---Read at least the abstract and introduction sections :)Describe whether the trait in question is an example of intersexual selection or intrasexual selection. Abstract Although external sexually dimorphic traits arecommonly found in males of combtooth blenny species,little is known about the benefit they can convey to malemating success. Indeed, while female preferences forlarge males have been demonstrated in some species, thepossible role played by dimorphic ornaments has beenneglected. We now report on the tentacled blenny, Pa-rablennius tentacularis, a species where males are char-acterized by bulb glands on the anal fin and both sexesexhibit a dark spot on the dorsal fin and orbital tenta-cles. Males are territorial, make nests in empty bivalveshells, and provide solitary parental care for the eggs.Using morphometric analysis and field collected data onmale and female external features, nest characteristicsand number of eggs in the nests, we have assessed thedevelopment of dimorphic traits in both sexes and malemating success. The results reveal that orbital tentaclesof males are more developed and more variable in sizethan those of females. Larger males exhibit longerorbital tentacles and larger anal glands but do not nec-essarily occupy larger nests. Male mating success is sig-nificantly correlated with the inner nest surface area andwith orbital tentacle size but not with body size. Theseresults provide support for a primary role of maleornaments in enhancing blenny male mating success andare discussed in the context of mate choice for direct andindirect benefits.IntroductionWhen Darwin (1871), referring to some Blenniidaespecies, penned: ".. a crest is developed on the head ofthe male during the breeding-season, and the body at thesame time becomes more bright-coloured. There can belittle doubt that this crest serves as a temporary sexualornament, for the female does not exhibit a trace of it."he was using an excellent model to indicate the possiblerole of sexual selection in shaping fish external traits.Combtooth blennies are one of the teleost familiesexhibiting the most diverse array of sexually dimorphictraits, including body size, colour pattern, enlargeddorsal fins, cephalic ornaments such as crests or differenttypes of tentacles, and specialized glands on the medianfins (Breder and Rosen 1966; Zander 1975; Papaco-stantinou 1979). Blenny dimorphic features can be eithertemporary, such as male spawning colours, or perma-nent (Thresher 1984). Among the latter, some are pres-ent only in males, while others are present in both sexesbut more pronounced in males (Smith 1974; Zander1975; Papacostantinou 1979; Thresher 1984).A crest on the head, as well as nasal, orbital, andnape tentacles, have been described in both sexes ofsome Mediterranean blennies (Zander 1975). In Salariapavo, one of the most extensively studied species (Fi-shelson 1963; Patzner et al. 1986; Ruchon et al. 1995;Gonçalves et al. 1996; Oliveira et al. 1999), the crest'sheight is known to be influenced by sexual selection,with males adopting an opportunistic mating tacticbeing poorly ornamented compared to dominant, terri-torial males (Ruchon et al. 1995; Gonçalves et al. 1996).Orbital tentacles have been described to be more devel-oped in males of Aidablennius sphynx and some Para-blennius species (Zander 1975); however, quantitativeinformation on their inter- and/or intra-sexual variabil-ity has never been collected. Another set of dimorphictraits in blennies that is permanent and found only inmales are the glands located on median fins: fleshy padson the leading edge of the anal fin or on the rays of the anal and dorsal fins (Eggert 1931; Wickler 1957; Smith1974; Zander 1975; Northcott and Bullock 1991). Theglands, developing on the two most anterior anal spines,called bulb glands, are globular and rugose, while thosedeveloping on the ends of soft anal and dorsal fin rays,called club glands, are elliptical and smooth (Zander1975). Their presence and morphology appear to varywidely among species (Smith 1974; Zander 1986). Inaddition, in some Mediterranean species the presence ofthese glands appears to vary with male mating tactics,being highly developed in territorial nesting males whileabsent or rudimentary in parasitic males (Ruchon et al.1995; Gonçalves et al. 1996; Oliveira et al. 2001a; Neat etal. 2003). However, the role of these glands in repro-duction and sexual selection is not well understood. Insummary, despite Darwin's indication that some blennyexternal traits may serve to enhance male attractiveness,detailed studies on the full set of dimorphic charactersdisplayed by a species in order to verify their intra- and/or inter-sexual variability and their possible relationwith male mating success, still remain scanty.Blenny reproductive patterns appear to be consistentthroughout the family (Breder and Rosen 1966;Thresher 1984; Patzner et al. 1986; Côté and Hunte1989a; Kraak 1994; Sunobe et al. 1995; Oliveira et al.1999). Males defend a breeding territory in which fe-males come to spawn in a cavity, such as holes, emptyshells, crevices, etc. Eggs are demersal, are laid in asingle layer on the inner surface of the nest, and areguarded exclusively by the male until hatching (Brederand Rosen 1966; Thresher 1984). In all species studied todate, egg batches at different stages of development havebeen found in the same nest, a robust indication ofpolygyny, and females have been described to sequen-tially lay eggs with different males (Patzner et al. 1986;Côté and Hunte 1989a; Santos and Barreiros 1993;Kraak 1994; Neat and Locatello 2002). Hence, themating system, often defined as a resource defencepolygyny, can be considered promiscuous. Male matingsuccess has consistently been shown to be positivelycorrelated with body size and/or nest size (Côté andHunte 1989a, b; Sunobe et al. 1995; Oliveira et al. 1999;Oliveira et al. 2000; Gonçalves et al. 2002; Neat andLocatello 2002). Other morphological and behaviouralmale traits, such as age, body colour, intensity ofcourtship and intensity of parental care, while playing amajor role in some species (Côté and Hunte 1993;Oliveira et al. 2000), appeared unrelated to male successin others (Kraak 1994). The variability of sexuallydimorphic traits, other than male size and coloration,was investigated only in the peacock blenny where theydid not appear to be significantly related to male matingsuccess (Oliveira et al. 1999; Gonçalves et al. 2002).In this study we examined the natural variation ofsome external traits and male mating success in thetentacled blenny, Parablennius tentacularis (Brünnich1768), a shallow water species inhabiting rocky sub-strates in the Mediterranean, Black Sea and the Atlantic(Zander 1986). This medium-sized blenny spawns inholes where males care for eggs; both sexes have a blackspot on the dorsal fin and orbital tentacles (Zander1986). Males, in addition, exhibit bulb glands on thespiny rays of the anal fin (Zander 1986). With the aim toinvestigate the correlates of male mating success, nestsand nesting males were collected in the field and data onmale traits, nest inner surface area and egg clutches wererecorded.

Question

---Read at least the abstract and introduction sections :)Describe whether the trait in question is an example of intersexual selection or intrasexual selection. Abstract Although external sexually dimorphic traits arecommonly found in males of combtooth blenny species,little is known about the benefit they can convey to malemating success. Indeed, while female preferences forlarge males have been demonstrated in some species, thepossible role played by dimorphic ornaments has beenneglected. We now report on the tentacled blenny, Pa-rablennius tentacularis, a species where males are char-acterized by bulb glands on the anal fin and both sexesexhibit a dark spot on the dorsal fin and orbital tenta-cles. Males are territorial, make nests in empty bivalveshells, and provide solitary parental care for the eggs.Using morphometric analysis and field collected data onmale and female external features, nest characteristicsand number of eggs in the nests, we have assessed thedevelopment of dimorphic traits in both sexes and malemating success. The results reveal that orbital tentaclesof males are more developed and more variable in sizethan those of females. Larger males exhibit longerorbital tentacles and larger anal glands but do not nec-essarily occupy larger nests. Male mating success is sig-nificantly correlated with the inner nest surface area andwith orbital tentacle size but not with body size. Theseresults provide support for a primary role of maleornaments in enhancing blenny male mating success andare discussed in the context of mate choice for direct andindirect benefits.IntroductionWhen Darwin (1871), referring to some Blenniidaespecies, penned: &#34;.. a crest is developed on the head ofthe male during the breeding-season, and the body at thesame time becomes more bright-coloured. There can belittle doubt that this crest serves as a temporary sexualornament, for the female does not exhibit a trace of it.&#34;he was using an excellent model to indicate the possiblerole of sexual selection in shaping fish external traits.Combtooth blennies are one of the teleost familiesexhibiting the most diverse array of sexually dimorphictraits, including body size, colour pattern, enlargeddorsal fins, cephalic ornaments such as crests or differenttypes of tentacles, and specialized glands on the medianfins (Breder and Rosen 1966; Zander 1975; Papaco-stantinou 1979). Blenny dimorphic features can be eithertemporary, such as male spawning colours, or perma-nent (Thresher 1984). Among the latter, some are pres-ent only in males, while others are present in both sexesbut more pronounced in males (Smith 1974; Zander1975; Papacostantinou 1979; Thresher 1984).A crest on the head, as well as nasal, orbital, andnape tentacles, have been described in both sexes ofsome Mediterranean blennies (Zander 1975). In Salariapavo, one of the most extensively studied species (Fi-shelson 1963; Patzner et al. 1986; Ruchon et al. 1995;Gonçalves et al. 1996; Oliveira et al. 1999), the crest'sheight is known to be influenced by sexual selection,with males adopting an opportunistic mating tacticbeing poorly ornamented compared to dominant, terri-torial males (Ruchon et al. 1995; Gonçalves et al. 1996).Orbital tentacles have been described to be more devel-oped in males of Aidablennius sphynx and some Para-blennius species (Zander 1975); however, quantitativeinformation on their inter- and/or intra-sexual variabil-ity has never been collected. Another set of dimorphictraits in blennies that is permanent and found only inmales are the glands located on median fins: fleshy padson the leading edge of the anal fin or on the rays of the anal and dorsal fins (Eggert 1931; Wickler 1957; Smith1974; Zander 1975; Northcott and Bullock 1991). Theglands, developing on the two most anterior anal spines,called bulb glands, are globular and rugose, while thosedeveloping on the ends of soft anal and dorsal fin rays,called club glands, are elliptical and smooth (Zander1975). Their presence and morphology appear to varywidely among species (Smith 1974; Zander 1986). Inaddition, in some Mediterranean species the presence ofthese glands appears to vary with male mating tactics,being highly developed in territorial nesting males whileabsent or rudimentary in parasitic males (Ruchon et al.1995; Gonçalves et al. 1996; Oliveira et al. 2001a; Neat etal. 2003). However, the role of these glands in repro-duction and sexual selection is not well understood. Insummary, despite Darwin's indication that some blennyexternal traits may serve to enhance male attractiveness,detailed studies on the full set of dimorphic charactersdisplayed by a species in order to verify their intra- and/or inter-sexual variability and their possible relationwith male mating success, still remain scanty.Blenny reproductive patterns appear to be consistentthroughout the family (Breder and Rosen 1966;Thresher 1984; Patzner et al. 1986; Côté and Hunte1989a; Kraak 1994; Sunobe et al. 1995; Oliveira et al.1999). Males defend a breeding territory in which fe-males come to spawn in a cavity, such as holes, emptyshells, crevices, etc. Eggs are demersal, are laid in asingle layer on the inner surface of the nest, and areguarded exclusively by the male until hatching (Brederand Rosen 1966; Thresher 1984). In all species studied todate, egg batches at different stages of development havebeen found in the same nest, a robust indication ofpolygyny, and females have been described to sequen-tially lay eggs with different males (Patzner et al. 1986;Côté and Hunte 1989a; Santos and Barreiros 1993;Kraak 1994; Neat and Locatello 2002). Hence, themating system, often defined as a resource defencepolygyny, can be considered promiscuous. Male matingsuccess has consistently been shown to be positivelycorrelated with body size and/or nest size (Côté andHunte 1989a, b; Sunobe et al. 1995; Oliveira et al. 1999;Oliveira et al. 2000; Gonçalves et al. 2002; Neat andLocatello 2002). Other morphological and behaviouralmale traits, such as age, body colour, intensity ofcourtship and intensity of parental care, while playing amajor role in some species (Côté and Hunte 1993;Oliveira et al. 2000), appeared unrelated to male successin others (Kraak 1994). The variability of sexuallydimorphic traits, other than male size and coloration,was investigated only in the peacock blenny where theydid not appear to be significantly related to male matingsuccess (Oliveira et al. 1999; Gonçalves et al. 2002).In this study we examined the natural variation ofsome external traits and male mating success in thetentacled blenny, Parablennius tentacularis (Brünnich1768), a shallow water species inhabiting rocky sub-strates in the Mediterranean, Black Sea and the Atlantic(Zander 1986). This medium-sized blenny spawns inholes where males care for eggs; both sexes have a blackspot on the dorsal fin and orbital tentacles (Zander1986). Males, in addition, exhibit bulb glands on thespiny rays of the anal fin (Zander 1986). With the aim toinvestigate the correlates of male mating success, nestsand nesting males were collected in the field and data onmale traits, nest inner surface area and egg clutches wererecorded.

Accepted Answer

Intrasexual selection occurs when there is a competition between members of the same sex usually…