Browsing by Author "Monroe, Michelle K."
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Item Duetting behavior varies with sex, season, and singing role in a tropical oriole (Icterus icterus)(Oxford University Press, 2017-08-11) Odom, Karan J.; Logue, David M.; Studds, Colin E.; Monroe, Michelle K.; Campbell, Susanna K.; Omland, Kevin E.Females and males of many animals combine their vocalizations into coordinated acoustic duets. Duets can mediate both cooperation and conflict between partners, and are common in tropical, sedentary species that may use duets for multiple functions year-round. To elucidate the full range of duet functions, we need to study the individual-level behaviors that generate duets throughout the year. We evaluated multiple functions of duetting behavior in female and male Venezuelan troupials (Icterus icterus) during the breeding and nonbreeding seasons, including territory defense, maintaining contact with a mate, and paternity guarding. In both sexes during both seasons, song initiation rates were predicted by conspecific solo and duet rates. However, troupials were more likely to answer their mate to form duets after conspecific duets than after conspecific solos, supporting a territory defense function of duets. Troupials that answered their mate to form duets were also more likely to move toward their mate (than duet initiators and soloists), suggesting that duet participation also functions to maintain contact. During the breeding season, males were particularly likely to fly toward their mate after answering to form a duet. This finding may indicate that males answer to guard paternity, although other predictions of paternity guarding were not supported. Examining individual-level behaviors during both the breeding and nonbreeding season revealed multiple functions of troupial duets. Our results are consistent with social selection acting on females and males to maintain contact and territories year-round, and possibly sexual selection on males for functions tied to the breeding season.Item Typical Males and Unconventional Females: Songs and Singing Behaviors of a Tropical, Duetting Oriole in the Breeding and Non-Breeding Season(Frontiers Media S.A., 2016-02-25) Odom, Karan J.; Omland, Kevin E.; McCaffrey, David R.; Monroe, Michelle K.; Christhilf, Jennifer L.; Roberts, Natalie S.; Logue, David M.Recent research emphasizes that female song is evolutionarily important, yet there are still few species for which we have quantified the similarities and differences between male and female song. Comparing song rates and the structure of female and male song is an important first step to forming hypotheses about functional and evolutionary differences that may exist between females and males, especially in year-round territorial species that may use their songs for breeding and non-breeding activities. We compared female and male singing rates and song structure in a tropical New World oriole, the Venezuelan troupial (Icterus icterus) during both the breeding and non-breeding season and between the dawn and day. Males sang solos at particularly high rates during the breeding season before dawn. Females, however, sang at consistent rates year-round, primarily during the day. Females answered 75% of male day songs, producing duets, whereas males answered only 42% of female songs. Duets were common year-round, but occurred more often during the non-breeding season. Structurally, female songs were higher pitched and shorter than male songs. We detected no sex differences in the number or order of syllables, however, interestingly, answers were shorter than duet initiations and solos, and, during the breeding season, songs that initiated duets were characterized by higher syllable diversity than were answers or solos. The fact that males sing more during the breeding season supports the classical hypothesis that male song is a sexually selected trait. However, our findings that females sing solos and answer the majority of male songs to create duets year-round suggests that female song may have evolved to serve multiple functions not exclusively tied to breeding.