Temperature-dependent development of Carpophilus marginellus Motschulsky, 1858 (Coleoptera: Nitidulidae) and its larval morphological characteristics

Carpophilus marginellus Motschulsky is a storage pest that damages fruits, dried fruits, grains, and other agricultural produce. Because the beetle is also saprophagous and has been found on corpses, it is of forensic interest. Despite its agricultural and forensic importance, biological research on this species and this family is lacking. Most damage is caused by the larval stage, but there are no morphological studies on the larvae of this species. Herein, we photographed the three instars using optical and scanning electron microscopy (SEM) to visualize their morphology more vividly. We also described the structure of the different parts and compared the morphological differences between the different instars for accurate identification. In addition, we reared C. marginellus at seven constant temperatures between 16 and 34 °C, recorded the developmental duration and accumulated degree days (ADD) of each developmental stage, measured the body length, head capsule width, and the distance between the urogomphi at different times. The mortality rate at each stage was also calculated. Based on the above data, we plotted an isomorphen diagram, isomegalen diagram, and survival curve, established linear thermal summation models and curvilinear Optim SSI models, and performed a cluster analysis of the head capsule width and the distance between the urogomphi. The morphological and developmental information of C. marginellus provided in this study is useful for identifying the species, mass rearing, pest management, and forensic postmortem interval (PMI) estimation.