Systematics and Ecology of Southeast Asian bumblebees
File(s)
Author(s)
Thanoosing, Chawatat
Type
Thesis
Abstract
Bumblebees (Hymenoptera: Apidae: Bombus) are important pollinators, especially in temperate areas. They also inhabit in tropical montane biomes in Southeast Asia (SEA), leading to the question, whether these bumblebees are truly tropical species or are they restricted to temperate-like habitats. However, the fundamental knowledge about SEA bumblebees has been insufficient. To understand better, their systematics and ecology have been studied in this thesis. First, the taxonomy of SEA bumblebees is reviewed to clarify their classification and identification, based on specimen collections and surveys. Twenty-three species of bumblebee have been collected in SEA. Second, a widely-distributed SEA species with colour variation, Bombus flavescens was selected as a model for reconstructing biogeographic history. Species delimitation was studied using evidence including morphology and COI barcodes. The results show that all variations within the flavescens complex belongs to the same species, with a common ancestor in the temperate Himalaya. Third, elevation of habitats, activity pattern, and climatic niches of SEA bumblebees were assessed, based on specimen databases and field observation. SEA bumblebee species live at different elevations. The selected species are still active during the warmest time of the year, but in early morning or late afternoon to avoid heat stress. They can survive in the tropical conditions of high temperature and humidity. Fourth, the bumblebee pollen diets provide evidence to assess specialisation in the tropics, where flowering trees are the predominantly resources for bees. Pollen morphology and metabarcoding of pollen-diet samples were used. Bumblebees in Thailand and Vietnam foraged from native plants, not only from herbs but also from shrubs and trees. The finding of this study suggests that SEA bumblebees include both of temperate and tropical species. The signs of tropical adaptation in SEA bumblebees are observed. This thesis extends biological knowledge of SEA bumblebees, providing a stronger foundation for their conservation.
Version
Open Access
Date Issued
2022-05
Date Awarded
2023-01
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Vogler, Alfried
Williams, Paul
Publisher Department
Life Sciences
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)