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Tergal and Sternal Glands in Ants

. 4 BY BERT HOLLDOBLER HILTRUD ENGEL Department of Biology M CZ Laboratories, Harvard University Cambridge, Massachusetts INTRODUCTION Chemical signals, or pheromones as they are generally called, play a central role in the complex communication system of ant societies. During the last 20 years a number of exocrine gls have been identified as the anatomical sources for a diversity of pheromones which mediate sexual social behavior in ants (for reviews see Wilson 1971, Blum 1977, H611dobler 1978). In recent years, however, several hitherto unkwn exocrine glular structures have been discovered in ants the behavioral functions of some of them have already been determined. In this paper we will review these findings will report the new results of our comparative morphological study of tergal sternal gls in ants. MATERIAL METHODS For histological investigations live specimens were fixed in alcoholic Bouin (Dubosqu Brasil) or Cary (Romeis 1948), embedded in methyl methacrylate, sectioned 8/ thick with a Jung Tetrer I microtome (Rathmayer 1962). The staining was Azao (Heidenhain). The SEM pictures were taken with an AMR 1000 A Scanning Electron Microscope. For some of the species which could only be identified to the generic level, the respective number is given of the voucher specimens, which are deposited in the ant collection of the MCZ (Harvard University). *Manuscript received by the editor May 3, 1979. Psyche RESULTS [December Tergal gls a. Pygidial gl In a detailed anatomical study of Myrmica rubra Janet (1898) described a pair of clusters of a few glular cells, located under the third gastric tergum. Each cell sends a duct through the intersegmental membrane between the third fourth gastral terga. We discovered a similar, but considerably larger paired glular complex at the same anatomical position in vomessor eockerelli N. albisetosus (H611dobler et al 1976). Kugler (1978) recently investigated a number of myrmicine ants in many of them he found the gl, which had "distinct s, produced by invagination of the intersegmental membrane between abdominal tergum 6 tergum 7 (pygidium)". Kugler suggested that these glular organs be called pygidial gls. We accept this termilogy, because it describes the anatomical designation of the organ more precisely than the term "dorsal gl" or "tergal gl", originally suggested (H611dobler et al 1976, H611dobler Haskins 1977). However, it has to be pointed out that the pygidium of the ants (the last exposed tergum) is the 7 th abdominal tergum is t homologous to the pygidium of the Coleoptera (8 th abdominal tergum). Hence, the pygidial gls of ants are t homologous to the pygidial gls of Coleoptera. In a previous study (H611dobler Haskins 1977) we found pygidial gls with large s in several ponerine myrmeciine ants (Amblyopone, Paraponera, Ectatomma, Odontomachus, Pachycondyla, Platythyrea, Rhytidoponera, Myrmecia) we demonstrated that the virgin females of Rhytidoponera metallica attract males by the release of a pheromone from these gls. In his anatomical studies of Rhytidoponera metallica R. convexa, Whelden (1957, 1960) described a pair of cell clusters each comprising 8-15 glular cells. Each cell sends a duct through the membrane connecting the 6th 7 th abdominal segments. We are w certain that Whelden already had discovered the pygidial gl in Rhytidoponera; his histological methods, however, may t have enabled him to detect the large s associated with the glular cell clusters. Similar paired glular structures were found by Whelden (1957) in the ponerine species Stigmatomma (=Amblyopone) pallipes. 1978] HOlldobler & Engel Gls in Ants Finally, independently of our investigations, Maschwitz (pers. communication) found a pygidial gl in chinensis, which he called the "dorsal gl" (Maschwitz SchiSnegge, 1977). The new anatomical investigations presented in this paper reveal that the pygidial gls are much more common in ants than previously assumed. Usually the organ consists of a pair of lateral clusters of glular cells, each cell sending a duct through the intersegmental membrane between the 6th 7th abdominal terga. Depending on the species, the intersegmental membrane can be invaginated to different degrees, so that it can form a more or less volumius (Fig. 1, 2, 3, 4). if is present, the glular structures can easily be missed during the dissection histological sectionings are therefore required to determine whether or t the pygidial gl is present. As we have already indicated for vomessor as confirmed by Kugler (1978) for several other myrmicine species, the pygidial gl can be associated with a special cuticular structure on the pygidium (7 th tergum), (Fig. 5, 6, 7). Our histological studies demonstrated, however, that the absence of such structures does t necessarily indicate the absence of Figure 1. Schematic illustration of glular cells that send ducts through the intersegmental membrane. When the membrane is increasingly more invaginated, it forms an increasingly larger (a to c). Psyche [December pygidial gls. Thus, in several myrmicine species, in which we (H611dobler et al 1976) Kugler (1978) previously assumed the pygidial gl to be absent, we find that we w detect this organ by histological methods. Tables a b list the species of the major subfamilies that we investigated histologically indicate the type of tergal gls found. b. Postpygidial gl Dorsal glular, structures which open posteriorly to the pygidial gl, between the 7th 8th abdominal terga (spiracular plate), we call postpygidial gls (Fig. 8). Whelden (1957, 1960) described gls in the 5 th gastral segment of Rhytidoponera convexa R. metallica. For R. convexa he writes: "Even the largest of these is less than half the size of the fourth-segment gls In the extreme case, there may be but a single gl cell on each side. It is often difficult to distinguish such a unicellular gl from an oecyte, despite the usually distinct difference in size of the two cell types. Only the identification of a duct certainly distinguishes such a gl from the ductless oecyte. In many individuals this second pair of gls could t be found". Whelden (1960) makes similar statements for R. metallica. Our results are somewhat different. We found well developed postpygidial gls in the 4 species of Rhytidoponera investigated (Table a). In all specimens we found a pair of clusters of glular cells. Each cluster contains about 15-20 cells each cell sends a duct through the intersegmental membrane close to the spiracular plate (Fig. 9, 10). In some ant species the postpygidial gl consists of only a few glular cells, in others the postpygidial gl is associated with a well developed (Table la, lb). Sternal gls In several species we discovered intersegmental sternal gls (Table 2). They can consist of a few glular cells that send their channels through the intersegmental membrane, or of large clusters of glular cells associated with volumius s. These s are formed by invaginations of the intersegmental membranes (Fig. 8). In several species (Fig. 12) we found two large sternal gls with s between the 7 th 6th, 6th 5th sterna. The latter glular organ is usually associated with a special cuticular structure on the 6th sternum (Fig. 12). In Paltothyreus 1978] HOlldobler & Engel- Gls in Ants tarsatus we found well developed sternal gls between the 7th 6th, 6t 5t, 5 t 4t sterna, but s. Instead, the duct openings are associated with filament-like protrusions of the intersegmental membrane (Fig. 13, 14). Other abdominal gls The glular vem apparatus of ants is composed of the Dufour’s gl (alkine or accessory gl) the poison gl. Although the vem apparatus of ants is very well studied (see reviews by Maschwitz Kloft 1971, Blum Hermann 1978 a, b), other gls, such as Koschevnikov’s gl (sting gl), Bordas’s gl sting sheath gls, kwn from other Hymeptera, have t been firmly established in ants. Koschevnikov (1899) found in honeybees Vespa paired clusters of glular cells located laterally near the intersegmental membrane between the quadrate plate the spiracular plate. Each individual cell sends channels into gathering ducts, which connect with the intersegmental membrane. Altenkirch (1962) found similar gls in most Apidae that she had studied. There are indications that this gl might also be present in some species of the primitive ant subfamilies Myrmeciinae Ponerinae. Whelden (1957) described a pair of clusters of gl cells, located slightly dorsally on each side of the sting of Stigmatomma (=Amblyopone)pallipes. Each cell sends a "rather tortuous duct.., down inward, to open through a membrane which is above the sting". Robertson (1968) found "sting gls" in Rhytidoponera "toward the region of the triangular plate, where they are attached to the intersegmental membrane". She described similar gls in Bothroponera sp. (=Pachycondyla), sjostedji Myrmecia gulosa. In the latter species the gls are described as "two well formed masses of gl cells, each cell attached to the intersegmental membrane in the region of the triangular plate by a long, simple, cuticular duct". Table 3 (A) lists the species in which we found paired glular structures, closely resembling the "sting gls" described by Robertson. In all cases the glular cells are located near the triangular plate, from each cell a rather long duct leads downwards opens through a membrane near the base of the sting (Fig. 15). Although we could t precisely locate the openings of the ducts, we assume they opened in the sting chamber. Psyche [December Altenkirch (1962) Maschwitz (1964) discovered a so-called sting sheath gl in several bee species. It consists of a palisade epithelium located in the sheath valves. In some ant species we found a distinct palisade epithelium in the sheath valves /or single glular cells with long individual ducts (Table 3 (B), Fig. 16, 17). Janet (1898) describes similar single gl cells, located near the sheath valves, in Myrmica rubra. Bordas’s gls, as they were described by Bordas (1895) in Terebrantia reexamined by Rathmayer (1962) in several sphecid wasps, could t be identified in ants, although some of clusters of the single gl cells which send their ducts through the membrane of the sheath valves could be related to the Bordas’s gls. It is obvious to us that the glular structures, associated with the sting apparatus of ants, need to be investigated in greater detail in future studies. In several ant species (Table 3 (C)) we found a highly developed palisade epithelium in the 7 th sternum (Fig. 8). It is especially conspicuous in several species in the army ants Eciton Neivamyrmex, but it is t strongly developed in Dorylus. In the dolichoderine species in Aneuretus this epithelium seems to be closely associated with the sternal gl (Pavan’s gl). In the African weaver ant (Oecophylla longida) we discovered a sternal gl under the 7th sternum, which is quite different from the glular epithelium described above (Htilldobler Wilson 1976, 1978). This structure consists of an array of single glular cells that send short channels into cuticular cups on the outer surface of the sternite. In ne of the other formicine species investigated, listed in table b, did we find this type of sternal gl. But in Campotus sericeus we detected different clusters of glular cells in the last sternum. Each cell sends a long channel through the intersegmental membrane near the vagina into the ventral part of the "sting chamber". We discovered similar paired glular cell clusters in most myrmicine species we investigated. The gl is especially distinct in vomessor Veromessor, where the glular cell channels penetrate the membrane near the vagina (Fig. 18). The function of the intersegmental gls: The functions of most of the glular structures described in this paper are t yet kwn, but in a few species the function of the 1978] HOlldobler & Engel Gls in Ants pygidial gl has already been identified. In vomessor cockerelli N. albisetosus the strongly smelling secretion of the pygidial gls releases a "panic alarm" response in workers, apparently specifically designed against army ant predation (HiSlldobler in prep.). Kugler (in press) demonstrated that in Pheidole biconstricta the pygidial gls produce an alarm-defense secretion. A quite different function has been discovered in Rhytidoponera metallica. Here the wingless virgin females attract males by the release of a pheromone from the pygidial gl (Htilldobler Haskins 1977). Since Rhytidoponera workers also have a well-developed pygidial gl are attracted to its secretions, we believe we have t yet discovered the whole functional spectrum of this organ. In chinensis, Maschwitz Sch6negge (1977) demonstrated that the pygidial gl secretions serve together with poison gl substances as a recruitment trail pheromone. We obtained similar results when we recently reexamined the anatomical source of the trail pheromone of Pachycondyla (=Termitopone) laevigata. This ant species conducts well organized predatory raids on termites. During raiding the workers move in a single file, one closely behind ather, along a powerful trail pheromone laid down by leading scout ants. Blum (1966) has identified the hindgut as the source of this recruitment trail pheromone. We cant confirm his findings. In our experiments with artificial trails laid with extracts from several abdominal gls, only the pygidial gl secretions released massive trail-following behavior in P. laevigata (Htilldobler Traniello in prep.). A careful observational study of the traillaying behavior of P. laevigata workers revealed that t the anus but rather the pygidial gl is dragged over the ground. Although the pygidial gl of P. laevigata has definite , it is very well developed is associated with an elaborate cuticular structure on the 7th tergum (Fig. 19, 20). The glular secretion is apparently stored in the many cavities of this structure. When trailing, the ants rub this structure with its special applicator surface over the ground deposit thereby the trail pheromone. Traniello (pers. communication) observed species of Odontomachus during nest emigrations performing the same trail laying behavior. We suspect that in Odontomachus also the pygidial gl secrets a trail pheromone (Fig. 21). In Bothroponera (=Paehycondyla) tesserida we previously analyzed the signals involved in the tem running recruitment technique (Htilldobler et al 1973, Maschwitz et al 1974). We Psyche [December discovered that the cues responsible for "binding" the follower behind the leader ant include both a surface pheromone mechanical stimuli. Although we could extract this surface pheromone, we were t able to identify its anatomical source; all experiments with secretions from the kwn exocrine gls had negative results. After the recent discovery of the pygidial gl in Pachycondyla we have begun to conduct tem running experiments with Pachycondyla crassa* P. harpax*, using dummies contaminated with pygidial gl secretions. Our preliminary resuits strongly indicate that pygidial gl substance might be the source of the tem running pheromone in these species. In the doryline army ants raiding emigrations are conducted along chemical trails deposited by workers. For Neivamyrmex, Watkins (1964) Watkins et al (1967), for Eciton hamatum, Blum Portocarrero (1964), identified the hindgut as the source of the trail pheromone. In addition, Chadab Rettenmeyer (1975) Topoff Mirenda (1975) demonstrated that besides the relatively long-lasting hindgut trail-substance, other signals (possibly more volatile secretions) are involved in the organization of "mass recruitment" in Eciton Neivamyrmex. We believe that our morphological investigations provide new possibilities for the analysis of chemical communication in army ants. Both Neivamyrmex Eciton have large pygidial gls with distinct s (Fig. 22, 23). The postpygidial gl is smaller, but still considerably larger than in most of the other investigated species’. In both army ant species the 7th tergum is relatively small. Therefore, the s of the pygidial gl postpygidial gl open directly above the anus at the abdominal tip (Fig. 23). In workers (all castes) of Eciton the dorsal membrane near the exits of the of the pygidial gls is conspicuously modified to a brush-like structure (Fig. 24). These morphological features strongly * P. crassa was observed tem running by W. L. Brown, Jr. (pers. communication) at the western base of Ubombo Mts., Zulul, by B. H/511dotiler in Shimba Hills Reserve (Kenya). P. harpax was observed tem running by S. Levings (pers. communication) on Barro Colorado Isl, Panama. Whelden (1963) described two gls at the extreme posterior end of the gaster of Eciton burchelli workers. Although the description is t very accurate, from his drawings we can conclude that he found the pygidial gl postpygidial gls. 1978] HOlldobler & Engel Gls in Ants suggest that the tergal gls might be involved in the chemical trail communication of army ants. We have begun to test this hypothesis with Eciton hamatum. The pygidial gl secretion of E. hamatum has a strong, characteristic smell. The secretion is probably skatole (Traniello pers. communication), the substance that gives army ants their typical "fecal odor". Recently Brown et al (1978) demonstrated that skatole is an effective growth inhibitor for bacteria fungi repels insectivorous snakes (Watkins et al 1969). Our first, preliminary tests demonstrated that Eciton workers follow artificial trails drawn with crushed pygidial gls. When we simultaneously offered trails drawn with hindgut contents pygidial gl secretions, the latter were significantly preferred during the first minute. When we used trails drawn with secretions of the poison gl or Dufour’s gl as controls, the ants always followed the pygidial gl trails. We have to stress, however, that these experiments must be considered pilot tests. The preliminary results, however, are striking eugh to warrant a more detailed investigation in the future. It is interesting to te that the anatomy of the pygidial gl in the African army ant, Dorylus molesta, is quite different from that of Eciton Neivamyrmex (Fig. 25). In this species the 7 th tergum is considerably larger than in species of the latter genera, the s of the pygidial gls do t open at the abdominal tip. In Dorylus, however, we found single glular cells with channels opening directly at the anus, a feature we have t detected in other ant species (Fig. 25, 26). Finally, our morphological study of the pygidial gl of Veromessor pergei has led to results that are suggestive of the function of this organ. In this species the 7 th tergum is relatively small, as a result the large s of the pygidial gls open at the tip of the gaster (Fig. 27). Veromessor forages in wellorganized columns (Went et al 1972; Wheeler Rissing 1975; Bernstein 1975). Several observations suggest that these foraging columns are organized by a trail pheromone, though trail pheromone gl has yet been identified. Clearly, the large pygidial gl has to be considered as a possible source for the trail pheromone. The function of most of the newly discovered sternal gls is unkwn. Only in Paltothyreus tarsatus could we demonstrate experimentally that foragers lay a recruitment trail with sternal gl secretions (HiSlldobler in prep.). Psyche [December CONCLUSIONS Since we first found the pygidial gl widespread in the subfamilies Myrmeciinae Ponerinae, we speculated that this gl might be a primitive mophylogenetic trait in ants generally (Htilldobler Haskins 1977). The results reported in the present paper fully confirm this assumption. A well-developed pygidial gl was found in the most primitive ant, thomyrmecia macrops, in representatives of all major subfamilies except in the Formicinae (Table b). We agree with Kugler (1978) that the "anal gls" cf the Dolichoderinae Aneuretinae are homologous to the pygidial gls of other ant subfamilies. Considering the variation in the morphology of the pygidial gls, even within a single subfamily, we think that the morphological variation of the "anal gls" of dolichoderine aneuretine species does t warrant a separate termilogy. In fact the term "anal gl" is misleading, because the gls do t exit from the anal opening of the gaster, as is sometimes inferred, but between the 6th 7th abdominal terga (Fig. 28). This was clearly demonstrated by Pavan Ronchetti (1955). It is our view also Kugler’s (pers. communication) that the "anal gls" should be called pygidial gls. Kugler (1978) concluded from his comparative studies of myrmicine species that usually those species that have reduced or modified stings also have well-developed pygidial gls. He assumes that the pygidial gl replaces the sting apparatus as a chemical defense device. Our finding that well-developed pygidial gls occur in , a genus with a very effective sting apparatus, in many stinging ponerine species, does t support Kugler’s conclusions. ACKWLEDGEMENTS This paper would t have been possible without the help of many people. We would like to thank all the collectors mentioned in Table 1, including Donald W. Windsor, who helped finding the acacias in the Canal Zone. Special thanks to Robert W. Taylor, who sent us the precious thomyrmecia. Barry Bolton, William L. Brown, Jr., William H. Gotwald, Jr. Roy Snelling identified many species for us. We are grateful to Ed Seling for his superb assistance during the SEM work. Frank M. Carpenter’s many suggestions improved the manuscript greatly. This work was supported by NSF grant BNS 77-03884. 1978] H611dobler & Engel TABLE la Gls in Ants List of species of the poneroid complex (Taylor 1978) that were investigated histologically, the types of tergal gls found. When the histological series was incomplete we could t make a definite statement, the column is marked with "?". When the cuticular structure on the pygidium was only slightly sculptured, we marked the column with "-(+)". MYRMECIINAE Myrmecia pilosula R. J. Bartell R. W. Taylor Brindabella Ranges, Australia PONERINAE Amblyopone australis C. P. Haskins Manjimup, W. Australia Amblyopone pallipes Platythyrea cribida J. Traniello Carlisle, Mass. K. Horton R. Silberglied Kenya Rhytidoponera metallica C. P. Haskins Blackwell Range, Queensl, Australia Rhytidoponera perthensis C. P. Haskins Boddington, W. Australia + Rhytidoponera purpurea C. P. Haskins Black M ountain, Kuranja, Queensl Psyche [December .x2_ .x2_ Rhytidoponera violacea C. P. Haskins Kings Park, W. Australia Paltothyreus tarsatus B. H6ildobler Kenya Pachycondyla crassa B. H611dobler Kenya Pachycondyla laevigata Term it opone Plectroctena strigosa N. Franks J. Traniello BCI, Panama B. Htilldobler Kenya neutralis C. P. Haskins Manjimup, W. Australia pavesii B. H611dobler + Kenya nitidia B. HiSlldobler Kenya regis B. HiSlldobler Kenya Odontomachus haematoda C. P. Haskins BCI, Panama TABLE la Continued 1978] HOlldobler & Engel Gls in Ants DORYLINAE Neivamyrmex nigrescens Eciton B. H611dobler Arizona A. Aiello R. Silberglied J. Traniello BCI, Panama B. H611dobler hamatum Dorylus molesta Kenya PSEUDOMYRMECINAE Pseudomyrmex ferruginea A. Aiello R. Silberglied Canal Zone, Panama Pseudomyrmex pallidus M. MiSglich Florida B. H611dobler Tetraponera spec. (78 26) Kenya MYRMECINAE Myrmica americana J. Traniello Carlisle, Mass. J. Traniello Carlisle, Mass. B. H/511dobler Arizona Tetramorium caespitum desertorum -(+) -(+) californicus B. H611dobler Arizona TABLE la Continued Psyche [December badius B. H611dobler Florida G. Alpert Mexico Veromessor pergei vomessor cockerelli B. HiSlldobler Arizona B. HiSlldobler Arizona vomessor albisetosus Aphaegaster rudis J. Traniello Concord, Mass. Aphaegaster huachucana Pheidole militicida B. H611dobler Arizona B. H611dobler Arizona B. H611dobler Arizona N. Weber Timehri, Guyana -(+) (worker & soldier) Pheidole desertorum A tta sexdens (several castes) TABLE la Concluded 1978] HOlldobler & Engel Gls in Ants TABLE b List of species of the formicoid complex (Taylor 1978) that we investigated histologically, the types of tergal gls found. Collector Locality THOMYRMECIINAE thomyrmecia macrops R. W. Taylor Eyre Peninsula S. Australia ANEURETINAE Aneurett simoni E. O. Wilson Ratnapura, Sri Lanka DOL1CHODERINAE Liometopum apiculatum Comyrma bicolor Iridomyrmex pruisus B. H6lldobler Arizona B. HBlldobler Arizona B. HBlldobler Arizona B. HiSlldobler FORM1CINAE Oecopylla longida Pachycondyla spec. Kenya R. Silberglied Nairobi Arboretum, Myrmecocystus mexicanus Kenya B. H611dobler Arizona Myrmecocystus mimicus Myrmecocystus mendax Formica perpilosa Campotus sericeus M. M6glich Sri Lanka Psyche TABLE 2 [December List of species of the poneroid complex in which we found intersegmental sternal gls. Species Location of gls between abdominal segments 76 65 54 Myrmecia pilosula Rhytidoponera purpurea Paitothyrcus tarsatus Pach.vcondyla crassa neutralis pavesii Leptogen.vs nitida regis Tetraponera sp. (78 26) 1978] HOlldobler & Engel Gls in Ants Psyche [December Figure 2. Above: Sagital section through pygidial gls of Amblyopone australis. The gl has distinct , but 10-15 glular cells (GC) with channels in each cluster. Below: Pygidial gl of Amblyopone pallipes with distinct (R) 30-40 glular cells in each cluster. 1978] HOlldobler & Engel Gls in Ants Figure 3. Above: Sagital section through pygidial gls of thomyrmecia macrops: Very large (R); each cluster consists of 50-80 cells; GC glular cells; CH channels of glular cells. Below: Pygidial gl of Myrmica americana: distinct , 10-15 cells in each cluster. Psyche [December californicus: definite , Above: Sagital section through pygidial gls of but large cell clusters, each containing 30-35 glular cells (GC). Below: Pygidial gl of Pseudomyrmexferruginea: distinct ; intersegmental membrane forms a chitius duct (D) into which the individual glular channels open. Figure 4. 1978] Gls in Ants Figure 5. pavesii (GC Above: Sagital section through the pygidial gl of glular cells; CH channels of GC; CS cuticular structure on the th 7th tergum). Below: Close-up view of sagital section through cuticular structure of 7 tergum of neutralis. 3O6 Psyche [December Figure 6. Above: Sagital section through pygidial gl of reg,o. Below: SEM photograph of cuticular structure of 7th tergum of L. regis. The tergum is cut so that the well-structured cavities under the surface can be seen. (Lettering as in Fig. 5). 1978] HOlldobler & Engel Gls in Ants Figure 7. SEM photograph of cuticular structure of 7 tergum of Plectroctena strigosa. Above: View of the anterior part of the tergum. The cuticular grooves are clearly visible. Below: Close-up view of cuticular structure; the tergum is cut, so that the cavities beneath the grooves are visible. Psyche [December PPg ge Figure 8. Schematic illustration of tergal sternal gls in . (Lettering as in Fig. 5; sg sternal gl; ge glular epithelium; ppg postpygidial gl; pg pygidial gl). 1978] HOlldobler & Engel Gls in Ants Figure 9. Above: Sagital section tlarougla pygidial gl postpygidial gl, with large s of Rhytidoponera perthensis. Below: Postpygidial gl only; te the glular cells with channels. (Lettering as in Fig. 8; R ). Psyche [December Figure 10. Above: Sagital section through pygidial gl postpygidial gl of Plectroctena strigosa. Below: Pygidial gl. (Lettering as in Fig. 5; PPG pygidial gl; R ). postpygidial gl; PG 1978] H6lldobter & Engel Gls in Ants Figure 11. Above: Sagital section through the pygidial gl of Platythyrea cribida. The large is folded in this section. Each cell cluster contains 50-70 cells. Below: Section through postpygidial gl of P. cribida; each cluster contains 15-20 cells. (Lettering as in Fig. 3). Psyche [December Figure 12. Above: Sagital section through sternal gl between 5th 6th sterna of neutralis. Usually the 6th sternum has a distinct cuticular structure (CS), very similar to that on the 7th tergum. Below: Section through both sternal gls (Between 5th 6th, 6th 7th sterna) of nitida. (Lettering as in Fig. 5; R ). 1978] Gls in Ants Figure 13. SEM photograph of the sternal gl area between the 6 7 sterna of Paltothyreus tarsatus. The picture below is an enlargement of the lighter rectangle in the picture above. The openings of the glular cell channels in the intersegmental membrane are clearly visible. Psyche [December Figure 14. Above: SEM photograph of the glular cell openings of the sternal gl of Paltothyreus tarsatus. te the filament-like protrusions of the intersegmental membrane. Below: Sagital section through the same area. (Lettering as in Fig. 5). 1978] HOlldobler & Engel Gls in Ants Figure 15. "Sting gls" of Myrmecia pilosula (above) Amblyopone pallipes (below). (Lettering as in Fig. 5). Psyche [December Figure 16. Gls associated with the sting sheath. Above: Sagital section through sheath valve with glular cluster channels in Odontomachus haematoda. Below: Myrmecia pilosula. (Lettering as in Fig. 5). 1978] HOlldobler & Engel Gls in Ants Figure 17. Gls associated with sting sheath in Paltothryeus tarsatus. Above: Sagital section through glular cells with channels. Below: Sagital section through glular cell cluster with channels. (Lettering as in Fig. 5). Psyche [December Figure 18. Glular cell clusters in the 7 abdominal sternum of vomessor cockerelli (above) Veromessor pergei (below). GE glular epithelium in the 7th sternum. (Lettering as in Fig. 5). 1978] HOlldobler & Engel Gls in Ants th Figure 19. SEM photograph of the 7 tergum of Pachycondyla (=Termitopone) laevigata. Glular applicator surface (GA) is shown in greater detail in the picture below. Psyche [December Figure 20. Above: Sagital section through the pygidial gl of Pachycondyla (=Termitopone) laevigata. Below: SEM photograph of the cuticular structure (GA in Fig. 19) on 7th tergum. The cut open area shows the large cavities associated with the structure. (Lettering as in Fig. 5 Fig. 18). 1978] Gls in Ants Figure 21. Sagital section through the gaster of Odontomachus haematoda, showing the well developed of the pygidial gl (PG). Psyche [December Figure 22. Above: Sagital section through the gaster of Neivamyrmexnigrescens, showing the pygidial gl (PG), postpygidial gl (PPG) anus(A). Below: Close up of sagital section through pygidial gl postpygidial gl of N. nigrescens. (Lettering as in Figs. 5 8; R ). 1978] HOlldobler & Engel Gls in Ants Figure 23. Above: SEM photograph of tip of the gaster of Eciton hamatum. Below: Sagital section through the same segments. (Lettering as in Fig. 8; S sting; GE glular epithelium in 7th sternum). Psyche [December Figure 24. Eciton hamatum." SEM photograph of the intersegmental membrane between 6th 7th terga, where the pygidial gls open. Below: Close up of the brushlike structure. Gls in Ants Figure 25. Schematic drawings of sagital sections through the gaster tips of Dorylus molesta (left) Eciton hamatum (right). (Lettering as in Fig. 8" a anus; ag anus gls). Figure 26. Sagital section through anus of Dorylus molesta worker; AG gl; A anus. anus Psyche [December 1978] HOlldobler & Engel Gls in Ants Figure 28. Above: SEM photograph of abdominal tip of Liometopum apicuth th latum. "PG" indicates where the pygidial gl opens between 6 7 terga. "A" indicates opening of anus; SG sternal gl (Pavan’s gl). Below: Sagital section through gaster of L. apiculatum. PG of pygidial gl; 7. 7th tergum. Psyche http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png

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