NORSK ENTOMOLOGISK TIDSSKRIFT - Norsk entomologisk forening

A nest of Vespula saxonica (Eabr.) (Hym., Vespidae) 37
of various grey shades, had unfortunately been damaged during
the removal of the nest, but the size of the nest might have nearly
been that of the head of a man. The contents of the nest, a total
of three combs, were almost intact with the exception of a destroyed
peripherical part of the lower comb.
Several factors have to be considered when a wasp nest is
studied :
a) the hibernating queen begins the construction of a comb
at the centre, and the outer cells are therefore the youngest;
bj the queen lays an egg in a cell as soon as it is finished and
the zonation of capped cells will therefore gradually move
outward; c) when an adult emerges, the cell will be cleaned
and re-used; d) the development from egg to imago takes
about four weeks depending on the temperature and the time
of the season; e) males are produced from small as well as
large cells.
The age of a nest and the size of the population might be estimated
by the position of capped cells and the size of the combs.
The length of the diameters of the almost circular upper, intermediate
and lower combs in the actual nest were approx 11,5
centimeter, approx. 12 centimeter and 9.5 centimeter, respectively.
The pronounced concentric zonation of the upper, that is the
oldest, comb indicates clearly the stages of development, see fig. 1.
Unfortunately the photograph does not display the eggs, or
young larvae recorded in the re-used cells of zones b. and d.
respectively. Three zones with capped cells indicate that a third
brood is developing in the centre of the comb i.e., zones a. and b.
a second brood in the intermediate zones c. and d. respectively,
while the cells in the outer zone e. are used for the first time. If
the development had not been interrupted, the adults from the
capped cells in the centre would have emerged before the
end of July. As it takes about twelve weeks to produce three
successive broods, the queen may have founded the nest at the
end of April.
The number of large cells, greatly exceeding that of the small
ones, indicates that the colony had passed its peak before the nest
was removed. The old queen was found in the nest but had been
dead for several days, and some workers had started egg-laying.
They do not operate so very neatly and had deposited two or
more eggs in a number of the cells. The social organization of the
inhabitants would have degenerated within a few weeks and
the recorded eggs and at least the youngest larvae would never
have fulfilled their development.