ABSTRACTLOS CLAROSCUROS DEL CAFÉ: SOCIOECOLOGICAL COMPLEXITIES IN THE COFFEE-BIODIVERSITY NEXUS IN SOUTHERN MEXICOMaría Estelí Jiménez SotoCoffee is one of the most demanded commodities worldwide, supporting the livelihoods of 25 million families. Coffee has been traditionally cultivated within biodiversity hotspots, making these ideal places for biodiversity conservation. Research has pointed out that biodiverse coffee systems support biodiversity and ecosystem functions. However, less is known about the specific ecological mechanisms supporting higher biodiversity and abundance of natural enemies of coffee pests in complex agroecosystems. Resource heterogeneity could be an important factor for arthropod communities; yet, this is still an ongoing scientific exploration in coffee systems. A second area of attention in coffee studies comprises human perceptions of the associated biodiversity in coffee agroecosystems. Most studies highlight the importance of biodiverse coffee smallholdings in delivering food security and contribute to livelihoods of peasant households. However, farm workers are a marginalized sector within the coffee production chain, and much less work has examined the lived-experience of farm workers in coffee agroecosystems. I disentangle the socio-ecological complexities of coffee plantations through three disciplines: agroecology, political ecology, and multi-species ecologies. I examine coffee plantations as spaces constructed by the actions of human and non-human entities, the ecological meanings and narratives constructed from our scientific endeavors, market forces, and peoples’ everyday lived experiences. My research takes place in the Soconusco region in Mexico, a well-known coffee-producing region in the country. The methodologies I use include observations, field and laboratory experiments, ethnographic research, and participant observation in the coffee plantation system. In my work, I demonstrate how ecological mechanisms and abiotic factors drive species diversity and interactions in shaded-coffee plantations, focusing primarily on ants, an important group of natural enemies in coffee systems. I show that diversity of nesting resources drive species coexistence through niche partitioning. I demonstrate that the availability of nectar resources influence colony reproduction. I show that the availability of connectivity resources at the local scale relate to biological pest control of the coffee berry borer, the most important insect coffee pest worldwide. Finally, I present the contradictions and social struggles that arise when conservation narratives meet the everyday-lived-experience of farmworkers in organic shade-grown coffee plantations in Southeast Mexico.