Insects and their Allies  

Strepsiptera: stylops

These insects are very small parasites of other insects and are rarely seen as they spend most of their life within the host. Males can appear very different from females are their distinguishing characteristics are given below:

Halictophagus species (male)
Halictophagus species

Male Strpsiptera

  • 1-8 millimetre wingspan
  • Large berry-like eyes
  • Fan-shaped antennae
  • Forewings reduced to knobs (similar to the halteres of flies)
  • Large membranous hind wings with reduced venation
  • Mouthparts are reduced and non-functional
Halictophagus species (female on bug)
Halictophagus species

Female Strpsiptera

  • Larvae-like body
  • Wingless
  • Legless
  • Reduced mouthparts

Larvae appear grub-like

Life Cycle
Stylopids reproduce sexually and females most likely protrude through the abdomen of the host and release pheromones to attract males. After mating the eggs develop and hatch into first instar larvae within the females body. They then make their way out through her genital opening to find a new host. At this stage the larvae are active, have long thin legs and are able to jump distances up to a few centimetres. After finding a host the larvae burrows in through the cuticle and moults into a legless second instar which completes development within the body of the host. Most stylopids pupate protruding from the host and emerge without killing it. Males will fly off to find a female to mate with while females will emerge and stay on the original host.

All species of female and larvae stylopids parasitise a variety of insect orders with most not confined to a single host species. Male stylopids have greatly reduced mouthparts and do not feed.

Stylopids are found over much of the country and in Australia they mostly parasitise bugs (Hemiptera) although some other insect orders such as Orthoptera and Blattodea are affected. The free living stages of this order are rarely found. Most male Halictophagus species (above) are parasites of Cicadellidae species (Hemiptera).