Released estimates of the number of ovarioles found in the ovaries

Released estimates of the number of ovarioles found in the ovaries of honey bee, L. wet weight and ovariole number. This study provides baseline data on ovariole number in commercial honey bee queens in the United States at a time when honey bee populations are declining; the method described can be used in studies relating ovariole number in queens to egg production and behavior. L. (Hymenoptera: Apidae), however, there are upwards of one hundred ovarioles per ovary, whereas workers of this species typically have fewer than 10 ovarioles per ovary (Snodgrass 1956; Velthuis 1970; Chaud-Netto and Bueno 1979). This striking difference in ovariole number (and corresponding reproductive capacity) between queens and workers is a result of programmed cell death of ovarian tissue during worker development of larvae not fed a diet of royal jelly (Reginato and Cruz-Landim 2002; Reginato and Cruz-Landim 2003). workers of different genotypes can differ in their number of ovarioles (Thuller et al. 1998). Variation in worker ovariole number is usually correlated with several behavioral traits, including the sugar concentration of nectar loads and the display of the retinue response to queen mandibular pheromone (Linksvayer et al. 2009; Kocher et al. 2010). Worker ovariole number is therefore a phenotype that can provide insight into the evolution of the female castes in interpersonal insects (Amdam et al. 2006; Amdam et al. 2009). Workers with more ovarioles per ovary are also more likely than workers with fewer ovarioles to order GSK1120212 be the dominant egg layers in queenless colonies (Makert et al. 2006). These and other research of employee ovariole number rely upon their accurate quantification. That is typically achieved by spreading the average person ovarioles in a drop of saline; the observer after that sights the freshly dissected ovary through a stereomicroscope and counts the ovarioles straight. Making a precise perseverance of the amount of ovarioles in a queen ovary, nevertheless, is more difficult as the typical seriously tracheated queen ovary includes 10 or even more times the amount of ovarioles as an average worker ovary (Body 1). Furthermore, the reported range for ovariole amount per ovary in honey bee queens is certainly wide, from 100 to 180 ovarioles per ovary (Snodgrass 1956). Open up in another window Figure 1. Manual dissection of an ovary of the queen. (A) Intact ovary taken off the queen’s abdominal with a dorsal midline incision. Scale bar, 500 m. (B) Start of the destructive procedure for counting ovarioles in a freshly dissected queen ovary. Level bar, 500 m. Top quality figures can be found online Due to the problems in counting many ovarioles, it really is unclear what proportion of the reported variation displays genetic Rabbit Polyclonal to GFP tag or environmentally induced developmental distinctions and what proportion basically reflects the issue of obtaining accurate counts from freshly dissected cells. The functional need for this variation among queens can be unclear. Perform queens with an increase of ovarioles lay even more eggs than queens with fewer ovarioles? It’s been argued that the large numbers of ovarioles within an average queen bee renders the precise amount meaningless: (Grosch et al. 1977). As opposed to this watch, studies of bugs with a smaller sized amount of ovarioles, such as for order GSK1120212 example employee ovaries (Chaud-Netto and Bueno 1979). Sectioning and staining The wax blocks that contains the embedded ovaries had been sectioned utilizing a rotary microtome with durable visible disposable microtome blades (C.L. Sturkey, Inc., www.sturkey.com). Brief ribbons of 10 m-heavy sections were installed in a pool of drinking water on the non-frosted part of Superfrost Plus slides (Fisher, www.fishersci.com). The slide was after that used in a slidewarmer established at 48 C. Once the warmed sections got visibly flattened, the drinking water was drained from the slide. The slide was after that cooled briefly on the counter (for about 1 minute), blotted firmly with bibulous paper, and order GSK1120212 came back to the slidewarmer over night. Slides were kept at room temperatures in a protected container until staining. The initial sections collected had been from the broadest area of order GSK1120212 the ovary and included oocytes with huge amounts of yolk and huge trophocytes. Afterwards sections included oocytes with much less yolk and smaller sized trophocytes and had been overall simpler to count, which means this level was generally chosen for mounting and staining. Significantly distal sections weren’t gathered and counted as this may cause short ovarioles to be missed. Immediately prior to staining, paraffin was removed from sections by immersion in xylene (three changes, 5 minutes each) and re-hydrated in a graded series of ethanols of descending concentrations, 5 minutes per change (100%, 100%, 95%, 70% with lithium carbonate,.