Archaeologia Islandica - 01.01.2010, Page 92

VÉRONIQUE FORBES, ALLISON BAIN, GUÐRÚN ALDA GÍSLADÓTTIR AND KAREN B. MILEK
pleted, and after ascertaining that the dif-
ferences between beetle assemblages from
samples taken in deposits associated with
the same archaeological event were negli-
gible. Identifiable insect parts, such as
heads, pronota and elytra (wings cases) of
beetles and trae bugs; heads and abdomens
of fleas and lice, and puparia of sheep keds,
were identified and counted. The mini-
mum number of individuals for each taxon
was then calculated using the body part
encountered the most frequently.
Results: General characteristics
of the insect assemblages
A total of 2694 individual insects were
identified from context A-E, which are
listed in Table 2. In order to facilitate
comparisons between contexts and sites,
both the total counts per context and per
litre of archaeological sediment
processed are provided. The taxonomical
order of beetles used follows the Islenskt
skordýratal or List of Beetles from
Iceland (Ólafsson 1991).
The insect remains present in
Vatnsfjörður’s deposits were likely pre-
served by anoxic waterlogging, even
though these were not saturated with
water. Anoxic waterlogging can be
defined as a set of conditions ‘restricting
biological activity through unavailability
of some compounds and the toxic effect of
others’ (Kenward 2009, 84). It is likely
that anoxic conditions occurred in these
deposits due to the accumulation of ‘self-
preserving’ organic matter. It seems that
large concentrations of organic matter
maintain a high water content, which
inhibits decomposition (Hall & Kenward
1990, 389). The preservation was general-
ly excellent in most samples, except those
grouped into context D (S-13-14-17) and
(although to a lesser extent) in context B,
for which a higher degree of fragmenta-
tion and the presence of thin and brittle
insect parts were noted. One possible
explanation for context D is that deposits
that were situated in sediments closer to
the topsoil were better drained and aerat-
ed, which affected the preservation of
insect fragments. Deeper levels from this
context were better preserved. It is also
worth mention that context C generated by
far the largest of the five archaeoentomo-
logical assemblages, with 229.47 counts
per litres of sediments, while each of the
four other contexts yielded less than 50
individuals per litres. It is unlikely that this
is due to differential preservation condi-
tions, but rather is the result of longer and
constant use of the room, which is dis-
cussed later in the paper.
Differential preservation of species
might have occurred in some of the
deposits. Soft-bodied arthropods such as
human lice (Pediculus humanus) might
have decayed where more sclerotized bee-
tle and flea parts survived. Nevertheless,
there is no evidence that remains of fleas
and smaller beetles are missing from the
archaeoentomological assemblages.
Results: Ecological groups
This study utilizes ecological groupings
to facilitate the interpretation of the
archaeoentomological assemblages. This
method was first used in the 1970s to
analyze substantial insect assemblages
from the site of York in the United
Kingdom (Kenward 1976; Kenward &
Hall 1997). Essentially, it involves
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