Ontogenic time and worker longevity in the Australian stingless bee, Austroplebeia australis

Little is known about the biology and life cycle of the Australian stingless bee, Austroplebeia australis (Friese). The ontogenic times for developing offspring, as well as the longevity of adults, drive the overall life cycle of a social colony. The developmental times for brood within stingless bee species which build cluster-type nests, such as A. australis, are as yet unreported. A technique was developed whereby ‘donor’ brood cells were separated from the main brood cluster and ‘grafted’ into hive annexes, allowing workers from within the colony to access the brood ‘grafts’ for hygiene and maintenance activities, whilst enabling observation of developing brood. The mean ontogenic time for A. australis workers, maintained at ~27 °C, was 55 days, which is similar to that reported for other stingless bees. The maximum longevity of A. australis was determined by marking cohorts of worker bees within five colonies. Workers within all colonies demonstrated extended longevity, with an overall maximum longevity of 161 days, with the oldest bee living for 240 days. Extended longevity may result from evolutionary adaptations to the floral resource scarcity, which is regularly experienced in semi-arid, inland Australia, the natural habitat of A. australis

The thermal environment of nests of the Australian stingless bee, Austroplebeia australis

The greatest diversity of stingless bee species is found in warm tropical regions, where brood thermoregulation is unnecessary for survival. Although Austroplebeia australis (Friese) naturally occurs in northern regions of Australia, some populations experience extreme temperature ranges, including sub-zero temperatures. In this study, the temperature was monitored in A. australis colonies' brood chamber (n = 6) and the hive cavity (n = 3), over a 12-month period. The A. australis colonies demonstrated some degree of thermoconformity, i.e. brood temperature although higher correlated with cavity temperature, and were able to warm the brood chamber throughout the year. Brood production continued throughout the cold season and developing offspring survived and emerged, even after exposure to very low (-0.4 °C) and high (37.6 °C) temperatures. Austroplebeia australis, thus, demonstrated a remarkable ability to survive temperature extremes, which has not been seen in other stingless bee species

The Australian stingless bee industry : a follow-up survey, one decade on

In 2010, an online survey was conducted to assess the current status of the Australian stingless bee industry and its recent development. This was a follow-up survey conducted approximately one decade after the first study, by Heard and Dollin in 1998/99. It showed that the Australian industry had grown over the past ten or so years but is still underdeveloped. There was a 2.5-fold increase in the number of bee keepers and a 3.5 fold increase in the number of domesticated colonies. Seventy-eight percent of bee keepers were hobbyists, 54% of whom owned only one colony. Most colonies were kept in suburban areas. Two species, Tetragonula carbonaria and Austroplebeia australis, dominated the relatively short list of species kept. There was a high demand for Australian stingless bee colonies and their honey, but with less than 250 bee keepers currently propagating colonies, and many of them on a small scale, it is difficult to meet this demand. Pollination services were provided by less than 4% of the major stakeholders within the industry. Further research and development in the area of colony propagation may see this industry grow more quickly

Delimiting the species within the genus Austroplebeia, an Australian stingless bee, using multiple methodologies

Austroplebeia Moure is an Australian stingless bee genus. The current descriptions for the species within this genus are inadequate for the identification of specimens in either the field or the laboratory. Here, using multiple diagnostic methodologies, we attempted to better delimit morphologically identified groups within Austroplebeia . First, morphological data, based on worker bee colour, size and pilosity, were analysed. Then, males collected from nests representing morphologically similar groups were dissected, and their genitalia were imaged using light microscopy and scanning electron microscopy. Next, data for the geometric morphometric analysis of worker wing venations were obtained. Finally, molecular analysis, using mitochondrial 16S ribosomal RNA (16S rDNA), was conducted on workers from representative nests for each group which displayed morphological similarities. Data deriving from the four different diagnostic approaches were compared, resulting in the separation of two groups, plus an unresolved species complex

Microbial diversity in stingless bee gut is linked to host wing size and influenced by the environment.

Stingless bees are important social corbiculate bees, fulfilling critical pollination roles in many ecosystems. However, their gut microbiota, particularly the fungal communities associated with them, remains inadequately characterised. This knowledge gap hinders our understanding of bee gut microbiomes and their impacts on the host fitness. We collected 121 samples from two species, Tetragonula carbonaria and Austroplebeia australis across 1200 km of eastern Australia. We characterised their gut microbiomes and investigated potential correlations between bee gut microbiomes and various geographical and morphological factors. We found their core microbiomes consisted of the abundant bacterial taxa Snodgrassella, Lactobacillus and Acetobacteraceae, and the fungal taxa Didymellaceae, Monocilium mucidum and Aureobasidium pullulans, but variances of their abundances among samples were large. Furthermore, gut bacterial richness of T. carbonaria was positively correlated to host forewing length, an established correlate to body size and fitness indicator in insects relating to flight capacity. This result indicates that larger body size/longer foraging distance of bees could associate with greater microbial diversity in gut. Additionally, both host species identity and management approach significantly influenced gut microbial diversity and composition, and similarity between colonies for both species decreased as the geographic distance between them increased. We also quantified the total bacterial and fungal abundance of the samples using qPCR analyses and found that bacterial abundance was higher in T. carbonaria compared to A. australis, and fungi were either lowly abundant or below the threshold of detection for both species. Overall, our study provides novel understanding of stingless bee gut microbiomes over a large geographic span and reveals that gut fungal communities likely not play an important role in host functions due to their low abundances