Heqietologica. 68(3), 201.2, 299-307 © 2012 by The Herpetologists' League, inc. ARE FEMALES MATERNAL MANIPULATORS, SELFISH MOTHERS, OR BOTH? INSIGHT FROM PYTHONS DALE F . DENARDO^''*, OLIVIER LOURDAIS^'^, AND ZACHARY R. STAHLSCHMIDT^'^ ''School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA ^Centre d'Etudes Biologiques de Chizé, CNRS UPR 1934, 79360 Villiers en Bois, France ^Department of Psychology and. Neuroscience, Dalhousie University, Halifax, NS B3H 3Z1, Canada ABSTRACT: During reproduction, females often modify their behavior relative to the nonreproductive condition. These changes are frequently attributed to maternal efforts to optimize offspring development and survival (i.e., the maternal manipulation hypothesis). However, Schwarzkopf and Andrews (2012) recently challenged this concept as oversimphfied, emphasizing that females should optimize their own lifetime fitness, and therefore maternal efforts may be directed at tlie female's future reproductive effort in addition, or even in contrast, to current reproductive effort. To provide insight into the relative importance of current versus future reproductive effort in shaping matemal behavior, we systematically e.vplore a single study system—pythons. Pythons show distinct matemal behaviors during gravidity (modified basking effort), peri- oviposition (nest site selection), and postoviposition (egg brooding). By e.\amining each component, we reveal that python matemal effort is predominandy aimed at current offspring. Yet, at times, females will make decisions that benefit tlieir future reproductive potential at a cost to their current effort. Therefore, matemal behavior likely reflects a focused effort to maximize fitness tlirough optimizing current reproductive investment, but such effort is not without consideration of future reproductive potential. Key words: Brooding; Matemal Manipulation Hypothesis; Parental care; Snakes; Thermorégulation INDIVIDUAL Btness is derived from fecundity as well as offspring quaHty because quality highly influences survival and fitness of the offspring (Fox, 1975; Sinervo and Doughty, 1996; Madsen and Shine, 1998). Therefore, maternal physiology and behavior during reproduction have received considerable at- tention. Females often modify tlieir behavior and physiology when they are reproductive. The most commonly examined adjustment, at least among ectotliermic vertebrates, is al- tered thermoregulatory behavior when fe- males are gravid or pregnant compared to when they are nonreproductive. This change in maternal behavior is the basis of the "maternal manipulation hypotliesis" (MMH; Shine, 1995), which posits that females actively regulate developmental conditions in order to optimize offspring quality. Indeed, embryonic tliermal sensitivity is a universal feature of vertebrates (Farmer, 2000), and it has been widely demonstrated Üiat maternal diermoregulation associated witli reproduc- tion accelerates development and enhances offspring quality in support of die MMH (for review, see Shine 2006). GORRESPON'DENCE: e - m a i l , d e n a r d o @ a s u . e d u Recently, Schwarzkopf and Andrews (2012) provided an alternate explanation for repro- duction-associated changes in behavior and physiology. They "propose, more generally than the MMH and consistent with life- history theory in general, that females should behave in ways that maximize their own lifetime reproductive success (Wuson et al, 2005; Marshall and Uller, 2007)." They went on to state that "although maximizing lifetime reproductive output does not preclude pro- viding benefits to offspring, it may also mean that females sometimes alter their behavior in ways that are neutral, or even detrimental, to offspring fitness ... ." For consistency witli Shine (2012, in this issue), we will refer to Schwarzkopf and Andrews' (2012) alternate approach as the "selfish mother hypothesis" (SMH). Although tliere is limited supportive empir- ical data, Schwarzkopf and Andrews provided a conceptual rationale for tlie S M11. First, females exposed to inadequate thermal con- ditions in the laboratory may abort and sometimes consume tlieir offspring (Shine and Downes, 1999; Rock and Cree, 2003), dius maximizing future reproduction over the fitness of their current offspring. In both of tlie referenced papers, however, the condition 299