Chewing insects, pollinators, and predators on Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) plants fertilized with dehydrated sewage sludge

Fertilization with dehydrated sewage sludge can speed up the recovery process of degraded areas due to nutrients concentration, favoring the development of pioneer plants such as Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) and the emergence of insects. This study aimed the evaluation of chewing, pollinating insects, predators, their ecological indices and relationships on A. auriculiformis plants fertilized with dehydrated sewage sludge. The experimental design was completely randomized with two treatments (with and without dehydrated sewage sludge) and 24 repetitions. The prevalence of chewing insects Parasyphraea sp. (Coleoptera: Chrysomelidae), Nasutitermes sp. (Blattodea: Termitidae), and Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae), defoliation, and ecological indices of abundance of Coleoptera and Orthoptera were observed on fertilized A. auriculiformis. Acacia auriculiformis plants, with a superior number of branches/tree, revealed greater abundance of Coleoptera and Orthoptera, species richness of pollinating insects, defoliation, numbers of Parasyphraea sp. and T. collaris. The ones with larger leaves/branches displayed greater abundance of species richness of Coleoptera and Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae). Therefore, the use of A. auriculiformis plants, fertilized with dehydrated sewage sludge, is promising in the recovery of degraded areas due to the ecological indices increase of chewing and pollinators insects and spiders in the analyzed area.

Arthropod fauna on the abaxial and adaxial surfaces of Acacia mangium (Fabaceae) leaves

Acacia mangium (Willd., 1806) (Fabales: Fabaceae) is a fast growing, rustic, pioneer species, with potential to fix nitrogen, and for programs to recover degraded areas. The objective was to evaluate the distribution and the functional diversity of interactions and the K-dominance of arthropod groups on A. mangium saplings. The number of individuals of eleven species of phytophagous insects, three bee species, and fourteen natural enemy species were highest on the adaxial leaf surface of this plant. Abundance, diversity and species richness of phytophagous insects and natural enemies, and abundance and species richness of pollinators were highest on the adaxial A. mangium leaf surface. The distribution of five species of sap-sucking hemipterans and six of protocooperating ants (Hymenoptera), with positive interaction between these groups, and three bee species (Hymenoptera) were aggregated on leaves of A. mangium saplings. Aethalion reticulatum (L.) (Hemiptera: Aethalionidae) and Bemisia sp. (Hemiptera: Aleyrodidae); Brachymyrmex sp. and Camponotus sp. (Hymenoptera: Formicidae); and Trigona spinipes Fabricius (Hymenoptera: Apidae) were the most dominant phytophagous insects, natural enemies, and pollinators, respectively, on A. mangium leaves. Knowledge of preferred leaf surfaces could help integrated pest management programs.

Insects and spiders on Acacia mangium (Fabaceae) saplings as bioindicators for the recovery of tropical degraded areas

Acacia mangium is a pioneer species with fast growth and frequently used in the recovery of degraded areas. The objectives were to evaluate insects and spiders, their ecological indices and interactions on A. mangium saplings in a tropical degraded area in recovering process. The experimental design was completely randomized with 24 replications, with treatments represented by the first and second years after A. mangium seedling planted. Numbers of leaves/branch, branches/sapling, and ground cover by A. mangium saplings, Hemiptera: Phenacoccus sp. and Pachycoris torridus; Hymenoptera: Tetragonisca angustula and Trigona spinipes, Brachymyrmex sp., Camponotus sp. and Cephalotes sp.; Blattodea: Nasutitermes sp. and Neuroptera: Chrysoperla sp.; abundance, species richness of pollinating insects, tending ants, and the abundance of Sternorrhyncha predators were greatest in the second year after planting. Numbers of Hemiptera: Aethalium reticulatum, Hymenoptera: Camponotus sp., Cephalotes sp., Polybia sp., T. angustula, T. spinipes, tending ants, pollinating insects, Sternorrhyncha predators and species richness of tending ants were highest on A. mangium saplings with greatest numbers of leaves or branches. The increase in the population of arthropods with ground cover by A. mangium saplings age increase indicates the positive impact by this plant on the recovery process of degraded areas.