Biochemical adaptation for dormancy in subitaneous
and dormant eggs of Daphnia magna.
Well-fed, amictic females produce typical, thin-shelled amictic eggs that are subitaneous and develop without arrest into females.
Under these conditions, the food concentration remains high, and amictic females produce only subitaneous eggs.
To initiate these experiments, subitaneous eggs were collected from stock cultures maintained on a high concentration of C.
This life-table experiment was initiated by placing subitaneous eggs individually into 2.8 mL cryule vials filled with three concentrations of C.
For one calanoid copepod (Onychodiaptomus sanguineus), both temperature and photoperiod can be used as cues to switch between production of diapausing and subitaneous eggs (Hairston and Kearns, 1995).
A method for distinguishing subitaneous and diapausing eggs in preserved samples of the calanoid copepod genus Diaptomus.
While active during winter these copepods make subitaneous (immediately hatching) eggs (Hairston and Munns, 1984); in early spring they switch to making diapausing eggs, and they continue to do so until they are eliminated in late spring or early summer by sunfish predation.
Here we provide evidence that temperature and photoperiod acting together are sufficient to effect the rapid transition, as observed in Bullhead Pond, from subitaneous to diapausing eggs.
sanguineus to make subitaneous or diapausing eggs in a pattern consistent with the seasonal phenology observed in Bullhead Pond.
We mated 144 females in 125-ml glass jars (one female and two males per jar) at 8:16 L:D photoperiod and 4.8 [degrees] C (i.e., short-day and cold conditions to ensure that all clutches produced were subitaneous; see Hairston and Olds, 1986, 1987).
pulex, populations consist of females, which produce subitaneous
(direct-developing) eggs, apomictically.