Beauty alone is insufficient: female mate choice in the barn swallow

Abstract

The barn swallow, Hirundo rustica, is a model species for studying sexual selection, particularly female mate choice. Although there have already been several reviews of female mate choice and its geographic variation in this species, all of them have focused on secondary sexual characteristics. Here, for better understanding of the general pattern of female mate choice and their influence on male phenotype, I review all of the female mate choice criteria ever reported in the barn swallow, emphasizing the importance of relatively inconspicuous male traits. These include resources defended or provided by males, such as territory and paternal investment. In addition, females prefer a nestling-like vocalization, enticement call, which is particularly noteworthy because females prefer immature calls. This pattern contrasts with female choice based on secondary sexual characteristics, in which more mature, elaborate male traits are almost always favored. Nestling-like male traits are widespread, and thus female avoidance of, rather than preference for, mature forms might be common. In addition to selection on the target trait itself, these resources and nestling-like male traits would also matter in understanding the evolution of the overall male phenotype and its geographic variation, due to the interrelationships among male target traits and those among female mate preferences. Female preferences for inconspicuous traits are highly dependent on ecological factors such as nest predation pressure, and thus overall male phenotype including secondary sexual characteristics might be more predictable than previously thought. Future studies should focus on not only conspicuous secondary sexual characteristics but inconspicuous male traits.

Female choice for sick males over healthy males: Consequences for offspring

“…Females may have used pheromone as a first trait to evaluate males to then correct their decision after copulation as implied by the differential allocation hypothesis. As a matter of fact, females of several species use a number of traits to have a "balanced" assessment of male quality (e.g., Hill, Enstrom, Ketterson, Nolan, & Ziegenfus, 1999;Hankison & Morris, 2003;Hasegawa, 2018) which is in agreement with theory (Candolin, 2003;Møller & Pomiankowski, 1993). Perhaps extended filters occur after copulation, whereby females assess other traits that may be coupled with male condition (e.g., Evans, Zane, Francescato, & Pilastro, 2003).…”

Probability of incubation by male Japanese Barn Swallows increases with plasma testosterone level

“…50%; e.g. Arai et al , Hasegawa , ), and thus males can simply sit on clutches to monitor and physically protect their offspring from predators (and from competitors such as Tree Sparrows Passer montanus ; Ministry of the Environment ; also see Komdeur & Kas for increased nest attendance of males in response to high nest predation rates in Seychelles Warblers Acrocephalus sechellensis ). Because high‐testosterone males exhibit poor physiological conditions such as low body condition (Safran et al , Hasegawa et al ), sitting on warm clutches may also function as social huddling, saving energy reserves.…”

“…The Japanese Barn Swallow Hirundo rustica gutturalis is a suitable study model for this research goal. Unlike the nominate subspecies H. r. rustica , in which only the females incubate (Turner ), some, but not all, male H. r. gutturalis incubate (mean proportion of incubation by males = 6%, range 0–20%; Hasegawa et al , Hasegawa , ), as in the sister subspecies, H. r. erythrogaster (e.g. mean 9%, Smith & Montgomerie ; reviewed by Turner ).…”

“…mean 9%, Smith & Montgomerie ; reviewed by Turner ). Male Barn Swallows lack brood patches, but male incubation still has an adaptive function by slowing egg cooling (Voss et al ), and hence shortening the period of incubation (Hasegawa ). The low rate of extra‐pair paternity (<3%; Hasegawa et al ) in this ‘outdoor’ population (i.e.…”

Mineralogical and textural characteristics of nest building geomaterials used by three sympatric mud-nesting hirundine species

“…Nest quality plays a significant role in breeding performance and success in mud-nesting hirundine species 7 , yet it has been principally studied in terms of site and habitat selection 8 – 11 , territory quality 12 and the properties of nest-lining feather material 13 . However, little is known about the quality of the soil materials used for nest construction 14 , 15 .…”