Lee, W.-L. | Search bioRxiv

bioRxiv2025

Integrative taxonomy and distribution of Apis species in Malaysia

Southeast Asia is the centre of diversification for honey bees (genus Apis). Hence, accurate identification of honey bees found here is instrumental in paving the way for studying evolutionary relationships, biogeographic patterns, and management of these key pollinators. In this study, we characterized Apis species diversity across peninsular Malaysia and Borneo Malaysia using an integrative approach combining morphological traits and mitochondrial markers (CO1 and 16S rRNA). Field collections included both managed and wild colonies of A. mellifera, A. cerana, A. dorsata, A. florea, and A. andreniformis from peninsular Malaysia, as well as two additional cavity-nesting species of Borneo A. koschevnikovi and A. nuluensis. Species identification was performed based on morphological features, nesting ecology, and subsequently validated through sequencing. Samples collected from peninsular Malaysia showed congruence between field/morphological and molecular identification. In contrast, cavity-nesting bees from Borneo exhibited overlapping morphological characteristics leading to misidentification of species. These findings suggest the reliability of carrying out field-based identification of honey bees in peninsular Malaysia but requires molecular validation for Borneo region. The limitations of morphology-based interpretation for Borneo cavity-nesting bees highlights the need for more population-level and speciation studies on these species.

ecology↗

bioRxiv2020

Overexpression of Mdm36 reveals Num1 foci that mediate dynein-dependent microtubule sliding in budding yeast

Current model for spindle positioning requires attachment of the microtubule (MT) motor cytoplasmic dynein to the cell cortex, where it generates pulling force on astral MTs to effect spindle displacement. How dynein is anchored by cortical attachment machinery to generate large spindle-pulling forces remains unclear. Here, we show that cortical clustering of Num1, the yeast dynein attachment molecule, is limited by Mdm36. Overexpression of Mdm36 results in an overall enhancement of Num1 clustering but reveals a population of dim Num1 clusters that mediate dynein-anchoring at the cell cortex. Direct imaging shows that bud-localized, dim Num1 clusters containing only [~]6 copies of Num1 molecules mediate dynein-dependent spindle pulling via lateral MT sliding mechanism. Mutations affecting Num1 clustering interfere with mitochondrial tethering but not dynein-based spindle-pulling function of Num1. We propose that formation of small ensembles of attachment molecules is sufficient for dynein anchorage and cortical generation of large spindle-pulling force.

cell biology↗