Two aspects of the behaviour of Aleochara bilineata Gyll. (Coleoptera: Staphylinidae)

PROCEEDINGS OF THE ASSOCIATION FOR THE STUDY OF ANIMAL BEHAVIOUR Abstract of a paper read at the Ordinary Meeting of 23rd September, 1958, and reported by title only in the previous issue (7, 115) . TWO ASPECTS OF THE BEHAVIOUR OF Aleochara bilineata Gyll . (Coleoptera : Staphylinidae) BY C . D . PUTNAM Department of Zoology, Cambridge 1 . Non-random behaviour by adults in a Yveloped a preference for one alternative as the maze . Seventy-three adults of A leochara bilineata result of learning, although there was no differeach made a series of 20 choices in a Perspex Yence between the alternatives . It seems possible maze with neither reward nor punishment in that learning could occur under these circumeither arm . Their behaviour was markedly nonstances, if escape from the end of the arm acted random, as many of the beetles deviated signifias a reward, and if the beetles were not aware cantly from equal choice of the two alternatives, when they chose that choice of either alternative i .e . chose one alternative fifteen or more times would have the same result . out of twenty ; 58 . 91 per cent. of the beetles did 2. Host finding and selection by the first-instar so, whereas if they had chosen at random only larvae . The females of A . bilineata lay their eggs 4 .14 per cent . would have done so . On any in the soil, and the first-instar larvae, lj-2 mm . occasion the beetles tended to choose the same long, have to find suitable puparium of the host, alternative as that chosen previously. On the Erioischia brassicae Bche . (Diptera : Anthosecond choice 71 . 24 per cent. of the beetles myiidae), in which to complete their developchose the alternative they chose the first time ment . The behaviour of these larvae was studied (cf. 50 per cent . expected if choices at random), under experimental conditions . Host-finding 78 . 8 per cent. of those which had chosen the movements were apparently random in the sense same alternative twice chose the same one on that they were not directed by stimuli from the their third choice, and of these 82 . 9 per cent . hosts . In a universe with equal numbers of unchose the same one again on their fourth choice . suitable puparia (Calliphora) and E. brassicae However, after from one to four choices of one puparia the two types of puparia were not alternative and then one choice of the other, attacked equally often, the former only being beetles showed no preference for either on their attacked very rarely ; the larvae also avoided next choice . 29 beetles each made two series of attacking puparia already attacked by their own twenty choices in the Y-maze, from a few hours species . Thus they could distinguish unsuitable to thirteen days apart, and tended to show either hosts, and, to a large extent, refrain from attacking them . Such host-finding and selection bea significant preference for the same alternative, haviour is not unusual in insect parasitoids, but or no preference for either, in both series . it has not been previously recorded for a larval It is thought that the beetles made their first choice in the maze at random, and then deparasitoid. Paper read at the Ordinary Meeting of the Association for the Study of Animal Behaviour at Birkbeck College, 9th January, 1959 . 1N PRAISE OF ANTHROPOMORPHISM By C . W. HUME U . F.A . W., London morphism," is out of fashion in consequence of The subjective experiences of brutes may be its having been used incautiously, and words like conceived of by analogy with human subjective "hunger" and "fear" are often written with experiences. This practice, known as "anthropo248