Ants affect citrus pests and their natural enemies in contrasting ways

Ants are one of the most abundant insect groups in citrus orchards. They help in controlling pests, but they can also facilitate the outbreak of other pests, such as those that produce honeydew. Moreover, ants can also affect natural enemies of pests. Here, we review how ants affect pest abundance, considering whether the pest produces honeydew and whether it spends part of its life-cycle in the soil (edaphic stages). We also investigated the effects of the presence of ants on natural enemies with a meta-analysis and how this effect is modified by honeydew production by the pest, the most abundant ant species, and the specialization and mode of dispersal (winged or wingless) of the natural enemy. The presence of ants decreased the abundance of non-honeydew producing pests, but increased the abundance of honeydew producers. Ants increased the abundance of pests without edaphic stages, but decreased pests with such stages. In addition, the identity of the most abundant ant species affected the abundance of natural enemies; the ants Iridomyrmex rufoniger and Lasius grandis had a negative impact whereas other ant species did not affect the abundance of natural enemies. Moreover, the presence of ants decreased the abundance of generalist and winged natural enemies of honeydew-producing pests. Our review provides crucial information on the effects of ants on biological control practices in citrus orchards, and increases our understanding of the relationships between ants, pests and their natural enemies

Ant diversity decreases during the dry season:A meta-analysis of the effects of seasonality on ant richness and abundance

Tropical studies traditionally describe insect diversity variation throughout the year. The temporally structured responses of insect assemblages to climate seasonality vary across ecosystems due to gradients of resource availability and limiting ecological factors. These idiosyncratic responses might be particularly true across the vast geographical range of the Brazilian territory, including various environments that harbor one of the most diverse ant faunas worldwide. This study addressed the relationship between ant diversity and climatic seasonality, performing a quantitative review of the published data on ant diversity collected in Brazil. We investigated the seasonality effect on ant abundance and richness described in the literature in 47 papers published between 2000 and 2018. These studies were developed mainly in the Atlantic Forest biome and collected ants with pitfall traps on the soil/litter stratum. We initially carried out a vote-counting procedure by comparing the number of significant results describing seasonal differences in the ant assemblage. We found that most papers described a similar pattern of ant abundance, richness, and species composition between seasons. However, when we performed a meta-analysis, we observed a clear pattern of higher ant abundance and richness in the wet/summer season compared with the dry/winter season. Our meta-analysis reveals that the ant diversity decreases in the dry season, strongly in the Cerrado biome. Additionally, we point out differences in the sampling effort across biomes, indicating the need for further investments in studies focused on temporal diversity patterns, including seasonal effects, on the insect assemblage in biomes less investigated so far. Abstract in Portuguese is available with online material

From species descriptions to diversity patterns:The validation of taxonomic data as a keystone for ant diversity studies reproducibility and accuracy

Research findings in natural sciences need to be comparable and reproducible to effectively improve our understanding of ecological and behavioural patterns. In this sense, knowledge frontiers in biodiversity studies are directly tied to taxonomic research, especially in species-rich tropical regions. Here we analysed the taxonomic information available in 470 studies on Brazilian ant diversity published in the last 50 years. We aimed to quantify the proportion of studies that provide enough data to validate taxonomic identification, explore the frequency of studies that properly acknowledge their taxonomic background, and investigate the primary resources for ant identification in Brazil. We found that most studies on Brazilian ant diversity (73.6%) explicitly stated the methods used to identify their specimens. However, the proportion of papers that provide complete data for the repository institutions and vouchered specimens is vanishingly small (5.8%). Additionally, only 40.0% of the studies consistently presented taxon authorities and years of description, rarely referencing taxonomic publications correctly. In turn, the number of specialists and institutions consulted for ant identification in Brazil has increased in the last years, along with the number of studies that explicitly provide their taxonomic procedures for ant identification. Our findings highlight a shift between generations regarding the recognition of taxonomy as fundamental science, deepening our understanding of biodiversity

Riqueza, abundância e diversidade de Euglossina (Hymenoptera, Apidae) em três áreas da Reserva Biológica Guaribas, Paraíba, Brasil Richness, abundance, and diversity of Euglossina (Hymenoptera, Apidae) at three areas of the Guaribas Biological Reserve, Paraíba, Brazil

O estudo realizou-se em três áreas da Reserva Biológica Guaribas, uma área com vegetação característica de Mata Atlântica, outra com vegetação característica de Tabuleiro Nordestino e a terceira, chamada de Transição, formada por um mosaico dos dois tipos vegetacionais. Foram coletados 2314 indivíduos pertencentes a 11 espécies de Euglossina. Utilizou-se como iscas seis fragrâncias artificiais: eugenol, eucaliptol, escatol, beta ionona, acetato de benzila e vanilina. Na área de Mata, foram coletados 850 indivíduos de 11 espécies, na área de Tabuleiro 737 indivíduos de cinco espécies e na área de Transição 727 indivíduos de seis espécies. A área de Mata apresentou a maior diversidade (H' = 0,94) e a maior riqueza. O coeficiente de similaridade binário de Sørensen indicou que as áreas mais semelhantes, com relação à composição das espécies, foram às de Tabuleiro e Transição (Ss = 0,92). O coeficiente de similaridade de Morisita apontou que as áreas de Mata e Transição são idênticas (Cmh = 1), com relação às abundâncias relativas das espécies. A área de Transição assemelha-se mais à área de Tabuleiro (quanto à composição e diversidade) e mais à área de Mata (quanto à abundância relativa), o que sugere que algumas espécies de Mata também forrageiam na área de Transição.<br>The study was carried out at three areas of the Guaribas Biological Reserve, one area with typical Atlantic rain forest vegetation, one with a Savanna-like vegetation typical of coastal ecosystems, locally known as 'Tabuleiro', and another called Transition area, containing a mosaic of the two former types of vegetation. A total of 2314 individuals belonging to 11 species of Euglossina were sampled, using traps. Six artificial fragrances were used as baits: eugenol, cineol, skatol, beta ionone, benzyl acetate, and vanillin. From the Forest area 850 males belonging to 11 species were sampled, from the Savanna-like vegetation 737 males belonging to five species were sampled, and from the Transition area 727 males belonging to six species were sampled. The highest diversity (H' = 0.94) and richness were obtained from the Forest area. The Sørensen binary similarity coefficient showed that regarding species composition Savanna-like vegetation and Transition were the most similar areas (Ss = 0.92). The Morisita similarity coefficient showed that Forest and Transition areas were identical (Cmh = 1) regarding relative abundance of species. Transition area is more similar to an open area of Savanna-like vegetation, in terms of composition and diversity, and more similar to the Forest area, regarding relative abundance, suggesting that some Forest species also forage in the Transition area

Abelhas Euglossini (Apidae) de áreas de Mata Atlântica: abundância, riqueza e aspectos biológicos Euglossine bees (Apidae) from Atlantic Forest sites: abundance, richness, and biological aspects

<abstract language="eng">Collection data of Euglossinae males from Parque Estadual do Rio Doce (PERD) and Viçosa, both areas with remnants of Atlantic Rain Forest (Mata Atlântica) in Minas Gerais state, Brazil are presented. Comparisons made among three fragments with different sizes and states of disturbance from Viçosa showed differences in abundance of most common species and apparently, Eulaema nigrita Lepeletir, 1841 can be an useful indicator of disturbed sites. Some populations of euglossine bees seems to be restrict to a forest fragment, there being few or no flow of individuals or species of one fragment to another, even when they are only 1 km apart. 15 species of euglossines were sampled in PERD, and the most abundant was Eulaema cingulata (Fabricius, 1804). At Viçosa, 10 species were sampled, E. nigrita was the predominant one. Methyl salicylate attracted no males at both sites, in spite of large numbers of species and individuals sampled using this bait in other regions. The majority of species and individuals were collected in the rainy season. Only 0,58% of sampled males carried orchid pollinia (Catasetum Richard, Cycnoches Lindley and Coryanthes Hook) on their bodies. Emergence data of four species of Euglossa Latreille, 1802 reared from trap nests suggest that sex ratio in Euglossini is not a constant within the tribe. A list of 57 euglossine species now known to occur in Mata Atlântica are offered