Measures Of Male Quality Research Articles

Female pied flycatchers trade between male quality and mating status in mate choice

According to mate choice theory, females should consider both male quality and mating status when choosing a mate. In birds, strong experimental evidence indicates that females prefer males with elaborate traits. No comparable evidence exists to determine whether females take male mating status into account or how they may trade between male quality and male mating status. We studied mate choice of female pied flycatchers ( Ficedula hypoleuca ) in outdoor aviaries where the effect of territory quality could be eliminated and where we could control which males were mated and which were unmated. We used male plumage colour as our measure of male quality. In the aviaries, focal females could easily compare males and assess their plumage colour and mating status, and resident females were prevented from attacking prospecting females because of separation in different compartments. The study provided evidence for a trade–off in mate choice. Females may compromise by choosing an already mated male if he is more brightly coloured and, presumably, of higher quality than available unmated males. The study did not support the idea that polygyny is based on male deception of females, but the results were consistent with the female aggression hypothesis.

Testicular Asymmetry and Secondary Sexual Characters in Red Junglefowl

The left testis tends to be larger than the right in most avian species. Moller (1994) hypothesized that the degree of directional asymmetry in the testes should be greater in high-quality males and hence should be positively correlated with secondary sexual traits. We examined both directional and absolute testicular asymmetry in Red Junglefowl (Gallus gallus), as well as the size of the left and of the larger testis, to determine whether these mea­ sures correlated with any of several potential phenotypic indicators of male quality. Such indicators included comb size; body size and condition; and fluctuating asymmetry in skeletal, plumage, and ornamental head traits (because fluctuating asymmetry may reflect an individual's ability to overcome developmental stresses). We found no evidence to support Moller's (1994) hypothesis of a relationship between directional testicular asymmetry and our measures of male quality. Moreover, there was little evidence to suggest a relationship between absolute testicular asymmetry, size of the left testis, or size of the largest testis and any measure of male quality. Finally, unlike some other studies, we did not find a tendency for the left testis to be larger than the right. Only 4 of 16 sexually mature males had a larger left testis at 10 months of age, whereas 10 of 19 males had a larger left testis at 12 months of age.

Male quality and song repertoires in western meadowlarks (Sturnella neglecta)

The relationship between song repertoire size and measures of male quality and reproductive success was examined in a Manitoba population of western meadowlarks (Sturnella neglecta). Repertoire size correlated positively with the singer's wing length but not with mass or territory size. Males with larger repertoires tended to pair earlier and males with higher pairing success had larger repertoires. Repertoire size correlated positively with fledging success independently of pairing success. As suggested for other species, repertoire size might serve as a signal to females of male quality. We suggest mechanisms by which this signalling system is maintained.

Mate-choice criteria of Ipswich sparrows: the importance of variability

Mate choice of female Ipswich sparrows, Passerculus sandwichensis princeps, was investigated with respect to a measure of territory quality (size) and a measure of male quality (singing vigour). These two measures were not correlated. Females used both territory size and male song rate to choose mates, but the importance of each trait differed between the 2 study years. In each year, the trait that varied more among males was more important in mate choice. Thus, it appears that mate choice criteria must not only be reliable but also sufficiently variable, although it is not known whether variability is important because it contributes to reliability or because more variable traits are more easily assessed.

Paternity and paternal care in the swallow, Hirundo rustica

Paternal care in the monogamous swallow, Hirundo rustica, measured in terms of frequency of feeding of young, was positively related to the certainty of paternity. Male parental care increased with the absolute number of pair copulations and decreased with the absolute and relative number of extra-pair copulations by his mate. Nearly identical results were obtained using either relative or absolute number of male feedings as a measure of the intensity of parental care. Male swallows apparently estimated their certainty of paternity from the interest that neighbouring males were taking in their mates during the fertile period. When the number of extra-pair copulations involving their mates was experimentally increased, males significantly decreased their feeding rates compared with controls. Paternal care was not related to several measures of male quality (body condition, arrival time, mite infection, song rate, or mate guarding rate).

Male quality, reproduction, and survival in the great tit (Parus major)

Three possible measures of male quality (social dominance, song, and size), reproduction, and survival were studied in a single population of great tits. Winter dominance position on a feeder was related to strophe length (number of phrases per strophe), inversely related to positive drift (decrease of the singing rate of the phrases in a strophe), but not related to song repertoire size. Neither winter dominance position nor song were related to size (wing length, tarso-metatarsus length, weight). Singing capacity was not correlated with individual reproductive success in a single breeding season, using a rather limited data set. However, “better” singers (males which sing longer strophes, show less positive drift, and have larger song repertoires) survived better and had a higher individual lifetime reproductive success (on the basis of a male's recruited offspring of all breeding seasons). Our results show that there exist measurable differences whereby birds that are dominant in winter sing “better”, survive longer, and produce more surviving offspring during their life time. We suggest that differences in male quality are the common cause (direct and indirect) of all these effects.