Evolution of thorax architecture in ant castes highlights trade-off between flight and ground behaviors
- Instituto Gulbenkian de Ciência, Portugal
- CNRS UMR 7625, Université Pierre et Marie Curie, France
Figures
Figure 1 with 2 supplements
Variation in length of first (T1) and second (T2) thoracic segments in ants shows characteristic differences depending on caste and species.
(A) Relative lengths of T1 and T2 (left) show clear differences between queens and workers for 11 ant species. T3 (right) constitutes a small portion of the total length of the thorax in both queens and workers and, when present (when T3/TL > 0.0), is indistinguishable between castes. Numbers correspond to sample sizes and are equal for both panels (Table 1). (B) Gradient of investment in neck strength vs flight/storage musculature sorts individuals into three categories. Queens fall into two discrete categories based on the relative lengths of T1 and T2. While the use of T1/T2 in (A) emphasizes the distinction between workers and queens and within species variation, T1/TL and T2/TL in (B) enables the distinction between queen types across species with large differences in body size. Measurements and ratios are available in the Dryad data repository under DOI doi: 10.5061/dryad.d62p2/1 (Keller et al., 2014). Species codes: A. aus = Amblyopone australis; B. lut = Brachyponera lutea; C. vid = Carebara vidua; C. was = Cataulacus wasmanni; L. nig = Lasius niger; L. per = Leptothorax pergandei; M. pha = Monomorium pharaonis; N. api = Neoponera apicalis; P. bar = Pogonomyrmex barbatus; P. lab = Polyrhachis laboriosa; T. aet = Tetraponera aethiops.
Figure 1—figure supplement 1
Measurements used in this study.
The length of the first (T1 = pronotum), second (T2 = mesonotum) and third (T3 = metanotum) dorsal thoracic plates was measured along the dorsal midline. Total thoracic length (TL) was measured as the diagonal length in profile from the anterior-most point of the first thoracic segment to the posterior-most point of the third thoracic segment (also known as Weber's length). For each of the specimens measured, images of dorsal and profile views are available in the Dryad data repository under DOI doi: 10.5061/dryad.d62p2/2. Note that the total length of the thorax (TL) is always greater than the sum of the lengths of the dorsal thoracic plates (T1 to T3), because in ants (as in most Hymenoptera) the first abdominal segment (A1 = propodeum) is fused dorsally to the thorax and occupies most of the posterior part of the mesosomal region. A2 = second abdominal segment. Scale bars = 1.0 mm.
Figure 1—figure supplement 2
Differences in length proportion of thoracic segments among castes in nine representative species from different subfamilies.
T2 is always larger than T1 in queens (top), while T1 is larger than T2 in workers (bottom). (A) Aneuretus simoni (Aneuretinae); (B) Discothyrea testacea (Proceratiinae); (C) Ectatomma tuberculatum (Ectatomminae); (D) Myopopone castanea (Amblyoponinae); (E) Myrmecia chasei (Myrmeciinae); (F) Myrmica emeryana (Myrmicinae); (G) Pseudoponera stigma (Ponerinae); (H) Pseudomyrmex gracilis (Pseudomymecinae); (I) Tapinoma erraticum (Dolichoderinae). White-black-white on thick bars equals length of T1, T2, and T3 respectively. Note that T3 has no distinguishable dorsum in workers of most species. Scale bars upper left, 1 mm. All images by April Nobile/antweb.org.
Figure 2 with 2 supplements
Skeletomuscular specialization of queens and workers in ants.
The dorsal plate of T1 is always enlarged in workers relative to queens (left column; multiple individuals from 52 genera examined, Table 2). Queens can either (A) have a reduced T1 and huge T2-associated wing muscles (represented here by Oecophylla smaragdina), or (B) show a slightly enlarged T1 and associated neck muscles (represented here by Neoponera apicalis). T1, T2, and T3, first, second and third thoracic segments respectively; A1, first abdominal segment. Workers of N. apicalis lack a discernible T3. Internally (right column), the wing muscles in queens (red) fill most of the thoracic cavity, while the T1 muscles (blue) are narrow and close to the thoracic wall. In all workers examined (see Table 1 for list of species and sample sizes), the T1 notopleural muscles (np, dark blue) that support the anteroventral plates (yellow) fill the anterior portion of the cavity. The dorsal cervical muscles (dc, light blue; see also Figure 2—figure supplement 1B) that in winged queens originate at the anterior phragma and pull the head up at contraction, show a shifted position in workers. In the absence of phragma, these muscles originate at the dorsal boundary between T1 and T2. Rather than being short and thin, they form long and thick bundles that stretch the entire length of the enlarged T1 cavity to their place of insertion on the back of the head (Figure 2—figure supplement 2). Figure 1—supplement 1 has photos of many more species of ‘reduced T1’ and ‘intermediate T1’ species for comparison of external thoracic morphology.
Figure 2—figure supplement 1
Thoracic musculature in queen and worker ants.
(A) Sagittal section of a queen (Polyrhachis laboriosa) reveals the thoracic cavity filled by the longitudinal (lw) and dorsoventral (dw) indirect wing-muscles (he, head; T1, pronotum; T2, mesonotum; T3 metanotum; A1, first abdominal segment; A2, second abdominal segment; ap, anterior phragma). (B) Anterior view of the queen's T2 shows the thin dorsal cervical muscle pair (dc) that originates at the anterior phragma (ap). (C) Removing the wing muscles and the dorsal plates of T1 and T2 exposes the notopleural muscle pair (np) inside the anterior part of the thorax (left column is dorsal view, right column is profile view; tissues are stained with methylene blue). These muscles are thin and narrow in queens (first row P. laboriosa, second row Neoponera apicalis). Equivalent muscles in ant workers are hypertrophied, and fill the T1 cavity completely (third row, N. apicalis). Scale bar = 1 mm.
Figure 2—figure supplement 2
Internal anatomical adaptations in ant workers for powerful head movement.
(A) One dorsal pair of prothoracic muscles (dc, dorsal cervical) traverses the enlarged workers' T1 cavity and pulls the head up at contraction; the expanded prothoracic endosternum (pe) is the origin for two pairs of muscles (dorsal and ventral) that move the head up-and-down. (B) Skeletal preparations of 18 species (Table 1) revealed that workers show enlargement of the endosternum, an internal skeletal structure that branches inside T1 for attachment of muscles that, in bees, power up-and-down movement of the head (left column is profile view, right column is frontal view; represented by Neoponera apicalis; scale bar, 500 µm). While in queens, the T1 endosternum has an upper face (up) perpendicular to its basal stalk (ba), in workers the upper face rises almost parallel to the basal stalk and has a larger surface for the attachment of the muscles that pull the head. This modification of the endosternum in workers is only possible because the complete absence of wing muscles that occur in this caste leaves the thoracic cavity with sufficient space for the expansion of T1 internal structures. In queens (as is the case in all castes of honey bees), the perpendicular orientation of the endosternal face is necessary for the occurrence of the longitudinal wing muscles across the thoracic cavity.
Figure 3
Phylogenetic reconstruction reveals a single origin of a hypertrophied T1 in workers and multiple independent origins of ‘reduced’ T1 in queens.
The latter is associated with modifications in modes of colony foundation. Tree branches and tree background are colored for queen morphology and founding behavior respectively, according to the parsimony ancestral reconstruction. Typical queen-worker dimorphism shown to the right to illustrate ratio T1/T2 (not to scale). Species with wingless queens are marked with an asterisk. Phylogeny was pruned from Moreau et al. (2006). Placement of Sphecomyrma† and Martialis after Grimaldi et al. (1997) and Rabeling et al. (2008), respectively. Metapolybia and Scolia wasps are included as outgroups. Data on the species are analyzed, and their morphology and type of colony founding behavior are summarized in Table 3. Numbers correspond to major taxonomic groups within Formicidae after Ward (2007): 1, Sphecomyrminae†; 2, Leptanillinae; 3, Martialinae; 4, Proceratiinae; 5, Amblyoponinae; 6, Paraponerinae; 7, Agroecomyrmecinae; 8, Ponerinae; 9, dorylomorphs; 10, myrmeciomorphs; 11, dolichoderomorphs; 12, ectaheteromorphs; 13, Formicinae; 14, Myrmicinae.
Tables
Table 1
Ant species studied for morphometrics and/or internal anatomy
| Morphometrics | Dissections | ||||
|---|---|---|---|---|---|
| Subfamily | Species | q | w | q | w |
| Amblyoponinae | Amblyopone australis | 6 | 8 | 2 | 2 |
| Dolichoderinae | Tapinoma simrothi | – | – | 6 | 10 |
| Ectatomminae | Ectatomma ruidum | – | – | 3 | 5 |
| Formicidae | Lasius niger | 15 | 15 | 2 | 4 |
| Oecophylla smaragdina | – | – | 2 | 5 | |
| Polyrhachis laboriosa | 13 | 5 | 3 | 8 | |
| Myrmeciinae | Myrmecia simillima | – | – | 2 | 4 |
| Nothomyrmecia macrops | – | – | 1 | 4 | |
| Myrmicinae | Carebara vidua | 5 | 3 | 1 | 1 |
| Cataulacus wasmanni | 15 | 15 | 3 | 3 | |
| Leptothorax pergandei | 13 | 15 | 1 | 3 | |
| Messor barbarus | – | – | 3 | 8 | |
| Monomorium pharaonis | 15 | 15 | 2 | 4 | |
| Monomorium subopacum | – | – | 2 | 3 | |
| Pogonomyrmex barbatus | 15 | 17 | 4 | 5 | |
| Ponerinae | Brachyponera lutea | 15 | 15 | 3 | 5 |
| Harpegnathos saltator | – | – | 2 | 4 | |
| Neoponera apicalis | 7 | 12 | 4 | 10 | |
| Pseudomyrmecinae | Tetraponera aethiops | 11 | 15 | 4 | 6 |
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q = number of queens examined; w = number of workers examined. Generic placement of Brachyponera lutea and Neoponera apicalis reflects the new reclassification of species within the former paraphyletic genus Pachycondyla (Schmidt CA, Shattuck SO, The higher classification of the ant subfamily Ponerinae [Hymenoptera: Formicidae], with a review of ponerine ecology and behavior. Under review).
Table 2
List of species surveyed for relative length of thoracic segments
| FAMILY/subfamily | species | queen | worker | ||
|---|---|---|---|---|---|
| Museum | Voucher code | Museum | Voucher code | ||
| FORMICIDAE | |||||
| Aenictinae | Aenictus vaucheri/binghami | MSNG | CASENT0903754 | AMNH | RAK0094 |
| Agroecomyrmecinae | Tatuidris tatusia | DADC | CASENT0178881 | BMNH | RAK0001 |
| Amblyoponinae | Adetomyrma sp | AMNH | RAK0003 | ||
| Amblyoponinae | Amblyopone australis | ANIC | CASENT0172213 | AMNH | RAK0005 |
| Amblyoponinae | Amblyopone mercovichi | MCZ | RAK0006 | ||
| Amblyoponinae | Apomyrma stygia | MNHN | CASENT0101445 | MCZ | RAK0083 |
| Amblyoponinae | Concoctio concenta | MCZ | RAK0011 | ||
| Amblyoponinae | Myopopone castanea | ANIC | CASENT0172069 | AMNH | RAK0012 |
| Amblyoponinae | Mystrium sp | CASC | CASENT0104559 | CASC | CASENT0076622 |
| Amblyoponinae | Onychomyrmex doddi | AMNH | RAK0014 | ||
| Amblyoponinae | Prionopelta punctulata | ANIC | CASENT0172312 | AMNH | RAK0016 |
| Amblyoponinae | Stigmatomma armigera | AMNH | RAK0004 | ||
| Amblyoponinae | Stigmatomma pallipes | ABS | CASENT0103553 | MCZ | RAK0009 |
| Amblyoponinae | Stigmatomma pluto | MCZ | RAK0010 | ||
| Amblyoponinae | Xymmer muticus | MCZ | RAK0007 | ||
| Aneuretinae | Aneuretus simoni | ANIC | CASENT0172259 | MCZ | RAK0074 |
| Cerapachyinae | Acanthostichus serratulus | AMNH | RAK0095 | ||
| Cerapachyinae | Cerapachys nitidulus | RAKC | RAK127 | AMNH | RAK0096 |
| Cerapachyinae | Cerapachys doryloides | AMNH | RAK0097 | ||
| Cerapachyinae | Cylindromyrmex brevitarsus | JTLC | CASENT0610653 | AMNH | RAK0098 |
| Cerapachyinae | Simopone schoutedeni | AMNH | RAK0099 | ||
| Dolichoderinae | Dolichoderus bispinosus | ALWC | CASENT0173835 | ALWC | CASENT0173833 |
| Dolichoderinae | Iridomyrmex lividus | ANIC | CASENT0172066 | ANIC | CASENT0172041 |
| Dolichoderinae | Leptomyrmex pallens | AMNH | RAK0075 | ||
| Dolichoderinae | Tapinoma erraticum | CASC | CASENT0173200 | AMNH | RAK0078 |
| Dolichoderinae | Technomyrmex albipes | CASC | CASENT0060419 | AMNH | RAK0079 |
| Dorylinae | Dorylus conradti/helvolus | MSNG | CASENT0903712 | AMNH | RAK0100 |
| Ecitoninae | Cheliomyrmex morosus | AMNH | RAK0101 | ||
| Ecitoninae | Eciton hamatum | JTLC | INBIOCRI001283500 | AMNH | RAK0103 |
| Ecitoninae | Labidus coecus | AMNH | RAK0102 | ||
| Ectatomminae | Ectatomma tuberculatum | JTLC | JTLC000014186 | AMNH | RAK0017 |
| Ectatomminae | Gnamptogenys annulata | AMNH | RAK0018 | ||
| Ectatomminae | Gnamptogenys striatula | MIZA | CASENT0178660 | AMNH | RAK0019 |
| Ectatomminae | Gnamptogenys bufonis | MCZ | RAK0020 | ||
| Ectatomminae | Gnamptogenys minuta | MCZ | RAK0021 | ||
| Ectatomminae | Rhytidoponera metallica | ANIC | CASENT0172346 | ANIC | CASENT0172345 |
| Ectatomminae | Typhlomyrmex pusillus | MIZA | CASENT0178662 | AMNH | RAK0023 |
| Ectatomminae | Typhlomyrmex rogenhoferi | AMNH | RAK0024 | ||
| Formicinae | Formica sp. (fusca group) | CASC | CASENT0173171 | AMNH | RAK0080 |
| Formicinae | Lasius flavus | CASC | CASENT0173149 | UCDC | CASENT0005406 |
| Formicinae | Oecophylla smaragdina | CASC | CASENT0173644 | AMNH | RAK0082 |
| Formicinae | Polyergus sp | RAKC | RAK0129 | RAKC | RAK0130 |
| Formicinae | Polyrhachis revoili | CASC | CASENT0403971 | CASC | CASENT0227558 |
| Heteroponerinae | Acanthoponera minor | AMNH | RAK0025 | ||
| Heteroponerinae | Heteroponera brouni | MCZ | RAK0128 | AMNH | RAK0026 |
| Heteroponerinae | Heteroponera relicta | AMNH | RAK0027 | ||
| Leptanillinae | Leptanilla swani | AMNH | RAK129 | AMNH | RAK0084 |
| Leptanilloidinae | Leptanilloides erinys/biconstricta | UCDC | CASENT0234616 | AMNH | RAK0104 |
| Martialinae | Martialis heureka | MZSP | CASENT0106181 | ||
| Myrmeciinae | Myrmecia gulosa | CASC | CASENT0103309 | CASC | CASENT0103310 |
| Myrmeciinae | Nothomyrmecia macrops | AMNH | RAK0086 | ||
| Myrmicinae | Aphaenogaster fulva | CASC | CASENT0104857 | CASC | CASENT0103585 |
| Myrmicinae | Carebara vidua | CASC | CASENT0260121 | CASC | CASENT0010803 |
| Myrmicinae | Cataulacus wasmanni | CASC | CASENT0498338 | CASC | CASENT0498558 |
| Myrmicinae | Leptothorax pergandei | MCZ | RAK0125 | MCZ | RAK0126 |
| Myrmicinae | Manica rubida | AMNH | RAK0090 | ||
| Myrmicinae | Messor barbarus | RAKC | RAK0123 | RAKC | RAK0124 |
| Myrmicinae | Metapone madagascarica | CASC | CASENT0004524 | MCZ | RAK0093 |
| Myrmicinae | Monomorium pharaonis | ABS | CASENT0104094 | ABS | CASENT0104095 |
| Myrmicinae | Myrmica wheeleri | MCZ | CASENT0102860 | MCZ | CASENT0102862 |
| Myrmicinae | Pogonomyrmex uruguayensis | RAJC | CASENT0172689 | RAJC | CASENT0103054 |
| Paraponerinae | Paraponera clavata | RAKC | RAK0122 | AMNH | RAK0028 |
| Ponerinae | Anochetus mayri | ABS | CASENT0103555 | MCZ | CASENT0003324 |
| Ponerinae | Asphinctopone silvestrii | MCZ | RAK0031 | ||
| Ponerinae | Belonopelta deletrix | MCZ | RAK0032 | ||
| Ponerinae | Bothroponera pachyderma | AMNH | RAK0054 | ||
| Ponerinae | Brachyponera croceicornis | AMNH | RAK0051 | ||
| Ponerinae | Centromyrmex brachycola | UCDC | CASENT0178343 | AMNH | RAK0033 |
| Ponerinae | Cryptopone gilva | CASC | CASENT0006055 | AMNH | RAK0034 |
| Ponerinae | Diacamma ceylonense | AMNH | RAK0035 | ||
| Ponerinae | Dinoponera lucida | AMNH | RAK0036 | ||
| Ponerinae | Dolioponera fustigera | MCZ | RAK0037 | ||
| Ponerinae | Emeryopone buttelreepeni | MCZ | RAK0038 | ||
| Ponerinae | Hagensia marleyi | MCZ | RAK0053 | ||
| Ponerinae | Harpegnathos saltator | AMNH | RAK0039 | ||
| Ponerinae | Hypoponera sp1. | AMNH | RAK0040 | ||
| Ponerinae | Leptogenys (Leptogenys) sp.1 | AMNH | RAK0041 | ||
| Ponerinae | Leptogenys (Lobopelta) sp.2 | AMNH | RAK0042 | ||
| Ponerinae | Leptogenys podenzanai | MCZ | RAK0043 | ||
| Ponerinae | Loboponera obeliscata | AMNH | RAK0044 | ||
| Ponerinae | Loboponera vigilans | AMNH | RAK0045 | ||
| Ponerinae | Myopias chapmani | ANIC | CASENT0172094 | ANIC | CASENT0172093 |
| Ponerinae | Neoponera apicalis | ALWC | CASENT0103060 | AMNH | RAK0048 |
| Ponerinae | Neoponera villosa | AMNH | RAK0058 | ||
| Ponerinae | Odontomachus bauri | CASC | CASENT0172630 | AMNH | RAK0030 |
| Ponerinae | Odontoponera transversa | BMNH | CASENT0900664 | AMNH | RAK0047 |
| Ponerinae | Ophthalmopone berthoudi | MCZ | RAK0049 | ||
| Ponerinae | Pachycondyla crassinoda | AMNH | RAK0050 | ||
| Ponerinae | Cryptopone guianensis | MCZ | RAK0052 | ||
| Ponerinae | Pseudoneoponera porcata | AMNH | RAK0055 | ||
| Ponerinae | Pseudoponera stigma | AMNH | RAK0056 | ||
| Ponerinae | Paltothyreus tarsatus | AMNH | RAK0057 | ||
| Ponerinae | Phrynoponera gabonensis | AMNH | RAK0059 | ||
| Ponerinae | Platythyrea punctata | ABS | CASENT0104429 | AMNH | RAK0060 |
| Ponerinae | Platythyrea turneri | MCZ | RAK0061 | ||
| Ponerinae | Plectroctena strigosa | AMNH | RAK0062 | ||
| Ponerinae | Ponera alpha | MCZ | RAK0063 | ||
| Ponerinae | Ponera pennsylvanica | CASC | CASENT0006086 | AMNH | RAK0064 |
| Ponerinae | Psalidomyrmex procerus | AMNH | RAK0065 | ||
| Ponerinae | Simopelta oculata | MCZ | RAK0066 | ||
| Ponerinae | Streblognathus peetersi | AMNH | RAK0067 | ||
| Ponerinae | Thaumatomyrmex atrox | AMNH | RAK0068 | ||
| Proceratiinae | Discothyrea oculata | AMNH | RAK0069 | ||
| Proceratiinae | Discothyrea testacea | ABS | CASENT0103848 | AMNH | RAK0070 |
| Proceratiinae | Proceratium croceum | ABS | CASENT0104440 | AMNH | RAK0071 |
| Proceratiinae | Proceratium pergandei | AMNH | RAK0072 | ||
| Proceratiinae | Probolomyrmex guineensis | AMNH | RAK0073 | ||
| Pseudomyrmecinae | Pseudomyrmex gracilis | ABS | CASENT0103779 | AMNH | RAK0087 |
| Pseudomyrmecinae | Tetraponera aethiops | AMNH | RAK0088 | ||
| Pseudomyrmecinae | Tetraponera attenuata | CASC | CASENT0217587 | AMNH | RAK0089 |
| Sphecomyrminae† | Sphecomyrma freyi† | AMNH | AMNH NJ-943 | ||
| SCOLIIDAE | Scolia nobilitata | AMNH | RAK0121 | ||
| VESPIDAE | Metapolybia cingulata | AMNH | RAK0120 | ||
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Information on museum holdings and voucher codes for queens and workers. ABS, Archbold Biological Station; ALWC, Alexander Wild Collection; AMNH, American Museum of Natural History; ANIC, Australian National Insect Collection; BMNH, British Museum of Natural History; CASC, California Academy of Science; DADC, David A. Donoso Collection; JTLC, Jack Longino Collection; MCZ, Museum of Comparative Zoology (Harvard); MIZA, Museo del Instituto de. Zoología Agrícola (Venezuela); MNHN, Muséum national d’Histoire naturelle; MSNG, Natural History Museum, Genoa; MZSP, Museu de Zoologia Universidade de São Paulo; RAJC, Robert Johnson Collection; RAKC, Roberto Keller Collection; UCDC; University of California Davis.
-
† denotes extinct taxa.
Table 3
Queen thoracic morphology and type of colony foundation across ants
| Subfamily | Genus | T1/T2 in queens | T1 in queens | Colony founding | References |
|---|---|---|---|---|---|
| Aenictinae | Aenictus | 2.742 | intermediate* | fission | (Gotwald and Cunningham-van Someren, 1976) |
| Agroeconomyrmecinae | Tatuidris | 0.111 | reduced | unknown | |
| Amblyoponinae | Amblyopone | 0.382 | intermediate | non-claustral | (Haskins and Haskins, 1951) |
| Amblyoponinae | Apomyrma | 0.338 | intermediate | unknown | |
| Amblyoponinae | Myopopone | 0.453 | intermediate | non-claustral | (Ito, 2010) |
| Amblyoponinae | Mystrium | 0.454 | intermediate | non-claustral | (Molet et al., 2009) |
| Amblyoponinae | Prionopelta | 0.514 | intermediate | non-claustral | (Ito and Billen, 1998) |
| Aneuretinae | Aneuretus | 0.096 | reduced | claustral | (Wilson et al., 1956) |
| Cerapachyinae | Cerapachys | 0.364 | intermediate | unknown ICF + fission | (Brown, 1975) |
| Cerapachyinae | Cylindromyrmex | 0.454 | intermediate | non-claustral | (Delabie and Reis, 2000) |
| Dolichoderinae | Dolichoderus | 0.061 | reduced | unknown | |
| Dolichoderinae | Iridomyrmex | 0.071 | reduced | claustral | (Hölldobler and Carlin, 1985) |
| Dolichoderinae | Tapinoma | 0.111 | reduced | claustral | (Kannowski, 1959) |
| Dolichoderinae | Technomyrmex | 0.071 | reduced | claustral | (Yamauchi et al., 1991) |
| Dorylinae | Dorylus | 0.372 | intermediate* | fission | (Kronauer et al., 2004) |
| Ecitoninae | Eciton | 0.469 | intermediate* | fission | (Schneirla, 1949) |
| Ectatomminae | Ectatomma | 0.325 | intermediate | non-claustral | (Dejean and Lachaud, 1992) |
| Ectatomminae | Gnamptogenys | 0.331 | intermediate | non-claustral | (‡) |
| Ectatomminae | Rhytidoponera | 0.363 | intermediate | non-claustral | (Ward, 1981) |
| Ectatomminae | Typhlomyrmex | 0.504 | intermediate | unknown | |
| Formicinae | Formica | 0.076 | reduced | claustral | (Stille, 1996) |
| Formicinae | Lasius | 0.053 | reduced | claustral | (Stille, 1996) |
| Formicinae | Oecophylla | 0.066 | reduced | claustral | (Hölldobler and Wilson, 1978) |
| Formicinae | Polyergus | 0.323 | intermediate | non-claustral† | (Mori et al., 1995) |
| Formicinae | Polyrhachis | 0.072 | reduced | claustral and non-claustral | (Lenoir and Dejean, 1994) |
| Heteroponerinae | Heteroponera | 0.485 | intermediate | non-claustral | (§) |
| Leptanillinae | Leptanilla | 2.685 | intermediate* | fission | (Masuko, 1990) |
| Leptanilloidinae | Leptanilloides | 3.021 | intermediate* | fission | (Donoso et al., 2006) |
| Martialinae | Martialis | n/a | unknown | unknown | |
| Myrmeciinae | Myrmecia | 0.485 | intermediate | non-claustral | (Haskins and Haskins, 1950) |
| Myrmicinae | Aphaenogaster | 0.117 | reduced | claustral | (Lubertazzi, 2012) |
| Myrmicinae | Carebara | 0.072 | reduced | claustral | (Robertson and Villet, 1989) |
| Myrmicinae | Cataulacus | 0.494 | intermediate | unknown | |
| Myrmicinae | Leptothorax | 0.090 | reduced | claustral | (Keller and Passera, 1989) |
| Myrmicinae | Messor | 0.110 | reduced | claustral and non-claustral | (Brown, 1999) |
| Myrmicinae | Metapone | 0.428 | intermediate | unknown | |
| Myrmicinae | Monomorium | 0.132 | reduced | claustral | (Bolton, 1986) |
| Myrmicinae | Myrmica | 0.071 | reduced | claustral and non-claustral | (Brown and Bonhoeffer, 2003) |
| Myrmicinae | Pogonomyrmex | 0.097 | reduced | claustral and non-claustral | (Johnson, 2002) |
| Paraponerinae | Paraponera | 0.086 | reduced | non-claustral | (#) |
| Ponerinae | Anochetus | 0.367 | intermediate | non-claustral | (Brown, 1978) |
| Ponerinae | Centromyrmex | 0.493 | intermediate | non-claustral | (Dejean and Fénéron, 1996) |
| Ponerinae | Cryptopone | 0.533 | intermediate | non-claustral | (Peeters, 1997) |
| Ponerinae | Ponera | 0.356 | intermediate | non-claustral | (Kannowski, 1959) |
| Ponerinae | Myopias | 0.282 | intermediate | non-claustral | (Peeters, 1997) |
| Ponerinae | Odontomachus | 0.411 | intermediate | non-claustral | (Brown, 1976) |
| Ponerinae | Odontoponera | 0.524 | intermediate | non-claustral | (Peeters, 1997) |
| Ponerinae | Pachycondyla | 0.385 | intermediate | non-claustral | (Peeters, 1997) |
| Ponerinae | Platythyrea | 0.417 | intermediate | non-claustral | (Peeters, 1997) |
| Proceratiinae | Discothyrea | 0.093 | reduced | non-claustral and claustral | (Dejean and Dejean, 1998) |
| Proceratiinae | Proceratium | 0.095 | reduced | non-claustral | (¶) |
| Pseudomyrmecinae | Pseudomyrmex | 0.479 | intermediate | non-claustral | (**) |
| Pseudomyrmecinae | Tetraponera | 0.558 | intermediate | non-claustral | (**) |
| Sphecomyrminae† | Sphecomyrma† | n/a | unknown | unknown | |
| OUTGROUPS | |||||
| Scoliinae | Scolia | 0.087 | reduced | non-social | (††) |
| Polistinae | Metapolybia | 0.074 | reduced | fission | (††) |
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Queen thoracic morphology and type of colony foundation across ants. The wasp taxa Scolia and Metapolybia are included as outgroups.
-
*
species with wingless queens. † denotes extinct taxa.
-
†
Polyergus is an obligatory social parasite of Formica spp.
-
‡
John Lattke, personal communication.
-
§
Rodrigo Feitosa, personal communication.
-
#
Haskins CP, Enzmann EV (1937) Studies of certain sociological and physiological features in the Formicidae. Ann NY Acad Scien 37:97-162; Michael Breed, personal communication.
-
¶
Fuminori Ito, personal communication; Keiichi Masuko, personal communication.
-
**
Philip Ward, personal communication.
-
††
James M Carpenter, personal communication.
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Evolution of thorax architecture in ant castes highlights trade-off between flight and ground behaviors
eLife 3:e01539.
https://doi.org/10.7554/eLife.01539
