Region(s): 

 approximate continental coinci- 

 dence with, 268-269 

 Australo- Papuan: 

 absence of placental mammals 



m, 270 

 fauna of, 270 



former land bridges in, 269-270 

 subdivisions of, 269-270 

 Ethiopian: 

 anifauna of Malagasy sub-region 



of, 271 

 boundaries of, 270-271 

 few gallinaceous species in, 271 

 fish and reptiles of Malagasy 



sub- region of, 271 

 geological history as explanation 

 of fauna of and oriental region, 

 271 

 isolation from Africa of Mala- 

 gasy sub- region of and evolu- 

 tion of mammals, 271 

 mammals in, 271 

 of fish fauna of, 271 

 similarity of fauna of at order 

 and family level to that of 

 Oriental region, 271 

 Holarctic: 

 differences in fauna of Palaearc- 

 tic and Nearctic sub- regions 

 of, 272 

 kinds and location of, list, 268 

 land bridge in and evolution of 

 animals of, 272 

 Neotropical: 

 area included in, 270 

 avifauna in, 270 

 endemic forms in, 270 

 fauna of West Indies in, 270 

 theories about distribution of 

 fauna in, 270 

 Oriental: 

 boundaries of, 271 

 characteristic species in, 271- 



272 

 exclusive species in, 271-272 

 marked difference in fauna of 

 northern and southern India in, 

 272 

 Releasers: 

 and triggering of actions of organ- 

 isms, 14 

 concept of as controlling instinctive 

 behavior, as development in 

 animal ethology, 6 

 minor characters possibly serving 

 as for critically necessary 

 behavior, 265-266 

 of behavior responses in symbio- 

 sis, 176 

 varieties of, 14 



438 lnde> 



Reproduction (see also Populations): 



adjustments in patterns of for 

 terrestrial habitats, 98 



and environmental adjustment, 217 



and genetic isolation of species, 

 259 



and geographic isolation of popula- 

 tions, 259-260 



and lack of interbreeding among 

 sibling species, 258 



and mechanical isolation of species, 

 259 



and population turnover, 217 



and production of organic matter, 

 30 



and protective devices of animals 

 in trophic levels, 196-198 



and secondary sex ratio, 214 



and tertiary sex ratio, 214, 214-215 



as affected by attainment of breed- 

 ing age by animals, 215 



as affected by erosion, 229 



as offset to mortality caused by 

 environment, 217 



as variation from random dispersal 

 of species, 34 



capacity of habitat for and death 

 rate, 211 



changes in physiological vigor 

 and, 241-242 



changes in primary sex ratio in, 

 214 



crowding of fruit flies and rate of, 

 223 



curtailment of in arctic tundra 

 during certain years, 320 



distinguishing between fecundity 

 and survival in, 224-225 



disturbance factor in and female 

 house mice, 224 



effect of photoperiodism on, 102 



effects of weather on fecundity in, 211 



egg fertility in experimental con- 

 ditions of, 224 



eggs in, and need for flooding of 

 soil, 115 



factors in survival of young in, 

 211-212 



failure of pairing behavior leading 

 up to and consequent species 

 isolation, 258-259 



high rate of and wildlife manage- 

 ment, 216-217 



increases in density of fruit flies 

 and survival in, 224 



in isolation and speciation, 258 



innate capacity of species in deter- 

 mining size of litter in, 210 



in Pacific salmon, 159 



in snowshoe rabbit population 

 cycle, 224 



Reproduction (Continued) 



in territories and lessening of 

 pressures of competition, 186 



low rate of and wildlife manage- 

 ment, 216-217 



low rate of in areas of mineral 

 deficiency in soil, 167 



low ratio of immature to adults 

 in and productivity yield, 216- 

 217 



nesti.ig habits of stream fishes in, 

 54 



nutritional values in and popula- 

 tion cycles, 241 



of aphids and consequent emigra- 

 tion, 228 



of aquatic larvae and naiads, 159 



of birds, nest failures in, 212 



of cold-blooded animals in tropical 

 rain forests, 347 



of desert animals as occurring in 

 wet season, 338-339 



of fish, methods for increasing in 

 lake management, 77 



of fish migrating between fresh 

 and salt water for spawning, 

 368-370 



of fish through stocking of prey- 

 predator combinations, 91 



of forest millipede, 143-144 



of grain weevil and optimum inter- 

 mediate density of population, 224 



of grasshopper, 107 



of house mice in stress situations, 

 223-224 



of laboratory mice and high popu- 

 lation densities, 223 



of lake organisms, 76-77 



of pink salmon and effects on of 

 overcrowding, 223 



of pond amphibians, 85-86 



of pond- marsh birds, 86 



of pond reptiles, 86 



of principal pond organisms, 88-90 



of snails and slugs, and presence 

 of moisture, 299 



of stream insects, 53-54 



of tiger-beetles, 112 



of toads and frogs in temporary 

 ponds, 88 



of voles, 142, 223 



overcrowding and tadpole growth 

 rate in, 224 



parental care in and number of 

 eggs or young produced per 

 litter, 211 



per iods of and adult- young r at ios , 2 1 6 



placement of eggs on stream bot 

 toms, 51 



presence of non-breeding popula 

 tion during, 215 



