No short-term physiological costs of offspring care in a cooperatively breeding bird

Abstract

The cost of reproduction results in a life-history trade-off where investment in current reproduction via costly parental care decreases subsequent fitness. Although this trade-off is thought to occur ubiquitously across animals, there is equivocal evidence that parental care behaviours are costly. A major challenge of studying the cost of parental care has been a lack of consensus over which physiological mechanisms underlie this trade-off. Here, we compare four traits believed to mediate the cost of parental care by examining whether glucocorticoids, oxidative stress, immune function or body condition represent a cost of performing offspring care and shape subsequent fitness. We use a 4 year dataset collected in free-living cooperatively breeding superb starlings (), a species in which parental and alloparental care effort varies widely among individuals and across years. Our results showed that within-individual change in physiology was unrelated to investment in offspring care, and physiological state during chick rearing did not predict the likelihood that an individual would breed in subsequent seasons. Instead, individuals that had elevated baseline corticosterone during incubation performed more nest guarding, suggesting that this hormone may play a preparatory role for investing in offspring care. Together, our results indicate that superb starlings modify their investment in offspring care according to their physiological state during incubation, despite there being no evidence of a short-term physiological cost of parental or alloparental care. Thus, breeding cooperatively appears to provide individuals with the flexibility to adjust their investment in offspring care and overcome any potential costs of reproduction.

Extreme and Variable Climatic Conditions Drive the Evolution of Sociality in Australian Rodents

“…The emergence of sociality would be adaptive in the context of facilitating cooperative behaviors that offset the physiological demands of living in a harsh environment (e.g., communal nesting, foraging, constructing shelters, engaging in group territory defense [21,[23][24][25][26]; Figures 3D-3F; Table S1). Moreover, cooperating as a group would be an effective strategy for individuals to offset the costs of reproduction [27][28][29]. An analysis of mammals has linked climatic patterns to the distribution of cooperative breeding on a global scale [30], and many desert rodents, including Australian species, are reported to engage in alloparental care [24,31].…”

Social dominance and reproduction result in increased integration of oxidative state in males of an African cichlid fish

“…We propose that studies on the oxidative cost of demanding life history events more generally (e.g. migration: (Eikenaar et al, 2020); parental care: (Guindre-Parker and Rubenstein, 2018)) should include analyses of how different components of oxidative stress are interconnected. Even in the absence of difference in mean values in redox markers between for examples breeders and nonbreeders, there might be differences in correlation structure that could provide important insights into the role of oxidative stress as a mediator of life history trade-offs.…”

Climate change as a catalyst of social evolution

“…Interestingly, emerging ecological trends appear to parallel these macroevolutionary patterns. Studies of social-living birds and mammals support the notion that exposure to stressful or unpredictable climatic conditions serve as an ecological primer for investment in cooperative behaviours (Blumstein and Armitage 1999, Canário et al 2004, Covas et al 2008, Guindre-Parker and Rubenstein 2018a, 2018b. Importantly, measurable improvements in performance of cooperative groups appears to be linked to the ability to flexibly adjust behaviours, such as coordination and synchronicity, when faced with adverse conditions.…”