Energetics of parental care in six syntopic centrarchid fishes

Abstract

We studied parental behavior in six syntopically breeding species of centrarchid fishes to determine whether energetic costs could contribute to our understanding of the diversity of parental care. We used a combination of underwater videography, radio telemetry and direct observation to examine how the cost of parental care varied with both its duration and intensity. Duration of parental care, activity patterns, and energetic costs varied widely among species. Overall, the duration of care increased with parental size between species. When energetic costs were adjusted for species-specific differences in the duration of parental care, the cost of parental care also increased with mean size of the species. Species with extended parental care exhibited stage-specific patterns of activity and energy expenditure consistent with parental investment theory, whereas fish with short duration parental care tended to maintain high levels of activity throughout the entire period of parental care. The only apparent exception (a species with brief parental care but stage-specific behavior) was a species with multiple breeding bouts, and thus effectively having protracted parental care. These data suggest that some species with short duration parental care can afford not to adjust parental investment over stages of offspring development. Using our empirical data on parental care duration and costs, we reevaluated the relationship between egg size and quality of parental care. Variation in egg size explained almost all of the observed variation in total energetic cost of parental care, and to a lesser degree, duration-the larger the eggs, the more costly the parental care. This research highlights the value of incorporating energetic information into the study of parental care behavior and testing of ecological theory.

Stress, nutrition and parental care in a teleost fish: Exploring mechanisms with supplemental feeding and cortisol manipulation

“…The energy requirements for parental care in bass largely are supplied by endogenous energy stores (i.e. lipids), making it essential that parental males build up the required energy reserves needed to sustain parental effort throughout the care period prior to spawning (Smith and Wootton, 1995;Cooke et al, 2006;Hanson et al, 2009;Gravel et al, 2010). Thus the energy gained through food supplements may not have been necessary to improve parental effort during the initial egg and egg-sac fry stages of the brood development period, which was when our behavioural assessments were conducted.…”

“…The parental care period is an inherently challenging and dynamic life stage requiring a large energetic reserve to maintain parental activities and sustain homeostatic setpoints; and for parental smallmouth bass this is compounded by a voluntary reduction in feeding, limiting their energetic budget (Ridgway and Shuter, 1994;Cooke et al, 2006;Hanson et al, 2009;Zuckerman and Suski, 2013). Food supplementation throughout the egg and egg-sac fry stage of brood development provided a consistent source of food energy during periods of energy-intensive parental activity, presumably off-setting the high energetic cost of parental care.…”

Cardiovascular performance of six species of field-acclimatized centrarchid sunfish during the parental care period

“…A common trait that arose in protocentrarchids that helps to define the family centrarchidae is the presence of sole paternal care (Gross, 1980). However, parental investment varies widely among these species (Cooke et al, 2006). For example, bluegill provide care for several days whereas smallmouth bass provide care for several weeks.…”

“…Parental care also requires variable activity levels . Therefore, we predicted that fish with intense parental care as indicated by high levels of relative energetic expenditure (Cooke et al, 2006) will be correlated with the degree of frequency modulation. We further predicted that those species with extended care will require more time to exhaust, recover more rapidly, and do so with increased scope, and have increased relative changes in heart rate (f H ) than fish with short duration care.…”

Adjustment of brood size and androgen levels in a teleost species with exclusive male parental care

“…Males may do so through modulation of female spawning rate via sexual and agonistic behaviours and through filial cannibalism (Manica 2002). Functionally, this may optimize their current and future reproductive effort, because care and defence behaviours are costly activities (van den Berghe 1992; Almada et al 1994;Gonçalves & Almada 1997Cooke et al 2006) and parental effort has been found to be proportional to brood size in several fish species (e.g. Magnhagen & Vestergaard 1993;Karino & Arai 2006).…”