The Ant Larvae of the Subfamily Leptanillinae (Hymenoptera, Formicidae)

Psyche: A Journal of Entomology, Mar 2019

George C. Wheeler, Jeanette Wheeler

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The Ant Larvae of the Subfamily Leptanillinae (Hymenoptera, Formicidae)

International Journal of species in genera: Leptanilla Emery species Leptomesites Kutt species Phaulomyrma G. C. E. W. Wheeler Sardinia North Africa India Malaya Queensland Western Australia Japan. Seemingly it is rare should Madagascar Asia Minor India or even perhaps in the warmer.parts of the N w World." Brown ( o years since Wheeler wrote in Japan) ): "The Leptanillinae... must be very ancient because the south- western corner of Australia in which it was taken is known to possess the oldest disjunct distribution with rarity. The genus Leptanilla w s established by Em ry in then or half ntury was kicked about ov however letter to Emery (date not given s Emery ) dissented ry was evidently convinced for in Liomyrmex. In he moved it to the vicinity o.f Monomorium sition. In Ern. Andr had it in the (irst tribe. "Myrmicidae v did not mention the genus but might have meant Wheeler and Wheeler to include it in the subfamily Myrmicinae, when he said that the ourth tribe ("Myrmicii") included "les autres genres de la sousamille des Myrmicinae." And later (9o) he excluded it from the Dorylinae when he says, "Donc, je maintiens la so.us-amille Dorylinae limite aux genres Dorylus, A enictus, Eciton et Cheliomyrmex.?" In Dalla Torre?s "Catalogus" (893) it was still in the Myrmicinae but near Trigonogaster and Pheidologeton. In 895 Emery was still of the opinion that it belonged in the subfamily "Myrmicini" in the second tribe ("Myrmicii") near H.ube?ria and Phacota. But nine years later (9o4), after describing the female o.f L. revelierei, he returned it to its original subfamily (Dorylinae). In the following year in Ashmead?s skeleto.n it stood between "??Liomyrmex?" and Epipheidole in the tribe Stenammini, subfamily Myr.micinae, family "Myrmicidae." In 9o7 Santschi described males o. 3 species, which he referred to the genus Leptanilla and claimed that their doryline affinities justi(ied Emery?s original allocation of the genus. It should be noted, however, that males of Leptanilla have never? been taken with female.s or workers; hence it is not certain that tho.se described by Santschi belong to this genus. In the "Genera Insectorum" Emery (9o) established for the genus a separate tribe (Leptanillini) in the subfamily Dorylinae, where it seemed destined to abide in isolation" Wheeler (9.o), Forel (97 and 923), and Wheeler (922) did not disturb it. Wheeler (923, p. 335) suggested that even further isolation might be necessary" "I believe that the tribe Leptanillini, which E,mery includes among the. Dorylinae, will have to be s.eparated out as a distinct subfamily (Leptanillinae). Dr. George C. Wheeler (inds that the larva of Leptanilla is. very aberrant, and the characters of the adult are either quite unlike, those of other Dorylinae or only super(icially similar and due to. convergence, or similarity of subterranean habits." By 932 (p. 57) the separation had been effected" "Emery, as is well known, regarded the Leptanillinae as constituting a special tribe of the Dorylinae, but Dr. G. C. Wheeler and I have raised the group to. subfamily rank." Bernard (951 raised the taxon to family rank. Brown and Nutting (I95O, p. I24) in their study of the wing venation for the family Fo.rmicidae wrote" "The position of the leptanillines is debatable. They are usually treated as a subfamily by modern authors, and the venation is so highly reduced in the forms we have seen that little may be deduced from them concerning relationships to the other subfamilies." Brown was apparently still puzzled in I954 (p. a8) for he wrote" "This little subfamily has suffered such drastic anatomical reduction in most of the usually valuable phylogenetic characters that it is doubtful whether we shall ever be certain of its true affinities It is possible that forms as yet unknown will reveal their ancestry more clearly. Until that time, however, subfamily rank for the Lept?anillinae may as we?ll be maintained. Present opinion seems to favor relating this group to the Dorylinae.?" The larvae of the Leptanillinae do, bear certain resemblances to. the known doryline larvae (Dorylus, zlenictus, Eciton, Cheliomyrmex) the long slender body and the small feebly sclero,tized mandibles. On the other hand, they differ in the constriction at the metathorax, the long hairs on the abdomen, the absence of hairs on the head and the shape of the head. But these differences beco.me trivial and insignificant beside the three which not only differentiate them from the Dorylinae, but also from all other known formicid larvae (I6O genera): the peculiar projection from the ventral surface of the prothorax; (2) the reduction of the spiracles from the normal ten pairs to a single .pair, which is located on abdominal somite III; and (3) the shape and stance of the mandibles. Subfamily LEPTANILLINAE Emery Elongate and very slender; slightly constricted at the metathorax; anterior end curved ventrally; remainder of body straight and clavate. With a curious complex structure projecting anteroventrally from the ventral surface of the prothorax. Only one. pair of spiracles, located on abdominal so.mite III; each spiracle opening eccentrically on a naked circular area. Body hairs simple; the minute hairs very abundant and uniformly distributed; a few conspicuous, long hairs sparsely scattered. Head naked and elongate. Antennae small, slightly raised, each with two sensilla. Labrum slightly broader than long, with the ventral border semicircular; posterior surface spinulose, with the spinules in rows. Mandibles apparently turned laterally (instead of medially, as is usual with ant larvae) feebly sclerotized; each with a rather long slender sharp-pointed apical tooth, which curves laterally; lateral (zouter) border furnished with several long slender sharp-pointed teeth; anterior surface with rows of spinules. Labium thin, flap-like and narrowed basally; lateral surfaces sclerotized; each palp a low ventrolateral projection bearing five, sensilla. Of all the ant larvae studied we have found the Leptanillinae the most difficult to process partly because o.f their small size but chiefly because of their extreme slenderness, fi_ slender larva is more apt to collapse than a stout one. Furthermore the constriction at the metathorax aggravates the difficulty o,f cleaning and predisposes to breakage in that region. As a result processing has ,often left us only fragments to mount on slides. Fragments are all right min fact, necessary for some parts- if none is lo,st and if they can be correctly oriented. References.--W. M. Wheeler (1923 , p. 335) used larval characters in establishing the subfamily (quoted above and also by (. C. Wheeler, 1928, p. 88-89 and tel.erred to by G. C. and E. Wheeler, I93O, p. 198) . G. C. Wheeler (1928, p. 89) justified W. M. Wheeler?s establishment of the subfamily. (Repeated G. C. and E. Wheeler, 193o, p. 199.) Kutter 1948 p. 294" "Alle his jetzt bekannt gewordenen Larven der Leptanillinae haben den teilweise chitinisierten, ventralen Tho.rakalanhang gemein, wie offenbar auch die Senkrechtstellung der Mandibeln, wiihrend der Besitz des als Tympanalorgan bezeichneten Organs noch nicht als typisch ffir alle Larven der Unterfamilie bezeichnet werden darf." Bernard, 1951, p. lO41" "Larves euc6phales, carnivores; nourries par les ouvrires." Genus Leptanilla Emery We are unable to separate Leptanilla generically from Leptomesites" the difference between the larvae of the two kno,wn species of the t:ormer are as great as the difference between e,it?her species and the lar;a o.f the latter. Therefore the subfamilial description will su,ffice for the genus. Bernard (I95I, p. Io7) described primitive larvae and mentioned the larva of Leptanilla as an example. Kutter (9.48, p. 292) differentiated the two genera by the absence of the naked area around the spiracle ("tympanum") and the structure ,ot: the ventral prothoracic projection. As we sho,w below, this distinction is no longer tenable. The two species of Leptanilla differ with respect to the following characters: size and shape of terminal boss; complexity ,o,f ventral prothoracic projection; size and arrangement of long body hairs; shape ot: head; number of teeth and spinules on the mandibles; and the sclerotized band bordering the spiracular area. Leptanilla revelierei sardoa Emery (Fig. -8) Length approximately .3 mm. Body elongate and slender; thorax slightly curved ventrally, slightly constricted at the metathorax; abdomen straight and clavate, the diameter increasing gradually to abdominal somite V and decreasing to the posterior end which is WHEELER ANT LARVAE 1965] H/?heeler and lheeler--Ant Larvae rounded and terminates in a small naked hemispherical boss. With a complex structure projecting anteroventrally rom the ventral surface o( the pro.tho.rax (see Fig. 4-5). With only one pair o spiracles, located on the third abdominal somite near the posterior border; each spiracle opening eccentrically on a naked circular area, which is bordered by a narrow heavily sclerotized band. Body hairs simple. O three type.s: (I) numerous, increasing in length rom o.oo5 mm on the tho.rax to. o.o2 mm at the posterio.r end, without alveolus and articular membrane, uniformly distributed but lacking rom the anterior portion o the prothorax, the. circumspiracular area and the terminal boss; (2) o.oi-o.I 5 mm long (sho.rtest on the prothorax), ew, conspicuous, the lo.ngest attenuated and flexible distally, with alveolus and articular membrane, absent rom t?he dorsal surface o abdominal somites III-IX; (3) about o.3 mm long, with attenuated flexible tip, two (one dorsal and one ventral) on the posterior end near the terminal boss. Head naked; elongate; widest above the antennal level; cranium subpyriorm in anterior view. Antennae small; slightly raised; each with two sensilla, each o which bears a spinule. Labrum slightly broader than long; the ventral border semicircular; posterior surface spinulose, the pinules in long rows, the rows co.ncentric with the ventral border. Mandibles with the toothed border directed laterally; feebly sclerotized; each with a rather long slender sharp-pointed apical tooth, which is curved laterally; lateral border with our long slender sharp-po.inted teeth.; a (ew vows o. rather large spinules on the anterior surface. Maxillae adnate to the labiu,m; palp a stalked hemispherical knob directed laterally and bearing five sensilla; no galea seen. Labium a thin flap, narrowed basally; lateral surfaces sclerotized; each palp a low ventrolateral projection bearing five sensilla; an isolated sensillum between each palp and the opening o( the sericteries; the latter a transverse impression on the anterio.r surface. EXPLANATION OF PLATE 2 Figs. 1-8. Letanilla ree:elierei sardoa. 1, head in anterior view, X417; 2, larva in side view, X76; 3, left mandible in anterior view, X847; 4, ventral prothoraeie structure in side view, X423; 5, ventral prothoraeie structure: left half in posterior view, right half in anterior view, X423; 6-8, three body hairs, X500. Figs. 9-18. Leltanilla s,ani. 9, head in anterior view, X417; 10, larva in side view, X76; 11, left mandible in anterior view, X1333; 12, left maxilla in anterior view, X847; 13 and 14, two body hairs, X S?00; 15 and 16, spiracle and eireumspiraeular area in side and surface phantom views (hairs omitted) X333; 17 and 18, ventral pro.thoracic structure in anterior view and in side view, X667. Material Studied.--Three larvae labeled "Sardegna: Golfo Aranci. I. 19o?9 A. Dodero." These are the specimens studied by G. C. Wheeler (I928). We studied them. first with a phase microscope; then they were dismo.unted, stained lightly, remounted and studied under both p?hase and light microsco.pes. Literature. The description and figures by G. C. Wheeler (1928, p. 85-87) have been completely revised for this article. Bernard, I95I Fig. 949 C, D afte.rG. C. Wheeler, 1928. Leltanilla swani Wheeler (Fig. 9-i8) Length about 1.4 mm. Body elongate and very slender; anterio.r end curved ventrally, slightly constricted at the. metathorax; remainder of body straight and clavate; diameter increasing gradually to abdominal somite VII and diminishing to the .posterior end, which is round-pointed and terminates in a small naked boss. With a complex structure projecting anteroventrally from the ventral surface, o.f the prothorax (see Fig. 17-I8). With only one pair of spiracles, located near the po.ste.ri.o.r border o.f abdominal somite III; each. spiracle opening eccentrically on a naked .circular area. Body hairs simple. Of two types: (I) abundant and uniformly distributed (except on the terminal boss and the circumspiracular area), minute (o.oo5-o.o24 mm long), longest near the posterior end, without alveolus and articular membrane; (2) long (o.o84-o.23 mm), slender, with the apical portion fine and flexible, with alveolus and articular membrane, few, conspicuous, absent from the dorsal surface of the abdomen. Head naked; elongate; widest at the level of the antennae; cranium subpyrifo.rm in anterior view. Antennae small and slightly raised; each with two sensilla, each o.f which bears a spinule. Labrum slightly broader than long, with the. ventral border semicircular; posterior surface spinulose, the spinules rather numerous and long, arranged in rows concentric with the ventral border. Mandibles with the toothed border directed laterally; feebly sclerotized; each with a rather long slender sharp-pointed apical tooth, which curves laterally; lateral border with six lo.ng slender sharp-pointed teeth; anterior surface spinulose, the spinules numerous, rather long and arranged in rows; posterior surface with one row of long spinules. Maxillae adnate to the labium; palp an irregular knob projecting laterally and bearing five sensilla; no galea seen. Labium a thin flap, narrowed basally; lateral surfaces sclerotized; each palp a low ventrolateral projectio.n bearing qve sensilla; an isolated sensillum between each palp and the opening of the sericteries; the latter a transverse slito.n the ventral border. ttheeler and tlheeleru Ant Larvae Material Studied.--Three larva,e from Chittering, Western Australia collected by D. C. Swan. These are the specimens referred to by W. M. Wheeler in 1932 (15. 56-57). We studied them first with a phase microscope; then they were dismounted, stained lightly, remounted and studied under both phase and light microscopes. In I963 Rev. B. B. Lowery of St. Ignatius College (Sydney, Australia) generously sent us 40 larvae of this species, which he had collected at Cunningham?s Gap in southern Queensland. The two best specimens have been kept in alcohol..Many others were processed according t.o our standard technique (I96o) and studied under both phase and light microscopes. Literature. W. M. Wheeler (I932, p. 56-57) compared the larva of L. swani with that o.f L. sardoa by quoting from a letter from G. C. Wheeler to whom he had sent the larvae for study. Genus Leptomesites Kutter As explained above under the genus Leptanilla, we are unable to separate Leptomesites genei?ically from Leptanilla. Therefore our subfamilial description will have to sutkic.e for this genus. Kutter (1948, p. 287) has characterized the genus thus." "K6rper sehr langgestreckt-zylindrisch, gegen das Ende keulenf.6rmig aufgetrieben. Labrum ohne gezfihnte, laterMe Lfippchen. Mandibeln abwfirts, gerichtet, gezfihnt. Auf der Ventralseite des Pro.thorax mit breitem, in der Mittelpartie mit chitinisiertem, quergerilltem, lappigem Anhang. Beiderseits dieses einzigartigen Anhanges je eine sehr lange, sichelf6rmig ventralwfirts gebogene Borste. (Ein Tympanalorgan, wie es yon der Leptanilla-Larve gemeldet wird, konnte nicht mit Sicherheit nachgewiesen werden.)" Leptomesites escheri Kutter (Fig. I9-28) Length about 1.5 mm. Body elongate and slender, apparently constricted at the metathorax; anterior end slightly curved ventrally; abdo.men clavate, with the posterior end narrowly rounded. Projecting ventrally from the anterior po.rtion of the. prothorax is a curious flap-like structure furnished with I4 ridges, o.n the posterior surface. Only one pair of spiracles present, on abdominal somite III (or? IV?). Body hairs simple. Of two types" (I) minute (o.oo9-o.o6 mm long), longest near the spiracle, numerous, uniformly distributed, Without alveolus and articular membrane; (:) short to very long (o.o4-o.o96 mm), a few o.n each somite, the apical portion fine and flexible, with alveolus and articular membrane. Head naked; elongate?; widest above the antennal level; cranium subovoidal. Antennae small and slightly raised; each with two sensilla, each of which bears a spinule. Labrum slightly broader than long; the ventral border semicircular; posterior surface spinulose, the spinules in long rows, the rows concentric with the ventral border. Mandibles with the toothed border directed laterally; feebly sclerotized; .each with a rather long slender sharp-pointed apical tooth, which is curved laterally; lateral border with nine long slender sharp-pointed teeth; anterior surface furnished with numerous short rows o,f lo,ng spinules, the rows so close together that the spinules overlap. Maxillae conoidal, pointing laterally; palp apical and consisting o i]ve sensilla; galea represented by two sensilla, each o which bears a digitio.rm spinule. Labium eebly bilobed, flap-like, narrowed basally; palp a low ventrolateral projection bearing five? sensilla; an isolated sensillum between each palp and the opening o the sericteries; the. latter a transverse slit on the ventral surface. Hypo.pharynx spinulose, the spinules in short transverse rows, the rows so close, together that the spinules overlap. Material Studied: --Two semipupae (?) ro.m southern India. These are the specimens studied by Dr. Heinrich Kutter (1948, p. 290-292) o Minnedo.r, Switzerland. In I963 we asked Dr. Kutter whether he would be willing to let us examine them. His generous response was to send them to us as a git. We studied them first with the phase microscope; then they we?re dismounted, stained lightly, remounted and studied under both phase and light microscopes. We were not able to inflate the wrinkled specimens; therefore our drawing o the larva in side view is a restoration. Literature. Kutter (I948, p. 29o-292): a description o the species; Fig. 6, larva in side view; Fig. 7, anterior end enlarged. LITERATURE CITED ANDRI, ERN. 1881-1582. Species des hym@nopt@res composant le groupe des formicides d?Europe, etc. ASHMEAD, W. H. 1905. A skeleton of a new arrangement .of the families, subfamilies, tribes and genera o.f the ants, or the superfamily Fo.rmicoidea. Canad. Ent. 37: 381-384. BERNARD, F. 1951. Super-famille des Formicoidea. In: P. P. Grass6 (ed.), Trait6 de Zoologie, 10 (2)" 997-1104. Masson et Cie, Paris. BROWN, W. L. 1954. Remarks on the internal phylogeny and subfamily classification of the family F.ormicidae. Insectes Sociaux 1" 21-31. BROWN, W. L., AND W. L. NUTTING 1950. Wing venation and the phylogeny of the Formicidae. Trans. Amer. Ent. Soc. 75: 113-132, 2 pl. DALLA TORRE, K. W. voN 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Vol. VII" Formicidae (Heterogyna). W. Engelmann, Leipzig. 289 p. EtERY, C. 1870. 1875. Studi mirmecologici. Boll. Soc. Ent. Ital. 2:9 p, pl. Le formiche ipogee con descrizioni di sp. nuo.ve o poco note. Ann. Mus. Cir. Genoa 7: 465-474. 1877. Saggio di un ordinamento naturale dei myrmicidei e considerazioni sulla filogenesi delle formiche. Boll. Soc. Ent. Ital. 9: 1-17, pl. FOREL, A. 1893. KUTTER, H. 1948. Peptides Advance s in Hindawi Publishing Corporation ht p:/ www.hindawi.com Submit your manuscr ipts BioMed Hindawi Publishing Corporation ht p:/ www.hindawi.com Stem Cells Zoology International Journal of Journal of Signal Hindawi Publishing Corporation ht p:/ www.hindawi.com Transduction Genetics Research International Hindawi Publishing Corporation ht p:/ www.hindawi.com Anatomy Research International International Journal of Microbiology Advances in Bioinformatics Hindawi Publishing Corporation ht p:/ www.hindawi.com Hindawi Publishing Corporation ht p:/ www.hindawi.com Hindawi Publishing Corporation ht p:/ www.hindawi.com Enzyme International Journal of Molecular Biology Journal of International Journal of Genomics Hindawi Publishing Corporation ht p:/ www.hindawi.com Journal of 1895. Die Gattung Dorylus Fabr. und die systematisehe Eintheilung der Formiciden . Zool. Jahrb. Abt. Syst . 8 : 685 - 788 . 1904. Le affinitt del genere Leptanilla e limiti delle Dorylinae . Arch. Zool. Napoli 2 : 107 - 116 . 1910. Fam. Formicidae, Subfam. Dorylinae in Wytsman's "Genera Insectorum." Fascicle 102 :34 p. pl . Sur la elassifieatio.n de la famille des formieides, avee remarques synonymiques . Ann. Soe. Ent. Belg. 37 : 161 - 167 . 1901. Apropos de la olassifieation des fourmis . Ann. Soe. Ent. Belg. 45 136 - 141 . 1917. Cadre synoptique aetuel de la faune universelle des fourmis . Bull. Soe. Vaud. Sei. Nat . 51 : 229 - 253 . 1923. Le monde social des ourmis du globe . 5 :174 p., pls. Librairie Kundig , Geneva. Beitrag zur Kenntnis der Leptanillinae. Eine neue Ameisengattung aus siid-Indien . Mit. Sehweiz. Ent. Ges. 21 : 286 - 295 . SANTSCHI , F. 1907 . Fourmis de Tunisie captures en 1906 . Rev. Suisse Zool . 15 : 305 - 334 . WHEELER , G. C. 1928 . The larva of Leptanilla . Psyche 35 : 85 - 91 . WHEELER , G. C. , AND ESTHER W. WHEELER 1930 . Two new ants from Java . Psyche 37 : 193 - 201 . WHEELER , G. C. , AND JEANETTE WHEELER 1960 . Techniques for the study ot ant larvae . Psyche 67 : 87 - 94 . WHEELER , W. M. 1910 . Ants: Their structure, development and behavior . Columbia University Press, New York. 663 p. 1922 . Ants o.f the American Museum Congo Expedition . Bull. Amer. Mus. Nat. Hist . 45 " 1 - 1139 . 1923 . Social life amo.ng the insects . Harcourt, Brace & Co., New York. 375 p. 1932 . An Australian Leptanilla . Psyche 39 : 53 - 58 . Volume 2014


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George C. Wheeler, Jeanette Wheeler. The Ant Larvae of the Subfamily Leptanillinae (Hymenoptera, Formicidae), Psyche: A Journal of Entomology, DOI: 10.1155/1965/28458