The Evolution of Luminescent Courtship Signals in Caribbean Ostracods
MetadataShow full item record
Kates, Hilary Suzanne Curran
Males of a unique group of Caribbean ostracods use luminescence in their mating process. These ostracods show high microhabitat specificity and complex extracellular species-specific luminescent courtship displays, which result in a symphony of firework-type displays over shallow Caribbean reef systems after nightfall. Each ostracod’s mating signal consists of a train of light pulses composed of an initial slow “call phase” and a terminal targeting “trill phase” of regular, more rapid and shorter, narrowly spaced pulses. Ostracod displays play a crucial role in sexual selection and therefore speciation in this group. We examined which characteristics of these displays might be used by individuals among three clades of luminescent Caribbean ostracods (Photeros-group, Kornickeria-group and ‘H’-group, based on morphological and molecular work) to differentiate conspecifics from other species. We hypothesized that the more variable initial phase characteristics used in species recognition are more important in shaping the evolution of Caribbean ostracods than those characteristics that make up the constrained trill phase. We combined frame-by-frame analyses of videos of displays from the field for two undescribed species with analyses of 22 species based on published data. We overlaid our findings onto an independently derived phylogeny based on molecular and morphological data of 14 of these 24 species to determine possible signal evolution patterns. Our findings suggest phylogenetic signatures in 5 aspects of the display signal: the duration of the complete signal train, duration and length of the initial phase, the number of pulses in the trill phase, and the amount of time between consecutive pulses in the trill.
ostracods; luminescence; courtship; signaling
dissertation or thesis