Erythroxylum simonis is an understory species found in Northeast Brazil. Due to its shaded habitat, E. simonis is subjected to seasonal oscillations of the environment, to which it must respond ecophysiologically. Th e objective of this study was to evaluate the eff ects of seasonality on the ecophysiology of E. simonis in a fragment of Seasonal Semideciduous Forest. Leaf area index, visible sky fraction and photosynthetically active radiation were measured for 10 individuals during the dry and rainy seasons. Soil moisture, temperature and monthly precipitation were measured, as well as photosynthetic rate, stomatal conductance, internal CO 2 concentration, transpiration, instantaneous water use effi ciency, instantaneous carboxylation effi ciency and chlorophyll content. Ecophysiological variables were correlated with environmental variables, with a greater association of rainfall and soil moisture with stomatal conductance, transpiration and photosynthetic rate, indicating that water availability has an eff ect on the ecophysiology of E. simonis. With the exception of instantaneous carboxylation effi ciency, gas exchange exhibited signifi cant diff erences among the months studied, with the highest values being for months with greater water availability, thus showing that the ecophysiology of the species responds to seasonal changes throughout the year.

This research aimed to determine an equation to estimate the leaf area of Erythroxylum simonis using the length and width of leaf blades. Two hundred leaf blades of this species were collected in Mata do Pau-Ferro, a State Park located in Areia, PB, Brazil. Regression analyses were used to determine the estimation equations. The linear, linear without intercept, quadratic, cubic, power and exponential statistical models were used. The criteria used for model selection were based on an examination of the coefficient of determination, the Akaike information criterion and standard error of the estimate. All the equations presented can be used to estimate the leaf area of E. simonis. From a practical point of view, the linear regression equation without intercept involving the product between length and width is recommended, using the equation Y=0.6426*LW, which corresponds to 64.26% of the product between length and width, with a coefficient of determination of 0.9936.

Studies of leaf surface are important for the ecophysiological context. We tested 12 allometric equations to estimate the leaf area of the endemic species Erythroxylum pauferrense Plowman, using different morphometric measurements (n = 600). The analysis of variance (p < 0.001), determination coefficient (R2 adj), standard error of estimates (S xy), and graphical interpretation of the dispersion of errors were used to select the models. The residual bias was estimated through the confidence interval using t-Student distribution (p = 0.01). Simple linear equations (Ŷ = 0.0244 + 0.7204 × CxL) and power functions (Ŷ = 0.7279 × CxL 0.9971) were validated from an independent sample of leaves, confirming their accuracy. The results are important to guide actions of conservation of the endemic species.

This work compares the diversity of beetles (Coleoptera) in areas of maize cultivation with fertilization (NPK) and without fertilization, and a field in secondary succession (capoeira) aiming to understand the relation of these organisms in the different systems. The study was carried out in a farm belonging to EMEPA-PB, in the city of Alagoinha, Para&iacute;ba state, Brazil, from July to August 2018. Insects were captured in Provid traps and collected every seven days during the vegetative period of the crop. The screenings were carried out at the Zoology Laboratory of the Universidade Federal da Paraiba and the specimens identified at the family level. Data were analyzed using the ANAFAU program. Ten families of beetles were found: Alleculidae, Cecindelidae, Coccinellidae, Carabidae, Scarabaeidae, Cleridae, Staphylinidae, Erotylidae, Chrysomelidae, and Tenebrionidae. Five families were common in all studied areas except for Staphylinidae that was absent in the fertilized area. Beetle families classified as predatory insects were more abundant in the non-fertilized maize system and secondary succession area, except the Coccinellidae family. The families considered as maize crop pests (Scarabaeidae, Chrysomelidae, and Tenebrionidae) had higher abundance in the fertilized maize system. The Erotylidae family also showed predominance in the non-fertilized area. We conclude that there is a greater diversity of beetle in the non-fertilized maize crop when compared to the other studied areas.