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Psyche 
[Vol. 95 
marginatus, N. orbicollis, and N. tomentosus. Additional trapping 
was conducted on the coastal mainland of Massachusetts and 
Rhode Island and on the islands of Martha’s Vineyard and Nan- 
tucket, but yielded no N. americanus. Trapping in Michigan, 
Arkansas, Missouri, North Carolina, Tennessee, Florida, Pennsyl- 
vania, New Jersey, and New York also gave negative results (L. 
Master and D. Schweitzer, personal communication). 
Trapping Methods 
N. americanus population size was estimated by three methods of 
live trapping. First, pitfall traps, baited with aged beef kidney placed 
along a transect at 25 meter intervals; second, a blacklight trap, 
which was moderately effective in attracting beetles to the ground 
near the light, and third, whole vertebrate carrion of various types, 
placed in the field for burial. A total of 467 pitfall trap-nights were 
logged, in addition to 16 hours of blacklight trapping, and 44 car- 
rion burial traps in five four-day trapping sessions between May 26 
and August 1, 1986. Carrion used for burial studies ranged in size 
from 20 grams to 500 grams and included mice, rats, starlings, 
chicks, squirrels, snakes, turtles, skates, Japanese quail, and ham- 
sters. For each of these carrion types, a 1.5 meter piece of dental floss 
was attached to the carcass so it could be located and exhumed after 
burial. The surrounding vegetation and soil surface were also exam- 
ined for beetles because unsuccessful competitors are often found 
near the area of burial (Wilson and Fudge 1984; personal observa- 
tion). All Nicrophorus individuals captured were identified to spe- 
cies, sexed, measured, and released. Pronotal width was used as an 
index of an individual’s size because it is highly correlated with 
weight (r = 0.96, N — 150). Each N. americanus was individually 
marked by lightly sanding the pronotum, painting it with a unique 
pattern and color(s) of enamel paint, and covering the paint with 
cyanoacrylate glue. 
Population Size Estimation 
A sequential Bayes algorithm (Gazey and Staley 1986) was used 
to estimate the population size of N. americanus on Block Island. 
This method was used because it was designed specifically for mul- 
tiple mark-multiple recapture studies with relatively small sample 
sizes. 
