Cladistic analysis of the fire ants of the Solenopsis saevissima species-group (Hymenoptera: Formicidae)

Results are presented from a phylogenetic study of the fire ants comprising the Solenopsis saevissima species-group (Hymenoptera: Formicidae). Six most-parsimonious trees were identified following a cladistic analysis utilizing 18 taxa and 36 morphological characters derived from three castes and two developmental stages. A strict consensus tree recovered the following relationships: ( S. daguerrei (( S. electra , S. pusilignis ) ( S. saevissima ( S. pythia ( S. interrupta , S. 'undescribed species' , S. weyrauchi ( S. richteri , S. invicta ( S. megergates ( S. quinquecuspis , S. macdonaghi )))))))). This phylogenetic hypothesis implies trends in fire ant evolution towards both polygyny (multiple egg-laying queens per colony) and large major worker size. The phylogeny also provides a test of Emery's Rule, which is not supported in its strictest sense because the social parasite S. daguerrei is not the sister species to its host species. A modified version of Emery's Rule is supported, because the social parasite is the sister species to a larger clade containing its hosts, as well as nonhosts.     

Cuticular Hydrocarbon Profiles Differentiate Tropical Fire Ant Populations (Solenopsis geminata,Hymenoptera: Formicidae)

The cuticular hydrocarbons (CHCs) from hexane rinses of workers from two Florida populations (dark and red forms) of the tropical fire ant, Solenopsis geminata, were separated by silica gel chromatography and identified by GC/MS analysis. Both the dark form and the red form produce similar CHCs with carbon chain lengths ranging from 17 to 35. However, the relative percentages of these CHCs were consistently different between the two color forms. The largest CHC component in the dark form is tricosane, and (Z)‐9‐tricosene for the red form. There were several significant differences in percent composition. For example, the dark form was characterized by a low tricosene:tricosane ratio (ca. 0.25), whereas this ratio was > 2.5 for the red form. The ratio of tricosene:tricosane can be used as a diagnostic biomarker to delimit the dark and red forms. Cluster analysis showed that the CHCs patterns of dark form colonies are completely separated from the CHC pattern of red form colonies. Differences in social behaviors like nestmate recognition and polygyny between workers from this dark form and the red form await further investigation.     

广东多刺蚁属一新种（膜翅目：蚁科）

在广东南岭自然保护区进行昆虫考察时发现多刺蚁属Polyrhachis 1新种,即:天井山多刺蚁P.tianjingshanensis,sp.nov.,隶属于多刺蚁属六刺多刺蚁亚属Myrmhopla。本新种与双色多刺蚁P.bicolor Smith相似,但触角、上颚和足均为黑色,前胸背板刺和并胸腹节刺粗长,远长于腹柄节刺,头、并腹胸和腹柄节具粗糙刻点。正模:工蚁,TL 11.5,HL 2.37,HW 2.23,CI 94,SL 3.43,SI 154,PW 1.83,AL4.75,ED 0.57;副模12工蚁:TL 11.4~11.7,HL 2.33~2.70,HW 2.20~2.73,CI 91~99,SL 3.37~3.65,SI 128~154,PW 1.77~2.03,AL 3.70~4.35,ED 0.53~0.63。正模:工蚁,广东南岭自然保护区天井山林场(24°41′N,112°59′E),450 m,2007-Ⅷ-18,侯占华采;副模:12工蚁,与正模同巢,侯占华采。模式标本保存于广西师范大学生命科学学院昆虫标本室。     

世界奇蚁属第三种记述(膜翅目:蚁科)

The third species of the ant genus Perissomyrmex in the world, P.fissus sp. nov., is collected from Ailao Mountain Nature Reserve of Yunnan Province. Perissomyrmex is a new record genus in China. Taxonomic key based on worker caste is provided for the 3 species: P.snyderi Smith, P monticola de Andrade, and P fissus sp. nov.     

Functional ultrastructure of the midgut of the fire ant Solenopsis saevissima Forel 1904 (Formicidae: Myrmicinae)

Solenopsis saevissima has a midgut composed of columnar, regenerative, and goblet cells. The midgut epithelium was covered by a basal lamina. Outside the basal lamina, layers of inner oblique, circular, and outer longitudinal muscles were present. Columnar cells showed a basal plasma membrane containing numerous folds, mitochondria, and the nucleus. Rough endoplasmic reticulum, Golgi bodies, membrane bounded vacuoles, and spherocrystals were found in this region. The apical plasma membrane was constituted by microvilli, which were above a region rich in mitochondria. Regenerative cells were found in groups lying by the basal lamina. Goblet cells were associated with an ion-transporting mechanism between the haemolymph and the midgut epithelium. These cells were lying by the midgut lumen and large microvilli were evident, but the cytoplasmic features were similar to the columnar cells.     

A Diverse Ant Fauna from the Mid-Cretaceous of Myanmar (Hymenoptera: Formicidae)

A new collection of 24 wingless ant specimens from mid-Cretaceous Burmese amber (Albian-Cenomanian, 99 Ma) comprises nine new species belonging to the genus Sphecomyrmodes Engel and Grimaldi. Described taxa vary considerably with regard to total size, head and body proportion, cuticular sculpturing, and petiole structure while all species are unified by a distinct shared character. The assemblage represents the largest known diversification of closely related Cretaceous ants with respect to species number. These stem-group ants exhibit some characteristics previously known only from their extant counterparts along with presumed plesiomorphic morphology. Consequently, their morphology may inform hypotheses relating to basal relationships and general patterns of ant evolution. These and other uncovered Cretaceous species indicate that stem-group ants are not simply wasp-like, transitional formicids, but rather a group of considerable adaptive diversity, exhibiting innovations analogous to what crown-group ants would echo 100 million years later.     

Vairimorpha invictae N. Sp. (Microspora: Microsporida), a Parasite of the Red Imported Fire Ant,Solenopsis invicta Buren (Hymenoptera: Formicidae)12

ABSTRACT. Vairimorpha invictae n. sp. infects the red imported fire ant, Solenopsis invicta Buren, in Brazil. The parasite is dimorphic, producing two morphologically distinct types of spores, which develop sequentially in the same fat cells or oenocytes in the fat body. The binucleate free spores develop from disporous sporonts; the uninucleate octospores develop from multinucleate sporonts within a sporophorous vesicle. Infected cells are transformed into large sacs which contain both types of spores in mature adult hosts. Mature free spores are often present by the time the larvae pupate, but mature octospores are found only in adult hosts. Masses of spores may be seen through the intact cuticle by low power phase-contrast microscopy; there are no other physical signs and no behavioral signs of infection. Attempts to transmit the infection in the laboratory failed.     

Individual and Cooperative Food Transport of the Red Imported Fire Ant (Hymenoptera: Formicidae): Laboratory Observations

The red imported fire ant, Solenopsis invicta Buren, is a significant urban and agricultural pest with a global distribution. However, the food transport patterns of S. invicta are poorly understood. In the present study, food of different sizes were provided to S. invicta colonies and transport for a short distance was observed under laboratory conditions. Individual transport of small food (1 × 1 mm deli meat) and cooperative transport of food of larger sizes (2 × 2 mm, 4 × 4 mm, and 8 × 8 mm deli meat) was observed. The majority of transporters were small workers. During cooperative transport, ants were either around or on the food, pulling/pushing the food item in multiple directions, leading to a slow process with frequent deadlocks. Individual transport required significantly shorter time in the preparation and transportation stages, but food transport was more likely to deviate from the nest. This observation suggests that the cooperative transport of S. invicta is closer to uncoordinated.     

喜马拉雅地区红矛猛蚁Myopopone castanea (Smith)记述

矛猛蚁属Myopopone Roger分布于东洋界和马来西亚界,目前为止该属仅知1种:红矛猛蚁M.castanea (Smith).首次在中国西藏记录到红矛猛蚁的分布,并系统记述了矛猛蚁属的特征、红矛猛蚁工蚁和蚁后的特征,提供了详尽的测量数据和插图.     

Eco-ethological Study on Raiding Behaviour of the European Amazon Ant,Polyergus rufescens Latr. (Hymenoptera: Formicidae)

In this paper we report the results of a detailed study on the behavioural ecology of slave raiding in the European amazon ant, Polyergus rufescens Latr. The field study, supported also by a video-tape recording technique, was conducted over an unbroken period of 53 days, during which observations of the activity of the residents (both slave-makers and slaves) were made for 10 h each day. It was possible to observe 38 slave raids distributed over 32 days, among which 27 were followed by the sack of 10 different nests of Formica cunicularia Latr., whereas 11 failed because of various reasons. Simple, compound and multiple raids occurred. We recorded the timing, frequency, distance, and direction of slave raids, including the number of participants and the type of captured brood. Moreover, particular attention was paid to the atmospheric conditions present at the moment of the raid onset. Information was also collected about the behaviour of the “activators” and the scouts before and during the movement of the storming column. Both dealate and winged P. rufescens queens, having emerged from the mixed colony during 6 sexual flights, were seen following the outbound raiding column during 4 raids. Finally, some peculiar behaviour, such as digging out the soil near the target nest to facilitate the entry of the raiding swarm, and the pillage of adult ants (eudulosis) was recorded and described. Data have been compared with what is known about the other species of the genus Polyergus.     

Seasonal Activity and Foraging Preferences of the Leaf-Cutting Ant Atta sexdens piriventris (Santschi) (Hymenoptera: Formicidae)

Leaf-cutting ants are known for their habit of foraging. These habits can be influenced by several factors, including variations in topography, soil, and climate among others. The objective of this research was to study the seasonal activity and foraging preferences of the leaf-cutting ant Atta sexdens piriventris (Santschi). The study was carried out from January to October of 2007 in grasslands of the state of Santa Catarina, Brazil. Nests of A. sexdens piriventris were randomly selected and the forager’s activities were recorded. Damaged plant species, soil fertility, and climatic conditions were recorded. The maximum foraging activity in the summer was recorded during periods of darkness or low light (between 7 p.m. and 5 a.m.). In autumn and spring, foraging was the highest in the morning, but during winter time the foraging activity was high in the afternoon. Fourteen plant species were frequently visited during our study with the lowest foraging activity being recorded at very low (1 to 4°C) or very high temperatures (above 26°C). The number of exploited plant species was higher in winter (13) than in summer (9). Baccharis trimera (Asteraceae) (43%) and Paspalum spp. (Poaceae) (33%) were the most exploited plants among the identified species.     

四川省蚂蚁区系研究（膜翅目：蚁科）

研究了四川（含重庆）蚂蚁的种类和分布,得知目前分布于四川的蚂蚁共有78种,分别隶属于5亚科27属,并发现1新种;古蔺立毛蚁Paratrechina gulinensis,sp.n。提供了新种的特征描述,根据地貌环境和气候的差异。将四川蚂蚁分为4个动物地理域,并讨论了四川蚂蚁区系的特点。     

Polygyny and Monoandry in the Ant Formica japonica (Hymenoptera: Formicidae)

Queen number, mating frequency and nest kin-structure of the ant Formica japonica were studied in the field and the laboratory. Nest excavation in the study site, the east slope of Mt. Fuji, Gotenba, Japan, revealed that F. japonica is weakly polygynous all year round and the queen number increases after the nuptial flight season, suggesting the adoption of newly mated queens by established nests. Dissection and laboratory rearing demonstrated that nearly all queens in polygynous nests had mated and were fertile with mature oocytes in their ovaries. Multilocus DNA fingerprinting was used to examine kin relationships among ants found in the same nests. The fingerprint band patterns were apparently governed by a simple genetic rule and suggested monoandry (single mating per queen). The mean band sharing score of DNA fingerprints among full sisters was 0.90, and the mean value between queens and their daughters was 0.75. Comparison of DNA fingerprints of adult and pupal workers with pupal gynes suggested that multiple queens in a nest may contribute unequally to gyne (new queen) production.     

Thelytokous Parthenogenesis in the Fungus-Gardening Ant Mycocepurus smithii (Hymenoptera: Formicidae)

The general prevalence of sexual reproduction over asexual reproduction among organisms testifies to the evolutionary benefits of recombination, such as accelerated adaptation to changing environments and elimination of deleterious mutations. Documented instances of asexual reproduction in groups otherwise dominated by sexual reproduction challenge evolutionary biologists to understand the special circumstances that might confer an advantage to asexual reproductive strategies. Here we report one such instance of asexual reproduction in the ants. We present evidence for obligate thelytoky in the asexual fungus-gardening ant, Mycocepurus smithii, in which queens produce female offspring from unfertilized eggs, workers are sterile, and males appear to be completely absent. Obligate thelytoky is implicated by reproductive physiology of queens, lack of males, absence of mating behavior, and natural history observations. An obligate thelytoky hypothesis is further supported by the absence of evidence indicating sexual reproduction or genetic recombination across the species'' extensive distribution range (Mexico-Argentina). Potential conflicting evidence for sexual reproduction in this species derives from three Mycocepurus males reported in the literature, previously regarded as possible males of M. smithii. However, we show here that these specimens represent males of the congeneric species M. obsoletus, and not males of M. smithii. Mycocepurus smithii is unique among ants and among eusocial Hymenoptera, in that males seem to be completely absent and only queens (and not workers) produce diploid offspring via thelytoky. Because colonies consisting only of females can be propagated consecutively in the laboratory, M. smithii could be an adequate study organism a) to test hypotheses of the population-genetic advantages and disadvantages of asexual reproduction in a social organism and b) inform kin conflict theory.For a Portuguese translation of the abstract, please see Abstract S1.     

中国圆鳞蚁属一新种记述(膜翅目:蚁科)

A new species of the ant genus Epitritus Emery, E. dayui sp. nov., is collected in Xishuangbanna Nature Reserve, Yunnan Province, China. Up to date, 4 species of the genus are known in China: E. hexamerus Brown, E. formosus Terayama, Lin et Wu, E. hirashimai Ogata, and E. dayui sp. nov. A key based on worker and female castes is proposed for the 4 known species of Epitritus of East Asia.     

Effects of contaminants on bait acceptance by Solenopsis invicta (Hymenoptera: Formicidae)

Three commonly used fire ant baits, Amdro (0.73% hydramethylnon [AI]), Ascend (0.011% abamectins [AI]), and Maxforce (1.0% hydramethylnon [AI]), were exposed to potential, volatile contaminants. The contaminants included the insecticides Orthene Fire Ant Killer (75.0% acephate [AI] ), Cyren (44.6% chlorpyrifos [AI]), and Tempo 2 (24.3% cyfluthrin [AI]); cigarette smoke; gasoline (unleaded, 89 octane); and fertilizer (10-10-10). Fire ant baits previously exposed for 48 h to these contaminants were analyzed using gas chromatography analysis. Orthene Fire Ant Killer, Cyren, Tempo 2, cigarette smoke, and gasoline had volatile components transferred to the baits. Baits exposed to these products were used in a field evaluation of bait acceptance by Solenopisis invicta Buren, the red imported fire ant. Uncontaminated Amdro was significantly preferred by S. invicta over Amdro contaminated by smoke, Cyren, Tempo 2, and gasoline. Uncontaminated Maxforce was significantly preferred over Maxforce contaminated by Tempo 2, Cyren, and gasoline, and uncontaminated Ascend was preferred over Tempo 2- and Cyren-contaminated Ascend. Orthene-exposed Amdro, Maxforce, and Ascend baits, and smoke-exposed Maxforce and Ascend baits were not significantly different from the control. These results indicate that volatile insecticides and products can contaminate fire ant baits. Some insecticides and products, such as gasoline, can significantly affect bait palatability and may adversely impact control.     

Response of Solenopsis invicta (Hymenoptera: Formicidae) to potassium oleate water solution

Abstract In contrast to floating on the surface of distilled water, ants were immediately submerged after being placed in the potassium oleate (PO) water solution, which led to immobilization within minutes. However, some workers survived after being immersed in 0.03% PO water solution at 25°C for up to 640 min. Elevated temperature of the PO water solution is needed to kill ants within a shorter time frame. At 50°C and 0.13% PO concentration, total mortality was achieved with 10-min immersion for all ants, including brood and adult ants. Soil has a negative effect on the effectiveness of potassium oleate; however, such negative effect can be overcome by increasing either treatment temperature or duration of the treatment. In addition to immobilizing and lethal effect, PO repels ants. PO may have the potential to be incorporated into immersion treatment for the quarantine of imported fire ants to reduce the use of synthetic contact insecticides.     

Gamergate reproduction in the antStreblognathus aethiopicus Smith (Hymenoptera: Formicidae: Ponerinae)

Summary We examined morphological and behavioral features of the reproductive biology of the ponerine ant,Streblognathus aethiopicus. Investigation of the ant's ovaries and spermathecae showed that each colony had a single reproductive (= gamergate). Morphologically this individual could not be distinguished from her nestmates, while the only clear-cut behavioural difference between the gamergate and workers was that the former laid eggs. Experimental removal of the gamergate from colonies resulted in the enlargement of the ovaries in some of the workers. This appears to show that the reproductive is able to suppress reproductive activity of her nestmates.

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Fortpflanzung dürch Gamergaten bei Streblognathus aethiopicus Smith (Hymenoptera: Formicidae: Ponerinae)

Zusammenfassung Wir untersuchten Aspekte der Morphologie und des Verhaltens der Fortpflanzungsbiologie beiStreblognathus aethiopicus (Unterfamilie Ponerinae). Die Untersuchung der Ovarien und Spermatheken zeigte, daß jede Kolonie über eine einzige Gamergate verfügte. Dieses Individuum konnte morphologisch nicht von seinen Nestgenossen unterschieden werden. Auch im Verhalten kann sie nur durch das Eierlegen erkann werden. Wurde die Gamergate im Experiment aus der Kolonie entfernt, vergrößerten sich bei einigen der Arbeiterinnen die Ovariolen. Demzufolge kann die Gamergate die Fortpflanzungsaktivität der Nestgenossen unterdrücken.