Here is my "spin" on this at this point.
I think if one reads the past posts in this thread carefully you will find that black and white crappie can feed on zooplankton. It may not have been specifially stated that way since white crappie tend to have a larger portion of their diet as minnows as compared to black crappie.
If you dig into the good fishery literature you will find that white crappie will at times feed heavily on zooplankton. In a PA reservoir, Mathur and Robbins 1971 concluded that plankton feeding by adult white crappie was due to their long gill rakers. Becker says zooplankter type organisms are a significiant food throughout the life of white crappie. but insects and forage fish are usually the major food of large white crappie. The percentages of zooplankton, insects and fish seem to vary somewhat with each study. In an IA study plant materials & insect adults never accounted for more than 5% of the diet of white crappie.
I think white crappie tend to eat more fish and less invertebrates than the black crappie for probably two reasons. 1. White crappie may have a slightly greater "preference" for fish than black crappie. 2. and more importantly ecological conditions may play a big role in diet of the two crappie species. White crappie seem to be more tolerant of cloudier water or are found to be more successful or occur more frequently in "muddier" or cloudier water than black crappie who succeed best in clearer waters where larger zooplankton forms thrive. Normally zooplankton at least the larger forms of zooplankton do not thrive as well in muddier conditions compared to clearer waters. Phytoplankton (zooplankton food) also does not grow as well in muddier water compared to clearer water; it is a light thing. Cloudier water probably contains relatively more minnow forage items than larger zooplankton items and white crappie thrive there and thus eat what is most abundant, small fish. Clearer water typically has relatively more forms of larger zooplankton and fewer forage minnows thus black crappie thrive better in those conditons and a big part of their diet becomes zooplankton since it is relatively more abundant or "easier" to eat/catch. White crappie may have more minnows in their diet due to a particular lake has a stronger small fish community than the assemblage of larger forms of zooplankton, thus these whites eat more small fish since they are relatively more abundant.
Bottomline, I think both types of crappie can utilize large zooplankters and the extent that each eats those zooplankters depends on how abundant the larger zooplankters are in each individual lake/pond compared to the abundance and compositon of the small fish community.
