The social soil-dwelling bacterium Myxococcus xanthus can form multicellular structures, known as fruiting bodies. Experiments in homogeneous environments have shown that this process is affected by the physicochemical properties of the substrate, but they have largely neglected the role of complex topographies. We experimentally demonstrate that the topography alters single-cell motility and multicellular organization in M. xanthus. In topographies realized by randomly placing silica particles over agar plates, we observe that the cells’ interaction with particles drastically modifies the dynamics of cellular aggregation, leading to changes in the number, size, and shape of the fruiting bodies and even to arresting their formation in certain conditions. We further explore this type of cell-particle interaction in a computational model. These results provide fundamental insights into how the environment topography influences the emergence of complex multicellular structures from single cells, which is a fundamental problem of biological, ecological, and medical relevance.

Chaetochlorops Malloch is a small genus endemic to the New World with a peculiar morphology of the male terminalia. The genus is recorded from Brazil–Amazon and Atlantic forests– and Nicaragua for the first time. Detailed images of the external and internal morphology of all species are provided here. Also, an additional host plant for C. inquilinus is given.

Two new species belonging to the braconid genus Bracon (Braconinae) are described from the tropical rainforest of Los Tuxtlas in the state of Veracruz, Mexico, B. laurae sp. nov. and B. rosamondae sp. nov. These species are morphologically similar and were reared from fruits of three Lauraceae species, Damburneya ambigens, D. salicifolia and Nectandra turbacensis. However, comparison of their DNA barcoding locus and a fragment of the nuclear ribosomal 28S gene confirmed their allospecificity. These two species share a number of morphological features with the two described Neotropical Bracon species that are known to be phytophagous (seed predators), B. phytophagus Quicke and B. zuleideae Perioto & Lara. We therefore propose a new species-group for the above four species, the B. phytophagus Quicke species-group, and suggest that the two newly described species also have a phytophagous feeding strategy.

Besides recruitment and dispersal, fruits are key resources for the maintenance of insect communities. This study is focused on the insects inhabiting the fruits of 4 wild Lauraceae species. Although the trees of this family are important elements of tropical forests, their interaction with insects, especially in association with fruits, remains poorly studied in wild tree species. Our study aims to characterize the diversity of insects associated with fruits of Damburneya ambigens, Damburneya gentlei, Damburneya salicifolia, and Nectandra turbacensis, in the rainforest of Los Tuxtlas, Veracruz. We present an illustrated taxonomic list of species, annotated with a comprehensive review of the insects’ natural history and their interactions with Lauraceae species. We reared 54 insect species from approximately 6,500 fruits, some of which represent potential new species and records for Mexico. Insect species diversity was high and differed between Lauraceae species. The reared insects comprise a wide variety of distributional ranges, feeding types, and habitats. This research provides novel information about the interactions among insects and fruits of Lauraceae and the complexity of their trophic networks in tropical rainforests. Furthermore, it evidences the importance of wild fruits as resources for insect communities.