Animal pollinators are critical to global food production, yet their populations face threats from habitat loss, landscape simplification, and changing agricultural practices. This thesis integrates field experiments, global synthesis, and open data infrastructure to quantify how animal pollinators shape agricultural production from flowers to food systems.
A review of pollinator nutrition in agricultural systems reveals that habitat enhancement initiatives have historically emphasised floral provisioning for bees while often overlooking the distinct resource requirements of non-bee pollinators. Many important crop-visiting taxa, particularly flies and beetles, require non-floral resources including larval substrates and nesting sites that extend beyond pollen and nectar. This broader perspective on pollinator resource needs provides context for understanding why generalised habitat enhancements produce inconsistent crop pollination benefits.
Experimental studies in blueberry examine how co-flowering plants, protective structures, and floral traits influence pollinator behaviour and crop outcomes. A manipulative field experiment demonstrates that attractive co-flowering basil plants reduce pollinator visitation to adjacent blueberry flowers, though berry weight remains unaffected, indicating that competitive effects on visitation may not translate to yield impacts when baseline pollination exceeds threshold levels. Cultivar-level variation in floral morphology reveals that structural accessibility, particularly corolla length-to-width ratios, shapes honeybee visitation patterns, with morphological constraints potentially limiting visitation even when nectar rewards are substantial. Protective cover experiments across two cultivars with contrasting pollination requirements show that polyethylene tunnels and anti-bird netting differentially affect insect visitation and yields depending on pollinator taxon, cultivar reproductive biology, and flowering phenology. One cultivar exhibited high pollinator dependency while the other achieved substantial parthenocarpic yields, demonstrating how cultivar selection can influence vulnerability to pollination deficits.
A global meta-analysis synthesising experimental evidence from 848 studies across 277 crop species quantifies, for the first time, pollinator dependency across both crop production quantity and quality outcomes. Approximately 16% of global crop production volume, equivalent to yields from 236 million hectares and valued at 759 billion USD annually, depends on animal pollination. Although cereals and sugar crops dominate production volumes, pollinators disproportionately sustain nutrient-dense foods critical for dietary quality, including fresh fruits, vegetables, nuts, seeds and spices. The analysis reveals substantial variation in pollinator dependency both across and within crop species, with quantity metrics showing higher dependency than quality metrics, yet demonstrating that examining these dimensions in isolation substantially underestimates true dependency. Critical knowledge gaps persist, with widely cultivated crops including important staples and high-value perennials supported by little experimental pollination research, particularly in regions with limited research capacity.
To address these persistent knowledge gaps, this thesis introduces CroPolEx, the first comprehensive global dataset harmonising experimental outcomes from crop pollination and breeding system studies. Beyond quantifying pollinator dependency, CroPolEx enables assessment of pollen limitation, self-incompatibility, and parthenocarpy across diverse crops and production systems, providing an openly accessible resource supporting research, policy development, and agricultural decision-making.
Collectively, these findings position pollinators as central to food security, nutrition, and land-use policy rather than simply one agricultural input. By integrating focused experimental investigation of pollinator-plant interactions with comprehensive global synthesis and open data infrastructure, this thesis provides mechanistic insights into crop pollination alongside evidence-based tools for managing pollinator-dependent production systems in the face of global pollinator declines.