Unveiling the underground: Habitat creation and nesting ecology of the native ground-nesting bee Lasioglossum (Homalictus) dotatum

Freya M Jackson

doi:10.60867/00000182

Ground-nesting bees are important pollinators, yet their nesting ecology and habitat requirements have rarely been studied. This thesis investigates the nesting behaviour, environmental responses, and habitat preferences of Lasioglossum (Homalictus) dotatum, a common yet understudied native ground-nesting bee in Australia. Using field surveys, controlled trials, and behavioural observations, this research provides the first comprehensive ecological account of this species while exploring practical strategies for conservation and habitat creation. Initial surveys across southwest Western Australia found L. dotatum nesting in urban and suburban areas, most densely close to water sources such as irrigation. Analysis of soil from 20 nest aggregations showed that nests occurred in sandy, neutral to alkaline soils shaped by human landscaping. These findings led to a multi-year experiment testing nest establishment across six soil types, including natural and commercial soil types. Females initially nested most in a brown sandy loam, but nesting there declined as the surface hardened and cracked, and a red, well-drained loamy sand supported the most consistent nesting over time. In contrast, commercially processed soil types with poor structure supported fewer nests. This suggests that nesting depends not only on soil characteristics but also on how soils change over time. Additional experiments showed that adding rock gravel to the surface increased nesting activity. To understand this preference, a separate behavioural study found that females may use rocks to conceal nest entrances and defend against enemies. Females shared nest entrances and alternated between foraging and guarding, providing the first record of nest guarding in this species and consistent with communal nesting. Drawing on all previous findings, enhanced bee beds using local sand, rock cover, and supplementary watering attracted more nests than controls and allowed long-term monitoring of nesting phenology. Nesting activity peaked in autumn and late spring and continued at a lower level through winter, suggesting more than one generation per year. Together, this thesis expands our understanding of L. dotatum and provides practical, evidence-based strategies for supporting ground-nesting bees in urban and managed environments.

Unveiling the underground: Habitat creation and nesting ecology of the native ground-nesting bee Lasioglossum (Homalictus) dotatum

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