@article {52605, title = {Complex coevolution of wing, tail, and vocal sounds of courting male bee hummingbirds}, journal = {Evolution}, year = {2018}, month = {May-01-2020}, abstract = {

Phenotypic characters with a complex physical basis may have a correspondingly complex evolutionary history. Males in the \‘bee\’ hummingbird clade court females with sound from tail-feathers, which flutter during display dives. On a phylogeny of 35 species, flutter sound frequency evolves as a gradual, continuous character on most branches. But on at least six internal branches fall two types of major, saltational changes: mode of flutter changes, or the feather that is the sound source changes, causing frequency to jump from one discrete value to another. In addition to their tail \‘instruments\’, males also court females with sound from their syrinx and wing feathers, and may transfer or switch instruments over evolutionary time. In support of this, we found a negative phylogenetic correlation between presence of wing trills and singing. We hypothesize this transference occurs because wing trills and vocal songs serve similar functions and are thus redundant. There are also three independent origins of self-convergence of multiple signals, in which the same species produces both a vocal (sung) frequency sweep, and a highly similar non-vocal sound. Moreover, production of vocal, learned song has been lost repeatedly. Male bee hummingbirds court females with a diverse, coevolving array of acoustic traits.

}, keywords = {courtship, Mellisugini, Sonation, Wind Tunnel}, doi = {10.1111/evo.13432}, url = {http://doi.wiley.com/10.1111/evo.13432}, author = {Clark, Christopher J. and McGuire, Jimmy A. and Bonaccorso, Elisa and Berv, Jacob S. and Prum, Richard O.} } @article {52604, title = {Age-dependent variation in the terminal investment threshold in male crickets}, journal = {Evolution}, year = {2018}, month = {Jan-02-2018}, abstract = {

The terminal investment hypothesis proposes that decreased expectation of future reproduction (e.g., arising from a threat to survival) should precipitate increased investment in current reproduction. The level at which a cue of decreased survival is sufficient to trigger terminal investment (i.e., the terminal investment threshold) may vary according to other factors that influence expectation for future reproduction. We test whether the terminal investment threshold varies with age in male crickets, using heat-killed bacteria to simulate an immune-inducing infection. We measured calling effort (a behavior essential for mating) and hemolymph antimicrobial activity in young and old males across a gradient of increasing infection cue intensity. There was a significant interaction between the infection cue and age in their effect on calling effort, confirming the existence of a dynamic terminal investment threshold: young males reduced effort at all infection levels, whereas old males increased effort at the highest levels relative to na\ïve individuals. A lack of a corresponding decrease in antibacterial activity suggests that altered reproductive effort is not traded against investment in this component of immunity. Collectively, these results support the existence of a dynamic terminal investment threshold, perhaps accounting for some of the conflicting evidence in support of terminal investment.

}, keywords = {Age-dependent reproductive effort, fecundity compensation, Gryllodes sigillatus, residual reproductive value, trade-offs}, doi = {10.1111/evo.13443}, url = {http://doi.wiley.com/10.1111/evo.13443}, author = {Duffield, Kristin R. and Hampton, Kylie J. and Houslay, Thomas M. and Hunt, John and Rapkin, James and Sakaluk, Scott K. and Sadd, Ben M.} } @article {47572, title = {Reproductive character displacement of female, but not male song discrimination in an avian hybrid zone}, journal = {Evolution}, year = {2017}, month = {Nov-05-2017}, abstract = {

Divergence of male sexual signals and female preferences for those signals often maintains reproductive boundaries between closely related, co-occurring species. However, contrasting sources of selection, such as interspecific competition, can lead to weak divergence or even convergence of sexual signals in sympatry. When signals converge, assortative mating can be maintained if the mating preferences of females diverge in sympatry (reproductive character displacement; RCD), but there are few explicit examples. Pied flycatchers (Ficedula hypoleuca) are sympatric with collared flycatchers (F. albicollis) on the Baltic island of \Öland, where males from both species compete over nestboxes, their songs converge, and the two species occasionally hybridize. We compare song discrimination of male and female pied flycatchers on \Öland and in an allopatric population on the Swedish mainland. Using field choice trials, we show that male pied flycatchers respond similarly to the songs of both species in sympatry and in allopatry, while female pied flycatchers express stronger discrimination against heterospecific songs in sympatry than in allopatry. These results are consistent with RCD of song discrimination of female pied flycatchers where they co-occur with collared flycatchers, which should maintain species assortative mating despite convergence of male sexual signals.

}, doi = {10.1111/evo.13267}, url = {http://doi.wiley.com/10.1111/evo.13267}, author = {Wheatcroft, David and Qvarnstr{\"o}m, Anna} } @article {15175, title = {Calling Songs of Field Crickets (Teleogryllus oceanicus) With and Without Phonotactic Parasitoid Infection}, journal = {Evolution}, volume = {52}, year = {1998}, month = {Jan-02-1998}, pages = {166}, abstract = {

The field cricket Teleogryllus oceanicus has been introduced to Hawaii, where it is parasitized by an acoustically orienting parasitoid fly, Ormia ochracea. Previous work showed that call parameters from parasitized populations differ from those in unparasitized populations in a direction expected if selection by flies is occurring. Here we examined songs of males collected in the field and compare calling song characters of crickets later found to harbor parasitoid larvae with those of males free of parasitoids. The two groups differ significantly in several song characteristics, particularly the trill-like long chirp given at the beginning of each song. Males with longer long chirps containing shorter interpulse intervals are more likely to be parasitized, suggesting that the flies find such males more attractive. Depending on the traits females prefer, sexual selection may oppose natural selection in altering T. oceanicus song in parasitized populations.

}, issn = {00143820}, doi = {10.2307/2410931}, url = {http://www.jstor.org/stable/2410931?origin=crossref}, author = {Zuk, Marlene and Rotenberry, John T. and Simmons, Leigh W.} } @article {13434, title = {Reproductive Character Displacement and Speciation in Periodical Cicaadas with Description of a New Species, 13-Year Magicicada neotredecim}, journal = {Evolution}, volume = {54}, year = {2000}, month = {Jan-08-2000}, pages = {1313 - 1325}, issn = {0014-3820}, doi = {10.1111/evo.2000.54.issue-410.1111/j.0014-3820.2000.tb00564.x}, url = {http://www.blackwell-synergy.com/toc/evo/54/4}, author = {Marshall, David C. and Cooley, John R.} }