Navegando por Autor "Luna, P."
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Item Recruitment and entropy decrease during trail formation by foraging ants.(2020) Lourenço, Giselle Martins; Ferreira, Fabíola Keesen; Fagundes, Roberth; Luna, P.; Silva, Alcides Volpato Carneiro de Castro e; Ribeiro, Sérvio Pontes; Arashiro, EveraldoSocial insects utilise a complex spatial orientation system mediated by chemical signals. This study investigated how the foraging behaviour of ants (Dorymyrmex thoracicus) varies depending on the quantity of an available resource using a feld experiment. Further, we demonstrated computationally that ant displacement is compatible with a model based on pheromone deposition. Our experiment tested how the resource size (large or small) and availability (one or two simultaneous patches) of resources ofered infuence the number of recruited ants (trafc fow) and the speed of trafc fow both moving towards a resource and returning to the colony. The results showed that the returning fow was higher than the going fow independent of resource. The trafc fow towards a single resource was higher than the fow for either of two simultaneous resources patches ofered; thus, multiple resources sources split the fow, regardless of the fact that resource size did not afect foraging choices. Our results indicated that the ants used an orientation mechanism that can be reproduced by a theoretical computer model. With our model, we showed that initially, the displacement of ants followed no clearly detectable pattern. However, with increasing levels of ant recruitment and consequent pheromone deposition on the most used trails, returning displacement revealed the formation of shorter and more organised trails. The model revealed key transition between periods of order and disorder that continued until the fow of information reached an organised state (Shannon entropy). This study highlights an exceptional mechanism of foraging optimisation in eusocial insects.Item Temporal shifts in butterfy diversity : responses to natural and anthropic forest transitions.(2020) Lourenço, Giselle Martins; Luna, P.; Guevara, R.; Cruz, Wesley Francisco Dáttilo da; Freitas, André Victor Lucci; Ribeiro, Sérvio PontesButterfy species often synchronize their life cycles to seasonality, as increasing temperature and rainfall act as clues of resource availability. Nevertheless, human-made forest edges cause major changes in the microclimatic conditions that may jeopardize the synchrony between insects and favorable conditions for their emergence, conversely to natural ecotones. Here, the distribution of fruit-feeding butterfies was studied over one year in three diferent habitats (forest interior, forest ecotone, forest edge) to examine if: (i) species richness and abundance varies among habitats and subfamily/tribe over the year; (ii) temperature and rainfall afect the abundance and temporal distribution of species richness; and (iii) the beta diversity and its monthly partition are similar among habitats. The present study was carried out in the Rio Doce State Park, Brazil, a 36,000 ha forest reserve. In total, 11,594 individuals representing 98 butterfy species were collected. The butterfies presented a nonuniform distribution of abundance in all habitats, with greater abundance, richness and species diversity during the wet season. Butterfy abundance increased with high temperatures in all habitats. The contribution of species turnover and nestedness varied over the months, overlapping with the seasonal changes. Understanding how rates of species turnover vary over time in diferent habitats can help explain the vulnerability of species to environmental changes, allowing comparison of assemblages over time