Published: September 6th, 2016
Here we describe our detailed protocol for the preparation of single-cohort honeybee colonies – a useful tool for analyzing the role-associated worker physiology. We also describe detailed protocols for treating workers with juvenile hormone and ecdysone to evaluate the involvement of these hormones in the regulation of worker behavior and/or physiology.
Honeybee workers are engaged in various tasks related to maintaining colony activity. The tasks of the workers change according to their age (age-related division of labor). Young workers are engaged in nursing the brood (nurse bees), while older workers are engaged in foraging for nectar and pollen (foragers). The physiology of the workers changes in association with this role shift. For example, the main function of the hypopharyngeal glands (HPGs) changes from the secretion of major royal jelly proteins (MRJPs) to the secretion of carbohydrate-metabolizing enzymes. Because worker tasks change as the workers age in typical colonies, it is difficult to discriminate the physiological changes that occur with aging from those that occur with the role shift. To study the physiological changes in worker tissues, including the HPGs, in association with the role shift, it would be useful to manipulate the honeybee colony population by preparing single-cohort colonies in which workers of almost the same age perform different tasks. Here we describe a detailed protocol for preparing single-cohort colonies for this analysis. Six to eight days after single-cohort colony preparation, precocious foragers that perform foraging tasks earlier than usual appear in the colony. Representative results indicated role-associated changes in HPG gene expression, suggesting role-associated HPG function. In addition to manipulating the colony population, analysis of the endocrine system is important for investigating role-associated physiology. Here, we also describe a detailed protocol for treating workers with 20-hydroxyecdysone (20E), an active form of ecdysone, and methoprene, a juvenile hormone analogue. The survival rate of treated bees was sufficient to examine gene expression in the HPGs. Gene expression changes were observed in response to 20E- and/or methoprene-treatment, suggesting that hormone treatments induce physiological changes of the HPGs. The protocol for hormone treatment described here is appropriate for examining hormonal effects on worker physiology.
The European honeybee, Apis mellifera, is a eusocial insect with a highly organized society1. Worker honeybees (labor caste) are engaged in various tasks to maintain colony activity, and these tasks change according to the worker honeybee's age after eclosion, which is referred to as age-related division of labor2-4. Young workers (<13 days old) take care of the brood in the hive by secreting royal jelly (nurse bees), while older workers (>15 days old) collect nectar and pollen outside of the hive (foragers)2-4. The physiology of the workers changes in association with this role shift. For example, the function of ....
1. Preparation of Single-cohort Colonies
An overview of the protocol for preparing single-cohort colonies is illustrated in Figure 1A. Time-course of experiments from preparing single-cohort colonies to sample collection is shown in Figure 1B. Workers that satisfied the behavioral criteria for nursing behavior or foraging behavior were collected from single-cohort colonies, and HPG development was estimated in these workers. Table 1 shows the classification of HPG development in.......
Preparation of single-cohort colonies
Here we described the protocol used in our previous study16 to prepare single-cohort colonies for analysis of HPG physiology associated with the shift in the role of worker bees. Nurse bees and precocious foragers that satisfied the criteria described in procedures 1.6-1.7 and Figure 2 were observed in the single-cohort colonies (Table 1). The photographs in Figure 2 would be useful in classific.......
This work was supported by a Grant-in-Aid for Scientific Research (B) and a Grant-in Aid for Scientific Research on Innovative Areas 'Systems Molecular Ethology' from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. T.U. was the recipient of a Grant-Aid from the Japan Society for the Promotion of Science for Young Scientists.....
|Marker pen for the application of marks to bees
|Breeding case insect
|homogenization of tissue
|the reagent for total RNA extraction
|PrimeScript RT reagent kit
|the reagent for reverse transcription
|SYBR Premix ExTaq II
|the reagent for real-time PCR
|LightCycle 1.2 Instrument
|the instrument for real-time PCR
|LightCycle Capillaries (20μl)
|the material for real-time PCR
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