A 3D model to illustrate the nest architecture of Acromyrmex balzani (Hymenoptera; Formicidae)

ABSTRACT For eusocial insects, the nest is a place where the main social interactions occur. The nest architecture ensures protection from predators and the environment, as well as suitable conditions for brood rearing, food storage, and in some cases the cultivation of fungus farms. Variations in nest architecture can occur, according to the environmental conditions. In order to elucidate the internal organization of nests, most studies use 2D schemes and photographs to illustrate the nest architecture models. However, 3D models can provide a different and more realistic view of the nest architecture. The aim of this study was to describe the nest architecture and colony size of the grass-cutting ant Acromyrmex balzani (Emery), using 3D models to illustrate these features. The structures of eight colonies were measured and the data were used to create a 3D model of each nest. Externally, the nests had one or more piles of loose soil and waste, with a single straw turret over the entrance. Underground, the nests had from 2 to 6 chambers, at a maximum depth of 122 cm. It could be concluded that the observed nest architecture of Acromyrmex balzani followed, at least in part, the pattern already reported in the literature. However, this is the first report of connection between two chambers made by two shafts, as well as the presence of the turret at the nest entrance/exit, regardless of the season of the year. These differences evidence that the nest structures may vary, depending on intrinsic or local environmental conditions.

Nest Architecture Development of Grass-Cutting Ants, Atta capiguara (Hymenoptera: Formicidae)

ABSTRACT Atta capiguara grass-cutting ants are commonly found in the Cerrado biome, in open fields. Although grass-cutting ants build giant nests, little has been elucidated about this building pattern and when chambers and tunnels emerge. The present study describes the nest architecture development of A. capiguara grass-cutting ants from data on 31 cement-molded nests. A. capiguara nests grow with increases in the number of fungus chambers and emergence and increase of waste chambers and foraging tunnels. The structural growth of A. capiguara nests in the first year and a half of age (18 months) is vertical, with the building of the first chambers in the soil profile. After 18 months, the nests grow sideways with the addition of chambers and tunnels, and the first waste chambers appear. Between 18 and 54 months, the number of fungus chambers increases from 1-3 to 21-32, and the chambers are concentrated at the soil surface, although they can be found more than 3 m deep. In addition, the total volume of the waste chambers increases with the increment in the fungus chambers volume. Thus, this study contributes to understanding the nest architecture development of A. capiguara grass-cutting ants and demonstrates that the total volume of waste chambers is proportional to the total volume of fungus chambers suitable for the colony.

Nest architecture and colony characteristics of Meliponula (Axestotrigona) ferruginea (Hymenoptera, Apidae, Meliponini) in Cameroon

Stingless bees have evolved adaptive nest constructions strategies which have resulted in sophisticated nest architecture inmany species while others lack certain structural components. However, no information exists on the nest biology andecology on the genus Meliponula in Cameroon. This study aims to contribute to knowledge on the nest architecture andcolony characteristics of Meliponula (Axestotrigona) ferruginea. Meliponula ferruginea belongs to the genus Meliponulaand subgenus Axestotrigona. This species was first described by Le Peletier De Saini-Farrgeau (1836) and Michener (Thebees of the world, The Johns Hopkins University Press, Baltimore and London, 2000) recently. In Cameroon the specieshas been collected in the northern parts of the country, but there has been no attempt to describe the nest architecture. Ourstingless bee survey from the Bamenda highlands afromontane forests of Cameroon reveals that this species can either nestin tree trunks or in abandoned traditional hollow hives. Interestingly, 50% of colonies studied nested in traditional hollowhives originally baited for honeybees (Apis mellifera adansonii). The nest entrance of Meliponula (Axestotrigona) ferruginea ranged from 1 to 1.5 cm (1.2±0.0.24 cm) in diameter, while the external entrance tube extended up to 1.6±0.0.4cm and the nest entrance tube can go up to 5 cm inward in depending on the thickness of the tree trunk. The nest is made upof sticky brown 5–7 (6±0.98) involucra sheets. The size of brood area depends on the age and condition of the nest. Thelength of the nest could be between 5.5 and 7.6 cm (6.8±0.98 cm) and up to 13± 4.16 cm combs with a comb diameter ofabout 7.5±1.29 cm. The cells and storage pots are oval in shape but the storage pots are much larger, about 3 times the sizeof cell. Generally, this study shows a lot of similarities with other previously studied species in terms of the nestcharacteristics and measurements. However, the above characteristics can be very useful in taxonomical, phylogenetic andecological studies of M. ferruginea.

Notes on the nest of the social wasp Pseudopolybia langi (Hym., Vespidae, Polistinae)

Abstract Detailed descriptions of the architecture of Pseudopolybia langi nests are presented for the first time. Structural variations in the arrangements of nest parts are described and compared with features observed in other species of Pseudopolybia and other epiponine genera.

Notes on social wasps of the group of Mischocyttarus(Omega) punctatus (Ducke), with description of six new species (Hymenoptera, Vespidae, Polistinae)

ABSTRACTA revision of the taxonomic status and an identification key for wasp species of the genus Mischocyttarus related to M. punctatus (Ducke, 1904) are presented here. Six new species are proposed (M. tayrona Silveira sp. nov.; M. anchicaya Silveira sp. nov.; M. caxiuana Silveira sp. nov.; M. verissimoi Silveira sp. nov.; M. rodriguesi Silveira sp. nov.; M. ryani Silveira sp. nov.), raising to nine the number of species in the M. punctatus group. The highest diversity of the group concentrates in northern South America, in Andean areas and Amazonia. New information concerning the very peculiar nests of these wasps is also given.

Bionomics of Melipona mondury Smith 1863 (Hymenoptera: Apidae, Meliponini) in relation to its nesting behavior / Bionomia de Melipona mondury Smith 1863 (Hymenoptera: Apidae, Meliponini) em relação ao seu comportamento de nidificação

Melipona mondury Smith 1863 is an important stingless bee species pollinator and honey/pollen producer, but threatened by fragmentation of habitats throughout its range. This article presents the identification and partial characterization of nesting substrates, bionomic including population features of M. mondury by comparing data between nest architecture of natural beehive and boxes colonies. Nineteen colonies (13 in boxes and six in beehives) were analyzed with regards to substrate nesting, nest characteristics (e.g. length and width of the combs, height and diameter of the pollen and honey jar) and bee population. The average volume and diameter of the trunks cavities used for nesting of M.mondury were18.4 L and 15.8 cm; the average number of combs was 9.26; the average diameter and height of the honey pots were 2.81 cm and 3.29 cm, and the average volume of honey stored was 15.85 mL; the average height and diameter of pollen pots was 3.21 cm and 2.93 cm, respectively, while the average mass of pollen deposited was equal to 12.56 g. The population ranged from 3537 to 10281 individuals between colonies. The results suggest that the conservation of M. mondury should involve reforestation with native species from Atlantic Forest, and the dimensions of boxes should be based on the average size of the nests in the natural environment in order to support strategies of conservation and sustainable management of this species.

Melipona mondury Smith 1863 é uma espécie de abelha sem ferrão, importante polinizadora, produtora de mel e de pólen, mas ameaçada pela fragmentação dos habitats ao longo de sua área de ocorrência. Este artigo apresenta a identificação e a caracterização parcial dos substratos de nidificação e as características bionômicas, incluindo as populacionais, de M. mondury, comparando os dados de arquitetura do ninho entre colônias de cortiço e caixas rústicas. Dezenove colônias (13 em caixas rústicas e seis em cortiços) foram analisadas em relação aos substratos de nidificação, características do ninho (e.g.: comprimento e largura dos favos de cria, altura e diâmetro dos potes de pólen e mel) e população das abelhas. Foram encontrados volume e diâmetro médios da cavidade dos troncos nidificados por M. mondury, de 18,4 L e 15,8 cm; número médio de favos de cria de 9,26; diâmetro e altura médios dos potes de mel de 2,81 cm e 3,29 cm, sendo o volume médio de mel armazenado de 15,85 mL; altura e diâmetro médios dos potes de pólen de 3,21 cm e 2,93 cm, enquanto a massa média de pólen depositado foi de 12,56 g. A população variou de 3 537 a 10 281 indivíduos entre as colônias. Os resultados sugerem que a conservação de M. mondury deve envolver o reflorestamento com espécies nativas da Mata Atlântica; e as dimensões das caixas racionais foram definidas com base no tamanho médio dos ninhos no ambiente natural, para subsidiar estratégias conservacionistas e de manejo racional.

Nesting of social wasps (Hymenoptera: Vespidae) in a riparian forest of rio das Mortes in southeastern Brazil / Nidificação de vespas sociais (Hymenoptera: Vespidae) em floresta ripária do rio das Mortes no Sudeste do Brasil

The survival of social wasp species depends on the success in founding new nests. These species can use plant species with different specific characteristics for nesting, with nest architecture varying according to the habits of those plant species. The nesting of social wasps in natural environments was studied in the period from October 2005 to September 2007 in the rio das Mortes riparian forest, municipal district of Barroso, Minas Gerais State, Brazil, with the objective of evaluating the different types of plant substrate used by social wasps for nesting, and to investigate whether there is a relationship between nest construction type and the habits of plant species. A total of 171 colonies of social wasps belonging to 29 species were recorded, which used 78 plant species as nesting substrate (76 Angiosperms and two Pteridophytes) of arbustive, herbaceous, arboreal, epiphyte and liana habits. Species with phragmocyttarus and gymnodomous nests were observed nesting, with higher incidence, in arboreal plants and their deciduousness did not affect the nesting. The preservation of natural areas is suggested in order to guarantee a higher availability of nesting places for the social wasp species, ensuring their higher efficiency in the environmental services and biological control of agricultural pests.

A sobrevivência das espécies de vespas sociais depende do sucesso na fundação de novos ninhos. Essas espécies podem utilizar para nidificação de diferentes espécies vegetais com características específicas, com a arquitetura dos ninhos que variam em relação aos hábitos dessas espécies vegetais. A nidificação de vespas sociais em ambiente natural foi estudada no período de outubro de 2005 a setembro de 2007 em uma floresta ripária do rio das Mortes, município de Barroso, Estado de Minas Gerais, Brasil, com o objetivo de avaliar os diferentes tipos de substratos vegetais utilizados por vespas sociais para nidificação, e investigar se há relação entre o tipo de construção dos ninhos com os hábitos das espécies vegetais. Foram registradas 171 colônias de vespas sociais pertencentes a 29 espécies, que utilizaram como substrato de nidificação 78 espécies vegetais (76 Angiospermas e 2 Pteridófitas) de hábitos arbustivo, herbácea, arbóreo, epífita e liana. Espécies com ninhos fragmocítaros e giminódomos nidificaram, com maior incidência, em plantas arbóreas e a deciduidade das mesmas não afetou a nidificação. Sugere-se a preservação das áreas naturais de modo a garantir maior disponibilidade de locais de nidificação para as espécies de vespas sociais, assegurando maior eficiência nos serviços ambientais e no controle biológico de pragas na agricultura.

Nesting biology of four species of Trypoxylon (Trypargilum) (Hymenoptera: Crabronidae) in Chaco Serrano woodland, Central Argentina

Trypoxylon (Trypargilum) (Crabronidae) wasps are solitary spider predators that can build their nests in artificial trap-nests, which enables study of their nesting architecture and biology. Twenty traps (each containing 15-30 internodes of cane) were placed in each of nine sites of Chaco Serrano Woodland in Central Argentina (Córdoba) in October 2005, and were recovered in June 2006. We obtained 91 nests of four species of Trypoxylon (Trypargilum). In the laboratory, each Trypoxylon nest was sectioned longitudinally to study its architecture. The number of brood cells was counted, and the occurrence and length of vestibular and intercalary cells and the pre-closing plug space were recorded. We measured the diameter of the cane entrance, total length of the nest, length of each brood cell, maximum thickness of mud partitions and closing plug thickness. We also recorded the cell contents: the wasps, their natural enemies and the prey spiders. Mortality was assessed and the sex ratio calculated for each species. Finally, the nests were examined to help clarify the function of the vestibular cell. The nest architecture was similar in the four species, with linear brood cells located one after the other separated by mud partitions, as in other species of the subgenus Trypargilum. Forty-eight percent of the nests had vestibular cells, but only two had intercalary cells. The thickness of the mud partitions and the length of the brood cells differed among species and were related to the size of the emerged wasp. The diameter of the nest entrance was directly related to the average length of the fore-tibia. Sex ratios of all species did not deviate from 0.5. Mortality due to parasitoids (Eulophidae; Melittobia sp.) was similar among species, while the mortality due to cuckoo wasps (Chrysididae) in T. lactitarse was higher than in the other species. The presence of vestibular cells was not related either to the mortality due to natural enemies or to the orientation of the trap in the field. Spiders in the family Araneidae were the most frequently collected prey. Rev. Biol. Trop. 58 (4): 1177-1188. Epub 2010 December 01.

En este trabajo se estudia la biología de la nidificación de cuatro especies de Trypoxylon (Trypargilum) recolectadas a partir de 91 nidos-trampa en el Bosque Chaqueño Serrano de Córdoba, Argentina. La arquitectura de los nidos fue similar para las cuatro especies: celdas de cría ubicadas linealmente, una detrás de la otra separadas por tabiques de barro, como es habitual en otras especies del subgénero Trypargilum. El 48% de los nidos presentó celda vestibular, mientras que sólo dos nidos presentaron celdas intercalares. El ancho de los tabiques y el largo de las celdas de cría difirió entre las especies y estuvo relacionado con el tamaño de las avispas que emergieron. Así mismo, el diámetro del nido-trampa estuvo directamente relacionado con el tamaño corporal promedio de las especies de mayor y menor tamaño. La mortalidad debida a parasitoides (Eulophidae; Melittobia sp.) fue similar para las cuatro especies, mientras que la causada por cleptoparásitos (Chrysididae) fue mayor en T. lactitarse. No fue posible relacionar la presencia de celda vestibular con la mortalidad debida a enemigos naturales para ninguna de las especies. La familia de arañas más frecuentemente utilizada como presa fue Araneidae.

Epipona media cooper (Hymenoptera: Vespidae), a social wasp new to the Brazilian Atlantic Forest

An occupied nest of Epipona media Cooper was discovered and collected in a cabruca (cocoa plantation with native tree cover). This is the first record of E. media from Bahia State. We described the nest structure and compared the adults with the closely related species Epipona tatua Cuvier.

Nest thermoregulation in Polybia scutellaris (White) (Hymenoptera: Vespidae)

Polybia scutellaris (White) builds large nests characterized by numerous spiny projections on the surface. In order to determine whether or not the nest temperature is maintained because of homeothermic conditions of the nest individuals or otherwise, we investigated the thermal conditions within the nests built by P. scutellaris. We measured the temperature within active and abandoned nests. The temperature in the active nest was almost stable at 27°C during data collection, whereas the temperature in the abandoned nest varied with changes in ambient temperature. These results suggest that nest temperature was maintained by the thermogenesis of the individuals of the colony. This is the first report of nest incubation caused by thermogenesis of species of Polybia wasps.

Ninhos de Centris (Heterocentris) terminata Smith (Hymenoptera: Apidae, Centridini) em fragmentos de Mata Atlântica secundária, Salvador, BA / Trap-nests used by Centris (Heterocentris) terminata Smith (Hymenoptera: Apidae, Centridini) at secondary Atlantic Forest fragments, in Salvador, Bahia State

Foram analisados 95 ninhos de Centris (Heterocentris) terminata Smith, fundados em ninhos-armadilha, entre novembro de 2001 e janeiro de 2003, em dois fragmentos urbanos (CFO-UFBA e PZGV) de Mata Atlântica secundária, em Salvador, BA (13º01Æ W e 38º30Æ S). O maior número de nidificações ocorreu de dezembro a fevereiro (verão), não havendo ninhos fundados nos meses de agosto, setembro e outubro (inverno-primavera). Emergiram 280 adultos de C. terminata (n = 347 células), sendo 164 machos e 116 fêmeas, resultando em razão sexual de 1: 0,42. Durante esse período, a emergência de machos foi significativamente superior a de fêmeas (c2 = 9,342; gl =10; P < 0,05). Os ninhos foram fundados em ninhos-armadilha de madeira com 6, 8, 10 mm de diâmetro, sendo que 84,2 por cento deles foram construídos com 8 e 10 mm. Cada ninhos possui de uma a sete células, dispostas em série em série linear e partições construídas com uma mistura de areia e resina ou óleo. O macho é significativamente menor que a fêmea, sendo que esta última emerge a partir das primeiras células construídas. A mortalidade de imaturos foi baixa, ocorrendo em 14,1 por cento das células (n= 49), sendo 13,0 por cento por falhas no desenvolvimento e 1,2 por cento por parasitas Coelioxys sp. (Hymenoptera: Megachilidae) e Tetraonyx sp. (Coleoptera: Meloidae). Na área estudada, fatores meteorológicos, especialmente a pluviosidade, mostraram-se mais determinantes da abundância temporal do que inimigos naturais. O longo período de atividade anual, abundância local e adequação aos ninhos-armadilha sugerem bom potencial de C. terminata para manejo visando a polinização de plantas nativas e cultivadas.

Ninety-five nests of Centris (Heterocentris) terminata Smith were collected in trap-nests, during November/2001 and January/2003, at two fragments (PZGV e CFO-UFBA) of secondary Atlantic Forest, in Salvador, Bahia State (13º01Æ W e 38º30Æ S). The highest nest frequencies occurred from December to February (summer), with no nests foundations from August to October (winter - early spring). Two-hundred eight adults emerged from 347 brood cells, being 164 males and 116 females (1: 0.42). During the study period sex ratio was male biased (c2 = 9.342; gl = 10; P < 0.05). C. terminata nested in holes with diameters 6, 8, 10 mm, but 84,2 percent were constructed in 8 and 10 mm. nests had one to seven cells arranged in a linear series with the cellÆs partitions built with a mixture of sand and resin or oil. Male is significantly smaller than female, which emerges from the first cells constructed. Immature mortality occurred in 14.1 percent of brood cells (n = 49), of which 13.0 percent were due fail in development and 1.2 percent due to parasitism of Coelioxys sp. (Hymenoptera: Megachilidae) e Tetraonyx sp. (Coleoptera: Meloidae). In the study site, weather, mainly pluviosity, rather than natural enemies influenced seasonal population abundance. The long period of nesting activity, local abundance and usage of trap nests, suggest the potential of C. terminata for management aiming at pollination of native and cultivated plants.

Promotion of thermoregulatory insulation in nests of neotropical wasps by building extra-combs with empty cells / Promoção de isolamento térmico em ninhos de vespas neotropicais pela construção de favos com células vazias

We examined the hypotheses that the empty combs of Polybia occidentalis Olivier (Hymenoptera: Vespidae) nest insulate the inside of the nest. To examine this hypotheses, two kinds of temperature measurements were carried out: 1) with the outer comb of the nest intact (Control) and 2) removed (Treatment), using a large and a small nest. In the large nest, the daily nest temperatures (outer part, Tn1; inner part, Tn2) in Control were lower by 0.6°C (Tn1) and 1.2°C (Tn2) than those in Treatment, because of a higher ambient temperature (Ta) throughout temperature assessment in Treatment. However, the excess temperature (Tn - Ta) in Control was higher than that in Treatment. The value was higher by 0.7°C at Tn1 and 0.1°C at Tn2. In the small nest, the excess temperature in outer part was similar between experiments, while that in inner part of Control was lower than that of Treatment. The temperature fluctuation in the nests was lower in the Control than that in Treatment both the outer and inner part of the comb. We conclude that the unused comb is ecologically invaluable for raising and protecting the brood from extreme changes in ambient temperature during the winter period, because it helps not only keeping a higher nest temperature but also decreasing the temperature fluctuation around the brood combs. In addition, such a high temperature may influence the performance of adult wasps.

Examinou-se a hipótese de que os favos vazios dos ninhos de Polybia occidentalis Olivier (Hymenoptera: Vespidae) atuam como isolamento térmico dos elementos internos da colônia. Para avaliar essa hipótese dois tipos de medidas de temperatura foram tomadas: 1) com o favo externo intacto (Controle) e 2) removido (Tratamento), usando um ninho grande e um ninho menor. As temperaturas diárias no ninho grande (parte externa Tn1; parte interna Tn2), no Controle, foram 0,6°C (T n1) e 1,2°C (Tn2) mais baixas que aquelas do Tratamento, devido à temperatura ambiente (Ta) mais alta durante todo o período avaliado. Entretanto, a temperatura excedente (Tn - Ta) no Controle foi mais alta que no Tratamento. O valor foi 0,7°C mais alto em Tn1 e 0,1°C em Tn2. No ninho menor, a temperatura excedente na parte externa foi semelhante entre os experimentos, e na parte interna a temperatura do Controle foi inferior à do Tratamento. A flutuação térmica nos ninhos foi menor no Controle que no Tratamento, tanto na parte externa quanto interna dos favos. Conclui-se que o favo sem uso é ecologicamente muito importante para criar ou proteger a cria das alterações extremas de temperatura ambiente no inverno, uma vez que ele auxilia na manutenção de temperatura alta no ninho e também no decréscimo da flutuação de temperatura ao redor dos favos de cria. Além disso, essas temperaturas mais altas influenciam as atividades dos adultos.

Nesting biology of the trap-nesting Neotropical wasp Trypoxylo n(Trypargilum) aurifrons Shuckard (Hymenoptera, Crabronidae)

The present study was carried out in three localities of the state of São Paulo, Brazil: Araras (Dec/03-Dec/06), São Carlos (Nov/04-Nov/06) and Rifaina (Jul/04-Dec/06). Trap-nests were distributed among sites in the sampling areas and were collected every 35 days. Data from 295 nests indicate that T. aurifrons is a multivoltine species, with higher rates of nest building and cell production in the warm, rainy season. The trap-nests used by the females ranged from 117 to 467 mm in length and 3.1 to 16.6 mm in diameter. All nests showed deep plugs and a vestibular cell was found in 37 percent of the complete nests. The number of cells per nest ranged from one to 12. Females were larger than males, emerged from longer cells and their cocoons were significantly larger. A secondary 1:1 sex ratio was found in Araras and Rifaina. No correlation was observed between the diameter of the trap-nest and sex ratio. Males were usually oviposited in the first brood cells. Male and female developmental time from egg to adult was longer in the cold, dry season. Trypoxylon aurifrons provisioned their nests mainly with orb-spiders from the family Araneidae. The most important mortality factor was the death of immature forms, probably due to development failure. The most important parasitoid was Melittobia sp.

Este estudo foi realizado em três localidades do estado de São Paulo: Araras (dez/03-dez/06), São Carlos (nov/04-nov/06) e Rifaina (jul/04-dez/06). Ninhos-armadilhas foram distribuídos em diferentes sítios das áreas amostradas e coletados a cada 35 dias. Dados de 295 ninhos mostraram que T. aurifrons é uma espécie multivoltina, com maiores taxas de nidificação e produção de células na estação quente e chuvosa. Os ninhos-armadilhas utilizados pelas fêmeas variaram de 117 a 467 mm de comprimento e de 3,1 a 16,6 mm de diâmetro. Todos os ninhos apresentaram parede de fundo e célula vestibular foi constatada em 37 por cento dos ninhos completos. O número de células por ninho variou de um a 12. Fêmeas emergiram de células e pupários maiores, sendo significantemente maiores que os machos. Razão sexual secundária igual a 1:1 foi observada em Araras e Rifaina. Não foi encontrada correlação significativa entre a razão sexual e o diâmetro do tubo. Machos foram encontrados principalmente nas primeiras células de cria. O tempo de desenvolvimento ovo-adulto foi mais longo na estação fria e seca. Trypoxylon aurifrons aprovisionou seus ninhos principalmente com aranhas da família Araneidae. O principal fator de mortalidade foi a interrupção do desenvolvimento das formas imaturas e o parasitóide mais freqüentemente encontrado foi Melittobia sp.

Nest architecture of a bagworm species: Rhythmic pattern in the arrangement of sticks.

Nest architecture of a bagworm species, Clania crameri was examined. Fortytwo bags (nests) were collected from the host plant, Clerodendron indicum and number of sticks used in each bag was counted. Furthermore, length of each stick in each nest was measured (in mm) clockwise one after another serially beginning with the longest stick. The data obtained were subjected to frequency analysis and power spectrum analysis. Results clearly reveal that the larvae of bagworms do not glue together sticks of different size randomly but with a definite pattern.