Supplementary studies on ant larvae: Formicinae (Hymenoptera: Formicidae).
Psyche 89(1-2):175-182, 1982.
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SUPPLEMENTARY STUDIES ON ANT LARVAE:
FORMICINAE (HYMENOPTERA: FORMICIDAE)'
This article describes formicine larvae received since the prepara- tion of our most recent supplement (1980). The larva of Proformica has not been previously described. Also included are references to formicine larvae in the literature and a discussion of the status of Colobopsis.
The terms describing body profile and mandible shape are explained in our 1976 monograph. Our own contributions are cited by year and page only.
Genus ACANTHOMYOPS Mayr
The larvae are very active and can quickly change their posture from circular to linear or reverse.
Genus FORMICA Linnaeus
Alpert and Ritcher 1975289. Adults of the scarabaeid beetle Cremastochilus armatus feed on larvae of Formica fusca and Formica obscuripes.
Genus LASIUS Mayr
Lasius sitkaensis Pergande
Akre and Hill 1973. The pselaphid beetle Adranes tayiori Wick- ham possesses trichomes (tufts of golden hairs) on the abdomen, tips of elytra and venter. These trichomes are highly attractive to half-grown or smaller ant larvae, less so to larger larvae and workers. The beetles are fed by the larvae through trophallaxis and obtain other nutrients by feeding on dead larvae and workers. Beetles are often seen walking about with larvae actively holding on to the trichomes with their mouthparts; Fig. 4 (p. 531) shows a larva so attached.
'Manuscript received by editor June 10. 1982. adjunct Research Associates, Desert Research Institute. Reno. NV: present address: 326 Laurel Ridge Road. San Antonio. TX 78253.
Genus MYRMECOCYSTUS Wesmael
Snelling ( 1976:22) quoted our characterization ( l968:2 1 1) of the genus and compared the larvae of this genus with those of Lasius. Page 23: "I provided some erroneous identifications to the Wheel- ers. These may be corrected: "lugubris'=creightoni; 'rnojave'=testa- ceus; 'sernirufus'=kenne&i (Calif .) and depilis ( Ariz.)" Page 7: "These data, albeit fragmentary, seem to indicate that protein, such as that derived from the tissues of other insects is essential for larval development." Page 6: "The insect fragments are placed among the larvae and these must fend for themselves. I have seen no indication that larvae of these species are fed by tro- phallaxis."
Page 8: Larvae are subject to desiccation; hence they are to be found in the upper chambers of the nest only in the evening and early morning. When the surface begins to warm up the brood is removed to deeper chambers.
Genus PROFORMICA Ruzsky
Profile pogonomyrmecoid. Integument of venter of anterior body somites and of portions of labium, maxilla and labrum papillose. Body hairs mostly with bifid tip. Antenna large. Head hairs few, with 2- or 3-branched tip. Labrum large and subrectangular. Mandible ectatommoid, with one medial tooth. The specialization index is 18.
Prqforrnica ferreri Bondroit
Length (through spiracles) about 3.7 mm. Profile pogonomyrme- coid (i.e., diameter greatest near middle of abdomen, decreasing gradually toward anterior end and more rapidly toward posterior end, which is rounded; thorax more slender than abdomen and forming a neck, which is curved ventrally). Anus posteroventral and with a small posterior lip. Leg, wing and gonopod vestiges present. Spiracles small and decreasing in diameter posteriorly. Integument of venter of anterior somites papillose; dorsal surface of posterior somites sparsely spinulose, the spinules minute and in short to long transverse rows. Body hairs sparse, moderately long (0.024-0.07 mm), with simple, bifid or multifid tip. Cranium suboctagonal, slightly broader than long. Antenna large, with 3 (or 2) sensilla, each bearing a spinule. Head hairs few, short (0.013-0.04 mm long), unbranched or with bifid tip. Labrum large, subrectangular, slightly
Wheeler & Wheeler - Ant larvae
Figure 1. Pyformicaferrari. a. Head in anterior view. X 100; b, larva in side view. X33: c. two body hairs. X320: d. left mandible in anterior view. X320. broader than long, with ventral border erose; anterior surface with 12 sensilla; with minute papillae near ventral border; ventral surface papillose and with 6 sensilla; posterior surface densely spinulose, the spinules minute and arranged in rows which radiate from the dorsolateral angles, the rows continuous. near the base but broken distally; posterior surface with about 6 sensilla. Mandible large; ectatommoid (i.e., subtriangular; with a medial blade arising from the anterior surface and bearing a small medial tooth; apex curved medially to form a tooth); anterior and posterior surfaces with longitudinal rugae. Maxilla rather large; with paraboloidal apex; integument papillose, the papillae bearing minute spinules; palp a short rounded knob bearing 5 (1 encapsulated and 4 bearing a spinule each) sensilla; galea digitiform with 2 apical sensilla. Labium prominent; integument papillose; with a dorsal transverse welt bearing minute spinules in transverse rows; palp a low knob with 5
178 Psyche [VOI. 89
(1 encapsulated and 4 bearing a spinule each) sensilla; an isolated sensillum medial to each palp; opening of sericteries wide and with a sclerotized projection at each side. Hypopharynx with minute spinules in transverse rows. (Masterial studied: 16 larvae from
Huesca, Spain, courtesy of X. Espadaler.) Genus OECOPHYLLA F. Smith
Hinton 195 1 : 169. The larvae of Wurthia aurivillii Kemner and W. myrmecophila Roepke (Pyralididae) feed on the brood of ants of this genus.
Genus ACANTHOLEPIS Mayr
A cantholepis frauen feldi Mayr
Tohmk and Tohmk 1975: 136-138. "Les 5 stades larvaires sont identifies grace A leur forme, leur dimension et surtout leurs poils." Fig. 3 (p. 136).
Genus BRACHYMYRMEX Mayr
Brachymyrmex admotus Mayr
Length (through spiracles) about 1.6 mm. Very similar to Bra- chymyrmex depilis (1953: 139) except in the following details. Type 2 body hairs twice as long (0.15 mm). Head hairs 2- or 3-branched: 0.038-0.075 mm long. Mandible with apical tooth slightly more curved medially. Palp and galea subequal in height; galea more slender. Labial palp taller. (Material studied: 6 larvae from Costa Rica, courtesy of Jack Longino.)
When we defined bbpraesaepium" (1953: 180) we had overlooked the first description (without a name) of the structure by W. M. Wheeler and Bailey (1920:270-271): - "In a study undertaken by the senior author and Mr. George C. Wheeler of the larvae of a large number of other ant genera, no structure.comparable to the Pseu- domyrmine trophothylax has been found, except in certain species
19821 Wheeler & Wheeler - Ant larvae 179 of Camponotus of the subgenus Colobopsis. In all the species of the latter subgenus examined the larva is very hypocephalic and the ventral portion of the first abdominal segment projects considerably beyond the thoracic segments and presents a pronounced concavity or basin in the mid-ventral region precisely in the position of the trophothylax of the Pseudomyrminae. A feeble vestige occurs in many Camponotus larvae belonging to other subgenera. No solid pellet is deposited in the basin of Colobopsis, but it may, perhaps, be used to hold a supply of the liquid food regurgitated by the workers or of the saliva secreted by the larva itself for the benefit of its attendants." We later found pellets in the praesaepium of Colo- bopsis ( 1970:650).
Genus CAMPONOTUS Mayr
Camponotus rasilis W. M. Wheeler
Petralia and Vinson 1979. Venter-description and SEM. Genus COLOBOPSIS Mayr
Colobopsis was established by Mayr in 186 1 as a genus. In 1889 Emery "reduced it to a subgenus under Camponotus, owing to the existence of forms intermediate between these two groups and the relatively unimportant distinguishing characters of Colobopsis" (W. M. Wheeler 1904: 139). And there it has remained through W. M. Wheeler's "Key to the Genera and Subgenera of Ants" (1922), Emery's "Genera Insectorum" (1925), Creighton's "The Ants of North America" (1 950). Brown (1973: 179) did not employ subgen- era; so he had to synonymize it with Camponotus or raise it to generic rank; he chose the former.
However, we have noticed of late a tendency among myrmecolo- gists to elevate Colobopsis to generic rank (e.g., Snelling 198 1 :404). Although we have some doubts about adult characters, we can cer- tainly support the elevation by larval characters. In 1953: 18 1 we wrote: "The genera of this tribe are so similar that we cannot distin- guish them; hence we have not attempted to key them. Colobopsis is, however, exceptional; differences of generic magnitude separate it not only from the other subgenera of Camponotus but also from the other genera of Camponotini."
1. Posterior '/ of venter of All
raised to form transverse welt,
and, on either side ridges from
the welt extend forward
2. Body hairs numerous
3. Body hairs of 5 types: (1) 2- to
6-branched; branches all in
same plane, the most numer-
ous type; (2) simple, short,
slightly curved; (3) few, sim-
ple, long and whip-like; (4)
few, denticulate (5) few, un-
4. Antenna small
5. Head hairs numerous, long
1. Praesaepium formed from
ventral surface of TI11 and
AI: anterior border of A11
forms ventral wall; no side
2. Body hairs sparse
3. Body hairs of 3 types: mostly
(1) simple or (2) bifid; few (3)
very long and whip-like; none
4. Antenna minute, peg-like
5. Head hairs moderately numer-
Colobopsis pylartes W. M. Wheeler
Petralia and Vinson 1979. Venter-description and SEM. Genus POLYRACHIS F. Smith
Hinton 195 1 : 169. The larvae of Wurthia aurivillii Kemner and W. rnyrrnecophila Roepke (Pyralididae) feed on the brood of ants in this genus.
Polyrhachis dives F. Smith
Hinton 195 1 : 167. The larvae of Batrachedra myrmecophila Snell. (Cosmopterygidae) feed on the brood of this ant. LITERATURE CITED
AKRE, R. D., AND W. B. HILL. 1973. Behavior of Ailranes iay/ori, a myrmecophilous beetle associated with I.usiu.s sitkaensis in the Pacific Northwest. J. Kansas Entomol. Soc. 46:526 536.
ALPERT, G. D., AND P.O. RITCHER. 1975. Notes on the life cycle and myrmecophilous adaptations of Cr~t~~u.s/ocheilu.s armutufi. Psyche 83:283-29 1.
19821 Wheeler & Wheeler - Ant larvae 181 BROWN, W. L. 1973. A comparison of the Hylean and Congo-West African Rain Forest ant faunas. Pages 16 1 - I85 in "Tropical Forest Ecosystems in Africa and South America: a comparative review." Eds. B. J. Meggers et al., Smithsonian Press. Washington.
CREIGHTON, W. S. 1950. The ants of North America. Bull. Mus. Comp. Zool. Harvard Coll. 104:1585. 57 pi.
EMERY, C. 1889. Intorno ad alcune formiche della fauna palearctica. Ann. Mus. Civ. Stor. Nat. Genova 27:485-520.
EMERY, C. 1925, Hymenoptera. fam. Formicidae. subfam. Formicinae. Genera Insectorum, Fasc. 183, 302 p.. 4 pi.
HINTON, H. E. 1951. Myrmecophilous Lycaenidae and other Lepdoptera: a sum-
mary. Proc. South London Entomol. and Nat. Hist. Soc. 1949-1950, 1 11 - 175. MAYR, G. 1861. Die europaeischen Formiciden. Wien I Vol. PETRALIA, R. S., and S. B. VINSON. 1979. Comparative anatomy of the ventral region of ant larvae and its relation to feeding behavior. Psyche 86:375-394 SNELLING, R. R. 1976. A revision of the honey ants, genus Myrmecocystus. Natur. Hist Mus. Los Angeles Co. Sci. Bull. 24. 163 p. SNELLING, R. R. 1981. Systematics of social Hymenoptera. Pages 370-453 in "Social Insects" Vol. 11. Ed. H. R. Hermann. Academic Press, New York. TOHME HENRIETTE AND G. TOHME. 1975. Description des castes dlAcantholepis frauenfeldi Mayr et des diffkrents stades larvaires. Bull. Soc. Entomol. Egypte 59:131-141.
WHEELER, G. C., AND JEANETTE WHEELER. 1953. The ant larvae of the subfamily Formicinae. Ann. Entomol. Soc. Amer. 46: 126- 17 1, 175-2 17. WHEELER, G. C., AND JEANETTE WHEELER, 1968. The ant larvae of the subfamily Formicinae: supplement. Ann. Entomol. Soc. Amer. 61:205-222. WHEELER, G. C., AND JEANETTE WHEELER. 1970. Ant larvae of the subfamily Formicinae: second supplement. Ann. Entomol. Soc. Amer. 63:648-656. WHEELER, G. C., AND JEANETTE WHEELER. 1976. Ant larvae: review and systhesis. Entomol. Soc. Washington Mem. No. 7: 108 p. WHEELER, G. C., AND JEANETTE WHEELER. 1980. Supplementary studies on ant larvae: Ponerinae, Myrmicinae and Formicinae. Trans. Amer. Entomol. Soc. 106:527-545.
WHEELER, W. M. 1904. The American ants of the subgenus Colohopsis. Bull. Amer. Mus. Nat. Hist. 20:139-185.
WHEELER, W. M. 1922. Key to the genera and subgenera of ants. Bull. Amer. M us. Nat. Hist. 45:63 1-7 10.
WHEELER, W. M., AND I. W. BAILEY. 1920. The feeding habits of pseudomyrmine and other ants. Trans. Amer. Phil. Soc. (Philadelphia) (Art.4):235-279.
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