I expect that the answer is a combination of these and probably other factors that we have not even considered. But it is fun to contemplate here, snug and warm, in our winter lairs.



It is clearly a combination, and don't assume that the queen is the only one involved.  My thesis work was on the Big Headed Grasshopper (Aulocara elliotii) (it has blue knees).  Like most grasshoppers, the eggs are laid in pods (look a bit like bunches of bananas) in the ground.  The develop inside the egg goes to a specific point, then stops for the winter (diapause).  



Abstract
Diapause termination, postdiapause duration, and field hatch of the bigheaded grasshopper, Aulocara elliotti (Thomas), were studied in southwest Montana during a 3-yr period. In general, >70% of the sampled population had completed diapause by mid-November each year. Postdiapause embryonic developmental rates were obtained from a function fitted to hatch versus time data collected at constant temperatures ranging from 15 to 42°C. The population model design system was used to predict hatch at 2 sites in southwestern Montana for 3 yr. First-instar occurrence was monitored by sweep net samples and used to assess the accuracy of the predictions. When simulated hatch was compared with field occurrence of 1st instars, the 50% occurrence dates were very similar (within 2.2 ± 1.1 d for all 5 comparisons). 

Aulocara elliotti (Orthoptera: Acrididae): Diapause Termination, Postdiapause Development, and Prediction of Hatch (PDF Download Available). Available from: https://www.researchgate.net/publication/233673134_Aulocara_elliotti_Orthoptera_Acrididae_Diapause_Termination_Postdiapause_Development_and_Prediction_of_Hatch [accessed Dec 13 2017].



One of my Ph.D. Committee Members spent her whole career looking at this development, it's triggers, and 'maternal influence' - the condition of the female laying the eggs had carry-over effects on the offspring.


Typically, diapause ends in the spring, and development proceeds. We know that part of this is a certain number of degree days below a set threshold.  Just after I first married, we got the Jan thaw in MT, and I and my bride went out to a field near Townsend, MT and panned for grasshopper eggs.  By my count, the eggs would need at least a couple of weeks at elevated temperatures to break diapause.  We got home late in the day, and I took the pan with several hundred grasshopper eggs, covered in a layer of dry sand, and set it in the laundry room of our Apartment.  My wife asked - Aren't you going to take them up to the lab and put them in an incubator?  I said, Nah, no need, I'm forcing early diapause break, it's take a couple of weeks.   


We were tired from the trip and the work, so went to bed early.  Next morning, she woke before me.  Next thing I hears was "JERRY!!!".   She was looking into the laundry room.  There in the room on the tile floor were tiny, first nymphs grasshoppers jumping around.   That was one of those thngs that wives never let you forget.

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