Common Sawfly

<em>Cladius grandis</em> is a sawfly in the family Tenthredinidae, with a Holarctic distribution spanning Europe and North America, documented from Canada, the United States, and multiple European countries. The species is primarily associated with rose family shrubs and trees, with larvae feeding externally on the leaves of cultivated and wild roses (<em>Rosa</em> spp.) as well as related plants. Larvae are pale green and slug-like in appearance, resembling the related rose slug sawfly larvae, and feed by skeletonizing leaves, stripping the upper epidermis and leaving a characteristic translucent "window" pattern that later turns brown. Infestations can cause cosmetic damage to cultivated roses and reduce the vigor of heavily attacked plants. Adults are small, black, wasp-like insects. The species is assessed as Near Threatened on the IUCN Red List, though the reasons for this designation and supporting population trend data specific to this species are not extensively documented in widely available sources. It typically produces multiple generations per year under favorable conditions in temperate climates. Pupation occurs in the soil, and overwintering takes place as prepupae or pupae. Biological traits such as average lifespan, body measurements, and comprehensive dietary data beyond host plant leaf tissue remain poorly documented in standardized ecological databases.