Stable and persistent male-like behavior during male-to-female sex change in the common clownfish Amphiprion ocellaris

Bidirectional sex‐change behavior and physiological aspects in the Gorgeous goby Lythrypnus pulchellus (Gobiidae)

“…The experiments determined the brief window immediately following the formation of male–male and female–female pairs, which is the “challenge” period (Wingfield et al ., 1990) when the social status is established (dominance phase; Reavis & Grober, 1999) to subsequently initiate sex change (Parker et al ., 2022; Reavis & Grober, 1999). As in most fish species living in social or haremic groups, L. pulchellus sex change is socially controlled, and sex is determined by social status (Muñoz‐Arroyo et al ., 2019, 2020).…”

“…showing that the rapid emergence of the new courtship and mating behavior may be better indicators for behavioral sex change than increased aggressive behavior alone (Parker et al, 2022). Nevertheless, the early social status establishment did not significantly affect the time of protandrous and protogynous sex change when one individual was larger than the other one.…”

“…Pradhan, Connor, et al, 2014;Sakai et al, 2003;Semsar & Godwin, 2003;Todd et al, 2019). Sex change can occur in as little as 4 (female-to-male) and 6 days (male-to-female) in T. okinawae (Sunobe & Nakazono, 1993;Yamaguchi, 2016) in contrast with the protandrous species pattern, such as A. ocellaris, in which the transition from male-to-female gonad is as long as 6 months (Parker et al, 2022).…”

“…Possibly, the differences in the periods of social status establishment between same-sized and different-sized pairs but no difference in the overall time required for sex change in L. pulchellus could be due to the following reasons: (a) individuals in pairs were never in contact with each other before the experiment; in contrast Reavis and Grober (1999) used groups of individuals with great difference in size between them and who also had prior knowledge of each other to form stable hierarchy before stimulating sex change by removing the only male from the group (MR); (b) although the increase in the frequency of the aggressive behavior "approach" was an important signal by which periods of social status were determined in L. pulchellus, if the "nest defense" is also considered, it may mean that periods of dominance establishment would be similar between same-sized and different-sized pairs (Reavis & Grober, 1999;Shapiro, 1981) is not progressively female-like as sex change progresses until after the gonadal sex change is complete (Parker et al, 2022) but similar to other well-established models like the protogynous wrasses of several species (Godwin et al, 1996;Nakashima et al, 2000;Sakai et al, 2002;Todd et al, 2019;Warner & Swearer, 1991), angelfish Centropyge vroliki (Sakai et al, 2003), and bidirectional gobies like L. dalli and Trimma okinawae (Black, Mooreb, et al, 2005;Grober & Sunobe, 1996;Pradhan, Solomon-Lane, & Grober, 2014;Reavis & Grober, 1999;Rodgers et al, 2005Rodgers et al, , 2007. However, in L. pulchellus, unlike behavior, hormones do not gradually move in the direction of the new sexual phenotype over the course of sex change.…”

“…Sex change, in most cases, is under social control (Kobayashi et al ., 2012; Kuwamura et al ., 2023; Lamm et al ., 2015; Prim et al ., 2022), which means the loss of a dominant male in a small social group. This situation generates a permissive social environment for a subordinate individual (usually the largest female in the group) to ascend to the dominant position in the social hierarchy and sex change (Godwin, 1994a; Lorenzi et al ., 2006; Manabe et al ., 2007; Parker et al ., 2022; Sunobe & Nakazono, 1993; Warner & Swearer, 1991). The presence of a dominant individual in a social group suppresses the sex change of the subordinates, which is mediated via aggression and monopolization of resources and provokes stress to subordinates, increasing cortisol (Ct) synthesis as the dominant stress corticosteroid signal in fish (Perry & Grober, 2003).…”