Supplement to Harvesting Ants and Trap-Door SpidersMoggridge, John Traherne
Science
Supplement to Harvesting Ants and Trap-Door Spiders
Moggridge, John Traherne
Ants; Trap-door spiders
A fortnight later (July 27) another cluster of eggs was laid, and
this time between the hours of five and eight P.M. When the lamp was
brought in at the latter hour, I perceived what I took to be a drop
of water hanging from the gauze cover above and rather in front of
the spider's door, the very position occupied by the cluster of eggs
previously described. On closer inspection this proved to be a drop
of a pellucid colourless liquid, in which some thirty eggs floated.
One egg was laid on the gauze at some distance from the main group,
and several were also attached to the inside of the tin box.
At midnight I found that the drop had coagulated and contracted, and
by the following morning the mass was quite dry and resembled the
former group, only that it was not quite so convex.
Some of the eggs forming this cluster were much larger than any in
the preceding one, and one measured as much as a line in length by
half a line in breadth. This group is shown magnified at fig. B, 8,
Plate XV., and some of the separate eggs more highly magnified at
fig. B, 9.
Between this date and the end of November when the spider died, eggs
were laid on seven distinct occasions--viz., on July 31, August 11,
15, 31 (when I again found the eggs floating in a drop of liquid,
having been deposited on the gauze between two and half-past four
o'clock in the afternoon); September 9 (23 eggs laid on the earth
near the entrance to the nest); September 19 (about 30 eggs on the
gauze), and November 4 (about 30 eggs on the gauze).
Thus, between July 13 and November 4, this spider laid nine clusters
of eggs, all but one of which were placed on the same part of the
gauze cover, above and a little in front of the door, and the total
number of eggs deposited cannot have been less than 250. It is
difficult to understand why she should have laid these eggs outside
the nest, unless indeed she knew them to be sterile, and so treated
them as refuse. I can scarcely believe that such a procedure is in
accordance with the ordinary habits of these spiders; for, if the
eggs and young are habitually exposed, then the perfect concealment
of the nest would lose one of its most important uses. When we
remember that there are minute hymenopterous insects which lay their
eggs within the eggs of the spiders, we can see how important it
may be that the entrance to a nest, which is at once nursery and
stronghold, should be closed by a well-fitting door, and one which
may exclude, not only the larger and more powerful enemies of the
full-grown spiders, but also the tiny and almost imperceptible
assailants of the eggs and young.
Public-domain text, read in full here on John Shaqi.
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