Search

The twig-girdler beetle Oncideres albomarginata chamela (Chemsak and Giesbert) (Cerambycidae: Lamiinae) detaches branches of Spondias purpurea L. (Sapindales: Anacardiaceae) that fall on the forest floor or remain suspended on vegetation. Many wood-boring beetles also oviposit in these branches and larval development creates cavities that are abandoned when the adults emerge. The objective of this study was to evaluate the role of wood-boring beetles as facilitators by creating new habitats for arthropods, and test for vertical stratification and temporal variation of arthropods associated with S. purpurea branches that were previously engineered by O. albomarginata chamela in a tropical dry forest (TDF) in Jalisco, Mexico. In order to determine the effects of vertical strata and seasons on branch colonization by arthropods, we placed 60 branches on the forest floor (ground stratum) and 60 were placed in trees (vegetation stratum) from February to April (dry season), and from August to October 2016 (rainy season), for 240 branch samples in total. We collected 8,008 arthropods, which included 7,753 ants (14 species) and 255 nonsocial arthropods (80 species) from 13 different orders. We observed a greater arthropod abundance in the branches in the vegetation stratum in the dry season compared with the rainy season, whereas the richness and abundance of arthropods in the ground stratum were greater in the rainy season compared with the dry season. We concluded that wood-boring beetles are important habitat facilitators for arthropods, and that the vertical position of branches and the seasonal variations in TDFs differently affect the colonization of the abandoned cavities by arthropods.

Dung beetle community dynamics are determined by regional rainfall patterns. However, little is known about the temporal dynamics of these communities in tropical dry forests (TDFs). This study was designed to test the following predictions: 1) Peak diversity of dung beetle species occurs early in the wet season, with a decrease in diversity (α and β) and abundance throughout the season; 2) Nestedness is the primary process determining β-diversity, with species sampled in the middle and the end of the wet season representing subsets of the early wet season community. Dung beetles were collected in a TDF in the northern Minas Gerais state, Brazil over three sampling events (December 2009, February and April 2010). We sampled 2,018 dung beetles belonging to 39 species and distributed among 15 genera. Scarabaeinae α-diversity and abundance were highest in December and equivalent between February and April, while β-diversity among plots increased along the wet season. The importance of nestedness and species turnover varies between pairs of sample periods as the main process of temporal β-diversity. Most species collected in the middle and end of the wet season were found in greater abundance in early wet season. Thus, the dung beetle community becomes more homogeneous at the beginning of the wet season, and as the season advances, higher resource scarcity limits population size, which likely results in a smaller foraging range, increasing β-diversity. Our results demonstrate high synchronism between the dung beetle life cycle and seasonality of environmental conditions throughout the wet season in a TDF, where the onset of rains determines adult emergence for most species., (© The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America.)

Bark and the ambrosia beetles dig into host plants and live most of their lives in concealed tunnels. We assessed beetle community dynamics in tropical dry forest sites in early, intermediate, and late successional stages, evaluating the influence of resource availability and seasonal variations in guild structure. We collected a total of 763 beetles from 23 species, including 14 bark beetle species, and 9 ambrosia beetle species. Local richness of bark and ambrosia beetles was estimated at 31 species. Bark and ambrosia composition was similar over the successional stages gradient, and beta diversity among sites was primarily determined by species turnover, mainly in the bark beetle community. Bark beetle richness and abundance were higher at intermediate stages; availability of wood was the main spatial mechanism. Climate factors were effectively non-seasonal. Ambrosia beetles were not influenced by successional stages, however the increase in wood resulted in increased abundance. We found higher richness at the end of the dry and wet seasons, and abundance increased with air moisture and decreased with higher temperatures and greater rainfall. In summary, bark beetle species accumulation was higher at sites with better wood production, while the needs of fungi (host and air moisture), resulted in a favorable conditions for species accumulation of ambrosia. The overall biological pattern among guilds differed from tropical rain forests, showing patterns similar to dry forest areas., (© The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.)