The Nettle Weevil (Phyllobius pomaceus), also known as the Green Nettle Weevil, is a small, common, and highly distinctive beetle found across Europe and parts of Asia.
Here is a deep review of its characteristics, life cycle, and ecological role.
🌿 Nettle Weevil (Phyllobius pomaceus) Deep Review
1. Classification and Description
| Category | Detail |
| Order | Coleoptera (Beetles) |
| Family | Curculionidae (Weevils or Snout Beetles) |
| Genus | Phyllobius (Short-nosed weevils) |
| Appearance | Length: 7–10 mm. |
| Coloration | The beetle’s actual exoskeleton is black, but it is almost entirely covered by a dense layer of tiny, hair-like, metallic scales. This scaling gives the weevil its characteristic bright metallic green, blue-green, or sometimes coppery/golden appearance. The scales are easily rubbed off with age, making older specimens appear darker or almost black. |
| Key Features | Rostrum (Snout): Relatively short, distinguishing it from long-nosed weevils. Legs: Typically dark brown to black (a key differentiator from similar species like P. pyri, which has orange tibiae). Femora (Thighs): The front femora have a conspicuous, forward-pointing tooth or hook, which is an essential identification feature. |
| Sexual Dimorphism | Females are often described as being more purely green, while males may have a more noticeable bluish-green sheen. |
| Distribution | Widespread and common throughout Western and Northern Europe, extending into North-Western Asia. |
2. Life Cycle and Habitat
P. pomaceus undergoes complete metamorphosis, with distinct egg, larval, pupal, and adult stages.
A. Adult Stage (April to July)
- Emergence: Adults emerge from the soil in late spring (typically April or May) and are active until late June or July.
- Habitat: They are most commonly found on low herbage, hedgerows, woodland rides, and roadside verges, often in areas dominated by their primary host plant.
- Adult Food Sources (Foliage Feeder):
- Primary Host: Common Nettle (Urtica dioica). This association gives the weevil its common name.
- Other Hosts: They also feed on the leaves of Meadowsweet (Filipendula ulmaria), various broad-leaved trees, shrubs, and can occasionally be found on cultivated plants like strawberries or roses.
- Feeding Damage: Adults chew crescent-shaped or ragged holes in the leaves and sometimes feed on buds and young shoots.
B. Egg and Larval Stage (Underground)
- Egg Laying: The female weevil lays its small, oval eggs in the soil, usually near the roots of the host plants.
- Larvae (Root Feeders):
- The larvae are creamy white with a dark head.
- They are subterranean, living within the soil and feeding on the roots of herbaceous plants and grasses.
- The larval stage is where most of the weevil’s growth occurs, and it is the stage that causes root damage, though P. pomaceus is generally not considered a major agricultural pest.
C. Pupal Stage (Overwintering)
- Overwintering: The weevil typically overwinters in the soil as a pupa (or sometimes as a mature larva).
- Transformation: The pupal stage is inactive, encased in a protective shell in the soil, where the final transformation into the adult beetle occurs before emergence the following spring.
3. Ecological and Pest Status
- Ecological Role: The Nettle Weevil plays a role in the food web. It is a common insectivore, helping to regulate the populations of its host plants. Conversely, its larvae and adults are prey for many species, including birds, predacious beetles, and parasitic wasps.
- Pest Status: While the larvae and adults feed on cultivated plants like strawberries, roses, and various garden plants, Phyllobius pomaceus is usually considered a minor or occasional pest. Significant damage or large infestations are uncommon, and it is largely considered a generalist insect of the natural environment.
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