 70% ethanol and later identified them according to the Ants of Costa Rica , and AntWeb . For all species found, we obtained an approximate head width measurement from AntWeb .