Alderflies
Sialidae
Classification
- Phylum: Arthropoda
- Subphylum: Hexapoda
- Class: Insecta
- Order: Megaloptera
- Family: Sialidae
Pronunciation
How to pronounce Sialidae: /ˈsaɪəˌlɪdiː/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Images
Summary
Alderflies are megalopteran insects belonging to the family Sialidae, consisting of about 66 species across nine extant genera. They are characterized by soft bodies, large wings, and a life cycle that includes an aquatic larval stage before emerging briefly as adults. They are often found near water bodies and play significant roles in freshwater ecosystems.
Physical Characteristics
Medium-sized insects, typically 10-25 mm in length, with soft bodies and large, delicate wings. The head of Sialis species is primarily black with yellowish markings, while Protosialis species have heads that are primarily yellowish with black markings. Alderflies lack ocelli and possess a dilated fourth tarsal segment that is deeply bilobed.
Identification Tips
Adult Sialis can be identified by their black heads with yellowish markings and two subapical teeth on their mandibles, while Protosialis species can be identified by the yellowish heads with black markings and three subapical teeth on their mandibles.
Habitat
Adults are most often found in association with riparian vegetation adjacent to open water; larvae prefer ponds and lakes but can also inhabit large rivers or pools in smaller, faster streams where plentiful silt is present.
Distribution
Alderflies are most speciose in the Holarctic region, with additional limited distributions in the Neotropics, Madagascar, Australia, the Oriental region, East Asia, and South Africa.
Diet
Adults generally appear to be largely non-feeding, relying primarily on reserves accumulated during the larval stages. The larvae are aquatic and active, utilizing strong mandibles for feeding.
Life Cycle
Females lay eggs on plant stems near water, with larvae dropping into water or ground upon hatching. The larvae grow for one to two years in an aquatic environment before undergoing a pupal stage on land, leading to metamorphosis into adults that live for 2 to 3 weeks.
Reproduction
Females deposit eggs in masses on foliage overhanging water, and adults spend their brief lifespan primarily focused on reproduction.
Ecosystem Role
Alderflies serve as indicators of freshwater ecosystem health due to their presence in specific aquatic habitats.
Economic Impact
Larvae are used as bait in fishing, impacting local fisheries.
Evolution
Alderflies are closely related to dobsonflies and fishflies, and the family contains several genera of fossil species as well.
Tags
- insect
- alderfly
- Sialidae
- Megaloptera