Ocorrência de besouros da ambrosia (Coleoptera: Curculionidae) em plantios de teca, mogno africano e fragmento florestal em Santarém, Pará, Brasil

Abstract

The use of exotic species in commercial forest plantations, such as teak (Tectona grandis L.f.) and african mahogany (Khaya spp.), has grown considerably, gaining relevance in the amazon region, but, due to the expansion of these in the form of monocultures, their individuals are subject to injuries caused by insects, such as beetles of the Scolytinae subfamily (Coleoptera: Curculionidae), known as Ambrosia beetles, capable of causing great damage to forest species. There is still little information about Scolytinae species and their hosts in the Amazon, which makes it difficult to estimate the real damage they cause and the appropriate control measures for these insects, in this way, the surveys with Scolytinae in the amazon region are necessary to contribute to the enrichment of information on the subject. Thus, this work aimed to carry out a faunistic and population fluctuation analysis of beetles of the Scolytinae subfamily (Coleoptera: Curculionidae) associated with plantations of teak, african mahogany and in a forest fragment, at the Experimental Farm of the Federal University of Western Pará (UFOPA), in the county of Santarém, Pará, Brazil. The insects collection was carried out from January to November of 2022, with fortnightly collections, through the installation of four modified ESALQ-84 ethanolic traps in each environment, at 1.5 meters above the ground, arranged in a zig-zag transect in the plots and linear in the forest fragment, with a distance of 10.0 meters between them. After collection, the captured specimens were packaged and sent to the UFOPA Entomology Laboratory, where they underwent sorting, assembly, drying in an oven, and subsequently counted and separated according to their morphological characteristics for taxonomic identification at the genus and morphospecies level. Faunistic indices of the morphospecies and their population fluctuations over the months of collection were determined in each area. During the 11 months of collection, 2,912 Scolytinae were collected and identified in 4 tribes, 12 genera and 16 morphospecies. The Xyleborini tribe had the highest number of Scolytinae in their genera and morphospecies. Ambrosiodmus, Ambrosiophilus, Xyleborus and Xylosandrus were the main genera found in the three study environments. The greatest richness of Scolytinae morphospecies occurred in the forest fragment. There was resemblance in morphospecies diversity between teak and african mahogany plots. The population fluctuation of the morphospecies in the two plots coincided with the rainy season in the region, while in the forest fragment the fluctuation coincided with the characteristics of the microclimate that is formed within it.