The coin was the first in the
RCM's series of glass insects on silver coins and took a little time to catch on with collectors. The series became popular, however, so the
RCM raised the mintage limits for subsequent issues - 10,000 to 12,500 coins.
The higher mintages enabled more collectors to start the series with the second or third coin. Those that wanted to have a complete set then had to compete with other collectors over the more limited number of "first" coins available (5,000 vs. 10,000).
The combination of "first coin" plus comparatively low mintage for the Ladybug coin within the series creates a situation where there is more demand than supply. So, the price has risen dramatically.
My personal view is that the series has mostly run its course and demand for all coins in the series will wane a bit. I think the Ladybug coin will be cheaper in the future, but that's just my opinion. I'm sure others will disagree.