Aj. Ali et al., Cyst production in the fairy shrimp, Streptocephalus proboscideus (Anostraca) in relation to algal and loricated rotifer diet, CRUSTACEANA, 72, 1999, pp. 517-530
Adult fairy shrimps, Streptocephalus proboscideus (Frauenfeld, 1873) reared
separately using algae (Scenedesmus acutus Meyen), a large loricate rotife
r (Brachionus calyciflorus Pallas, 1766) and mixtures of algal and animal d
iets (1:1 ratio on a dry weight basis) at a rate of 17 mu g DW ml(-1) day(-
1) produced a mean number of 184 +/- 38, 111 +/- 14, and 160 +/- 14 cysts p
er brood, respectively. Of these, the rotifer-only diet was significantly i
nferior to both other food types. Measurements of cyst volume revealed an e
ffect of food type. With all three types, S. proboscideus produced cysts in
the size range of 3.0-9.0 x 10(6) mu m(3). However, sizes smaller than 3.0
-9.0 x 10(6) mu m(3) occurred in algae-fed anostracans and those larger tha
n 3.0-9.0 x 10(6) mu m(3) in rotifer-fed individuals. When the mean cyst pr
oduction was expressed in terms of volume instead of numbers, there was a s
uggestion that the mixture of algae and rotifers was the superior combinati
on, while females reared on rotifers produced a significantly (38%) lower t
otal cyst volume. Hatchability of cysts, either dried or un-dried, was not
significantly different between treatments.