Pison, JURINE, 1808

Pulawski, Wojciech J., 2018, A Revision of the Wasp Genus Pison Jurine, 1808 of Australia and New Zealand, New Guinea, and the Pacific Islands (Hymenoptera: Crabronidae), Proceedings of the California Academy of Sciences 65, pp. 1-584 : 5-8

GENUS PISON JURINE

Pison Jurine in Spinola, 1808:255. Type species: Pison jurini Spinola, 1808 [correctly jurinei = Alysson ater Spinola, 1808 ], by monotypy.

Tachybulus Latreille, 1809:75 . Type species: Tachybulus niger Latreille, 1809 [= Alysson ater Spinola, 1808 ], by monotypy.

Nephridia Brullé, 1833:408 . Type species: Nephridia xanthopus Brullé, 1833 , by monotypy.

Pisonitus Shuckard, 1838:79 (as division of Pison ). Type species: Pison argentatum Shuckard, 1838 , designated by Pate, 1937:51.

Pisum Agassiz, 1846:293 , junior homonym of Pisum Megerle, 1811 . Unjustified emendation of Pison Jurine, 1808 .

Pisonoides F. Smith, 1858:104 (authorship attributed to Shuckard, as subgenus of Pison ). Type species: Pison obliteratum F. Smith, 1858 , by monotypy.

Parapison F. Smith, 1869:298 . Type species: Pisonoides obliteratus F. Smith, 1858 , designated by Pate, 1837c:47.

Pseudonysson Radoszkowski, 1876:104 (as Pseudo - Nysson , incorrect original capitalization and hyphenation). Type species: Pseudonysson fasciatus Radoszkowski, 1876 : by monotypy.

Taranga W.F. Kirby, 1883:201 . Type species: Taranga dubia W.F. Kirby, 1883 [= Pison spinolae Shuckard, 1838 ], by monotypy.

Paraceramius Radoszkowski, 1887:432 , junior homonym of Paraceramius de Saussure, 1854 . Type species: Paraceramius koreensis Radoszkowski, 1887 , by monotypy.

Pisum W. Schulz, 1906:212 , junior homonym of Pisum Megerle, 1811 and Pisum Agassiz, 1846 . Unjustified emendation of Pison Jurine, 1808 .

Krombeiniellum Richards, 1962:118 . Substitute name for Paraceramius Radoszkowski, 1887 .

GENERIC DIAGNOSIS. – Pison , a widely distributed genus of crabronid wasp found on all continents except Antarctica and North America (where only the adventive P. koreense [Radoszkowski] occurs), is characterized by an emarginate inner eye margin, the antennal socket contiguous with the frontoclypeal suture, and the presence of two or three submarginal cells, the second of which is petiolate. Four other genera share these characters: Aulacophilus F. Smith, Aulacophilinus Lomholdt , Entomopison Menke , and Pisonopsis W. Fox. These genera differ as follows:

1. Aulacophilus has a conspicuously, longitudinally ridged mesopleuron, a transverse preapical ridge on the propodeum, the propodeal apex truncate, and gastral segment I almost as long as the remaining gaster and divided into a narrow basal petiole and a contrastingly nodose posterior part (the propodeal characters were first observed by Antropov, 1999). In Pison , the mesopleuron is not ridged, the propodeum has no preapical ridge and its apex is slightly projecting mesally, and the gaster is either sessile (the vast majority of species), or segment I is pedunculate, with the length exceeding the maximum width, but shorter than the remaining gaster ( difficile , eurygnathos , icarioides , obliteratum , pistillum , and woji ; in eurygnathos and icarioides segment I is bulging apically, in woji the basal portion is somewhat approaching the condition of Aulacophilus ).

2. Aulacophilinus was described in 1980, but most of its species were kept in Pison until the genus was properly defined by Menke (2016) and Pulawski (2017). It is characterized by a mandible that is unique within the Trypoxylini : both the outer and inner surfaces are punctate and setose throughout (except narrowly impunctate and asetose adjacent to the apical margin), the acetabular and condylar grooves are absent, and the inner margin is broadly expanded preapically, thus forming an apical truncation (the apical margin of the truncation being slightly concave). Unlike Pison , the clypeus is punctate throughout, without a shiny, medioventral lamella. Pison eurygnathos , however, is somewhat intermediate between Aulacophilinus and Pison : the clypeus without a lamella and the broadened preapically inner mandibular portion are as in Aulacophilinus . Unlike Aulacophilinus , however, the inner mandibular surface is impunctate and glabrous (as in Pison ), and the following are unique: two large preapical teeth on the inner mandibular margin, a broad, shallow condylar groove, and a sharp, conspicuous acetabular carina. Also, the setae on tergum I are erect (appressed in Aulacophilinus ).

3. Menke, in 1968, described Entomopison as a subgenus of Pison , and he raised it to full genus status in 2016. The genus is characterized by the conspicuously notched posterior mandibular margin, but otherwise it is a typical Pison . In Pison , the posterior mandibular margin is either straight (vast majority of species), or stepped ( P. nogorombu ), or slightly emarginate (the fossil P. electrum Antropov and Pulawski ).

4. To separate Pison and Pisonopsis, Bohart and Menke (1976:330) used four characters, as tabulated below:

Character Pison Pisonopsis

Marginal cell of forewing in most species acute distally, rounded or truncate distalextending well beyond outer ly, slightly extending veinlet of submarginal cell III. beyond outer veinlet of submarginal cell III.

Mandibular posterior margin not notched, except emarginate emarginate or conspicusly in some Neotropical species angulate (which are now separated as Entomopison ).

Oblique grooves on sterna III-IV absent present

Female tergum VI conical flattened or with pygidial plate delimited by carinae

Menke (1988:5) questioned the usefulness of these characters, correctly calling them “rather tenuous”. According to him, the only reliable difference between the two genera was in the mandible, whose outer surface is simple in Pison , but has an additional carina (that I call abductor ridge) in Pisonopsis . The abductor ridge, however, is also present in many Pison insulare of the Pacific Islands and in two new Australian species ( P. abductor and P. tridentatum ), rendering this difference ineffective. Separation of Pison and Pisonopsis , however, is easier now, after Menke (2016) recognized as the genus Entomopison those species with emarginate mandibles: in Pison , the mandibles are either entire, or ( P. nogorombu ) stepped, or slightly emarginate (the fossil P. electrum ), whereas they are emarginate or conspicuously angulate in Pisonopsis . Pisonopsis differs from Entomopison in having the abductor carina (which is absent in the latter genus).

NESTING BEHAVIOR. – Observation on nesting habits of the Australian Pison accumulated in parallel to species descriptions. Maindron (1879) was the first with observations on P. fenestratum (that he called P. nitidum ), although his observations were conducted on the island of Ternate in the Moluku Islands and his identification of the species is far from certain. Roth (1885) described the nests of P. spinolae and P. perplexum , although the first species was almost certainly misidentified and the second is actually P. argentatum . Froggatt (1894), Richards (1930), Cowley (1962), Sharell (1971), Naumann (1890a), Valentine and Walker (1991) and Harris (1994) published on the nesting of P. spinolae (Richards also on P. virosum , and Harris also on P. morosum ), and Cowley (1962) described its egg and larva. Cheesman (1928) observed the nesting habits of P. argentatum (as P. ignavum ), Evans (1981) that of four species nesting in the soil, and Naumann (1983) that of P. auratum . Evans, Matthews, and Hook (1981) described the nesting habits of six species. Pagden (1934) and Iwata (1964b) observed the nesting habits of P. punctifrons , respectively in Malaysia and in Japan.

Evans, Matthews, and Hook (1981) recognized three types of nesting among the Australian species. The first includes the species that nest in pre-existing cavities. Cells are separated by thin mud partitions and the nest is often closed off with a thick mud plug. This type is represented by Pison marginatum , P. spinolae , and P. westwoodii , although P. spinolae is also known to build free mud nests. Pison suspiciosum nests in bamboo tubes as well as in beetle burrows in wood, although Pagden (1934) reported it as building free nests out of mud. Pison auratum , which nests in abandoned nests of Sceliphron laetum (F. Smith) according to Naumann (1983), should also be categorized here, as well as P. morosum of New Zealand, which nests in abandoned galleries of woodboring insects (Harris, 1994), Pison nigellum of the Pacific Islands that nests in clay cliffs (Krombein, 1950), and the Old World species P. atrum (Spinola) , P. rugosum F. Smith , and P. strandi Yasumatsu which nest in plant stems or beetle burrows (Bohart and Menke, 1976), as well as the South African P. allonymum W. Schulz , that nests in old or abandoned nests of Bembecinus cinguliger (F. Smith) and B. oxydorcus (Handlirsch) or in vertical banks (Gess, 1981).

Members of the second type build free mud nests consisting of several cells attached to stems, roots, or leaves and coated with mud in such a way that the cells are not individually discernible from the outside. Evans, Matthews, and Hook (1981) listed only two species, P. ignavum and P. rufipes , as belonging here, but P. virosum also belongs here according to Richards (1930). I suspect that most of the Australian species build nests of this type, because the adults can be seen, often in great numbers, as they collect mud from shores of stagnant waters, either large pools of small rain puddles. Pison argentatum and the Old World species P. erythropus Kohl , P. koreense (Radoszkowski) and P. obliteratum F. Smith also belong here (Bohart and Menke, 1976).

The third type includes the species that nest in the ground and do not use mud at any stage of the nest construction. They carry the material extracted from the nest during the nest excavation using their psammophores and drop it in flight. Two species, P. areniferum and P. auriventre , were actually observed during nest digging (Evans, 1981), but two others, P. barbatum and P. ciliatum , were assigned to this type based on the possession of psammophores. Many more species with at least a genal psammophore are recognized in the current paper: P. argentifrons , P. aterrimum , P. contiguum , P. dentatum , P. fossor , P. kurandae , P. laticeps , P. minutum , P. notochthonum , P. occidentale , P. psammophilos , P. punctatum , P. pusillum , P. radians , P. setiferum , P. stenometopon , P. tomentosum , P. tridentatum , P. triodon , and P. xenognathos . Apparently they all nest in the ground. According to Janvier (1928), P. chilense Spinola also nests in the ground. The female of this species, however, does not possess a psammophore – to dig a nest, she brings some water to soften the ground, and then uses her mandibles first and then her forelegs to remove particles of the soil.

Like all other Trypoxylini , members of Pison prey upon small spiders, although they are great differences between the prey species. For example, P. rufipes preys upon Salticidae , while P. marginatum ¸ P. spinolae , and P. westwoodii make extensive use of orb-weaving spiders, primarily of Araneidae (Evans, Matthews, and Hook, 1981) , although Nephilidae are also used by P. marginatum (Gibson Hill, 1950) , and Tetragnathidae by P. spinolae (Evans, Matthews, and Hook, 1981) . Pison suspiciosum preys on Agelenidae , Araneidae , Salticidae , Tetragnathidae , and Theridiidae (Katayama, 1934; Iwata, 1964), and also on Oxyopidae (Krombein and Norden, 2001) and Lycosidae (Starr, 2004) . P. areniferum , P. barbatum , and P. ciliatum collect Oxyopidae , and P. auriventre preys on Lycosidae (Evans, 1981) .