Royal Entomological Society HANDBOOKS FOR THE IDENTIFICATION OF BRITISH INSECTS To purchase current handbooks and to download out-of-print parts visit: http://www.royensoc.co.uk/publications/index.htm This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 UK: England & Wales License. Copyright © Royal Entomological Society 2015 Handbooks for the Identification of British Insects vor. VI, Part 3(bJ SCOLIOIDEA, VESPOIDEA AND SPHECOIDEA HYMENOPTERA,ACULEATA 0 . W. Richards ROYAL ENTOMOLOGICAL SOCIETY OF LONDON Handbooks for the Vol. VI, Part 3(b) Identification of British Insects Editor: M. G. Fitton SCOLIOIDEA, VESPOIDEA AND SPHECOIDEA HYMENOPTERA,ACULEATA By 0. W. Richards 89 St Stephens Road London W13 8JA 1980 ROYAL ENTOMOLOGICAL SOCIETY OF LONDON The aim of the Handbooks is to provide illustrated identification keys to the insects of Britain, together with concise morphological, biological and distributional information. The series also includes a Check list ofBritish insects. Each handbook should serve both as an introduction to a particular group of insects and as an identification manual. Details of handbooks currently available, and an order form, can be obtained from the Royal Entomological Society, 41 Queen's Gate, London SW7 5HU. World List abbreviation: Handbk /dent. Br. Insects fi!) Royal Entomological Society of London, 1980 First published 1980 by the Royal Entomological Society of London, 41 Queen's Gate, London SW7 5HU. Printed by G. Donald & Company Limited, Osiers Road, London SW18 1NL. Contents Page Introduction . 3 General biology 4 Larvae. 5 Phylogeny 6 Check list and nomenclatural notes . 6 Notes on the keys and figures . 10 Superfamily SCOLIOIDEA 10 Family Sapygidae . 12 Family Tipbildae . 12 Subfamily Tiphiinae 12 Subfamily Methochinae 14 Subfamily Myrmosinae 15 Family Mutillidae . 16 Superfamily VESPOIDEA 18 Family Eumenidae. l!t Family Vespidae . 29 Subfamily Polistinae . I . 29 Subfamily Vespinae . 31 Superfamily SPHECOIDEA . 37 Family Spbecidae . 37 Subfamily Astatinae . 40 Subfamily Larrinae . 42 Subfamily Trypoxylinae 44 Subfamily Crabroninae 45 Subfamily Pemphredoninae 60 Subfamily Sphecinae 75 Subfamily Mellininae . 77 Subfamily Nyssoninae 78 Subfamily Philanthinae 82 References . 85 Plates of figures 89 Index . 112 Introduction The following account deals with three superfamilies, Scolioidea, Vespoidea and Sphecoidea, of the British Hymenoptera, Aculeata. There has been no complete work on these groups since Saunders (1896). It will be found that the Handbook introducing the Hymenoptera (Richards, 1956; revised edition 1977) defines most of the terms used; any others are illustrated or defined in the present work. The distribution of the species is given only in broad outline since our knowledge is certainly incomplete. Subspecies are not mentioned when (as in all but one relevant example) only the nominotypical subspeeies occurs in Britain. Similarly, subgenera are not indicated when only the typical one is British. In most aculeates, the male has 13 antennal segments and the female 12 (many exceptions in the Formicidae and in the Sphecidae: Crabroninae); the male normally has 7 visible gastral tergites and the female6. The illustrations of whole insects were drawn by Mr A. J. Hopkins, the remainder by myself. Reference is also made to a few figures of whole insects in Richards (1977). 3 General biology The aculeate Hymenoptera have a special interest because of their often elaborate nesting behaviour and the stages which exist between the simplest type and the most elaborate, culminating in full sociality. Even where these stages are not the actual steps which were followed in evolution they at least show the sort of changes which must have occurred in that process. The simplest type of behaviour is probably seen in Tiphia which hunts scarabaeoid larvae (Coleoptera) in their subterranean burrows. When found the grub is stung and an egg (or in some species more than one) is laid on it but no nest is made. The female also often kneads ("malaxates") the ventral surface of the prey's abdomen with her mandibles. In the next stage, in the non-British Scoliidae, the parasitised larva is dragged deeper into the soil and placed in a cell excavated by the wasp. Another simple type of behaviour is seen in some Pompilidae. A spider is caught and stung to paralysis, then carried to a suitable spot and hung on a grass stem while the wasp makes a small burrow enlarged at one end into a cell. The spider is taken in and an egg laid on it and the nest closed. This behaviour may be repeated so that each nest has only one cell, but in Sphecidae the first cell is made before the first prey is caught. Also the original burrow may lead to more than one cell. The first cell is closed when prey and egg are ready and a new cell then receives the same treatment. In these conditions not only the cell entrance but the entrance to the burrow may be closed either on every occasion when the wasp leaves or only when all the cells are complete. With this. type of behaviour the egg is normally laid on the last prey brought in and this is "mass provisioning". But if the egg is laid on the first prey brought in it may hatch before the wasp has completed the next cell. This gives the wasp the opportunity to make contact with its own larva and this, in turn, may lead to "progressive provisioning" where the wasp brings its larva food as it is required. In the extreme development, as shown by Baerends (1941) in Ammophila pubescens (cited as campestris), the wasp may tend three nests at different stages simultaneously. She enters each nest every day to see what its needs are. Some species of Ammophila are also exceptional in being "tool-users"; they hold a small stone in their mouth and use it to tamp down the soil when closing the nest. In some species of Bembix (non-British, but the genus occurs in Jersey), the egg is laid in an.empty cell and prey is not brought until it hatches. Many sphecoids are gregarious, building their nests near to one another. Some, such as our Ectemnius cephalotes, sometimes share a common burrow in rotten wood though presumably each female has her own nest-burrow out of the communal burrow. Finally, at least one South American wasp of the genus Microstigmus has become social. The nests are made of plant wool and hang from leaves or rocks. There may be up to 18 wasps of both sexes in one nest. Though there are no visible castes, dissection showed that one female had much better developed ovaries than the others and probably did all or most of the egg-laying. Other species of the same genus may practice either mass or progressive provisioning. Some of the steps in the elaboration of nesting behaviour which have been described in the scolioids, pompiloids and sphecoids may also be found in the Eumenidae. Prey-specificity in such groups as the Eumenidae and Sphecidae is of great interest. On the whole the type of prey is characteristic of each genus though the larger and more diverse genera may show more variation. We find that all the many species of Trypoxylon all over the world seem to prey on spiders; all Ammophila take caterpillars or rarely sawfly larvae; all Pemphredon and Passaloecus take aphids. On the other hand species of Tachysphex take a variety of orthopteroids­ acridids, blattids or mantids. Bembix is unusual in generally taking flies but in 4 Australia (according to Evans and Matthews) taking also Zygoptera (damsel-flies) and Hymenoptera; one species sometimes takes more than one kind of prey. One British species, Lindenius albilabris takes both mirid bugs and chloropid flies, sometimes both in one nest. It has always puzzled entomologists how the wasps recognise their specific prey which, as Fabre pointed out in the case of Cerceris bupresticida which stings Buprestidae of several genera which may often look superficially very different. Social life demands that the female lives long enough to make substantial contact with her offspring. Doubtless once there were a few workers to feed the queen she could easily live longer and even overlap several generations. A much more difficult step in the evolution of social life is the demand that some females should become sterile and only one or a few females lay eggs. ·On the face of it there would be a strong selection in favour of each female laying eggs since the genes of those that did not might not be represented in later generations. However, the haploid-diploid process of sex-determination in the Hymenoptera with the absence of a reduction division in the male spermatogenesis means that all males derived from one queen are genetically identical. Thus the female offspring of a queen which has only mated once will tend to resemble one another in three-quarters of their genes while if workers laid eggs their offspring would resemble them in only half their genes. On the assumption made by W. D. Hamilton that the interest of the females would be most strongly directed to those offspring which were genetically most similar to them, a possible way can be seen for the evolution of social behaviour. The workers would be more interested in rearing their mothers offspring than their own and selection could favour self-sterilization. There are still difficulties in explaining the evolution of the many queened colonies of tropical wasps but these might be partly overcome if, as seems to be the case, there is often much brother-sister mating within the colony. It may perhaps also be noted that what is called a "solitary" wasp differs only from a "social" bird in that the female wasp does not normally put the food directly into the mouth of her offspring.