Integrative taxonomic and ecological assessment of egg parasitoids attacking the corn leafhopper Dalbulus maidis (Hemiptera, Cicadellidae) in maize agroecosystems: Taxonomy and ecology of D. maidis parasitoids
Year: 2026
Type: preprint
Abstract: The corn leafhopper, Dalbulus maidis, is a devastating vector of maize stunt diseases across the Americas. While egg parasitoids are critical for the natural suppression of this pest, their application in biological control programs is frequently hindered by cryptic diversity and inherent limitations of morphology-based identification. To overcome these taxonomic impediments and address a critical knowledge gap in the Brazilian Cerrado, this study employed an integrative taxonomy approach to identify the D. maidis egg parasitoid complex and evaluate its seasonal dynamics. Using sentinel plants over a 25-month period, Anagrus virlai (Mymaridae) and Pseudoligosita longifrangiata (Trichogrammatidae) were identified and reported for the first time in the region. Molecular phylogenetic analyses using mitochondrial (COI) and nuclear (ITS2) markers successfully linked field-collected specimens to previously unassigned sequences, resolving historical taxonomic ambiguities. Comprehensive genetic distance matrices for both markers were generated, providing the first public COI barcoding sequences for P. longifrangiata with specific identity confirmed through morphological vouchers. Results revealed topological incongruences between the mitochondrial and nuclear phylogenies, suggesting mito-nuclear discordance potentially driven by the distinct evolutionary trajectories and effective population sizes of these genomes. The synergistic use of both markers was essential: the COI fragment ensured phylogenetic backbone stability, while ITS2 increased statistical support for terminal clades. Beyond taxonomy, ecological assessments revealed A. virlai as the dominant parasitoid, though its field efficacy was significantly and negatively impacted by rising temperatures. Conversely, P. longifrangiata exhibited resilience to climatic fluctuations but was suppressed by asymmetric interspecific competition. Collectively, these findings demonstrate that integrating molecular and morphological data is essential to accurately map parasitoid diversity. Moreover, the varying thermal sensitivities and competitive dynamics of these 3 species underscore the vulnerability of biological control services to climate change, highlighting the need for climate-resilient management strategies in Neotropical agroecosystems.
Source: HAL
Language: English
Topic: Hemiptera Insect Studies
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W7204744744