spider fly: meaning, definition, pronunciation and examples

Low (specialist/entomological)
UK/ˈspaɪ.də ˌflaɪ/US/ˈspaɪ.dɚ ˌflaɪ/

Technical/Scientific, occasionally informal descriptive

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Quick answer

What does “spider fly” mean?

A small, predatory fly of the family Acroceridae, which parasitises spiders.

Audio

Pronunciation

Definition

Meaning and Definition

A small, predatory fly of the family Acroceridae, which parasitises spiders; an insect resembling a spider in appearance or movement.

Can refer informally to crane flies or other long-legged flies whose appearance evokes a spider. In some contexts, used metaphorically to describe something that combines attributes of both creatures (e.g., something delicate yet predatory).

Dialectal Variation

British vs American Usage

Differences

No significant regional difference in the technical term. Informal descriptive use might be slightly more common in UK English for crane flies ('daddy longlegs').

Connotations

Neutral in scientific context. Can have a slightly eerie or unsettling connotation in descriptive use.

Frequency

Very low frequency in general discourse. Almost exclusively found in entomology texts or detailed nature writing.

Grammar

How to Use “spider fly” in a Sentence

The [spider fly] parasitises [spider].A [spider fly] was observed on [the window/leaf].

Vocabulary

Collocations

strong
parasitic spider flyhatchling spider flyAcrocerid spider fly
medium
resembles a spider flyspider fly larvae
weak
tiny spider flyunusual spider fly

Examples

Examples of “spider fly” in a Sentence

adjective

British English

  • The spider-fly life cycle is complex.
  • We studied spider-fly interactions.

American English

  • The spider fly lifecycle is complex.
  • We studied spider fly interactions.

Usage

Meaning in Context

Academic

Used in entomology, ecology, and evolutionary biology papers discussing parasitism.

Everyday

Virtually never used. Might be used by gardeners or naturalists describing an unusual insect.

Technical

Precise taxonomic reference to flies in the family Acroceridae.

Vocabulary

Synonyms of “spider fly”

Neutral

Acroceridsmall-headed fly (family)

Weak

crane fly (informal, imprecise)daddy longlegs (informal, imprecise)

Vocabulary

Antonyms of “spider fly”

spider predator (e.g., some wasps)spider prey

Watch out

Common Mistakes When Using “spider fly”

  • Using 'spiderfly' as one word (standard is two words).
  • Confusing it with a 'flying spider' (which doesn't exist).
  • Assuming it is a type of spider rather than a fly.

FAQ

Frequently Asked Questions

It is a true fly (order Diptera), not a spider. The name refers to its parasitic relationship with spiders or its spider-like appearance.

No. They are very small, rarely bite humans, and pose no threat. They are only a danger to their spider hosts.

Yes, but they are rarely noticed due to their small size and inconspicuous behaviour. Their presence indicates a healthy spider population.

They are different families. Spider flies (Acroceridae) are parasitic and have small, often humpbacked bodies. Crane flies (Tipulidae) are not parasitic, have long, slender bodies, and are often seen indoors.

A small, predatory fly of the family Acroceridae, which parasitises spiders.

Spider fly is usually technical/scientific, occasionally informal descriptive in register.

Spider fly: in British English it is pronounced /ˈspaɪ.də ˌflaɪ/, and in American English it is pronounced /ˈspaɪ.dɚ ˌflaɪ/. Tap the audio buttons above to hear it.

Learning

Memory Aids

Mnemonic

Imagine a fly wearing a tiny spider costume for Halloween – it's a 'spider fly'.

Conceptual Metaphor

HYBRID/CHIMERA (combining features of two distinct entities).

Practice

Quiz

Fill in the gap
The is an unusual insect because its larvae feed on the innards of living spiders.
Multiple Choice

What is a 'spider fly' primarily?

Practise

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Five interactive tools to remember words, train your ear, and build vocabulary in real context — drawn from this dictionary.

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