Although life histories are shaped by temperature and predation, their joint influence on the interdependence of life-history traits is poorly understood. Shifts in one life-history trait often necessitate shifts in another-structured in some cases by trade-offs-leading to differing life-history strategies among environments. The offspring size-number trade-off connects three traits whereby a constant reproductive allocation ( ) constrains how the number ( ) and size ( ) of offspring change. Increasing temperature and size-independent predation decrease size at and time to reproduction which can lower through reduced time for resource accrual or size-constrained fecundity. We investigated how and in a clonal population of change across their first three clutches with temperature and size-independent predation risk. Early in ontogeny, increased temperature moved and along a trade-off curve (constant ) toward fewer larger offspring. Later in ontogeny, increased temperature reduced in the no-predator treatment through disproportionate decreases in relative to . In the predation treatment, likewise decreased at warmer temperatures but to a lesser degree and more readily traded off for whereby the third clutch showed a constant allocation strategy of versus with decreasing . Ontogenetic shifts in and rotated in a counterclockwise fashion as temperature increased and more drastically under risk of predation. These results show that predation risk can alter the temperature dependence of traits and their interactions through trade-offs.

© 2024 Aaron A. King
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