Worcestershire Record No. 19 November 2005 p. 29
P.F. Whitehead, Moor Leys. Little Comberton, Pershore Worcestershire, WR10 3EH
On 12 August 2005 I placed a plastic bin lid on a dry compost heap in a garden in Evesham town (SP04). It remained there for two hours. When I retrieved it, the underside of the lid held 11 pseudoscorpions Lamprochernes nodosus (Schrank, 1803). Two of these, hopefully a male and female, were performing a ritualised mating dance, which is documented but rarely observed. One continually held the basal segment of the palp of the other in its right pincer whilst 'twitching' its free left pedipalp sideways very rapidly – like an automaton. The second specimen appeared to be in a near cataleptic state, with both palps fully extended outwards at 90o and somewhat inclined away from the first specimen.
According to Dr Mark Judson (in litt., 2 September 2005) this ritualised behaviour, similar to that observed in true scorpions, precedes the deposition of a spermatophore by the male. Unfortunately time to follow this up was unavailable.
Editor’s note. I wrote the following somewhat popular account of Pseudoscorpions for Worcestershire Wildlife News in April 2004 which may be of interest to readers who know little of the group. Further information can be found in the reference given at the end of this note.
Amongst my favourite predators are the pseudo- or false-scorpions. These tiny animals, 1-5 mms long, are related to spiders. They have eight walking legs and two front pedipalps for catching prey. In some species the pedipalps are relatively huge with one fixed and one moveable finger forming a structure reminiscent of the grasping claws of crabs and scorpions. Prey (usually springtails) are grasped with these, poisoned, then dragged to the mouthparts and eaten. Enzymes are passed into the prey to liquefy it internally, and it is then sucked dry – a feeding technique similar to many spiders. When breeding up to 20 eggs are carried in a brood sac beneath the body. After hatching the young develop to adults in 3-12 months through moulting, and then may live for 3-4 years. In winter, as the temperature falls, they move downwards into litter away from frost and some construct silken chambers where they hide, inert for several winter months. Many species spin a small silken chamber in which to retire while eggs develop, or during moulting. Pseudo-scorpions travel, and set up new distant colonies by phoresy, a system of clinging to a flying insect and dropping of when it lands, rather like catching a bus! (I didn’t mention the complexities of spermatophore transfer, an essential precursor to eggs, which can be found in the reference).
|LEGG G & JONES RE 1988 Pseudoscorpions (Arthropoda; Arachnida)
Synopsis of the British Fauna (New Series) No 40. Linnean Society of London and
the Estuarine and Brackish-water Science Association|
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