Cactus Flies

Neriidae

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Diptera
Superfamily: Nerioidea
Family: Neriidae

Pronunciation

How to pronounce Neriidae: /nɛˈɾi.aɪ.dii/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Telostylus philippinensis by the Smithsonian. Used under a CC0 license.

Chaetonerius comperei by the Smithsonian. Used under a CC0 license.

Summary

The Neriidae family, known as cactus flies, is a group of long-legged true flies that are typically found in tropical regions but also include genera present in North America and Australia. They breed in decomposing organic material, and their larvae and adults play a role in nutrient cycling.

Physical Characteristics

Most species are slender, long-legged flies. Many exhibit striped patterns that provide camouflage against tree bark. Males often have more elongated bodies, heads, antennae, and legs than females, with thickened fore-tibiae.

Identification Tips

Neriid flies can be identified by their long fore legs and the medial division on the upper face. The antennae are porrect, and the arista arises at the tip. Males have significant sexual dimorphism.

Habitat

Larvae develop in rotting vegetation, including decaying tree bark and rotting fruit. Adults aggregate on rotting vegetable matter or damaged tree trunks and are attracted to flowers.

Distribution

Primarily found in tropical regions, with some genera occurring in North America (specifically the southwestern United States) and one species found in temperate regions of eastern Australia.

Diet

Neriidae are saprophagous; their larvae feed on decaying plant matter.

Life Cycle

The larvae develop in rotting fruit and vegetable matter, and adult body size and shape are influenced by larval diet quality.

Reproduction

Males engage in combat for territory and access to females, exhibiting territorial behaviors. Males can influence the body size of their offspring based on their larval diet.

Ecosystem Role

Neriidae play a role in the decomposition of organic material through their larvae feeding on decaying plants, contributing to nutrient cycling in their ecosystems.

Collecting Methods

Using net traps near rotting vegetation or flowers
Light traps during warmer months

Preservation Methods

Pinning
Ethanol preservation

Evolution

Neriids are closely related to the Micropezidae and were previously treated as a subfamily. They exhibit significant evolutionary diversity in body size and shape due to larval diet effects.