How Task Performance Changes with Age in Two Types of Australian Stingless Bees

Jim Crocker
3rd July, 2024

How Task Performance Changes with Age in Two Types of Australian Stingless Bees

Image Source: Natural Science News, 2024

Key Findings

  • The University of Queensland studied worker bee behavior in two Australian stingless bee species, Tetragonula carbonaria and T. hockingsi
  • Young worker bees mainly clean, build brood cells, and collect honey, while middle-aged bees maintain food pots and structures
  • Older bees take on guarding and foraging tasks, but there is significant overlap in task timing among different cohorts
The University of Queensland recently conducted a study investigating the behavior and division of labor among worker bees in colonies of two commonly kept Australian stingless bee species: Tetragonula carbonaria and T. hockingsi[1]. Stingless bees are a highly social group found in tropical regions worldwide, yet their worker behavior and task allocation remain underexplored. This study aimed to fill that knowledge gap by observing how worker bees progress through various colony tasks over their lifespans. Researchers marked cohorts of 25–100 newly emerged female bees with paint dots and released them back into observation hives. They recorded the behaviors of these marked bees twice weekly within the nest and observed foragers through a clear plastic entrance tube. This process was replicated with 5–6 marked cohorts across three colonies for each species. The study found that T. carbonaria and T. hockingsi displayed similar patterns in the frequency and age distribution of behaviors. Young worker bees were primarily involved in cleaning, filling or constructing brood cells, and collecting honey from food pots. Middle-aged bees were more likely to build or maintain food pots or supporting structures, while the oldest bees took on guarding and foraging tasks. Despite these general trends, there was significant overlap in the timing of tasks, with some cohorts progressing to foraging in less than half the time of others. These findings align with previous research on the division of labor in social insects, such as honey bees. For instance, honey bees also show a progression from safer to riskier tasks as they age, a feature that appears to be ancestral and shared among stingless bees[2]. However, the study also highlights subtle differences between Tetragonula species and other stingless bees, suggesting variability even within closely related species. The study's methodology involved tracking gene expression and juvenile hormone (JH) levels, which play crucial roles in caste determination and division of labor in social insects. Previous research has shown that JH has acquired novel functions related to these processes, particularly in honey bees[3]. In contrast, stingless bees like Melipona scutellaris have maintained the ancestral gonadotropic function for JH, indicating variability in the physiological mechanisms underlying eusociality even within the same clade[3]. Moreover, the study's findings have intriguing implications for understanding the evolutionary history of eusocial behavior in bees. Earlier research has suggested that eusociality evolved once in the common ancestor of corbiculate bees, which include honey bees, stingless bees, bumble bees, and orchid bees[2]. The progression of tasks from safe to risky jobs observed in Tetragonula species adds to the evidence that this behavioral trait is an ancestral feature shared across stingless bees, despite their independent evolutionary origins from honey bees. Additionally, the study's focus on T. carbonaria and T. hockingsi is particularly relevant given recent observations of interspecific warfare between these species. Previous research documented aerial battles and hive usurpations, where T. hockingsi colonies attacked and took over T. carbonaria hives[4]. Understanding the division of labor within these species' colonies could provide insights into their competitive interactions and the factors driving such aggressive behaviors. In conclusion, this study by The University of Queensland contributes valuable knowledge about the division of labor and progression of tasks in stingless bees, particularly Tetragonula carbonaria and T. hockingsi. By comparing these findings with previous research on honey bees and other stingless bees, the study enhances our understanding of the evolutionary and physiological mechanisms underlying eusociality in bees.

GeneticsAnimal ScienceEvolution

References

Main Study

1) Age-related task progression in two Australian Tetragonula stingless bees

Published 2nd July, 2024

https://doi.org/10.1007/s00040-024-00978-z

Related Studies

2) The antiquity and evolutionary history of social behavior in bees.

https://doi.org/10.1371/journal.pone.0021086

3) Methyl farnesoate epoxidase (mfe) gene expression and juvenile hormone titers in the life cycle of a highly eusocial stingless bee, Melipona scutellaris.

https://doi.org/10.1016/j.jinsphys.2017.08.001

4) Bees at war: interspecific battles and nest usurpation in stingless bees.

https://doi.org/10.1086/678399


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