1988] 
Kozol, Scott, & Traniello — Nicrophorus 
169 
Prey Choice and Competition in Enclosures 
In order to conduct studies on prey choice and interspecific com- 
petition, a square screened enclosure measuring 1.3 m 2 and 25 cm 
high was sunk into the ground to a depth of 10 cm. A 20-liter bucket 
filled with potting soil was sunk into the ground inside the enclosure 
and a single carcass was placed on top. To investigate interspecific 
competition, a male and female N. americanus and a male and 
female N. orbicollis were introduced into the enclosure at dusk with 
a single carcass. The following morning all beetles were collected 
from the enclosure and the carcass was exhumed to determine which 
beetle(s) had buried it. Prey choice studies were conducted in a 
similar manner. A male and female N. americanus were placed in 
the enclosure, and avian and mammalian carcasses were simultane- 
ously available for burial. 
Laboratory Studies 
Ten of twenty broods monitored in the laboratory originated 
from burials in the field enclosure studies on Block Island. The 
other ten were initiated at Boston University using adults eclosed 
from laboratory broods. The size of prey used in the laboratory 
ranged from 60-206 grams. All broods were maintained at a con- 
stant temperature of 21°C with a 14:10 light:dark cycle. Nine broods 
were exhumed on the tenth day after burial and all larvae were 
counted, weighed, and returned to the brood chamber with the 
carcass and parent(s). Individuals were sexed, measured, and 
weighed on the day of eclosion. 
Results 
A total of 147 N. americanus (84 males, 63 females) were captured 
on Block Island (Table 1). The sex ratio of males:females captured 
did not differ significantly from 1:1 (x 2 test, p > 0.05). One hundred 
thirteen N. americanus were captured in pitfall traps, 19 at black- 
light traps, and 15 on carrion set out for burial. Nicrophorus beetles 
were trapped repeatedly and successfully on both rainy and windy 
nights provided the temperature was above 15°C. Seventeen of 147 
(11%) N. americanus were recaptured; 15 individuals (eight females 
and nine males) were recaptured once and two (females) were recap- 
tured twice. Eight of 17 recaptures occurred within four days of the 
