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1. It has long been known that foraging bumblebee workers vary greatly in size, within species, and within single nests. This phenomenon has not been adequately explained. Workers of their relatives within the Apidae exhibit much less size variation.2. For the bumblebee Bombus terrestris size, as measured by thorax width, was found to correspond closely with tongue length, so that larger bees are equipped to feed from deeper flowers.3. The mean size of worker bees attracted to flowers was found to differ between plant species, and larger bees with longer tongues tended to visit deeper flowers.4. Finally, handling time depended on the match between corolla depth and tongue length: large bees were slower than small bees when handling shallow flowers, but quicker than small bees when handling deep flowers.5. Size variation within bumblebees may be adaptive, since it enables the colony as a whole to efficiently exploit a range of different flowers. Possible explanations for the marked differences in size variation exhibited by bumblebees compared with Apis species and stingless bees (Meliponinae) are discussed.

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Over the past decade, drones have become a popular tool for wildlife management and research. Drones have shown significant value for animals that were often difficult or dangerous to study using traditional survey methods. In the past five years drone technology has become commonplace for shark research with their use above, and more recently, below the water helping to minimise knowledge gaps about these cryptic species. Drones have enhanced our understanding of shark behaviour and are critically important tools, not only due to the importance and conservation of the animals in the ecosystem, but to also help minimise dangerous encounters with humans. To provide some guidance for their future use in relation to sharks, this review provides an overview of how drones are currently used with critical context for shark monitoring. We show how drones have been used to fill knowledge gaps around fundamental shark behaviours or movements, social interactions, and predation across multiple species and scenarios. We further detail the advancement in technology across sensors, automation, and artificial intelligence that are improving our abilities in data collection and analysis and opening opportunities for shark-related beach safety. An investigation of the shark-based research potential for underwater drones (ROV/AUV) is also provided. Finally, this review provides baseline observations that have been pioneered for shark research and recommendations for how drones might be used to enhance our knowledge in the future.

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