An increase in the prevalence of obesity due to lockdown and confinement linked to COVID-19 is observed. Variations in the nutritional status of schoolchildren from Jujuy are analyzed in relation to confinement due to COVID-19 (2019–2021) and its relationship with socio-demographic variables and the school environment. This is an observational, descriptive study. Data from 56,695 schoolchildren aged 6–18 years old is analyzed based on two temporary cuts (2019 pre-confinement and 2021 post-confinement). The nutritional status of schoolchildren (underweight, overweight, and obese) was established using the IOTF (International Obesity Task Force) criterion. The prevalence of each nutritional phenotype was estimated by sex and age group, considering the following independent variables: setting (rural/urban), school management system (public/private), geographic altitude, and percentage of households with unmet basic needs (UBN) in the place where they attend school. Multiple proportions contrast was performed using Fisher's test, a transition matrix ws produced and a statistical model of proportional odds was fitted. It was observed that between 2019 and 2021, the prevalence of underweight decreased and the prevalence of overweight and obesity increased significantly. In 2021, 67% of schoolchildren maintained the same nutritional category that they had in 2019, 21% gained weight and 12% lost weight. The model explains about 52% of the total variability observed. The factors that are significantly correlated in the model are school cycle, age, geographic altitude, school setting, and % of households with UBN. The results indicate that during the COVID-19 pandemic, there was a shift to the right in the distribution of the nutritional status categories of the schoolchildren population in Jujuy, with a decrease in the prevalence of underweight and an increase in the prevalence of overweight and obesity with variations related to age, school location, geographic altitude, and socioeconomic characteristics of the households in the place where the children attended school.

The magnitude of facilitation by shelter-building engineers on community structure is expected to be greater when they increase limited resources in the environment. We evaluated the influence of local environmental context on the colonisation of leaf shelters by arthropods in a Mexican evergreen tropical rainforest. We compared the species richness and abundance of arthropods (total and for different guilds) colonising artificially rolled leaves in habitats differing in understory heterogeneity (forest edge > old-growth forests > living fences). Arthropod abundance of the most representative arthropod taxa (i.e., Araneae, Blattodea, Collembola and Psocoptera) colonising the rolled leaves was greater at forest edge, a trend also observed for average arthropod abundance, and for detritivore and predator guilds. In addition, fewer arthropod species and individuals colonised the rolled leaves in the living fence habitat, a trend also observed for most arthropod guilds. As forest edge is expected to have a greater arthropod diversity and stronger density-dependent interactions, a greater limitation of refuges from competitors or predators may have determined the higher colonisation of the rolled leaves in this habitat. Our results demonstrate that local environment context is an important factor that affects the colonisation of arthropods in leaf shelters.

Climbing plants provide efficient pathways for ants to access patchy arboreal resources. However, plant stems vary greatly in physical characteristics that are likely to influence ant locomotion. We collected, measured and identified ants foraging on 671 stems of climbing plants at the La Selva Biological Station, Costa Rica. We applied tuna baits to 70% of the observed stems to attract ants to a broad range of stem sizes. We used these data to examine relationships between relative stem roughness, growth form (herbaceous or woody), stem diameter and the body length of foraging ants representing 58 species. The size of the largest ants found on stems generally increased with stem size up to 3.2 mm diameter, whereas the size of the smallest ants present on stems did not vary with stem diameter. The largest ants in the forest (Paraponera clavata) used small stems (<2.7 mm diameter) only when attracted by baits. Average (± SE) ant body length was larger on woody (5.2 ± 0.32 mm) vs. herbaceous (3.3 ± 0.53 mm) stems, but did not differ between rough and smooth stems within these categories. Ant body-size distribution tended toward unimodality on smooth stems. We conclude that small stem diameter acts as a habitat filter based on ant body size, but only for the largest ants in the forest. The filter effect is reduced when ants are attracted to an artificially high quality resource.

Phytomass was determined for a tropical deciduous forest in Chamela, Jalisco, México. The mean canopy height was 6.9 m, and the total basal area was 25.6 m2 ha−1 (dbh > 3.0 cm). The estimated phytomass for this forest (85 Mg ha−1) is among the highest values for tropical dry forests with similar seasonal climates. A stepwise multiple regression analysis showed that phytomass can be predicted firstly by basal area (R2 = 0.88), then by wood specific gravity (R2 = 0.91), and finally by the inclusion of tree height in the regression (R2 = 0.92). Each new independent variable explained significant variance in the phytomass estimation.