Comparison between Winkler's extractor and pitfall traps to estimate leaf litter ants richness (Formicidae) at a rainforest site in southest Brazil

Abstract

The aim of this study was to compare in the same site the efficiency of the two most used techniques for sampling ant diversity, Winkler's extractors and pitfalls. We studied communities of leaf litter ants from the Brazilian Atlantic Forest, compared richness estimates for genera and species, and built species accumulation curves. These two methods resulted in a satisfactory sampling of richness; 21.3% of the genera and 47.6% of the species were collected exclusively with Winkler's extractors, whereas 6.4% of the genera and 9.5% of the species were collected exclusively with pitfalls. Winkler's extractor had proven to be the most efficient single sampling technique to estimate richness. However, pitfalls also recorded a significant portion of the total richness. Despite differences in efficiency, species accumulation curves for both techniques were similar, as well as the curve obtained with both methods combined. We noticed that Winkler's extractors were c. 74.0% more efficient than pitfalls in the Atlantic Forest. Therefore, sampling techniques must be used with a well-structured sampling design in order to advance knowledge on the ant fauna of Brazilian biomes, especially in the leaf litter, allowing more complete environmental analyses.Keywords: Atlantic rainforest, sampling techniques, species accumulation curves.Comparação entre extrator de Winkler e armadilha de queda para estimar a riqueza em espécies de formigas (Formicidae) de serapilheira em floresta tropical do sudeste do Brasil Resumo O objetivo deste estudo foi comparar, em um mesmo ambiente, a eficiência das duas técnicas de coletas mais utilizadas para amostrar a diversidade de formigas, o extrator de Winkler e a armadilha de queda (pitfall traps). Para a comunidade de formigas de serapilheira da Mata Atlântica, comparamos as estimativas de riqueza de gêneros, de espécies e as curvas de acumulação de espécies. Os dois métodos resultaram em uma amostragem de riqueza satisfatória, sendo 21,3 e 47,6% exclusivamente gêneros e espécies coletadas pelo extrator de Winkler e 6,4 e 9,5% pela armadilha de queda. O extrator de Winkler mostrou ser a técnica mais eficiente para amostrar a riqueza de uma área quando apenas uma das técnicas possa ser utilizada. No entanto, o uso da armadilha de queda registrou uma parcela não tão desprezível da riqueza. Quanto à eficiência das técnicas de coleta, as curvas de acumulação de espécies para os duas técnicas mostraram-se similares com a obtida com os dois métodos simultaneamente. Notou-se, portanto, que o extrator de Winkler apresenta uma eficiência de amostragem da riqueza na ordem de 74,0% maior que a armadilha de queda para ambiente de Mata Atlântica. Vale ressaltar que as técnicas de coleta devem estar associadas a um delineamento amostral bem estruturado para que se possa ampliar ainda mais o conhecimento sobre a mirmecofauna dos biomas brasileiros, principalmente daquelas com serapilheira, permitindo análises ambientais mais completas.Palavras-chave: Mata Atlântica, técnicas de coleta, curva de acumul...

Changes in Epigaeic Ant Assemblage Structure in the Amazon during Successional Processes after Bauxite Mining

“…Despite a higher number of pitfall trap units than Winkler samples, the latter method allowed us to sample smaller and cryptic species of the genera Carebara, Cyphomyrmex, Discothyrea, Hypoponera and Strumigenys. Pitfall traps collected exclusive species and, as expected, more active and larger ones (Olson, 1991;Orsolon-Souza, 2011), including all species of the genus Pseudomyrmex which mainly forage on plants. In our study, Winkler extractors could have their efficacy impeded due to the atypical rainfall, with rainfall rates being much higher than 17 years ago (MRN data).…”

Ant assemblage (Hymenoptera: Formicidae) in three wind farms in the State of Paraná, Brazil

“…Soil traps (pitfall) for capturing invertebrates with walking habit (Orsolon-Souza et al, 2011) consisted of 250 mL plastic cups (10 cm diameter, 12 cm height), buried with its leading edge at the ground level. Inside each trap, 150 mL water was added with two drops of detergent to break the surface tension of water, causing the insects to sink when they fall into the trap.…”

“…During construction, known impacts are related to the removal of vegetation, removal of soil and ground compaction by machines and actions that can destroy forest remnants and disable the permanence of species of animals (Meireles, 2008). Once deployed, the wind farm may interfere with the displacement of birds and mammals (Barbosa Filho, 2013).…”

Ant diversity sampling in the Brazilian Amazon: a comparison of litter collection and pitfall trapping

“…Studies of soil macrofauna require wellstructured and standardized sampling methodologies to adequately estimate species richness and uniformity (Véle et al, 2009). However, it is challenging to estimate species richness in megadiverse regions because the techniques used by researchers do not always provide a representative sample of total richness (Agosti & Alonso, 2001;Orsolon-Souza et al, 2011;Tista & Fiedler, 2011). Ants are a hyperdiverse group in tropical forests and particularly important in the soil macrofauna, as they are highly abundant, have a wide geographical distribution, and occupy a wide variety of niches (Andersen & Majer, 2004;Solar et al, 2016;Tiede et al, 2017).…”

“…Ants have been the subject of several ecological studies and have been sampled by various methods, including pitfall traps, bait traps, litter sampling, fogging, beating the vegetation and manual harvesting (Orsolon- Souza et al, 2011;Yusah et al, 2012;Cajaiba & Silva, 2014;Antoniazzi et al, 2020). In this study, we compared the performance of two methods usually used for catching soil ants: manual litter collection and pitfall traps (Nakamura et al, 2007).…”