Biology of <i>Synuchus nitidus</i>（Coleoptera: Carabidae）as a Bioindicator of Global Warming—Wing Morphology, Reproductive Strategy, and Feeding Habits

Ground beetles（Carabidae）have been utilized as bioindicators of environmental changes. In Japan, Synuchus nitidus（Motschulsky）（Coleoptera: Carabidae）is abundant throughout the country, except for the southern islands, northernmost areas, and high-altitude areas. The objective of this study was to assess their potential as an indicator species of global warming by analyzing data on their ecological traits, including flight capability, reproductive strategy, and feeding behavior. The observed low hindwing-to-body-length ratio and absence of flight muscles suggested that they are non-flying and depend on walking for movement and dispersal. This trait is advantageous for precisely monitoring the gradual shifts in latitude and elevation of their distribution resulting from global warming. Dissection findings revealed simultaneous egg development, indicating that variations in egg production can be assessed by examining ovarian eggs. A decrease in egg numbers at the same sites may be attributed to heat stress induced by global warming. Analysis of gut contents through dissection confirmed their carnivorous predatory nature, indicating that they occupy a high trophic level and that changes in their population have a high impact on the ecosystem. These findings support the suitability of this species as an indicator of global warming.