Coccinellids in lettuce agroecosystems of the desert southwest united states: ecology, diversity, and implications for biological control

Abstract

Lettuce production in the desert Southwest of the United States occurs in highly intensified agroecosystems characterized by extreme aridity, intensive irrigation, short crop cycles, simplified landscapes, and recurrent pest pressure. These conditions influence the diversity, ecology, and biological control potential of coccinellids in ways that differ from those reported in temperate cropping systems. This review provides a system-level synthesis focused specifically on the ecological constraints and conservation potential of coccinellids in desert lettuce agroecosystems. We summarize current knowledge on coccinellid diversity, community structure, and functional roles in desert lettuce agroecosystems, with emphasis on their interactions with aphids, whiteflies, thrips, and other lettuce pests. Available evidence indicates that aphids are the pest group for which coccinellid-mediated suppression is best documented, whereas interactions with whiteflies, thrips, and other minor pests are less consistent and often poorly studied. We further examine how prey accessibility, crop architecture, temperature variability, landscape simplification, seasonal vegetation gaps and pesticide use influence coccinellid performance and the continuity of biological control. In desert lettuce systems, coccinellid activity is constrained by seasonal vegetation gaps, short-term field occupancy, limited refuge habitats, and management practices that frequently disrupt beneficial arthropod communities. Conservation-oriented strategies, including habitat diversification, retention of non-crop vegetation, and reduced insecticide use, may improve their persistence and functional contribution. We identify major knowledge gaps in seasonal movement, overwintering habitats, thermal performance, compatibility with current integrated pest management practices, and landscape effects on predator fitness, and highlight research and management priorities to enhance coccinellid-mediated biological control in desert lettuce systems.