ABSTRACT. Seasonal activity of Dinoponera quadriceps Santschi (Formicidae, Ponerinae) in the semi-arid Caatinga of northeastern Brazil. We studied seasonal foraging patterns of the queenless ant D. quadriceps (Formicidae, Ponerinae) for 24 months in a Caatinga area of northeastern Brazil, an ecosystem characterized by strong climatic changes throughout the year, in order to determine if regulation of worker activity is based on environmental conditions (air temperature, relative humidity, precipitation) and/or food resources (potential prey: Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera, Orthoptera, Araneae, Chilopoda and Diplopoda). Foraging activity of D. quadriceps varied over the course of both years, with the highest frequency occurring from May to August, corresponding to the late rainy season and early dry season. This foraging activity was negatively correlated with temperature and positively correlated with the availability of potential prey, but not with total abundance of soil arthropods or with rainfall and relative humidity. Diet composition, in relation to the main taxonomic prey groups, seems to be common to the species, regardless of habitat. Our results suggest that D. quadriceps workers adjust foraging activity to the most suitable period of the year, to avoid thermal stress and increase efficiency. Thus, they present an appropriate behavioral response to seasonal fluctuations in the Caatinga.KEYWORDS. Ants; environmental factors; foraging; Neotropical region, seasonality.RESUMO. Atividade sazonal de Dinoponera quadriceps Santschi (Formicidae, Ponerinae) em caatinga semiárida do nordeste brasileiro. Foi estudado o padrão de forrageamento da formiga sem rainha D. quadriceps (Formicidae, Ponerinae) durante 24 meses em uma área de caatinga do nordeste brasileiro, um ecossistema caracterizado pelas fortes mudanças climáticas ao longo do ano, com objetivo de determinar se a atividade das operárias é regulada pelas condições ambientais (temperatura do ar, umidade relativa, precipitação) e/ou recursos alimentares (presas potenciais: Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera, Orthoptera, Araneae, Chilopoda e Diplopoda). A atividade de forrageamento de D. quadriceps variou ao longo dos dois anos, com a maior freqüência ocorrendo de maio a agosto, correspondendo ao final da estação chuvosa e início da estação seca. Essa atividade de forrageamento foi negativamente relacionada com a temperatura e positivamente relacionada com a disponibilidade de presas potenciais. Não houve relação com a abundância total de artrópodes de solo, precipitação e umidade relativa. A composição da dieta, em relação aos grupos taxonômicos das presas, parece ser comum à espécie, independente do habitat. Os resultados sugerem que as operárias de D. quadriceps ajustam sua atividade de forrageamento ao longo do ano para evitar estresse térmico e aumentar sua eficiência. Desta forma, elas possuem uma resposta comportamental apropriada para a flutuação sazonal da Caatinga.

We measured individual decisions regarding the adjustments of time, distance and direction of foraging in Dinoponera quadriceps. We observed two colonies in an area of secondary Atlantic Forest, FLONA-ICMBio, in Northeastern Brazil. The workers were individually marked. We recorded the displacement of workers, their returns to the nest with and without food, the time spent searching for food, maximum and total distance, inter-trip latency and direction of trips. The time spent searching for food, maximum distance and transport velocity did not vary with food size. The previous trip success reduced the latency between foraging trips and increased the percentage of success on the next trip. However, this previous success did not demonstrate a significant variation relative to the time spent searching on the next trip or direction of search. The workers maintained an individual directional fidelity during foraging. The adjustments of these foraging variables under individual control contributed to the efficiency at the colony level. D. quadriceps is compatible with the central place theory and risk sensitivity model of behavior.

This study characterizes the foraging activity of the queenless ant Dinoponera quadriceps (Kempf) (Hymenoptera: Formicidae) in its natural environment by testing the hypotheses that foraging activity presents both daily and seasonal rhythmic variations, and that these rhythms are related to environmental variables. Four colonies of D. quadriceps were observed in an area of secondary Atlantic forest in northeastern Brazil. Data collection was performed over 72 h every three months during an annual cycle. Both daily and seasonal foraging activity rhythms of D. quadriceps colonies were related to environmental factors, but colony differences also explained part of foraging variations. Foraging activity of D. quadriceps colonies was predominantly diurnal independently of season. In the early dry season, the colonies had two activity peaks, one in the morning and another in the afternoon, with a decrease in foraging at midday; however, during the rest of the year, foraging activity was distributed more evenly throughout the daylight hours. The daily rhythm of foraging activity was likely determined by an endogenous circadian rhythm year-round, but in the dry season, temperature and relative humidity also influenced daily foraging activity, with a negative effect of temperature and a positive effect of relative humidity. On a seasonal scale, foraging activity peaked in the early dry season and suddenly declined at the end of this season, increasing again at the late rainy season. The seasonal rhythm of foraging was negatively related to relative humidity and positively related to prey availability.

Conhecendo a importância da vegetação nas iniciativas de reabilitação de áreas degradadas e no fornecimento de bens naturais, objetiva-se com este trabalho analisar a importância socioambiental, econômica e cultural da faveleira, para o semiárido brasileiro. A caracterização como espécie-chave cultural (CKS) do bioma caatinga realizou-se com a aplicação de metodologia já usada em outros trabalhos, em analogia com fontes documentais, observações de campo em áreas rurais com a presença dessa xerófita e a realização de 57 entrevistas com populações rurais de áreas com a presença do vegetal nos municípios de São José do Seridó e Caicó/RN. Considerando as fontes informacionais escritas, 31 apontaram a resiliência do vegetal com as condições edafoclimáticas, com a fauna e a flora silvestre, na alimentação humana e dos seus animais, como fitoterápico, produto madeireiro, na geração de energia e as formas de propagação. A faveleira apresenta relevância na manutenção da fauna silvestre, de espécies da flora que se desenvolve sob o seu dossel, na reabilitação de áreas degradas, na alimentação humana, dos seus animais, produção de medicamentos, como produto madeireiro e na geração de energia. O fato do vegetal reunir cinco entre os sete critérios propostos na metodologia aplicada, o qualifica como sendo CKS do bioma caatinga. Palavras-chave: Euforbiaceae; Endêmico; Espécie-chave Cultural; Floresta seca.     ABSTRACT Knowing the importance of vegetation in the rehabilitation initiatives of degraded areas and the supply of natural resources, this work aimed to analyze the socioenvironmental, economic and cultural importance of the faveleira, for the Brazilian semiarid region. The characterization as a key cultural species (CKS) of the caatinga biome was carried out with the application of methodology already used in other studies, in analogy with documentary sources, field observations in rural areas with the presence of this xerophyte and the realization of 57 interviews with rural populations of areas with the presence of the vegetable in the municipalities of São José do Seridó and Caicó / RN. Written information sources, 30 have pointed out the resilience of the vegetable with the edaphoclimatic conditions, with the fauna and the wild flora, in the human food and of its animals, as phytotherapic, wood product, in the generation of energy and the forms of propagation. The faveleira has relevance in the maintenance of wildlife, species of flora that develops under its canopy, rehabilitation of degraded areas, human food, its animals, production of medicines, as a wood product and in the generation of energy. The fact that the plant meets five of the seven criteria proposed in the applied methodology, qualified as CKS of the caatinga biome. Keywords: Euforbiaceae; Endemic; Key Cultural Species; Dry forest.   RESUMEN Conociendo la importancia de la vegetación en las iniciativas de recuperación de áreas degradadas y en abastecimiento de bienes naturales, buscase con este trabajo analizar la importancia socioambiental, económica y cultural de la favelera para el semiárido brasileño. La caracterización como especie clave cultural (CKS) de un bioma se realizó con una aplicación de la metodología ya utilizada en otros trabajos, en analogía con fuentes documentales, las observaciones de campo en áreas rurales con la presencia de ese xerófilo y la realización de 57 entrevistas con poblaciones rurales de áreas con la presencia del vegetal en los municipios de São José del Seridó y Caicó/RN. Considerando las fuentes informacionales, 31 apuntaron la resiliencia del vegetal con las condiciones edafoclimáticas, con la fauna y la flora silvestre, en la alimentación humana y de sus animales, como terapia herbaria, producto maderero, en la generación de energía y las formas de propagación. La favelera presenta relevancia en la manutención de la fauna silvestre, de especies de la flora que se desarrolla bajo el su dosel, en la recuperación de áreas degradadas, en la alimentación humana, de sus animales, producción de medicamentos, como producto maderero y en la generación de energía. El facto del vegetal congregar cinco entre los siete criterios propuestos en la metodología aplicada, el califica como un CKS del bioma caatinga. Palabras clave: Euforbiácea; Endémico; Especie clave Cultural; Bosque seco.   RÉSUMÉ Connaissant l'importance de la végétation dans les initiatives de réhabilitation des zones dégradées et dans l'approvisionnement en biens naturels, ce travail vise à analyser l'importance socio-environnementale, économique et culturelle de la faveleira pour la région semi-aride brésilienne. La caractérisation en tant qu'espèce culturelle clé (CKS) du biome caatinga a été réalisée avec l'application d'une méthodologie déjà utilisée dans d'autres travaux, en analogie avec des sources documentaires, des observations de terrain en milieu rural avec la présence de ce xérophyte et 57 entrevues avec les populations rurales des zones où le légume est présent dans les municipalités de São José do Seridó et Caicó / RN. Compte tenu des sources d'informations écrites, 31 ont souligné la résilience du légume aux conditions édaphoclimatiques, à la faune et à la flore sauvage, dans l'alimentation humaine et ses animaux, comme phytothérapie, produit du bois, dans la génération d'énergie et les modes de propagation. La faveleira est pertinent dans le maintien de la faune sauvage, des espèces de flore qui se développent sous sa canopée, dans la réhabilitation des zones dégradées, dans la nutrition humaine, chez les animaux, dans la production de médicaments, comme produit du bois et dans la génération d'énergie. Le fait que la plante réponde à cinq des sept critères proposés dans la méthodologie appliquée, la qualifcomme CKS du biome caatinga. Mots-clés: Euforbiaceae; Endémique; Espèces culturelles clés; Forêt sèche.

Ant colonies can reproduce by two strategies: independent foundation, wherein the queen starts a new colony alone, and dependent foundation, in which workers assist the queen. In the queenless species Dinoponera quadriceps (Santschi), the colony reproduces obligatorily by fission, a type of dependent foundation, but this process is not well understood. This study describes a colony fission event of D. quadriceps in the field and analyzes the influence of the fission process on workers' extra-nest behavior. Based on observations of workers outside the nest, five distinct stages were identified: monodomic stage, polydomic stage, split stage, conflict stage, and post-conflict stage. The colony was initially monodomic and then occupied a second nest before it split into two independent colonies, indicating a gradual and opportunistic dependent foundation. After the fission event, the daughter colony had aggressive conflicts with the parental colony, resulting in the latter's disappearance. Colony fission affected workers' extra-nest behavior by increasing the frequency of rubbing the gaster against the substrate (which probably has a chemical marking function) and by decreasing the frequency of foraging during the split stage. After the fission event, the number of foragers was halved and foragers remained nearer to the nest during extra-nest activity. The spatial closeness of the parental and daughter colonies led to competition that caused the extinction or migration of the parental colony. Intraspecific competition was indicated by foraging directionality at the colony level, whereby areas of neighbor colonies were avoided; this directionality was stronger while both colonies coexisted.

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In social insects, task allocation can be more complex than workers merely falling into discrete task groups. Any activity performed by the colony cannot be fully understood in isolation from other activities because they may be interrelated. Investigating activities other than foraging is crucial to understanding the global functioning and organization of ant colonies. This study attempts to characterize the nest maintenance activity of the ponerine queenless ant, Dinoponera quadriceps, in its natural environment to determine the effects of environmental variables on the variations in both seasonal and daily rhythms and to discuss its differences and possible relationships to foraging. Four colonies of D. quadriceps were observed in an area of Atlantic Forest in northeastern Brazil. Data collection was performed over a period of 72 h every three months during an entire annual cycle. Nest maintenance activity in D. quadriceps colonies was observed during both the light and dark phases of the day. There was no significant difference between the day phases in the number of workers involved in this task. On the other hand, D. quadriceps colonies exhibited seasonal variation in nest maintenance activity, peaking in the early rainy season. The seasonal rhythm of nest maintenance was positively correlated with relative humidity and negatively correlated with prey availability and rainfall. Our results indicate the existence of an annual variation in the nest maintenance activity of D. quadriceps associated with environmental variables. However, it occurs equally both at night and day, countering the hypothesis that there is a daily rhythm.