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. 2003 Jan 22;100(3):1089–1094. doi: 10.1073/pnas.0337427100

Figure 3.

Figure 3

Relationship between number of male secondary sexual characters per species (i.e., the number of secondary sexual traits that were reported as more exaggerated in males than in females) and sex chromosome score of those species for various major taxonomic groups. Each data point is the mean value across the species scored (number of species scored indicated below in parentheses) within the following orders. (A) Insect orders: 1, Hymenoptera (N = 30); 2, Diptera (N = 49); 3, Coleoptera (N = 4), Hemiptera (N = 1), Homoptera (N = 4), and Orthoptera (N = 1); 4, Lepidoptera (N = 14). (B) Fish species: 1, Brevoortia aurea, Coregonus sardinella, Gobiodon citrinus, Oncorhyncus nerka, Rhinobatos productus, Symphurus plagiusa; 2, Carcharodon carcharinus, Charcharhinus limbatus, Rhizoprionodon terraenova, Salmo gairdneri, Scopeloberyx mizolepis, Scopeloberyx robustus, Xenentodon cancila; 3, Fundulus diaphanus, Parasalmo mykiss; 4, Cichlosoma nigrofasciatum, Poecilia reticulata; 5, Xiphophorus maculatus; 6, Poecilia sphenops; 7, Clarias gariepinus, Dasyatis americana, Saurida undosquamis, Scardinius erythrophthalmus; 8, Eleotris pisonis, Gambusia affinis, Gambusia holbrooki; 9, Apeltes quadracus, Colisa fasciatus; 10, Poecilia latinpinna. (C) Lizard families: 1, Gekkonidae (N = 1) and Pygopodidae (N = 1); 2, Phrynosomatidae (N = 73); 3, Polychrotidae (N = 6); 4, Lacertidae (N = 13); 5, Agamidae (N = 2). (D) Salamander genera: 1, Bolitoglossa (N = 5); 2, Oedipina (N = 3); 3, Thorius (N = 4); 4, Necturus (N = 5); 5, Nototriton (N = 1); 6, Hydromantes (N = 5); 7, Triturus (N = 6); 8, Siren (N = 1); 9, Aneides (N = 4); 10, Ambystoma (N = 3); 11, Pleurodeles (N = 1). (E) Frog genera: 1, Eupsophus (N = 2); 2, Physalaemus (N = 1); 3, Rana (N = 14); 4, Gastrotheca (N = 4); 5, Bombina (N = 1); 6, Hyperolius (N = 1); 7, Leiopelma (N = 3); 8, Xenopus (N = 17); 9, Bufo (N = 1); 10, Discoglossus (N = 1); 11, Crinia (N = 1) and Tomopterna (N = 1); 12, Buergeria (N = 1); 13, Hyla (N = 2); 14, Pyxicephalus (N = 1). (F) Snake families: 1, Tropidophiidae (N = 1); 2, Boidae (N = 2); 3, Colubridae (N = 79); 4, Viperidae (N = 31); 5, Elapidae (N = 29). (G) Bird orders: 1, Struthioniformes (N = 8); 2, Tinamous (N = 45); 3, Apodiformes (N = 7), Ciconiiformes (N = 260), Columbiformes (N = 15), and Gruiformes (N = 15); 4, Coraciiformes (N = 3), Cuculiformes (N = 8), Piciformes (N = 22), Psittaciformes (N = 7), Strigiformes (N = 27); 5, Passeriformes (N = 334); 6, Anseriformes (N = 57) and Trochiliformes (N = 20); 7, Trogoniformes (N = 2); 8, Galliformes (N = 24). In each panel, the least squares regression line is given (for illustrative purposes only) along with the Spearman rank order correlation coefficient (ρ).