The Effect of Larval Density on Pupation Rate and Time to Emergence from Pupation in $Tenebrio$ $molitor$ Linnaeus, 1758 (Coleoptera: Tenebrionidae) Reared on Two Different Feeds

In our research, the yellow mealworm, $Tenebrio$ $molitor$ L. was used. The effects of two different foods on the pupation rate and time to emergence from pupation of $T.$ $molitor$ at different larval densities were investigated. The experiments were carried out under continuous dark laboratory conditions with a temperature of 27±2ᵒC and a relative humidity of 60%±5%. Two different nutrient and four larval density groups were used in the study. The first nutrient composition consisted of dry yeast and wheat germ (150 gr in total, 1/2) The second nutrient composition consisted of whole wheat flour and corn flour (150 gr in total, 1/1). Insects were bred primarily on the tested nutrient media. Experimental sets were prepared at four different larval densities for both foods. The number of larvae in plastic containers was adjusted to 20, 60, 200 and 600. To ensure equality, all larvae were selected from small larvae. (between 50 mg-120 mg). In our study, pupation rates were high, especially in groups consisting of 20 and 60 larvae. The percentage of pupation decreased at 200 larval densities and sharply decreased at 600 larval densities in both diets. Especially the negative effects of the density are more obvious in the second food. The effects on intensity were more pronounced, especially in pupation of larvae, not in terms of pup time. As a result, it would be advantageous for the larvae density not to be above 200 in terms of getting more yield and increasing the reproduction rate from $T.$ $molitor$, which is demanded in large numbers as live feed. In conclusion, for the production of $T.$ $molitor$, which is commonly used as live feed, it is preferable to have a larval density below 200 in order to get a higher yield and better reproduction rates.