RED LEGGED SPIDER HUNTING WASP

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When the final attack came the position was face to face ; the wasp quickly side-stepped and placed its forefeet upon the spider, and simultaneously held it in a position which was slightly to one side. T h e wasp curved its abdomen under the spider and quickly inserted its sting into the abdomen between each pair of legs separately ; thus the spider was paralysed by the injected poison. The wasp now seized one of the spider's fore feet with its jaws, the leg was pulled straight and straddled, and the wasp then proceeded by short runs and attempted flights to drag its heavy bĂźrden towards the nest hole. When the spider first sensed the wasp's presence it did make some efforts to escape, but these efforts were never carried to their possible conclusion. This was probably due to mesmerism, because the spider's movements became the more restricted as the wasp's agitations became intensified and as its movements narrowed to within striking distance the spider appeared to be completely mesmerised, with its legs withdrawn, and appeared to be dead. Thus it remained having made but a very feeble effort to defend itself. T h e spider sensed the presence of the wasp by the vibrations transmitted through the webs and foliage and its inborn instinct differentiated between the vibrations of a trapped fly in its web and those of the hunting Episyron rufipes.

THE

PREY

Six paralysed spiders of the same species belonging to the family Araneomorphae w'ere recovered from the sand at the rabbit burrow. They comprised five females and only one male. The male appeared to have been completely paralysed but all the females were able to withdraw their legs when pulled. After their abdomens had been fixed with the legs extended, they were able to move their palps together and their forelegs slowly up and down as objects were passed over them. Each had an ovum adhering to its back. After these ova had been removed, two spiders remained alive for four weeks and one which was slightly larger then the others remained alive for six weeks in this paralysed State. REMARKS. The antennae were constantly waved and vibrated but it appeared unlikely that they assisted in locating prey apart from sensing obstacles and making measurements for the accurate insertion of the sting. The frequent hesitations and bewilderments of the wasp could only have been due to the temporary loss of the spider's spoor. Had the wasps hunted by sight these happenings would probably not have occurred so frequently.

This insect like the rest of the original Breckland fauna and flora has become very rare indeed during this last ten years, 1951-1961.