Effects of resource depression on use of inexpensive and escalated aggressive behavior: experimental tests using Anna hummingbirds

To test whether alterations in aggressive behavior are responses to short-term resource depression, use of inexpensive and escalated territorial defense by Anna hummingbirds was analyzed as a function of the degree to which food could be depressed by foraging activities of territory owners and intruders. On depressible territories use of gorget display (a low cost defense) decreased and durations of chases increased as time since the previous feeding by owners increased. On non-depressible territories neither variable was significantly correlated with time since feeding. The percentage of intruders chased by owners was positively correlated with time since feeding on both depressible and nondepressible territories, but the magnitude of this trend decreased as food production increased. Departures from the territory tended to occur shortly after feeding on both types of territories, but this tendency was stronger on depressible territories.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46868/1/265_2004_Article_BF00343199.pd

Mating patterns, mate choice, and birth season heterosexual relationships in free-ranging rhesus macaques

Birth season adult heterosexual nonkin relationships of 50 free-ranging female rhesus macaques ( Macaca mulatta ) in two social groups at Cayo Santiago, Puerto Rico were examined using focal follow (289 hr) and ad lib data. Eighty-eight percent of subjects had at least one relationship characterized by particularly high frequencies of spatial proximity, grooming, or both. These were designated “friendships.” Males intervened in aggressive interactions more frequently on behalf of Friends than non-Friends. Female aggressive support of males was extremely rare. Higher-ranking males experienced more friendships than lower-ranking males. High-ranking females had higher-ranking Friends than low-ranking females. Older females had higher-ranking Friends than younger females. Females groomed high-ranking Friends more than they were groomed by them, whereas they groomed low-ranking Friends less than they were groomed by them. In one social group, high-ranking females were more likely than low-ranking females to groom their Friends more than they were groomed by them. Males were more responsible than females for spatial proximity maintenance in 9 of 14 Friend dyads for which sufficient data were available. Neither male nor female dominance rank affected responsibility for proximity maintenance in Friend dyads.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41611/1/10329_2006_Article_BF02381951.pd

Shell Selection and Invasion Rates of Some Pacific Hermit Crabs

Three species of littoral hermit crabs from Horseshoe Cove, Bodega Head, Sonoma County, California, and three sublittoral pagurids from Chinimi Island, Eniwetok Atoll, Marshall Islands, have been examined with respect to their shell selection and invasion rates. Periodic removal of crabs from marked areas resulted in immigrations of surprising magnitude. By comparison of actual collection patterns with those predictable from the alternates of density dependence and density independence, there is an indication that the observed immigration rates result from density dependent dispersal. While our data are not conclusive, the method presented is of interest and of possible utility for examining problems of this nature. Shell selection is discussed from the bases of both laboratory and field observations. Each of the species is shown to utilize the shells of different gastropods with different frequencies. Finally, behavioral aspects are examined as they relate to the distribution of the California hermit crabs

The study of live : an introduction to biology

x, 841 p.; 24 cm

The Study of Life : An Introduction to Biology

656 tr. ; 26 cm