Spatial Distribution of Arthropods on Acacia mangium (Fabales: Fabaceae) Trees as Windbreaks in the Cerrado

Acacia mangium (Fabales: Fabaceae) is broadly used in restoration process of degraded lands in tropical and subtropical regions. Thus, our aim was to assess the spatial distribution of arthropods on tree crown (vertical- upper, median and lower canopy and horizontalnorth, south, east and west) and leaf surfaces (adaxial and abaxial) of A. mangium trees. Phytophagous arthropods and natural enemies were quantified biweekly in 20 trees during three years. The Shannon index (H') of phytophagous insects were higher on the abaxial surface of leaves on branches facing the west side and basal thirds, while the lowest index was found on the adaxial surface of leaves on branches facing north and on trunk of A. mangium. The natural enemies and pollinators presented the highest H' indexes on the abaxial surface of leaves on branches facing north on basal thirds of A. mangium, while the lowest index values were found on the adaxial surface of leaves on branches facing the other sides. Trigona spinipes Fabricius (Hymenoptera: Apidae, Meliponinae), Aethalion reticulatum (Hemiptera: Aetalionidae) and Pentatomidae sp.1 (Hemiptera) were the most abundant and with the lowest k-dominance on different parts of A. mangium trees. Camponotus sp.2 (Hymenoptera: Formicidae), Tetragonisca angustula (Latreille) (Hymenoptera: Apidae) and Polistes sp. (Hymenoptera: Vespidae) had higher abundance and lower k-dominance. These results may be a support for programs of pest control and maintenance of natural enemies and pollinators in future plantations of A. mangium. For instance, application of biopesticides may reach better results if aimed directly to the preferred sites of target organisms, beyond minimizing possible negative effects on non-target ones.