The black soldier fly, Hermetia illucens (BSF, Diptera: Stratiomyidae) is an insect with high protein value and a potential feed agent for animals aimed for human consumption. The growth parameters of BSF larvae reared on four substrates—restaurant-waste, fruit-waste, fish-waste, and commercial tilapia food—for 41 days before processing for inclusion into Oreochromis niloticus (Perciformes: Cichlidae, Nile tilapia) commercial fry diets at 30% (70:30) were determined. On fly larvae, the food substrate based on restaurant waste yielded the greatest larval weight and length. BSF larvae fed a fish-waste diet showed the shortest developmental time. The fruit-waste diet induced the lowest weight and length in the fly larvae/pre-pupae (immature stage). The pre-pupal protein values were similar to commercial food. On fry-fish, the diets with pre-pupae grown on fish waste showed the greatest yields regarding weight (biomass), length, and nutritional content. These results suggest the BSF has the potential to be used in fish feed and provides an alternative for commercial cultivation.

We examined the infective capacity of the mermithid nematodes, Romanomermis iyengari, Romanomermis culicivorax, Romanomermis wuchangensis, and Strelkovimermis spiculatus in fourth-instar mosquito larvae nearing pupation of Aedes aegypti, Aedes sierrensis, and Culex pipiens to determine their prevalence in the adults of these mosquitoes. We exposed 100 fourth-instar larvae to pre-parasitic nematodes (juvenile 2 stages) at a ratio of 10:1 (10 nematodes per mosquito larvae). Two days after the nematode applications, a sample of 20 pupae was taken and placed into transparent plastic cups with distilled water to observe the development and growth of pupae until they reached the adult phase with nematodes inside. The four species of nematodes showed the highest prevalence of infection on the Cx. pipiens mosquito, exceeding 55% parasitism, while R. wuchangensis and R. iyengari surpassed this value on Ae. sierrensis by 61.11% and 57.89%. Aedes aegypti was the least susceptible to nematodes, with parasitism values between 30% and 40%. In laboratory settings, we obtained high rates (26.32–77.78%) of parasitized adults when the three-mosquito species in fourth-instar larvae nearing pupation were exposed to infective nematodes. R. wuchangensis (1.86) and S. spiculatus (1.80) were infected Cx. pipiens with greater intensity and R. iyengari (1.33) and R. culicivorax (1.09) with less intensity. This evaluation offers valuable insights into the variability of nematode prevalence of infection and infectivity in fourth-instar larvae, which host mermithids capable of progressing through the pupal stage to adulthood.

The research aims to investigate the mortality effect of essential oil from Piper cordoncillo var. apazoteanum, an endemic plant from Campeche, Mexico, on early second-instar Aedes aegypti larvae; it also aims to identify the volatile compounds present in the fresh leaves of the plant. To test the effectiveness of the essential oil, we followed World Health Organization Standard Procedures. Larvae were observed for 17 consecutive days after treatment to determine the mortality and growth-inhibitory effect exerted by the essential oil. The results showed that the essential oil was effective in controlling mosquito populations. At a concentration of 800 ppm, the oil achieved an effectiveness rate of 70.00 ± 8.16% after 24 h, increasing to 100.00 ± 0.01% mortality after 72 h. With a concentration of 400 ppm, the effectiveness was 98.33 ± 0.17% by the end of the experiment. Furthermore, the obtained results demonstrated that the LC₅₀ value was 61.84 ± 6.79 ppm, while the LC₉₀ value was 167.20 ± 11.49 ppm. Essential oil concentrations inhibited the growth of immature insect stages, with concentrations between 800–100 ppm demonstrating very high inhibitory activity, and the lowest concentration of 50 ppm showing high inhibitory activity. The study also identified 24 chemical compounds representing 86.71% of the volatile compound composition of the fresh leaves of P. cordoncillo; the most abundant compounds were Safrole, Caryophyllene oxide, E-Nerolidol, and Calarene epoxide. The method used to extract the volatile compounds, solvent-free microwave extraction (SFME), is a promising alternative to traditional methods that avoids the use of potentially harmful solvents, making it more ecologically friendly and potentially safer for professionals handling the extracted compounds. Overall, the study demonstrates the potential of P. cordoncillo essential oil as an effective means of controlling mosquito populations, and provides valuable information on the chemical composition of the plant.Moreover, our study is the first to report on the biological activity and chemical composition of P. cordoncillo worldwide.

The presence of pathogens in fecundation hives represents a source of infection for queen bees. The objective of this investigation was to determine the prevalence of Varroa, Nosema, and Acarapis in hives for the production of mating nuclei (HPMN). 239 samples of adult bees of 17 apiaries of a queen bee breeding system were analyzed during the winter and summer of 2016. The prevalence of Varroa and Nosema was higher in winter (79.1% and 55.4%, respectively) than in summer (65.9% and 33.0%, respectively). However, Acarapis was not found. Varroa infestation was 2.55 ± 0.82 mites/100 bees, and Nosema 145 ± 24 × 10³ spores/bee (Standard deviation of the mean). The probability of finding Nosema, in the presence of Varroa, was 3.8 and 1.1 times higher in winter than in summer, respectively. We, therefore, conclude that HPMN has a higher incidence of varroasis and nosemosis during winter and nosemosis increases in the presence of varroasis. We, on the other hand, consider acariosis, absent in the region of study.

Identificación morfométrica de Varroa destructor y su plasticidad por la exposición a timol

Revisión del aceite de orégano spp. en salud y producción animal