Fig 1.
Crenuchus spilurus individuals.
Male above and female below. Note differences in size, shape and color of the anal and dorsal fins.
Fig 2.
Graphical representation of sizes of individuals used in dichotomous choice trials.
Blue squares represent males, red circles represent females used in A) female choice trials, and B) male choice trials. The > symbol represents trials using size-controlled individuals, other trials involved random selection of fish sizes.
Fig 3.
Relationship between measures of individual quality and body size in Crenuchus spilurus.
The function of (A) dorsal and (B) anal fins as ornaments increases as males grow. Females are represented by filled circles and are taken as a baseline measure of the fin function as swimming stability (driven solely by natural selection). Difference between curves (grey shaded areas) represents the function of male’s fins as ornaments. The cone format of this shaded area (with base toward highest values of SL) indicates an increase in the function as ornaments of male’s fins as individuals grow. Reproductive investment of females increases with size, as observed by the positive relationship of oocyte size (C) and fecundity (D).
Table 1.
Inferred parameters and significance values of exponent (x) power regression (Y = a·SLx) conducted to measure the relationship of several biotic characteristics against standard length (SL) of Crenuchus spilurus.
Regression lines are drawn in Fig 1.
Fig 4.
Association time of according with size-similar and size-dissimilar individuals.
Trials conducted under (A) female choice experiment, and (B) male choice experiment. Lines connect observations from the same individual.
Fig 5.
Spawning success in relation to size asymmetry of sailfin tetra couples.
Males and females more similar in body length (lower size asymmetry), are more likely to spawn than couples with larger size asymmetries. Shades of gray represent number of trials with similar size asymmetry (darker points represent more trials).