Integrative identification of insect flower visitors associated with avocado flowering in Western Australia.

Abstract

Accurate identification of insect flower visitors is fundamental for understanding crop pollination systems and supporting sustainable production. In Western Australia, avocado (Persea americana Mill.) production relies heavily on insect visitation, yet the taxonomic identity of native flower-visiting taxa remains poorly resolved. This study provides the first integrative identification of insects associated with avocado flowering in Western Australia using a combination of morphological examination and mitochondrial cytochrome c oxidase subunit I (COI) DNA barcoding. Insects were collected from commercial avocado orchards in Carabooda and Pemberton during the flowering seasons of 2019-2021. Besides honeybees, morphological assessment identified 5 dominant native bee taxa, primarily within Lasioglossum (Halictidae), and 3 hoverfly taxa (Syrphidae). DNA barcoding confirmed species-level identities for Lasioglossum lanarium (Smith), L. castor (Smith), and the syrphids Simosyrphus grandicornis (Macquart) and Eristalis tenax (Lannaeus) (≥99% to 100% sequence similarity). In contrast, COI sequences from 3 additional Lasioglossum lineages showed lower similarity to available reference records (eg 96%, 91%, and 94%) and are therefore treated conservatively as Lasioglossum sp. 3 to 5 (morphospecies) rather than assigned species-level names. Overall, 73% of putative avocado flower-visitor taxa were shared between regions, indicating a broadly consistent core assemblage across contrasting climatic zones. By clarifying the taxonomic identity and reporting confidence of key avocado-associated taxa, this study provides a baseline for future work evaluating visitation dynamics, pollen transfer, and management strategies in Australian avocado orchards.