September 2025
In the larval head of the Japanese rhinoceros beetle (Trypoxylus dichotomus), the horn primordium is stored as a sac-like structure with wrinkles inscribed in a specific pattern. When the larva molts into a pupa, hemolymph is pumped into this sac, causing the wrinkles to stretch and the sac to expand, which results in the formation of the horn. Multiple research groups in Japan have investigated the three-dimensional morphogenesis of this horn. For further information, see the following publications: Matsuda et al. (2024) Development 151: dev202082, DOI: 10.1242/dev.202082; Matsuda et al. (2021) Sci. Rep. 11: 1017, DOI: 10.1038/s41598-020-79757-2; Adachi et al. (2020) Sci. Rep. 10: 18687, DOI: 10.1038/s41598-020-75709-y; Ohde et al. (2018) PLoS Genet. 14: e1007651, DOI: 10.1371/journal.pgen.1007651. As if celebrating the emergence of the beetles, the veins of the nearby leaves trace patterns reminiscent of the wrinkles in the horn primordium.
July 2025
On the surface of Drosophila olfactory sensilla, many small holes (nanopores) are present in the cuticle, allowing odorant molecules to pass through. In mutants of the gore-tex/Osi23 gene, the number of nanopores is greatly reduced, and olfactory ability is also significantly weakened (Ando et al. (2019) Current Biology 29: 1512-1520, DOI: 10.1016/j.cub.2019.03.043). This drawing shows the famous Sengoku warlord Takeda Shingen wearing a helmet with horns resembling olfactory sensilla to enhance his "sense of smell" in battle. However, he is panicking after noticing that the left horn has very few nanopore-like holes, possibly due to a malfunction of the Gore-tex/Osi23 protein. We thank Dr. Shigeo Hayashi and Dr. Toshiya Ando, the authors of the original paper, for their advice in creating this illustration.
