Risk-sensitive foraging in a tropical lizard

Foraging opportunities can be unpredictable. When foragers face a choice
between resources that vary in predictability, foraging decisions not only
depend on the profitability of food but also on their physiological state.
This risk-sensitive foraging approach, in which animals take greater
foraging risks when starving, remains relatively untested in reptiles
compared to other taxa. We tested the risk-sensitive foraging theory in
the tropical lizard, Psammophilus dorsalis, by manipulating energy budgets
(satiated vs. 48-hour starved) and measuring foraging preferences for
options that differed in rewards: constant (2 mealworms) vs. variable (0
or 4  mealworms). We find that satiated lizards were risk averse
to variability in reward amounts and chose the constant food option more
frequently than the variable option. By contrast, starved lizards were
risk prone and chose the variable reward option more often than the
constant one. At the end of 28 foraging trials, these strategies resulted
in both starved and satiated groups achieving similar net resource gains.
As new support for risk-sensitive foraging in a tropical reptile species,
these results provide insight on how resource uncertainty influences
foraging strategies. For lizards in the tropics, which have high energy
requirements year-round, risk-sensitive foraging could be an effective
strategy in stochastic environments.