21 research outputs found

    The ontogeny of bumblebee flight trajectories: From naïve explorers to experienced foragers

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    Understanding strategies used by animals to explore their landscape is essential to predict how they exploit patchy resources, and consequently how they are likely to respond to changes in resource distribution. Social bees provide a good model for this and, whilst there are published descriptions of their behaviour on initial learning flights close to the colony, it is still unclear how bees find floral resources over hundreds of metres and how these flights become directed foraging trips. We investigated the spatial ecology of exploration by radar tracking bumblebees, and comparing the flight trajectories of bees with differing experience. The bees left the colony within a day or two of eclosion and flew in complex loops of ever-increasing size around the colony, exhibiting Lévy-flight characteristics constituting an optimal searching strategy. This mathematical pattern can be used to predict how animals exploring individually might exploit a patchy landscape. The bees’ groundspeed, maximum displacement from the nest and total distance travelled on a trip increased significantly with experience. More experienced bees flew direct paths, predominantly flying upwind on their outward trips although forage was available in all directions. The flights differed from those of naïve honeybees: they occurred at an earlier age, showed more complex looping, and resulted in earlier returns of pollen to the colony. In summary bumblebees learn to find home and food rapidly, though phases of orientation, learning and searching were not easily separable, suggesting some multi-tasking

    Orientation and navigation during adult transport between nests in the ant Cataglypis iberica

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    Cataglyphis iberica is a polydomous ant species in which adult transports between nests are frequently observed. When pairs of workers were captured and released at the same location, the transporters (Ts) fled directly towards their destination nest and reached it in most of the cases. The transportees (Te), on the other hand, fled in the opposite direction and only a third of them eventually reached their nest of departure. Additional experiments suggest that this result may be explained by the fact that the Ts ants have a memory of the compass direction of the nest they are heading to and that they adjust their course by using a sequence of memorised landmarks. As regards to the Te, the reversal of their direction of transport seems to be based essentially on celestial cues.Peer Reviewe

    Orientation and navigation during adult transport between nests in the ant Cataglypis iberica

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    Abstract Cataglyphis iberica is a polydomous ant species in which adult transports between nests are frequently observed. When pairs of workers were captured and released at the same location, the transporters (Ts) fled directly towards their destination nest and reached it in most of the cases. The transportees (Te), on the other hand, fled in the opposite direction and only a third of them eventually reached their nest of departure. Additional experiments suggest that this result may be explained by the fact that the Ts ants have a memory of the compass direction of the nest they are heading to and that they adjust their course by using a sequence of memorised landmarks. As regards to the Te, the reversal of their direction of transport seems to be based essentially on celestial cues

    Foraging ecology of the giant Amazonian ant Dinoponera gigantea (Hymenoptera, Formicidae, Ponerinae): activity schedule, diet and spatial foraging patterns

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    This study provides a detailed account of the natural history and foraging biology of the ponerine ant Dinoponera gigantea in a rainforest in north Brazil. The species nests on the ground and the colonies contain 70-96 workers. Ant activity is negatively correlated with temperature, and is more intense at dawn and dusk. Foragers leave the nest independently and search for food individually on the leaf litter, within ca 10 m around the nest. Workers are opportunistic feeders that collect seeds and fruits, and hunt for live prey as well as scavenge for dead animal matter. The dry weight of food items ranges from 400 mg (seeds, fruits). There is no nestmate recruitment during the search for or retrieval of food, irrespective of food type and size. Foragers have a high directional fidelity, and ants from neighbouring colonies may engage in ritualized territorial contests at the border of their foraging areas. The foraging ecology of D. gigantea is compared with other ponerine species living in tropical forests, as well as with other ant groups showing similar behavioural patterns.36182211222

    Nesting patterns, ecological correlates of polygyny and social organization in the neotropical arboreal ant Odontomachus hastatus (Formicidae, Ponerinae)

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Queen number varies in the population of O. hastatus in SE Brazil. Here, we evaluate how nesting ecology and colony structure are associated in this species, and investigate how reproduction is shared among nestmate queens. Queen number per colony is positively correlated with nesting space (root cluster of epiphytic bromeliads), and larger nest sites host larger ant colonies. Plant samplings revealed that suitable nest sites are limited and that nesting space at ant-occupied bromeliads differs in size and height from the general bromeliad community. Dissections revealed that queens in polygynous colonies are inseminated, have developed ovaries, and produce eggs. Behavioral observations showed that reproduction in polygynous colonies is mediated by queen-queen agonistic interactions that include egg cannibalism. Dominant queens usually produced more eggs. Field observations indicate that colonies can be initiated through haplometrosis. Polygyny in O. hastatus may result either from groups of cofounding queens (pleometrosis) or from adoption of newly mated queens by established colonies (secondary polygyny). Clumping of bromeliads increases nest space and probably adds stability through a strong root system, which may promote microhabitat selection by queens and favor pleometrosis. Rainstorms that frequently knock down bromeliads can be a source of colony break-up and may promote polygyny. Bromeliads are limited nest sites and may represent a risk for young queens leaving a suitable nest, thus favoring secondary polygyny. Although proximate mechanisms mediating queen number are poorly understood, this study suggests that heterogeneous microhabitat conditions probably contribute to the coexistence of variable forms of social structure in O. hastatus.582207217Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)University Paul SabatierFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [08/54058-1, 2000/00442-3]CNPq [304521/2006-0, 301853/2009-6

    How lost “passenger” ants find their way home

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    The dynamics of collective exploration and trail-formation in Monomorium pharaonis: experiments and model

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    When exploring a chemically unmarked area devoid of food sources, workers of the pest ant Monomorium pharaonis L. (Formicidae, Myrmicinae) leave scent marks on the ground and after 30–60min a network of diverging exploratory trails begins to emerge.Exploratory activity is affected by the nutritional state of the colony and a period of food deprivation induces a dramatic increase in the number of workers leaving the nest. A mathematical model based on a logistic growth equation is proposed to describe the exploratory recruitment observed. When travelling along exploratory trails the proportion of ants displaying trail-laying behaviour is higher for outbound than for nestbound workers. Outbound ants also show a greater propensity than nestbound ants to follow the scent marks of their nestmates. The chemical used to mark a novel area does not appear to be colony-specific and thus does not have a territorial function sensu stricto. The adaptive value of the collective exploratory behaviour observed in this study is discussed in relation to the common features of other pest ant species described in the literature.FLWNAinfo:eu-repo/semantics/publishe

    An Agent-Based Behavioural Model of Monomorium Pharaonis Colonies

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    Abstract. In this study X-machines and hierarchical organized X-machines will be used to model different aspects of the behaviour of social insect communities. The model is organized as a community of complex agents showing similarities to networks of P systems.
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