Reproductive strategies of the exotic Pharaoh's ant,Monomorium pharaonis (L.) (Hymenoptera: Formicidae) in Brazil

Summary

The production of sexual forms in laboratory colonies of Monomorium pharaonis was followed over a 19-month period. Cycles of production occurred at intervals of 4 months, with male investment inversely proportional to the number of gynes produced. There was a tendency for colonies to produce only males or females as total sexual production increased. Sperm counts of known-aged males suggest that they mate twice, in contrast to European populations. Sex-ratio was heavily female-biased, contrary to predictions for polygynous ant species.     

Mechanisms affecting load size determination inAtta cephalotes L. (Hymenoptera,Formicidae)

Summary The size of leaf-cutting ant foragers correlates more closely with the weight than the area of the leaf fragments they cut. This implies that the mechanism of load size determination is not a simple function of body geometry. Ants were found not to adjust the radius of cut to compensate for experimental changes in leaf weight during the process of cutting. However, ants changed their cutting behaviour according to the thickness of the region of the fragment being cut. Ants decreased their cut radius when cutting through leaf veins. Similarly, when cutting artificial laminae of varying thicknesses, ants reduced the cut arc radius when traversing thicker regions.Cut radius was not principally controlled by the position of the rear legs nor the overall body length but by mechanisms associated with the head and thorax of the ant.     

Feinstruktur des Komplexauges der Roten Waldameise,Formica polyctena (Hymenoptera,Formicidae)

Zusammenfassung Die Analyse der Feinstruktur des Komplexauges der Ameise Formica polyctena ergab, daß der dioptrische Apparat der insgesamt 750 Ommatidien aus einer lamellierten Cornealinse und einem euconen Kristallkegel besteht. Zwei Hauptpigmentzellen umgeben schalenförmig den Kristallkegel, 8 Nebenpigmentzellen schirmen das Ommatidium in seiner ganzen Länge von der Cornea bis zur Basalmembran ab. Jedes Ommatidium besteht in seinem distalen Teil aus 8 Retinulazellen, 2 gegenüberliegenden schmalen und je 3 gegenüberliegenden großen Sehzellen. Weiter proximal tritt eine 9. Retinulazelle hinzu. Die Mikrovillisäume der Sehzellen verschmelzen zu einem zentralen Rhabdom. Im distalen Teil sind die Mikrovilli in 3 Richtungen angeordnet. Es wird im besonderen die Orientierung der Mikrovilli zur Augenlängsachse und zur Ommatidien-Symmetrieachse untersucht. Auch die 9. Sehzelle bildet Mikrovilli. Das Rhabdom endet an 4 basalen Pigmentzellen.Auf den Mikrovillisaum folgt im Querschnitt des dunkel adaptierten Ommatidiums ein Kranz von großen intrazellulären Vakuolen. Die anschließende cytoplasmatische Zone der Retinulazellen enthält viele Pigmentgranula und Mitochondrien; multivesikuläre und multilamelläre Körper sowie Golgiapparate treten nur selten auf. Die funktionelle Bedeutung des Ommatidienaufbaues und die Verteilung der Organellen bei Dunkeladaptation werden diskutiert.

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The fine structure of the complex eye of the ant Formica polyctena (Hymenoptera, Formicidae)

Summary The fine structure of the compound eye of the ant Formica polyctena was investigated. The eye consists of a total of 750 ommatidia, each containing a dioptric apparatus of a lamellated cornea lens, a eucone-type crystalline cone, and 8 long pigment cells which surround the ommatidium for its total length, i.e. from the cornea to the basal membrane. Each ommatidium has in its distal portion 8 retinula cells—6 large plus 2 small ones. The retinula cells are arranged in such a way that 3 pairs of large cells, and the one pair of the small cells lie opposite each other. Further proximally, a 9th retinula cell is encountered. The fused, centrally located rhabdom is built up by the microvilli of all nine retinula cells. The rhabdom ends at 4 basal pigment cells. In dark adapted ommatidia, a ring of large intracellular vacuoles is to be seen immediately peripherally to the rhabdom. The outer, cytoplasmic zone of the retinula cells contains many pigment granules and mitochondria; multivesicular bodies, onion bodies and Golgi apparatus are of relatively rare occurrence. The functional significance of the ommatidial structure and the arrangement of the cell organelles in the dark adapted condition are discussed.

Für technische Hilfe danke ich Frau Langer und Frl. Müller, Herrn Prof. H. Markl für die Durchsicht des Manuskripts.     

Augenstrukturen bei verschieden gro\en Arbeiterinnen von Cataglyphis bicolor Fabr. (Formicidae,Hymenoptera)

Zusammenfassung Die Untersuchung der Oberflächenstruktur der Cornealinsen im Komplexauge von Cataglyphis bicolor mit dem Stereoscan-Elektronenmikroskop zeigt keine nipple-Struktur (Abb. 1). Die Zahl der Ommatidien hängt von der Körpergröße ab: die kleinsten Arbeiterinnen (Innendiensttiere) weisen minimal 600 Ommatidien auf, die größten (Jagdameisen) maximal 1200 Ommatidien (Abb. 2). Die verschiedenen Ethotypen unterscheiden sich zwar in ihren extremen Formen nach Körpergröße, Ommatidienzahl und Ommatidiendurchmesser, doch ist der Übergang völlig kontinuierlich.

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Surface structure of the complex eye in workers of various sizes of Cataglyphis bicolor Fabr.

Summary The surface structure of cornea lenses in the complex eye of the desert ant Cataglyphis bicolor was studied with the Stereoscan Electronmicroscop. There is no nipple structure. The number of ommatidia is correlated with the body size: the smallest worker ants (doing service inside the nest) possess 600 ommatidia, the largest (hunters) have 1,200 ommatidia at the most (Fig. 2). As in the case of body size there are sliding transitions between the various ethotypes with respect to the number of ommatidea and also their diameters.

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Wir danken Frl. D. Stachelin (Universität Zürich), Herrn R. Wessicken (ETH Zürich) und Herrn Dr. Ing. M. Koch (Techn. Hochschule Darmstadt) für ihre technische Hilfe.     

Ants (Hymenoptera,Formicidae) of Kyiv

Entomological Review - Altogether, 59 ant species from 22 genera of 4 subfamilies have been recorded in Kyiv. Four of them are occasionally introduced species which occur only in premises heated in...     

Morphology of a novel glandular epithelium lining the infrabuccal cavity in the ant Monomorium pharaonis (Hymenoptera, Formicidae)

A novel glandular epithelium lining the infrabuccal cavity and anterior pharynx is described in both workers and queens of the pharaoh's ant Monomorium pharaonis. The infrabuccal cavity, connected with the buccal tube, forms a ventral outgrowth of the anterior pharynx, and as such displays the tegumental lining with a cuticle and an epithelial layer. In its dorsal region, the cavity's epithelium reaches a thickness of approx. 11–12 μm in both workers and queens, which is considerably thicker than the epithelium lining the rest of the infrabuccal cavity. Also the possible role of the infrabuccal gland is discussed.     

Miocene ants (Hymenoptera,Formicidae) from Crimea

Ant imprints, new and previously known, from Middle Miocene deposits near Kerch (Crimean Peninsula, Russia) are described or redescribed. A new Myrmicinae species, Solenopsis atavinus sp. nov., is described based on a wingless female. A winged female similar to the earlier described Dolichoderus tauricus Dlussky, 1981 is found: due to the excellent preservation of this specimen, the new specimen and the holotype of D. tauricus are redescribed and can be reclassified as Ponerites tauricus (Dlussky, 1981), comb. nov. Oecophylla taurica sp. nov. is described based on a partly preserved imprint of a female thorax with a forewing, the venation of which allows it to be positively identified as a weaver ant. Two other species are transferred from the formal genus Camponotites to Oecophylla based on forewing venation: O. kraussei (Dlussky et Rasnitsyn, 1999), comb. nov. (Early Eocene, United States) and O. macroptera (Dlussky, 1981), comb. nov. (Middle Miocene, Stavropol, Russia). One of the studied forewing imprints is similar in venation to Paraphaenogaster microphthalmus Dlussky, 1981, described from the Middle Miocene of Vishnevaya Balka (Stavropol province, Russia) and so is attributed to this species. Dolichoderus tavridus sp. nov. is described based on a forewing.     

Observer ants: Storers of foraging area information inFormica rufa L. (Formicidae,Hymenoptera)

Summary The structure of a foraging area in Formica s. str. is maintained by specific foraging roads and by experienced ants familiar with the foraging area, namely foragers and observer ants which used to be foragers. After all the foragers have been removed, observer ants of a F. rufa nest experimental column resume foraging, rapidly restoring the initial structure of the foraging area. For a nest population to lose completely information of the foraging area of a column, not only foragers but also observer ants must be removed and direct access from the nest to experimental road blocked.

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Les fourmis observatrices: des stockeuses d'informations sur l'aire d'affouragement chez Formica rufa L.

Resume La structure de l'aire d'affouragement chezFormica rufa est maintenue grâce à des pistes d'affouragement spécifiques et des Fourmis expérimentées qui sont familiarisées avec l'aire d'affouragement: des fourrageuses et des observatrices qui sont habituellement des fourrageuses. Lorsque toutes les fourrageuses sont enlevées, les observatrices d'un nid expérimental deFormica rufa reprennent l'affouragement et rétablissent rapidement la structure initiale de l'aire d'affouragement. Pour que la population d'un nid perde toute information sur l'aire d'affouragement d'une colonne, il faut que non seulement les fourrageuses mais aussi les observatrices soient enlevées et que l'accès du nid à la piste soit empêché.

     

Homing Behaviour in Polyergus rufescens Latr. (Hymenoptera,Formicidae)

Homing mechanisms of the European slave-making ant Polyergus rufescens Latr. are investigated by field experiments. The analysis of the behaviour and paths of both homing scouts and raiders after passive displacement showed that: i. Scouts probably home by using a path integration system based on celestial cues; and ii. Displaced raiders do not seem to adopt such a vectorial orientation mechanism. Moreover, we found that passively displaced scouts exhibit a systematic search strategy for the nest after a rectilinear path. By contrast, raiders perform a similar search pattern just after release. Similarities between Cataglyphis and Polyergus homing behaviour are discussed.     

香茅醛缩醛类化合物的合成及其对小黄家蚁的驱避活性

【目的】香茅醛类化合物具有较好的蚂蚁驱避活性,本研究旨在筛选具有良好驱避活性的新的萜类蚂蚁驱避剂。【方法】以香茅醛为原料合成了香茅醛二甲缩醛、香茅醛二乙缩醛、香茅醛二正丙缩醛、香茅醛二异丁缩醛、香茅醛乙二缩醛、香茅醛1,2-丙二缩醛和香茅醛1,3-丙二缩醛等化合物。所得产品经纯化后,用IR, MS, ¹H NMR及¹³C NMR进行结构表征,并在不同浓度下对小黄家蚁Monomorium pharaonis进行驱避活性测试。【结果】各化合物对小黄家蚁具有一定的驱避活性：在10 mg/mL的浓度下,除香茅醛二甲缩醛以外,其他化合物的驱避率均达到70%以上,其中香茅醛二乙缩醛、香茅醛乙二缩醛和香茅醛1,3-丙二缩醛对小黄家蚁的驱避率分别为87.47%,100%和97.53%。浓度为2.5 mg/mL时,其中5个化合物的驱避效果明显下降,但香茅醛乙二缩醛和香茅醛1,3-丙二缩醛仍然表现出很好的驱避活性,驱避率分别为85.33%和97.10%。方差分析也表明,香茅醛1,3-丙二缩醛在同一浓度下驱避效果最佳,其次是香茅醛乙二缩醛。【结论】结果说明,香茅醛二乙缩醛、香茅醛乙二缩醛和香茅醛1,3 丙二缩醛可以用作小黄家蚁驱避剂,而香茅醛乙二缩醛和香茅醛1,3-丙二缩醛可以达到更好的驱避效果,使用浓度为2.5 mg/mL即可。本研究为良好萜类蚂蚁驱避剂的筛选提供了参考依据。     

Karyological studies of Japanese ants (Hymenoptera,Formicidae)

The karyotypes of nine Japanese ants in three subfamilies (Ponerinae, Formicinae, and Myrmicinae) were successfully analysed by the improved squash technique. Three ponerine species had 2n=7 and n=4 (Ponera scabra), 2n=22 (Brachyponera sinensis), and 2n=28 and n=14 (Cryptopone sauteri). Four formicine species had 2n=18 and n=9 (Camponotus sp. and C. tokioensis), 2n=26 and n=13 (Camponotus japonicus), and 2n=30 and n=15 (Lasius niger). Two myrmicine species had 2n=18 and n=9 (Leptothorax congruus), and 2n=37, 38, 39, and n=17, 18, 19, 20 (Pheidole nodus). It was found that the variation of chromosome number observed in P. nodus was caused by Robertsonian type polymorphism.