The costs of reproduction to males and females of a paternal mouthbrooding cardinalfish Apogon notatus

Abstract

In the cardinalfish Apogon notatus, starving males mouthbrood the eggs, and females are more active than males in courtship and in attacks against conspecific intruders upon their breeding territory, but sexual ornaments are developed in males. Condition factor, hepatosomatic index and fat body-somatic index declined in both sexes during the breeding season. The deterioration of somatic condition was more severe in females, suggesting that the overall energetic costs were larger for females which produced more than twice as many clutches as males brooded in a season. Selective mortality of females could be due primarily to the depletion of their energy reserves. The increased mortality in females is a possible mechanism for the male-biased operational sex ratio which may provide the potential for sexual selection on males. 2001 The Fisheries Society of the British Isles

To feed or to breed: morphological constraints of mouthbrooding in coral reef cardinalfishes

“…This expanded buccal volume has been attributed to larger osteological elements and/or increased flexibility of soft tissues in the brooding sex [24,34,39]. The significance of the larger buccal volume has been related to increased reproductive potential [40], and increased respiratory efficiency of both the eggs [37] and the brooding parent [41]. Despite these perceived advantages, causality between mouthbrooding and buccal volume cannot be assumed without further examination.…”

Breathing with a mouth full of eggs: respiratory consequences of mouthbrooding in cardinalfish

“…The cardinalfish males keep the eggs in the mouth at least until they hatch, which takes 1-2 weeks (Thresher 1984;Okuda 1999). Since the egg clutch virtually fills the oral cavity of the brooding males, the males do not feed, although they may eat some of the eggs (filial cannibalism) (Okuda & Yanagisawa 1996;Okuda 2001). The consequence of mouthbrooding on the nutritional status has been examined in several studies (e.g.…”

“…The consequence of mouthbrooding on the nutritional status has been examined in several studies (e.g. Smith & Wootton 1994;Okuda 2001), and in most cases the starvation is not so severe that it leads to a higher mortality of the mouthbrooding sex (Okuda 2001).…”

Short-term changes in energy allocation by Hemiodontidae fish after the construction of a large reservoir (Lajeado Dam, Tocantins River)

“…In the first years after the impoundment, we recorded reductions in reproductive activity for both species, while visceral fat and body mass increased consistently. The suppression of reproduction must have caused these alterations, considering that reproduction activities demand much energy (Okuda, 2001;McBride et al, in press). In natural regimes, gonad maturation and behavioral aspects cause a significant consumption of energy reserves, such as lipid tissues (Adams & Huntingford, 1997; Arrington et al, 2006), which are restored between to reduce, particularly for females.…”