Supporting Information Appendix S2: We used a two-member mixing model (Equation 6)
following Frost et al. (2005) in order to quantify the influence of short-term ingestion (3 h) on
the overall phosphorus and carbon content of a neonate. We therefore assumed a neonate
carbon content (neonate C) without any additionally ingested food after birth as 100%. The C
content of the neonate was used to calculate the phosphorus content of the neonate (neonate
P) assuming a P:C ratio of 8.7 mmol mol-1, which was the mean of all (starved) neonates in
our neonate nutrition experiment. Furthermore our model included terms for the amount of
additionally ingested phosphorus (Pi) and the amount of additionally ingested carbon (Ci).
Thereby Ci was assumed as percentage value between 0 (starvation) and 30 % of neonate’s C
content. Pi was calculated via Ci and the respective P:C ratio of the different diets between 1.5
and 6.7 mmol mol-1.
The model of neonate P:C ratio influenced by different amounts of additionally ingested
food predicts that the P:C ratio of the neonates would remain constant if they would starve
(Fig. A). This is in accordance to our laboratory data showing no effect of dietary P on
neonates P:C ratio when they starve. But if food with different P content was present, the
model predicts a decrease of neonates’ P:C ratios with lower dietary P. This decrease would
be intensified within an increasing amount of Ci, and Pi respectively. This complies with our
laboratory data showing explicitly lower neonate P:C ratios when they fed P-deficient food.
We conclude that Daphnia neonates could ingest at least 20%, in fact even up to 30%, of their
body C content within 3 h.
whole neonate P : C 
neonate P  Pi
neonate C  Ci
(6)
Two-member mixing model where neonate P is the phosphorus content of a neonate
and neonate C is the carbon content of a neonate. Pi is the amount of additionally
ingested phosphorus and Ci is the amount of additionally ingested carbon.
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Neonate P:C ratio (mmol mol )
10
9
8
model 0%
model 15%
model 20%
model 30%
lab without food
lab with food
7
6
0
1
2
3
4
5
6
7
Food P:C ratio (mmol mol-1)
Fig. A Two-member mixing model of neonate P:C ratios influenced by short-term ingestion
(three hours) of different proportions of food differing in dietary P. We tested for ingestion
amounts between 0% (= without food) and 30% relative to the body C mass. The model
predictions are plotted as diamonds. Additionally the mean of neonates’ P:C ratios measured
in the lab (see Fig. 4) are displayed as circles
Reference
Frost P.C., Hillebrand H. & Kahlert M. (2005) Low algal carbon content and its effect on the
C : P stoichiometry of periphyton. Freshwater Biology, 50, 1800-1807.
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