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The importance of symmetry in an insect communication system. A critical examination of “Symmetry in the songs of crickets” Simmons & Ritchie (1996). Luke Verburgt. Prof J.W.H. Ferguson. Dr T. Weber. Introduction. Males sing to attract females. Gryllus bimaculatus.
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The importance of symmetry in an insect communication system. A critical examination of “Symmetry in the songs of crickets” Simmons & Ritchie (1996) Luke Verburgt Prof J.W.H. Ferguson Dr T. Weber
Introduction Males sing to attract females Gryllus bimaculatus
Introduction Bandwidth 0.4kHz 5.3 kHz 4.9 ~ 150ms
Introduction FA Fluctuating Asymmetry (R-L) Developmental Instability
Introduction DA Directional Asymmetry (R-L) Genetically determined
Simmons & Ritchie (summary) • MALES • Harp size is correlated with body size • Call frequency is correlated with harp size • Call bandwidth is correlated with DA of harp • FA morph is correlated with DA of harp • Therefore: Females can “hear” how symmetrical a male is • FEMALES • Prefer pure-tones indicative of a symmetrical male • Therefore: • Females can “choose” symmetrical males acoustically
Conclusion for Males • Harp size is correlated with body size • Call frequency is correlated with harp size • Call bandwidth is correlated with DA of harp • FA morph is correlated with DA of harp Therefore: Females can NOT“hear” how symmetrical a male is
Kramer spherical treadmill Speaker Cricket Sphere
Female frequency response…. y = -0.7364067647x8+30.9904983205x7-563.878302226x6+5795.0167254032x5-36803.3533238713x4+147952.6446x3-367735.2038x2+516575.2812x-313757.8008
Multiple regression…. Area under BW curve 1) Area under Frequency curve 2) Poly-predicted Frequency preference F2,109 = 15.24; R2 = 0.22; p<0.001 Area under Frequency curve p=0.008 Poly-predicted Frequency preference p = 0.005
Conclusion for Females • FEMALES • Prefer pure-tones indicative of a symmetrical male • Therefore: • Females can NOT “choose” symmetrical males acoustically rather A female will tolerate a certain bandwidth range which is pre-defined by her frequency response range
Acknowledgements • Dr. H.U. Kleindienst • Heidrun Bamberg Funding & logistics • Dr. Xim Cerda • Marna Ferreira