Growth and male ornamentation in Xiphophorus montezumae
نویسندگان
چکیده
Juvenile growth rate is an important life-history trait that affects the size at maturity, and may influence the development of sexual ornamentation. The sword of several species of the genus Xiphophorus (Teleostei: Poeciliidae) is an elaborate secondary sexual trait that confers an advantage in terms of sexual selection, counterbalanced by locomotive and predatory costs. This study assesses differences in male juvenile growth, age, and size at maturation and their relationship with maximum body size and sword elongation in Montezuma swordtails (Xiphophorus montezumae). Fish size and sword length were measured over the course of 20 months. The size at which individual males initiated sword elongation varied considerably among individuals. Male maximum body size was correlated with early growth rate and age of maturation, and sword growth rate was positively correlated with male size at the onset of sword growth. Early growth in X. montezumae may provide valuable information about performance in subsequent stages and about probable future reproductive success.
منابع مشابه
The macromelanophore locus and the melanoma oncogene Xmrk are separate genetic entities in the genome of Xiphophorus.
Fish of the genus Xiphophorus are polymorphic for black pigmentation patterns. Certain intra- or interspecific hybrids exhibit enhanced expression of these patterns, leading in many cases to malignant melanoma. Because no recombination was ever observed between the pattern information and the genetic predisposition to develop melanoma after hybridization, a "tumor gene" (Tu) was postulated that...
متن کاملSpontaneous thyroidal tumors in the Swordtail Xiphophorus montezumae.
Early studies of the thyroid tumors of trout (3—5)have demonstrated the relationship between iodine supply and hyperplastic growth of thyroid cells. Experimental work with fishes provided much of the background for the present under standing of the etiology of human goiters. In con trast with encapsulated mammalian goiters, how ever, hyperplastic thyroids in fishes are remark able for their i...
متن کاملIs UV ornamentation an amplifier in swordtails?
Do distinct male morphs use the same ornaments in different ways? Female preference for UV ornamentation and male activity was examined in two different male size classes of the swordtail Xiphophorus nigrensis: intermediate and large. UV ornamentation is preferred by females for both size classes, while high male activity is not. Large males have significantly greater intensity and saturation o...
متن کاملThe turn of the sword: length increases male swimming costs in swordtails.
Sexual selection via female mate choice can result in the evolution of elaborate male traits that incur substantial costs for males. Despite increased interest in how female mating preferences contribute to the evolution of male traits, few studies have directly quantified the locomotor costs of such traits. A sexually selected trait that could affect movement costs is the sword exhibited by ma...
متن کاملGreen swordtails alter their age at maturation in response to the population level of male ornamentation.
Effects of the social environment on age at sexual maturation are assumed to require direct interactions, such as suppression of subordinates through aggression from dominants. Using green swordtails (Xiphophorus helleri), we demonstrate for the first time that females and males adjust their age at maturation in response to visual cues of male sexual ornamentation in the current environment: fe...
متن کامل