---

The essential oils of plants are composed of several volatile compounds, which may have different concentrations and may be determinant for their toxicity. Thus, in this work, sublethal and lethal effects of the compounds, geraniol and citronellal on the biochemical and reproductive parameters of Spodoptera frugiperda were investigated. For the geraniol compound the LD₃₀ of 9.42 mg/g and LD₅₀ of 13.65 mg/g was used, while for the citronellal LD₃₀ of 0.06 mg/g and LD₅₀ of 0.08 mg/g. Pure acetone was used in the control. Third instar caterpillars were treated topically in the prothoracic region by applying 1 μl of the respective compounds with a Hamilton^TM 50 μl syringe. After 48 h the caterpillars were macerated in sodium phosphate buffer at a ratio of 4 caterpillars / 5 ml of the buffer, the levels of total protein, total sugar, lipid and glycogen were measured. The daily posture was evaluated in order to determine the periods of pre-oviposition, oviposition, post-oviposition and egg quantity. The results showed a reduction in the concentration of proteins and sugars for both compounds and concentrations studied. There was no change in lipid concentration. Citronellal increased the concentration of glycogen for both concentrations. The oviposition period and the number of eggs were reduced. However, there was no difference for the pre-oviposition and post-oviposition periods. Thus, it is inferred that geraniol and citronellal compounds cause alterations in the biochemical parameters that reflect in the reproduction of S. frugiperda.

---

The effect of the inclusion of spineless cactus [0, 14.7, 29.4, 44.1, and 58.8% of Dry Matter (DM)] basis in replacement of Tifton hay on the intake and digestibility of nutrients, feeding behavior, and nitrogen compounds balance were evaluated. Five crossbred steers, rumen fistulated, with average body weight of 380±5.3 kg were assigned to a 5×5 Latin square design. The time spent with rumination activity linearly decreased (P< 0.05) with the inclusion of spineless cactus; and the feeding time showed a quadratic effect (P< 0.05), with a minimum time of 195 min d^-1 estimated with 35.7% of spineless cactus inclusion. The nutrient intake showed a quadratic effect (P< 0.05), with a maximum intake of DM (8.9 kg d^-1), Crude Protein (CP; 1.4 kg d^-1), and Digestible Organic Matter (DOM; 5.8 kg d^-1) estimated with 33.9, 29.9, and 41.8% of spineless cactus inclusion, respectively. Except (P> 0.05) to Neutral Detergent Fiber corrected to ash and protein (apNDF), the total digestibility of DM linearly increased (P< 0.05) with spineless cactus inclusion replacing Tifton hay. Except for plasma and urinary urea nitrogen, which were not affected (P> 0.05), there was a quadratic effect (P< 0.05) on nitrogen balance, with a maximum value of 170 g d^-1 estimated with 33.2% of spineless cactus inclusion. It is recommended to include 41.8% spineless cactus in replacement of Tifton hay for crossbred cattle, due to the higher DOM intake without altering the nitrogen efficiency use.