Navegando por Assunto "Sociedades de insetos"

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Acesso aberto (Open Access)
Efeitos da orfandade sobre o comportamento e longevidade de operárias de Scaptotrigona aff. postica (Hymenoptera: Apidae, Meliponini)
(Universidade Federal do Pará, 2018-04-02) LOPES, Bárbara dos Santos Conceição; CONTRERA, Felipe Andrés León; http://lattes.cnpq.br/0888006271965925
The death of the physogastric queen may imply the behavioral disorganization of eusocial bees workers, where they can assume diverse reproductive and behavioral strategies. For the worker longevity is related to the physiological effort exerted during their lifetime, but the colony's internal conditions also affect longevity, such as the presence or absence of a queen. In this sense, the objective of the study was to study the behavior and longevity of the population of stingless bee workers in orphaned colonies, comparing them with colonies with the present laying queen. In this sense, the objective of the study was to study the behavior and longevity of the population of stingless bee workers in orphaned colonies, comparing them with colonies with the present physogastric queen. For this, eight colonies of Scaptotrigona aff. postica were used, of those eight there were four colonies with a queen and four without a queen. Each colony had a total of 1.200 workers marked with different colors by day of birth (age zero), thus obtaining age groups. For 100 days, we observed the colonial foraging activity, the age of the workers who attending brood cells, age of foraging and longevity in all colonies, queenright (QR) and queenless (QL). Over time in QR colonies the foraging activity decreased slightly; however, the QL colonies presented a greater reduction in the number of foragers (X2 = 48.874; df = 1; p <0.001). In orphaned colonies we observe that over time, besides the young workers, the older workers also construct the brood cells; in the colonies with queen, the workers who participated in the construction of new brood cells were only those of young age (X2 = 116.11, df = 1, p < 0.001). In both colonies, QR and QL, the age of foraging increased over time, but in QL colonies we observed foragers with very advanced age (X2 = 66.546; df = 1; p < 0.001). The maximum longevity found for colonies workers with queen was 54 days of age and for orphaned workers was 79 days of age. Kaplan-Meier survival curves indicated significant differences between colonies QR and QL (p < 0.001). Thus, we conclude that (1) workers of S. aff. postica in colonies without queen actually decrease the external activity over time; (2) advanced orphan female workers continue to perform breeding cell construction, probably to try to produce males; (3) it is possible that the workers QL colonies start to avoid the foraging and perform this task only occasionally or they tend to perform this activity later; (4) the selfish behavior of reproducing itself, avoiding foraging and its risks, and thus staying longer in the colony can prolong the longevity of S. aff. postica in orphaned colonies.
Acesso aberto (Open Access)
Efeitos de perturbações antrópicas sobre os fatores ambientais e espaciais na estruturação de metacomunidades de insetos aquáticos na Amazônia Oriental
(Universidade Federal do Pará, 2022-07) OLIVEIRA, Stéfany Vitória Santos; FARIA, Ana Paula Justino de; http://lattes.cnpq.br/6041546003155327; https://orcid.org/0000-0003-2729-5358; SANTOS, Raphael Ligeiro Barroso; http://lattes.cnpq.br/7227882802366966; https://orcid.org/0000-0001-9717-5461
Anthropogenic pressures resulting from changes in land use have great potential to impact the dynamics of aquatic insect metacommunities, once they alter the environmental quality of streams, and may impose barriers to dispersal. The objective of this study is to evaluate the structuring of aquatic insect assemblages (Ephemeroptera, Plecoptera and Trichoptera orders - EPT) in Amazonian streams under natural conditions (control streams) and under disturbance by human activities (altered streams) is influenced by characteristics of fluvial habitats and by the spatial structure. Our hypotheses is that in control streams, habitat characteristics are the main structuring factor of EPT assemblages, and that in altered streams, habitat characteristics related to human disturbances and spatial structure are the main assemblage structuring factors. A total of 74 streams were sampled in the Capim River basin, Pará, Brazil, wich 38 are control streams and 36 are altered streams. In each of them, environmental variables associated with water chemistry, channel hydromorphology, sediment types, riparian vegetation and insect shelter were measured, in addition to the proportion of land uses and EPT assemblages. Our results showed that several environmental characteristics of the streams were affected by human activities. Environmental factors had a greater influence on the structuring of EPT assemblages than the other factors evaluated, both in the control and altered streams. The influence of the spatial factor was weak. The assemblages of altered streams were structured both by environmental variables affected by disturbances and by variables subject to natural variation, demonstrating that the assemblages in these environments are not governed only by environmental changes. Our study demonstrates the importance of the species sorting process in metacommunities of Amazonian streams, and the role of disturbance in this process.