Book Review: 1992. Life in Amber

We reviewed the evidence on the role of ants as plant biotic defenses, by conducting meta-analyses for the effects of experimental removal of ants on plant herbivory and fitness with data pooled from 81 studies. Effects reviewed were plant herbivory, herbivore abundance, hemipteran abundance, predator abundance, plant biomass and reproduction in studies where ants were experimentally removed (n = 273 independent comparisons). Ant removal exhibited strong effects on herbivory rates, as plants without ants suffered almost twice as much damage and exhibited 50% more herbivores than plants with ants. Ants also influenced several parameters of plant fitness, as plants without ants suffered a reduction in biomass (-23.7%), leaf production (-51.8%), and reproduction (-24.3%). Effects were much stronger in tropical regions compared to temperate ones. Tropical plants suffered almost threefold higher herbivore damage than plants from temperate regions and exhibited three times more herbivores. Ant removal in tropical plants resulted in a decrease in plant fitness of about 59%, whereas in temperate plants this reduction was not statistically significant. Ant removal effects were also more important in obligate ant-plants (=myrmecophytes) compared to plants exhibiting facultative relationships with hemiptera or those plants with extrafloral nectaries and food bodies. When only tropical plants were considered and the strength of the association between ants and plants taken into account, plants with obligate association with ants exhibited almost four times higher herbivory compared to plants with facultative associations with ants, but similar reductions in plant reproduction. The removal of a single ant species increased plant herbivory by almost three times compared to the removal of several ant species. Altogether, these results suggest that ants do act as plant biotic defenses, but the effects of their presence are more pronounced in tropical systems, especially in myrmecophytic plants.

Ants on plants: a meta-analysis of the role of ants as plant biotic defenses

In the Pacific region, the African big-headed ant, Pheidole megacephala, is now widespread in tropical areas; populations are also found at higher latitudes in Australia, New Zealand, and Japan. On most inhabited tropical islands in the Pacific, P. megacephala is well known as a household and agricultural pest. Because P. megacephala does not attack humans, this species is often not recognized as an important threat. The negative ecological impact of P. megacephala, however, may be greater than that of any other invasive ant species. In areas where it occurs at high density, few native invertebrates persist. Loss of invertebrate species that serve key functions in the natural community (e.g., important prey species) may have cascading effects leading to the subsequent loss of additional species. Pheidole megacephala tends to thrive in open, disturbed habitats with weedy vegetation that can support high densities of plant-feeding Hemiptera, which these ants tend for honeydew. Before 1900, P. megacephala was known in the Pacific region only from Aru Island (Indonesia) and Hawai'i. By the 1930s, it was found through much of Pacific Asia, Melanesia, and Polynesia, but it was not collected in Micronesia until 1950. Currently P. megacephala is known from virtually every tropical island group in the Pacific but not from many islands within the groups, particularly uninhabited islands. Quarantine efforts might be successful in keeping P. megacephala off these islands. Because P. megacephala does not commonly dominate areas with intact natural vegetation, setting aside relatively undisturbed habitat on inhabited islands may also be effective in protecting native invertebrates from attack by this ant.

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Biology and impacts of Pacific island invasive species. 3. The African big-headed ant, Pheidole megacephala (Hymenoptera: Formicidae).

https://www.locus.ufv.br/bitstream/123456789/21369/1/artigo.pdf

Biodiversity consequences of land-use change and forest disturbance in the Amazon:a multi-scale assessment using ant communities

Leaf-cutting ants, being the principal herbivores and ecosystem engineers in the Neotropics, have been considered to be a keystone species in natural ecosystems and agroecosystems, due to the direct and indirect effects of their plant defoliation activities. This review summarizes current concepts of the biological and ecological importance of leaf-cutting ants. The ants' pest status is briefly assessed from both ecological and evolutionary points of view. A general overview of control measures is provided. Leaf-cutting ants have evolved physical, symbiotic and behavioural mechanisms that allow them to overcome the chemical, biological, mechanical and cultural methods that have been used to manage their populations. Given the highly complex ecology of these ants, simple methods of control should not be expected. Sound management strategies must alternate between, and combine, different methods.

Leaf-cutting ants revisited: Towards rational management and control

Aunque el libro procura tomar varios temas criticos (ecologia, relaciones con plantas, mosaicos), debido a limites de espacio necesariamente excluye otros temas. En parte estos temas se pueden encontrar en libros como The Ants de Holldobler y Wilson (1990) y Ants: Standard methods editado por Agosti et al. (2000). Aun asi, se espera que el libro tenga utilidad por largo tiempo, hasta que los siempre cambiantes temas en biologia de hormigas permitan y favorezcan una segunda edicion, o hasta que otros mirmecologos colegas puedan editar y lanzar un nuevo texto que recoja los muchos cambios que ocurriran en los proximos anos. Sigue a continuacion una breve sinopsis de las partes y capitulos que comprenden el libro.

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Introducción a las hormigas de la región Neotropical

Esta guia materializa mas de dos anos de trabajo, pretende ser una herramienta sencilla y muy grafica a aquellos que estan implementando, redactando y evaluando proyectos de restauracion ecologica y que quieran estructurar un buen plan de monitoreo a diversos componentes del ecosistema a intervenir (e.g. flora, fauna, suelos). Por esto, en sus dos capitulos y trece secciones, el libro ha querido abarcar desde los aspectos
conceptuales del monitoreo hasta las tecnicas para diversos grupos, seleccionando indicadores simples pero a la vez robustos. Esperamos que esta guia se convierta en una herramienta de referencia para la comunidad cientifica y sobre todo para los practicantes de la restauracion ecologica.

Monitoreo a procesos de restauración ecológica aplicado a ecosistemas terrestres

Ant diversity was studied in three representative elements of a coffee landscape of the western Andes from Risaralda, Colombia. In a landscape sample of 500 ha, in rural zone of La Celia municipality, were sampled a forest, forest patches and sun coffee crops by means of lineal transects with 10 stations arranged each 10 m. For each station, in an area of 1 m2, leaflitter samples were processed in mini-Winkler sacks during 48 hours. 96 ant species from 34 genera and nine subfamilies were collected. Sampling efficiency was 81% on average, according to Chao 2 and Jacknife 1 and 2 estimators. Species as Cyphomyrmex cf. dixus, Pheidole biconstricta, Solenopsis sp.1 and Hypoponera sp.1 were abundant in these landscape units. Among these, P. biconstricta was catalogued like a dominant species at landscape and local scale. A low incidence of ants catalogued as potential pests in the landscape units was observed. Specimens of Atta cephalotes, Acromyyrmex aspersus and Acropyga exsanguis were recorded in less 5% of the samples. In general, it was observed a low incidence of ants catalogued as potential pest in the landscape elements. The exclusive presence of some species of genera as Acanthognathus, Amblyopone, Discothyrea and Gnamptogenys in theforest units?, added to low incidence of invasive or potential pest species, are proposed like characteristics that in set turned out indicators of the health (balance) and the heterogeneity of ant communities in the coffee landscape studied.

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Diversidad de hormigas (Hymenoptera: Formicidae)en un paisaje cafetero de Risaralda, Colombia

The stonefly genus Claudioperla is reported for the first time from Colombia based on adult male, female and larval specimens collected in the southwest Andean region of Cumbal, Narino Department at 3050 m.a.s.l. The collection site on River Blanco is a low order stream dominated by riffle zones with high slope and the riparian vegetation consists primarily of shrubs and grasses. This record from Colombia is the northernmost to be documented for the genus in South America.

Gustavo Zabala

Papers

Introducción a las hormigas de la región Neotropical

Monitoreo a procesos de restauración ecológica aplicado a ecosistemas terrestres

Diversidad de hormigas (Hymenoptera: Formicidae)en un paisaje cafetero de Risaralda, Colombia

The first record of Claudioperla Illies (Plecoptera: Gripopterygidae) from Colombia