Aridity promotes bet hedging via delayed hatching: a case study with two temporary pond crustaceans along a latitudinal gradient.
Climate change does affect not only average rainfall and temperature but also their variation, which can reduce the predictability of suitable conditions for growth and reproduction. This situation is problematic for inhabitants of temporary waters whose reproductive success depends on rainfall and evaporation that determine the length of the aquatic phase. For organisms with long-lived dormant life stages, bet hedging models suggest that a fraction of these should stay dormant during each growing season to buffer against the probability of total reproductive failure in variable environments. Thus far, however, little empirical evidence supports this prediction in aquatic organisms. We study geographic variation in delayed hatching of dormant eggs in natural populations of two crustaceans, Branchinella longirostris and Paralimnadia badia, that occur in temporary rock pools along a 725 km latitudinal aridity gradient in Western Australia. Consistent with bet hedging theory, populations of both species were characterised by delayed hatching under common garden conditions and hatching fractions decreased towards the drier end of the gradient where the probability of reproductive success was shown to be lower. This decrease was most pronounced in the species with the longer maturation time, presumably because it is more sensitive to the higher prevalence of short inundations. Overall, these findings illustrate that regional variation in climate can be reflected in differential investment in bet hedging and hints at a higher importance of delayed hatching to persist when the climate becomes harsher. Such strategies could become exceedingly relevant as determinants of vulnerability under climate change.
Laboratory of Aquatic Ecology, Evolution and Conservation, KU Leuven, Charles Deberiotstraat 32, 3000, Louvain, Belgium. tom.pinceel@bio.kuleuven.be.|Centre for Environmental Management, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa. tom.pinceel@bio.kuleuven.be.
Tom
0000-0001-7674-2674
T
Pinceel
Community Ecology Laboratory, Section Ecology and Biodiversity, Department of Biology, VUB (Vrije Universiteit Brussel), Pleinlaan 2, 1050, Brussels, Belgium.
Bram
B
Vanschoenwinkel
Laboratory of Aquatic Ecology, Evolution and Conservation, KU Leuven, Charles Deberiotstraat 32, 3000, Louvain, Belgium.
Wouter
W
Hawinkel
Laboratory of Aquatic Ecology, Evolution and Conservation, KU Leuven, Charles Deberiotstraat 32, 3000, Louvain, Belgium.
Karen
K
Tuytens
Laboratory of Aquatic Ecology, Evolution and Conservation, KU Leuven, Charles Deberiotstraat 32, 3000, Louvain, Belgium.|Water Research Group, Unit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
Luc
L
Brendonck
D000818:Animals; D002980:Climate; D057231:Climate Change; D003445:Crustacea; D061005:Ponds; D012098:Reproduction
Australia; Climate change; Diapause; Life history; Risk spreading