Parental effect of the marine heatwave and fish predator cues on
F2 generation
One of our important findings was that parental exposure to MHW (F1-MHW)
reduced reproductive success and grazing, but not survival of F2P. incisus when the F2 was returned to the control temperature.
The reduced F2 reproductive success and cumulative faecals may result
from reduced energy and resource investments for F1 reproduction,
further limited by the lower F1 grazing. Poor maternal provisioning was
likely the reason for the lower performance of F2 copepods whose
parental generation was exposed to MHW. A similar result has been
observed in a previous study on the same copepod species (Dinh et al.,
2021).
Across treatments, the main parental effect of FPC accounted for only
around ~2% positive effect of the cumulative nauplii
and faecals. The positive effect of parental exposure to FPC on the
reproductive outputs of offspring is common in zooplankton and this
effect may last for several generations after removing the predation
stress (see e.g. in Daphnia ambigua , Walsh, Cooley IV, Biles, &
Munch, 2015). However, the positive parental FPC effect on P.
incicus was at least an order of magnitude smaller than the negative
parental MHW effects on these life history traits and was unlikely to
shape the overall sensitivity of P. incicus to MHW. Both types of
non-consumptive predation stress, including direct and parental
exposure, had a generally small effect on P. incisus ,Pseudodiaptomus copepods account for the majority of the diet of
fish predator Lates calcarifer (Davis, 1985). MHW-induced strong
reduction in reproductive success of P. incisus may directly
affect the food availability for fish larvae in the coastal environment
(Chew et al., 2012).