Yusuke Kondo

UV response switch of a wing color in Papilio polytes butterflies is important for dimorphic female-limited Batesian mimicry.

Novel feeding adaptations often facilitate adaptive radiation and diversification. But the evolutionary origins of such feeding adaptations can be puzzling if they require concordant change in multiple component parts. Pelagic, heterorhabdid copepods (Calanoida) exhibit diverse feeding behaviors that range from simple particle feeding to a highly specialized form of carnivory involving piercing mouthparts that likely inject venom. We review the evolutionary history of heterorhabdid copepods and add new high-resolution, 3D anatomical analyses of the muscular system, glands and gland openings associated with this remarkable evolutionary transformation. We examined four heterorhabdid copepods with different feeding modes: one primitive particle-feeder (Disseta palumbii), one derived and specialized carnivore (Heterorhabdus subspinifrons), and two intermediate taxa (Mesorhabdus gracilis and Heterostylites longicornis). We used two advanced, high-resolution microscopic techniques — serial block-face scanning electron microscopy and two-photon excitation microscopy — to visualize mouthpart form and internal anatomy at unprecedented nanometer resolution. Interactive 3D graphical visualizations allowed putative homologues of muscles and gland cells to be identified with confidence and traced across the evolutionary transformation from particle feeding to piercing carnivory. Notable changes included: a) addition of new gland cells, b) enlargement of some (venom producing?) glands, c) repositioning of gland openings associated with hollow piercing fangs on the mandibles, d) repurposing of some mandibular-muscle function to include gland-squeezing, and e) addition of new muscles that may aid venom injection exclusively in the most specialized piercing species. In addition, live video recording of all four species revealed mandibular blade movements coupled to cyclic contraction of some muscles connected to the esophagus. These behavioral and 3D morphological observations revealed a novel injection system in H. subspinifrons associated with piercing (envenomating?) carnivory. Collectively, these results suggest that subtle changes in mandibular tooth form, and muscle and gland form and location, facilitated the evolution of a novel, piercing mode of feeding that accelerated diversification of the genus Heterorhabdus. They also highlight the value of interactive 3D animations for understanding evolutionary transformations of complex, multicomponent morphological systems.

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Significance: A stripe pattern is widely observed among animals and often used for warning or camouflage in caterpillars. However, its genetic background is largely unknown. This study showed that the Toll ligand Spätzle3 (Spz-3) is responsible for the silkworm Zebra locus, which causes black stripes on the anterior margin of each segment. Exhaustive knockdown experiments of spz- and Toll- related genes clarified that spz-3 and Toll-8 are involved in the melanin pigmentation of Zebra and another mutant. The Spz-3/Toll-8 signaling pathway is suggested to induce Zebra stripe-specific expression of the pigmentation gene yellow . This study sheds light on not only the unique aspect of Spz/Toll functions but also, stripe pattern pigmentation in caterpillars through co-option of a Toll signaling pathway.

The object of this paper is to explain the simulation methods of vertical and longitudinal forces applied to a vehicle body running on rough road. First, a background of the demands of rough road load and the present state of simulation methods are described. Then, the simulation method of histogram, which is important for durability procedure, is mentioned. A histogram of vertical force can be simulated from chassis characteristics from running on rough roads. Second, a computer simulation of vertical and longitudinal forces of running vehicle is discussed. The tire is modeled as a radial spring system which is connected to the chassis model and the propriety of this simulation is investigated by comparison with the actual test results. In conclusion, through the above-mentioned research and development, vertical and longitudinal force can be simulated for rough road running.