Despite the growing interest in cactus-derived edible coatings and lactic acid bacteria (LAB)-based biocontrol systems, information on the use of cactus mucilage as a functional matrix for LAB cultures for the control of postharvest fungal diseases remains limited. Thus, this study evaluated the efficacy of coatings formulated with the mucilage of Pilosocereus pachycladus (facheiro) and Nopalea cochenillifera (palm) and incorporated with a mixed LAB culture for the control of anthracnose caused by Colletotrichum siamense in ‘Margarida’ avocado. The mucilages exhibited suitable physicochemical and technological properties for application in coating formulations. In vitro assays showed that cactus mucilage (2–4% w/v) exhibited dose-dependent inhibition of C. siamense, with the highest values observed at 3–4% (w/v), depending on the mucilage matrix, reaching up to 82.0% inhibition. LAB strains also showed strong antifungal activity, with mycelial growth inhibition ranging from 34% to 100%. The three most effective and compatible LAB strains (Lactiplantibacillus plantarum 49, Lactiplantibacillus pentosus 129, and Limosilactobacillus fermentum 263) were combined in equal proportions (1:1:1, v/v) to prepare a mixed culture standardized to 9–10 log CFU mL⁻¹ . The interaction between mucilage and the mixed LAB culture was additive (Abbott index, AI = 0.6–1.1), indicating enhanced antifungal effects. The mixed LAB culture maintained high viable cell counts (>7 log CFU mL-¹) for 15 d at 25 °C in the coating matrix. In situ assays demonstrated that the coatings significantly reduced anthracnose lesion development (32–100%) on avocados artificially inoculated with C. siamense, with the highest efficacy and greatest stability observed for the palm mucilage + LAB formulation. The coatings also reduced weight loss during storage without negatively affecting other fruit quality attributes. Cactus mucilage coatings, particularly when combined with mixed LAB cultures, show potential for the biological control of postharvest anthracnose in avocado.
In post-mining landscapes of Amazonia, evaluating faunal responses during early successional stages is essential for understanding habitat restoration trajectories and for identifying sensitive bioindicators capable of tracking ecosystem recovery. Herbivorous beetles constitute a highly host-dependent group whose diversity, specialization, and spatial turnover can reveal how resource heterogeneity and vegetation structure shape community reassembly in regenerating ecosystems. The objective of this study was to assess whether a five-year period of natural regeneration provides sufficient structural and resource heterogeneity to support a weevil community (Coleoptera: Curculionidae) converging toward that of adjacent forest remnants. We sampled leaf-dwelling Curculionidae across seven natural regeneration sites and seven altered primary forest remnants using standardized arboreal arthropod beating methods. We recorded 482 individuals across 114 morphotypes, with forest remnants harboring greater richness, higher effective diversity, and distinct dominance–evenness patterns compared to natural regeneration sites. Tree richness was the main predictor of weevil abundance, species richness, and diversity of common taxa. Both habitats exhibited high species turnover among sampling units, yet multivariate analyses revealed clear compositional differences between forest and regenerating areas. Our findings indicate that five years of natural regeneration is insufficient for re-establishing a Curculionidae community structurally or compositionally comparable to forest remnants. These results demonstrate that the recovery of weevil assemblages remains strongly limited by reduced host-plant heterogeneity and suggest that enrichment planting of key tree species may accelerate restoration trajectories.
Individual dietary specialization is a fundamental phenomenon for understanding ecological niche dynamics, but its expression may vary depending on temporal scale and environmental context. We investigated the diet of the Amazonian cichlid Mesonauta festivus (Heckel 1840) across four floodplain populations, combining stomach content analysis, which reflects short-term assimilation, with stable isotope analysis, which integrates long-term feeding patterns. While stomach contents indicated high individual specialization and marked spatial heterogeneity, isotopic data revealed trophic convergence over time and strong similarity among populations. Dietary differences between sexes were observed only in some localities and were not associated with morphological variation. Overall, the findings suggest that individual specialization in M. festivus is transient and influenced by extrinsic factors in the short term. This study emphasizes the importance of integrating complementary methodological approaches to better understand the trophic dynamics of fish in Amazonian floodplain ecosystems.
We analyzed the temporal and spatial variability of precipitation concentration in the São Francisco River basin (SFRB), Brazil, on annual, and seasonal scales using the precipitation concentration index (PCI). The PCI was calculated from a high-resolution daily precipitation gridded dataset for the period 1961–2022. Annual and seasonal PCI values were used to investigate significant trends by applying the Modified Mann–Kendall (MMK) test and to assess the impact of climate change by comparing two 31-year climate periods (1961–1991 and 1992–2022). The results showed that precipitation concentration varies spatially across the SFRB, reflecting regional climate delineation and the distribution of wet and dry months. On an annual scale, the upper, middle and sub middle SFRB regions displayed irregular and highly irregular rainfall distribution while the lower SFRB region showed moderate precipitation concentration. In summer and autumn most of SFRB areas display moderate rainfall distribution, while in spring both moderate and irregular rainfall distribution were found in the middle and sub middle SFRB regions. In winter, irregular rainfall distribution was present in the upper SFRB, highly irregular rainfall distribution in the middle SFRB, moderate rainfall distribution in the sub middle SFRB and uniform distribution in the lower SFRB. Across almost the entire SFRB moderate rainfall distribution was found in wet season and highly irregular distribution in dry season. The most significant change from the first to the second period was found in the seasonal rainfall regime: in winter, the area with low precipitation concentration, indicating uniform rainfall distribution, increased to 100
Chemical defenses produced by lichens represent a yet underexplored force shaping trophic interactions beyond direct consumer deterrence. In termites, dietary intake of such compounds may extend their effects to gut-associated microbial consortia, with consequences for host physiology and colony performance. However, the extent to which lichen-derived metabolites influence microorganisms in insect hosts remains poorly understood. Here, we investigated the bacteriostatic effects of the lichen-derived phenolic compound atranorin on cultivable gut-associated bacteria of the Neotropical termite Constrictotermes cyphergaster (Termitidae: Nasutitermitinae), a generalist species known to include lichens in its diet. Atranorin is a widespread lichen secondary metabolite with documented antimicrobial activity, making it suitable for evaluating diet–microbiota interactions. Atranorin was extracted and chemically characterized from Parmotrema praesorediosum (Lecanorales: Parmeliaceae), yielding a highly pure compound subsequently used in bioassays. Cultivable bacteria were isolated from the crop and P3 hindgut of workers and soldiers, enabling controlled assays and revealing differences across gut compartments and castes. Antibacterial assays demonstrated that atranorin exerted a dose-dependent bacteriostatic effect across most isolates, significantly reducing bacterial growth even at low concentrations. However, microbial responses were taxon-specific, as Sphingomonas paucimobilis exhibited marked tolerance and proliferation under atranorin exposure. These findings suggest that atranorin can act as a selective chemical agent affecting the growth of cultivable gut-associated bacteria, rather than as a broad-spectrum antimicrobial. By linking a lichen-derived metabolite to differential bacterial responses, this study provides evidence that dietary secondary compounds may act as selective factors shaping host-associated bacteria.
