Sociobiology: Volume 42, Number 3, 2003

Feature Articles:

A New Gnamptogenys of the striatula Group from Bolivia, (Hymenoptera: Formicidae)

By Cynthia Morgan, William Mackay and José Pacheco

ABSTRACT
A new ant species, Gnamptogenys aspera, was found in a leaf litter extraction in a montane evergreen forest of Bolivia. This species from the striatula group is mahogany with red appendages, and fine punctures on its costulate sculpture. We include a description, key characters as well as a modified key to the species.


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A New Species of Aleocharine Staphylinidae (Coleoptera) That is Predaceous on Termites (Isoptera: Termitidae)

By David H. Kistner

ABSTRACT
A new genus of aleocharine Staphylinidae, Thoracophagus, type species T. congoensis is described together with its species, T. congoensis from the Congo Republic. Brief observations indicate that it is predaceous on termites and is somewhat prey specific.


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Abundance and Biomass of Termites (Insecta: Isoptera) in Dead Wood in a Dry Evergreen Forest in Thailand

By Akinori Yamada, Tetsushi Inoue, Atsuko Sugimoto, Yoko Takematsu, Takahiro Kumai, Fujio Hyodo, Ai Fujita, Ichiro Tayasu, Chirasac Klangkaew, Nit Kirtibutr, Toshiaki Kudo & Takuya Abe

ABSTRACT
The abundance and biomass of termites in dead wood were estimated in a dry evergreen forest in Thailand. Litter and dead wood were collected within ten 2 × 2 m quadrats on a 100 m transect, and then all termites in the litter and dead wood (= termites in dead wood) were dislodged. The biomass of litter and dead wood was 2.50 kg (dry weight) m-2, of which 76% was represented by dead wood with a diameter of ≥ 1 cm. A total of 239 pieces of dead wood (diameter ≥ 1 cm) were collected, and 38 of them contained termites. The frequency of termites in dead wood was significantly different between pieces with a diameter of 1-5 cm and pieces with a diameter of ≥ 5 cm. The abundance and biomass of termites in dead wood were 1269 termites m-2 and 3.53 g m-2, respectively. A total of 11 species, comprising Kalotermitidae, Rhinotermitidae and Termitidae, were collected; all of them belonged to the wood/litter-feeding group. Using our previous estimation for termites in the soil and data from other studies, the abundance and biomass of termites in the dry evergreen forest were estimated to be 7794 termites m-2 and 16.7 g m-2, of which 16 and 21%, respectively, were represented by termites in dead wood. Our study confirmed the importance of termites in dead wood in tropical seasonal forests.


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Diversity of Nest Types in Microcerotermes crassus (Termitinae, Termitidae, Isoptera) in a Dry Evergreen Forest of Thailand

By Yoko Takematsu, Tetsushi Inoue, Fujio Hyodo, Atsuko Sugimoto, Nit Kirtebutr & Takuya Abe

ABSTRACT
In a dry evergreen forest of Sakaerat, Thailand, five types of nests (arboreal, epigeal, hypogeal, inquiline and nests within wood) which were built by the genus Microcerotermes were observed. Morphologically, all samples collected from five nest types belonged to the same species and were identified as Microcerotermes crassus. This indicates that a single species can build different nest types in the same locality. Furthermore, the density of nests and the relative abundance were investigated. At 99 nests per plot area (165 nests per hectare), the nest abundance and the relative abundance was very much higher than in other Southeast Asian forests.


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The Interaction Among Workers of the Genera Atta and Acromyrmex (Hymenoptera: Formicidae) and Seeds of Mabea fistulifera (Euphorbiaceae), a Pioneer Tree Species in Brazil

By Ethel F. O. Peternelli, Terezinha M. C. Della Lucia, Luiz A. Peternelli, Sebastião V. Martins & Eduardo Euclydes de L. e Borges

ABSTRACT
The aim of this laboratory study was to investigate the interactions among workers of the genera Atta and Acromyrmex and the seeds of Mabea fistulifera. The interactions effects on seed germination were also investigated. Atta sexdens rubropilosa and Acromyrmex subterraneus subterraneus manipulated the seeds; carried them into the nest and discarded them after elaiosome removal. These results indicated that these ant subspecies are important for M. fistulifera seed transportation. However, Atta is more important because by their manipulation, seed germination is favored.


KEY WORDS: ant-plant interaction, Acromyrmex, Atta, Mabea fistulifera, myrmecochory, seed dispersal.

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Insectos Sociales en Ambientes Antropizados: Las Hormigas de la Ciudad de Coatepec, Veracruz, México

By Ismael R. López-Moreno, Martha E. Díaz-Betancourt & Teresa Suárez Landa

ABSTRACT
The aim of this study is to know the effect of urbanization and human activities on the ant species richness in the city of Coatepec, Veracruz, Mexico. On the base of 100 random sample points, we conducted a study on five different habitats: urban streets, coffee plantations, suggar cane plantations, secondary roads, and suburban vacant lots.
We registered a total of 40 ant species. The richest habitats in species were suburban vacant lots with an average of 9.5 species. In contrast, urban streets registered only an average of 4.8 species. The number of introduced species was 14 (35%) and the remaining 26 species (65%) were native of Mexico. Regarding their foraging behavior, we registered five different guilds: omnivorous species (14 species), carnivorous species (10 species), insect and honeydew feeders (10 species), fungus growing ants (3 species) and granivorous species (3 species).
According to a linear regression between the species richness and the area covered by cement, we found a negative correlation (r=-0.47 p< 0.05). This means that species richness diminishes with the increasing of urbanization.
The result of the analysis of numerical classification shows the formation of two large clusters. One related with typical urban environment, and the other associated with a more natural environment located in the suburbs like the coffee plantations. In general, the influence of urbanization and human activity has a negative effect on the ant species richness.


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Repellency of Vetiver Oils from Different Biogenetic and Geographical Origins against Formosan Subterranean Termites (Isoptera: Rhinotermitidae)

By Betty C-R. Zhu, Gregg Henderson, Robert P. Adams, Lixin Mao, Ying Yu & Roger A. Laine

ABSTRACT
Twelve vetiver oils from different biogenetic and geographical origin were tested for their repellency against Coptotermes formosanus Shiraki, (Formosan subterranean termite). Despite the variety of the constituents from different origins, all vetiver oils, except one, showed repellency. The possible termite-repelling components from the different origins are discussed.


KEY WORDS: vetiver oil, biogenetic and geographical origin, Coptotermes formosanus, repellency.

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Effects of Fire on Termite Generic Richness in a Savanna-like Ecosystem ('Cerrado') of Central Brazil

By Og DeSouza, Lidiamar Barbosa Albuquerque, Vânia Maria Tonello, Liliam Patrícia Pinto, & Ronaldo Reis Junio

ABSTRACT
Fire can affect ecological communities by direct elimination of organisms or through changes in resource availability, leading to diminished, increased, or unchanged richness. Termite generic richness (= number of genera) as well as termite abundance (= number of records per genus) are shown to not change following fire in a savanna-like ecosystem ('Cerrado') in central Brazil. Since fire is a natural recurrent event (i.e., predictable) in this ecosystem, it seems plausible that termites would have evolved mechanisms to cope with such a disturbance. Such mechanisms would include (i) inhabiting hard, protective, clay nests; (ii) temporary migration into adjacent less affected nearby, satellite, mounds; and (iii) absence of strict dietary specialization, coupled with low levels of competition, allowing niche overlap thereby minimizing adverse effects due to temporary reduction in food availability.


KEY WORDS: Isoptera, fire, cerrado, Brazilian savanna.

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Intercolony Aggression in Reticulitermes flavipes (Isoptera: Rhinotermitidae)

By Marc L. Fisher & Roger E. Gold

ABSTRACT
The relationship between intercolony aggression levels in Reticulitermes flavipes and the geographic distance between colony pairings was investigated. The study also examined the relationship between intercolony aggression and intercolony differences in soldier head length and pronotal width. There was a significant difference in the level of aggression demonstrated between colonies found in close proximity to one another (0.1 - 7.9 km), and those found farther apart (8.0 - 60.1 km). Closer colonies were more likely to be passive to one another. Differences in morphological size also yielded significant increases in the amount of aggression displayed between two colonies.


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Non-Specific Interaction Between Ants (Hymenoptera; Formicidae) and Fruits of Syagrus romanzoffiana (Arecaceae) in an Area of the Brazilian Atlantic Forest

By Maria S. de C. Morini, Rogério R. da Silva, & Luciane M. Kato

ABSTRACT
On the forest floor of a fragment of the Atlantic Forest which is considered to be in a stage of recuperation, located in southeastern Brazil, we recorded 54 species of ants interacting with the fruits of Syagrus romanzoffiana (Arecaceae). Myrmicinae was the subfamily which was the richest in species, followed by Ponerinae, Formicinae, Ecitoninae, Dolichoderinae, Pseudomyrmecinae and Cerapachyinae. The fruits of S. romanzoffiana can be classified according to whether or not they are preyed by the squirrel Sciurus ingrami, and the ant fauna that visits the fruits has an average similarity. Regarding diversity, the data suggest that there is no significant difference between ant assemblages at preyed and non-preyed-upon fruit falls. The results also indicate that there is no specific interaction between the ant fauna that visits the fruits of S. romanzoffiana, as it consists largely of species with omnivorous feeding habits.


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Chemical Signals Inducing Attraction and Alarm in European Reticulitermes Termites (Isoptera, Rhinotermitidae)

By Judith Reinhard, Alexandre Quintana, Leam Sreng & Jean-Luc Clément

ABSTRACT
Chemical signals causing attraction and alarm in four European subterranean termite species of the genus Reticulitermes (R. santonensis, R. lucifugus, R. grassei, R. banyulensis) were investigated. Natural extracts and isolated compounds from workers and soldiers were offered as odor source in a petri dish to groups of termites, and their behavioral reaction was registered. Pentane extracts of whole workers were attractive, and in three of the species induced a slight alarm reaction. The extracts contained 3-octanone, 3-octanol, and six fatty acids (C14-C18), presumably originating from the cuticle. Species-specific differences were quantitative. When tested individually or as synthetic mixture the worker compounds were significantly less effective than the natural extract. Only the ketone, the alcohol, and one of the fatty acids had any effect, functioning predominantly as attractants. Reticulitermes soldiers possess a frontal gland, which is employed for chemical defense of the colony, and contains species-specific mixtures of terpenes: monoterpenes, sesquiterpenes, diterpene alcohols, and a sesterterpene. All compounds of the frontal gland secretions proved to be highly attractive to the respective species, acting significantly stronger than worker compounds. The minor volatile compounds, the mono- and sesquiterpenes, function as alarm pheromone in Reticulitermes: they were the most attractive components, and also the ones inducing an intense alarm reaction in both workers and soldiers.


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Evaluation of the Use of the Inhibition Esterases Activity on Apis mellifera as Bioindicators of Insecticide Thiamethoxam Pesticide Residues

By Juliano Hideo Hashimoto, Maria Claudia Colla Ruvolo-Takasusuki & Vagner de Alencar Arnaut de Toledo

ABSTRACT
A trial was carried out to estimate the LC50 and esterase activity of Apis mellifera L. honeybees after the application of the insecticide thiamethoxam. In insects this product mimics acetylcholine at the central system ganglia. The estimated LC50 were as follows: for oral toxicity: 4.70 x 10-5, 7.40 x 10-5, 8.14 x 10-5, 10.10x10-5 mg/mL for the ages of newly emerged, 7, 14 and 21 days, respectively; for contact toxicity, 3.21, 3.50 and 4.51 mg/mL for newly emerged individuals and for the ages of seven and 14 days, respectively. Electrophoretic analysis showed a decrease in the activity of esterases 1, 2, 4 and 5 due to contact and oral toxicity, suggesting that alteration in the activity of those isozymes can be used to detect the presence of insecticide thiamethoxam pesticide residues.


KEY WORDS: Apis mellifera, thiamethoxam, esterases activity, bioindicators, neonictinoid.

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Biodiversity of Ants (Hymenoptera: Formicidae) in Golf Course and Lawn Turf Habitats in Kentucky

By Rolando López & Daniel A. Potter

ABSTRACT
The composition of ant communities in four suburban turf habitats, fairways, primary roughs, and naturalized roughs of golf courses, and low-maintenance lawns, was assessed by pitfall trapping. Relationships between ant diversity, species richness, and abundance, and overall abundance of other predatory arthropods also were examined. Two species, Lasius neoniger Emery and Solenopsis molesta (Say) represented 31.7 and 49% of the total ants captured across all habitats. Lasius neoniger predominated in fairways and naturalized roughs (57.9 and 52.7% of total ants captured, respectively), whereas S. molesta was most the abundant ant in primary roughs and lawns (66.7 and 43.8% of the total, respectively). Besides ants, the predominant predatory arthropods captured were mesostigmatid mites, spiders, Staphylinidae, Histeridae, and Carabidae. Ant species richness was greatest in low-maintenance lawns (18 species captured), and least in golf course fairways (13 species). Relatively similar numbers of ant species in fairways and roughs, compared to less intensively managed sites, nevertheless suggests that ants are relatively well adapted to golf course habitats. Management practices that conserve ant species diversity and abundance may contribute to stability of turfgrass ecosystems.


KEY WORDS: ants, Formicidae, turfgrass, species diversity, Solenopsis molesta, Lasius neoniger.

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Queen of the Army Ant Aenictus pachycerus (Hymenoptera, Formicidae, Aenictinae)

By Himender Bharti

ABSTRACT
The queen of Aenictus pachycerus has been discovered for the first time. This study provides a detailed description of the queen along with illustrations.


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Ants Nesting on Cecropia purpurascens (Cecropiaceae) in Central Amazonia: Influence of Tree Height, Domatia Volume and Food Bodies

By Vinícius Bonato, Rodrigo Cogni & Eduardo Martins Venticinque

ABSTRACT
Patterns of presence of ant colonies on Cecropia purpurascens CC Berg (Cecropiaceae) were investigated in central Amazonia. All individuals of C. purpurascens along a 14.3 km transect were searched for ants and their height, internode volume, and number of trichilia were recorded. Of the 50 C. purpurascens individuals studied, 32 (64%) were colonized by ants of four species: Azteca alfari Emery (Dolichoderinae) (N = 16), Camponotus balzani Emery (Formicinae) (N = 14), C. abdominalis (Fabricius) (Formicinae) (N = 1) and Crematogaster brasiliensis Mayr (Myrmicinae) (N = 1). Probability of C. purpurascens being colonized by ants increases with tree height, internode volume, and trichilium number. Of the three variables recorded, tree height was the most important in determining the presence of ants. Trees colonized by the two most common ant species (A. alfari and C. balzani) did not differ in height, internode volume, or number of trichilia. The patterns observed, the association between the identity of the ants and plant fitness, as well as the usefulness of this particular system for future studies are discussed.


KEY WORDS: ant-plant interaction, ants, Azteca alfari, Camponotus balzani, Cecropia purpurascens, Central Amazonia, mutualism.

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Electrophoretical Protein Profile in Apis mellifera (Hymenoptera; Apidae) Hypopharyngeal Glands Under Juvenile Hormone Effect When the Colony is Grown in the Absence of Brood

By Luciana Fioretti Gracioli, Márcia Regina Brochetto Brag, & Regina Lúcia Morelli Silva de Moraes

ABSTRACT
Twelve-day-old and 25-day-old Apis mellifera workers were treated or not treated with juvenile hormone at the moment of emergence and reared in the colony without brood. Having the brood interference apart, the hormone effect on the hypopharyngeal glands protein expression was determined through the electrophoretical protein profiles of the both groups of bees. In those conditions, the hormone induced changes that were different from the control. Protein bands of 66 and 48 kDa were intensified in the 12-day-old bees, whereas band of 42 kDa was reduced in the 25-day-old bees. That indicated a different effect of the juvenile hormone in the function of bee aging, which promoted a glandular protein activation in the young bees and, in contrast, an inhibitory action in the 25-day-old bees workers.


KEY WORDS: Apis mellifera, hypopharyngeal glands, brood, juvenile hormone, electrophoresis.

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Foraging Behavior in the Neotropical Swarm-Founding Wasp Parachartergus fraternus (Hymenoptera: Vespidae: Polistinae: Epiponini) During Different Phases of the Biological Cycle

By Leonardo C. Paula, Flávio R. Andrade & Fábio Prezoto

ABSTRACT
This study describes, for the first time, the foraging behavior in the swarm-founding wasp Parachartergus fraternus during the different phases of the biological cycle of colony. During the period of March to June of 2002. Seventy hours of direct observations were made of a colony of P. fraternus found on 02/25/02, in a branch of Dracaena marginata (Liliaceae), in Matias Barbosa municipality, Minas Gerais state, in the southeast region of Brazil. The number of vigilantes in the external part of the envelope, the temperature and the relative humidity of the air in the proximity of the nest and the total number of workers leaving and coming back to the nest during the interval were registered. Also the number of workers coming back with a solid load was recorded. The greatest foraging activity occurred in the hottest part of the day, generally between 12 at 14:30 hours, showing a positive correlation between the foraging activity and the temperature (r = 0,785; p <0,001) and a negative correlation with the relative humidity of the air (r = 0,703; p <0,001). The pre-emergency phase exhibited the largest efficiency index for returns with solid loads/hour (17,43%). Probably due to larger construction activity, nutritional demand of the offspring and climatic factors in this period of development of the colony.


KEY WORDS: Polistinae, Parachartergus fraternus, foraging behavior, nesting development, biological cycle.

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Foraging Activity Rhythm in the Neotropical Swarm-Founding Wasp Polybia platycephala sylvestris (Hymenoptera: Vespidae) in Different Seasons of the Year

By Maria Augusta Pereira Lima & Fábio Prezoto

ABSTRACT
This study describes the rhythm of foraging activity in the swarm-founding wasp Polybia platycephala sylvestris in different seasons of the year. From February to September 2001, 80 hours of direct observations were accomplished in colonies of P. p. sylvestris, in the Municipality of Juiz de Fora, Minas Gerais State, in southeastern Brazil. The number of workers leaving and coming back to the nest, the temperature and the humidity were registered during the observations. The results of foraging activity rhythm in P. p. sylvestris reveal a more intense activity during the hot and humid season (21,15 ± 13,94 exits of workers/hour) than in the cold and dry season (2,47 ± 2,0 exits of workers/hour). This activity the result of a complex interaction among the phase of colony development, nutritional and climatic factors, characterizing the foraging behavior of this species in the Neotropical region.


KEY WORDS: Polistinae, Polybia platycephala, foraging behavior, nesting development, biological cycle.

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Assemblage of Termites in a Fragment of Cerrado on the Coast of Paraíba State, Northeast Brazil (Isoptera)

By Josilene M. Sena, Alexandre Vasconcellos, Maria Avany B. Gusmão & Adelmar G. Bandeira

ABSTRACT
The fauna of termites was investigated in a fragment of cerrado (an open tree-dominated savannah-like vegetation) in a preservation area of the Reserva Biológica Guaribas (RBG), in the municipality of Mamanguape, State of Paraíba. A standardized sampling protocol was applied, made up of six transects of 65 m x 2 m, each one with five plots of 5 m x 2 m, with a distance of 10 m between each other, totalling 30 plots in an overall study area of 300 m2. Fourteen species of termites were found in the transects and six additional species were collected by chance, all of them belonging to the family Termitidae. The conspicuous nest builders found were Constrictotermes cyphergaster and Nasutitermes coxipoensis. The majority of the species were wood feeders, but humus feeders were the most frequent in the transects. The species richness here determined was the lowest ever reported in a Brazilian cerrado vegetation and one of the lowest reported in the Neotropical region. The size and the isolation time of the fragment and its distance from larger cerrado areas in the central region of Brazil may explain the low species richness. The taxonomic structure of the termite fauna was made up of species often found in other Brazilian biomes, like in the caatinga and in the Amazonian and Atlantic forests; however, five species seem to be endemic to areas of cerrado.


KEY WORDS: Isoptera, biodiversity, fragmentation, neotropical region.

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Relationship between Constrictotermes cyphergaster and Inquiline Termites in the Cerrado (Isoptera: Termitidae)

By Hélida Ferreira da Cunha, Diogo Andrade Costa, Kleber do Espírito Santo Filho, Lucivânio Oliveira Silva & Divino Brandão

ABSTRACT
Constrictotermes cyphergaster builds arboreal nests in Cerrado sensu stricto of Brazil; inquiline termites and termitophiles frequently inhabit their nests. Measurements of the nests and the support trees (nest width and diameter; tree trunk circumference and inclination), colony size of C. cyphergaster and of Inquilinitermes and number of termitophiles were studied at the Parque Estadual da Serra de Caldas Novas. These variables were subjected to a Principal Component Analysis, producing four principal components. The first principal component refers to a multidimensional axis of nest size, encompassing variables related to nest and colony size, such as abundance per caste of C. cyphergaster and I. microcerus, number of termitophile species and the measurements of the nest. The number of soldiers and workers of C. cyphergaster and soldiers of Inquilinitermes increased proportionally to the axis of nest size, while the number of Inquilinitermes workers increased more quickly then the increase in the nest size. Both Inquilinitermes occurred mainly in larger nests. Almost half of the nests (47,5%) were inhabited by I. microcerus and 10% by I. fur.


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Apis mellifera (Hymenoptera, Apini) Ovary Development in Queens and in Workers from Queenright and Queenless Colonies

By K. Patrício & C. da Cruz-Landim

ABSTRACT
A morphological study of the development of the ovaries in workers from queenright and queenless colonies and queens of Apis mellifera is presented and discussed. The mating stimulates the ovary development and the egg-laying. Mating prevention or egg laying prevention provokes reabsorption in the queens ovaries, characteristic of the queen stage or ovariole development. Ovary development was observed in queenless and in queenright colonies but the queen's presence, the worker's age and the type of tasks done by them interfere with their development.


KEY WORDS: ovary, queen, worker, Apis mellifera, development.

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Foraging Behavior and Subtask Hierarchical Structure in Acromyrmex spp. (Hymenoptera: Formicidae)

By Juliane F.S. Lopes, Roberto S. Camargo & Luiz Carlos Forti

ABSTRACT
This study considers the function and complexity of tasks during foraging of three Acromyrmex species. Foraging was classified as a team task composed of 2 or 3 processes: recruitment, selection, and collection. Each process was subdivided into different subtasks. Points were attributed to subtasks considering their hierarchical level to compare the complexity of foraging among species. Total scores obtained were 19 for A. balzani and 14 for A. crassispinus and A. rugosus, indicating different degrees of social complexity for grass-cutting and leaf-cutting ant species. Acromyrmex balzani, a grass-cutting ant species, shows a behavioral repertoire composed of more variable subtasks during foraging.


KEY WORDS: division of labor, foraging, leaf-cutting ants, task structure.

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The Life History and Colony Composition of Cylindrocaulus patalis (Coleoptera: Passalidae)

By Kyoko Ento, Kunio Araya & Masahiro Kon

ABSTRACT
The life history and colony composition of Cylindrocaulus patalis (Lewis, 1883) was investigated in Miyazaki Prefecture, Kyushu, southwest Japan, from May 2001 to October 2002. Cylindrocaulus patalis lives in family groups in galleries excavated in rotten wood. Adults were active from April to October and appeared to hibernate from December to March. The breeding season spanned June to August, the hot time of the year. Most observed colonies included a male and female pair year-round. Each pair raised only one offspring per year. Adult offspring appeared to stay with their parents until the following spring; some stayed until the next breeding season.


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Estimates of Foraging Population and Territory of Heterotermes tenuis Colonies using Mark-Release-Recapture (Isoptera: Rhinotermitidae)

By Ana Maria Costa-Leonardo, Fabiana Elaine Casarin, & João Ferreira Jr.

ABSTRACT
Heterotermes tenuis is an important economic pest in São Paulo state. Foraging populations of three field colonies of H. tenuis located on a University campus (UNESP, Rio Claro, SP, Brazil) were characterized. Foraging populations of H. tenuis colonies were calculated using four cycles of a mark-release-recapture program with a weighted mean method. The foraging population sizes of three colonies: A, B and C were 389,313 ±14,907; 265,589 ±12,635; and 641,600 ±12,127; respectively. Foraging biomasses were 0.77 kg in the colony A, 0.51 kg in the colony B and 1.17 kg in colony C. Mean worker biomass was approximately 1.9 mg. Foraging territories occupied an area ranging from 70 m2 to 131 m2 per colony. The maximum linear foraging distance traveled by H. tenuis was 28 m.


KEY WORDS: foraging population, territory size, Heterotermes tenuis, mark-release-recapture.

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Chemical Analysis of Food Processing by the Fungus-Growing Termite Macrotermes gilvus

By Toru Johjima, Tetsushi Inoue, Moriya Ohkuma, Napavarn Noparatnaraporn, & Toshiaki Kudo

ABSTRACT
In order to investigate the mechanism of food processing by the fungus-growing termite Macrotermes gilvus, we analyzed chemical composition of fallen leaves, foodstore, and newer and older part of fungus comb. Proportions of extractives changed considerably during food processing, while proportions of holocellulose remained mostly unchanged. Contents of water-soluble phenolics were much lower in the old part of the fungus comb than in the fallen leaves. Possible roles of foodstore and Termitomyces for reduction of litter toxicity are discussed.


KEY WORDS: fungus-growing termite, food processing, foodstore, chemical composition, phenolics.

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Intraspecific Variation in Shapes of Comb and The Petiole in Relation to Angle of Inclination of Nests in Pre-emergence Nests of a Paper Wasp, Polistes chinensis (Hymenoptera Vespidae

By Kazuyuki Kudô

ABSTRACT
The correlation between the angle of inclination of nests and the shapes of comb and the petiole was analyzed in pre-emergence nests of a Japanese paper wasp, Polistes chinensis. Shapes of comb and the petiole were round when the comb orientation was horizontal with a vertical cell axis, while those shapes were oval when the nest was built vertically with a horizontal cell axis. This first study revealed that the shape of the petiole was influenced by the angle of inclination. In addition, the surface area of the petiole, on which the ant repellent substances were expected to be effectively applied, did not correlate with the angle of inclination or the shape of the petiole. This suggested that foundresses of P. chinensis build variable shapes of the petiole with similar surface areas as the angle of inclination of the nests changed. To build the petiole with a similar surface area may be important for the lone foundress not only to diminish the effects of ant invasion but also to use the ant repellent substances effectively.


KEY WORDS: nest construction, nest structure, colony defence, social wasp, Polistes chinensis.

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Trends in Karyotype Evolution in the Ant Genus Camponotus (Hymenoptera: Formicidae)

By C.S.F. Mariano, J.H.C. Delabie, L.A.O. Campos & S.G. Pompolo

ABSTRACT
Camponotus has many species and its taxonomy is complex and problematic. Information on the chromosome structure of 41 species of Camponotus Mayr from several countries around the world was analyzed to understand the karyotype evolution in this genus. A tentative interpretation about the karyotypes evolution of these ants is given, on the base of Imai's Minimum-Interaction Theory and karyograph method. The number of chromosomes in the genus is extremely diverse, varying from n=9 to 25, and their morphology are acrocentric (A) or metacentric (M). Two groups of species exist with different inversion rates (Pinv), centric fission (Pfis) and centric fusion (Pfus). The karyotype of C. taylori (2K=24A) probably had evolved dominated by rearrangements like inversion-fusion (Pinv>Pfus>Pfis ), while the karyotypes with 2K=18 and 20M should be the final products of this chain. In species with higher chromosomal numbers (with n>12), the fission, inversion and fusion rates must have changed from an inversion-fusion to a fission-inversion dominance (Pfis>Pinv>Pfus ). The result agrees with the paraphyletism of Camponotus, found in phylogenetic information using molecular biology resources.


KEY WORDS: Camponotus, Formicidae, karyotype, evolution, biogeography.

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