Developmental models and morphological characteristics of the hide beetle, Dermestes frischii, under different constant temperatures

Many species of hide, larder, and carpet beetles (Coleoptera, Dermestidae) are economically important pests of stored products of animal and plant origin, and also have high forensic application value. This study investigated the developmental duration of the immature stage of Dermestes frischii (Kugelann, 1792) under six constant temperatures (19, 22, 25, 28, 31, and 34 °C) and found that development was longest at 19 °C, taking 97.4 ± 7.9 days, and was shortest at 31 °C, taking 31.3 ± 7.2 days. The isomorphen diagram was established based on the developmental events under the different constant temperatures, and the thermobiological parameters of D. frischii were evaluated using linear thermal summation and curvilinear Optim SSI models. The thermal summation constant was 559.89, while the intrinsic optimum temperature and lower and upper lethal developmental thresholds were 24.65, 13.37, and 34.98 °C, respectively. The mortality rate and the mean number of larval instars increased under higher or lower temperatures. The mean instar duration of the first to the fifth instar was generally similar, while the instar duration was the shortest under high temperatures with the fastest developmental rate. We conclude that temperature has a separate effect on the number and duration of the larval instar of D. frischii. In addition, the larval morphological parameters were measured, and the ultrastructures of the antennae, mouthparts, and urogomphi were characterized. This work provides important basic data for storage pest control and minimum postmortem interval estimation of D. frischii in forensic entomology research and application.