Jumat, 27 Mei 2011

LEBAH RATU 3 - 蜂后 - Queen bee

LEBAH RATU 3 - 蜂后 - Queen bee


Anatomy of Honeybee Ovary


Dearden PK. Germ cell development in the Honeybee (Apis mellifera); vasa and nanos expression. BMC Dev Biol. 2006 Feb 17;6:6. PMID: 16503992
Anatomy of honeybee ovary

Structure of the Honeybee ovary. A) Diagram of the morphology of an ovariole from a mated queen bee ovary. i) the late vitellarium, ii) the early vitellarium, iii) the germarium and terminal filament (the placement of germ cells in the terminal filament is unclear and thus not diagrammed). B) A projection of 25 confocal Z sections through the late germarium of a mated honeybee queen ovariole stained for DNA using Propidium iodide (red) and cortical actin using Alexa fluor 488 phalloidin (green). C) A single confocal section through the germarium of a honeybee queen ovariole, stained as per B, Note the circular actin-rich structures, possibly ring canals. D) Diagram of the morphology of a worker bee ovariole.
Apis mellifera have polytrophic meroistic ovaries, similar to those of Drosophila melanogaster. Despite this similarity, a number of differences in morphology and biology exist. One particularly important difference is that worker bee ovaries have many less ovarioles than those of queens. Workers in a queenright colony have small ovaries that are chemically repressed by the presence of the queen and her eggs. Removal of the queen from a colony can cause the reactivation of the worker bee ovaries and the workers may lay eggs.
Meroistic
In meroistic insect ovaries divisions of gonial cells lead to formation of clusters of sibling cells which remain interconnected by intercellular bridges forming a syncytium. In the meroistic ovary, the oocyte synthesizes little if any RNA. Most of the RNA which accumulates in the oocyte is synthesized by trophocytes.
Polytrophic
In the polytrophic meroistic ovary each ovariole contains a number of clusters of germ cells that form separate structural and functional units termed egg chambers. Each oocyte is associated with a cyst containing 1,3,7 or 15 trophocytes. The trophocytes are derived from the same cell as the oocyte.



Reducing Honeybee Queen Fighting Ability


 

Dietemann V, Zheng HQ, Hepburn C, Hepburn HR, Jin SH, Crewe RM, Radloff SE, Hu FL, Pirk CW. Self assessment in insects: honeybee queens know their own strength. PLoS One. 2008 Jan 9;3(1):e1412. PMID: 18183293
Honeybee queens

Three A. m. ligustica queens (circled) coexisting peacefully within a colony.
In China, beekeepers found a way to prevent queens from killing one another by ablating their mandibles. By forcing several queens to cohabit, they create more productive colonies for commercial exploitation.
Interestingly, queens with ablated mandibles refrain from engaging in lethal contests that typically characterize their reproductive dominance behavior and coexist peacefully within a colony. This suggests that weak queens exploit an alternative reproductive strategy and provides an explanation for rare occurrences of queen cohabitation in nature. The results of experiments described in theis article further indicate that self-assessment, but not mutual assessment of fighting ability occurs prior to and during the agonistic encounters.




AmTOR Knockdown Blocks Queen Fate and Results in Workers

 

 

Patel A, Fondrk MK, Kaftanoglu O, Emore C, Hunt G, Frederick K, Amdam GV. The making of a queen: TOR pathway is a key player in diphenic caste development. PLoS One. 2007 Jun 6;2(6):e509. PMID: 17551589
Honey bees (Apis mellifera) provide a principal example of diphenic development. Excess feeding of female larvae results in queens (large reproductives). Moderate diet yields workers (small helpers). The signaling pathway that links provisioning to female developmental fate is not understood. Authors of the article tested their hypothesis that it could include TOR (target of rapamycin), a nutrient- and energy-sensing kinase that controls organismal growth.

amTOR suppression on caste characters in honeybees

Effect of amTOR suppression on caste characters in honey bees. In comparison to control (GFP), amTOR RNAi (RNAi): a, reduced larval growth (exemplified by 4-day-old larvae in sections of a microtiter plate, larval volume is mean±s. e. arbitrary units a.u.); delayed development, b–c, where b is a snapshot of the full phenotypic variance in each group (individuals were 19 days old) – controls emerged with queen morphology, or had advanced pigmentation (indicates more rapid development) and large size. RNAi bees were lightly pigmented and small in size; the latter effect is shown also in d, the wet-weight at adult emergence and in e, the final adult size. Adult size did not overlap between treatment groups (e vs. f, where f shows the two control bees with lowest wet-weight: 155 and 161 mg; weight-range after RNAi was 108–136 mg). amTOR RNAi also reduced ovary size g, to ovariole numbers characteristic of workers (GFP range was 12–180, RNAi range was 2–7 ovarioles per ovary). In sum, the divergence between control and amTOR RNAi is characteristic of queen vs. worker development. Bars are means±s. e. (three asterisks P<1.0 10−3). Scale bars a: 10 mm; b, e, f: 5 mm.


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