Department of Entomology

Strepsiptera (Twisted-wing Parasites)

I. Background information

A. Origin of name

1. Latin - strepsi, twisted; ptera, wings
2. Relates to the form of the hind wings; membranous and appearing twisted and wrinkled.

B. Classification

1. Suborders - none
2. America north of Mexico - 4 families (1 fossil family), 12 genera, 109 species
3. World - 9 families, ? genera, 373 species
4. Estimate of undescribed species - ?%

C. Common names - Twisted-wing parasites
D. Type of metamorphosis - Holometabolous
E. Phylogenetic relationships

1. Related to Coleoptera.
2. Arnett (1985) has included Strepsiptera as a part of Coleoptera.
a. Metathoracic wings
b. Free prothorax with closely associated meso- and metathoraces.
c. Abdomen with sternites more heavily scleritized than tergites.
d. Triungulin-type larvae similar to those of the Meloidae and Rhipiphoridae.

II. Morphological characteristics

A. Males with forewings reduced to clublike structures

B. Males with the hind wings large and fanlike.

C. Males with antennae 4-7 segmented with some segments with long lateral processes.

D. Mouthparts vestigial

E. Small insects 0.5-4 mm.

F. Females are generally saclike without appendages or bedbuglike in some species (Eoxenos laboulbenei Peyerimhoff)

III. Biological summary for the order

A. Life history - often with hypermetamorphosis

1. Eggs - not produced
2. Larvae
a. Primary larvae - After mating females produce many tiny larvae, which escape from their bodies and the body of the host to the soil or to vegetation (triungulins - well-developed eyes and legs).
b. Secondary larvae - After finding a host triungulins enter the hosts body and molt into a legless wormlike stage that feeds within the host.
c. Up to seven molts occur.

3. Females continue developing in the skin of the last larval instar.
4. Pupae - skin of last larval instar forms a puparium and a pupa is formed within the puparium like the Diptera.
5. Adults

a. Males free-living
b. Females saclike living in host.

B. Habitat and Habits

1. Parasitic on Thysanura, Orthoptera, Hemiptera, Homoptera, Diptera, and Hymenoptera.
2. Some families are specific to certain orders others are not as shown in the table below.

Family Mengeidae Mengenillidae Corioxenide Halictophagidae Callipharixendae Bohartillidae Elenchidae Myrmecolacidae Stylopidae

Host Unknown, fossil Thysanura Hemiptera Homoptera, Orthoptera, Blattaria, and Diptera Hemiptera Unknown Homoptera Formicidae (ants), Orthoptera, Mantodea Hymenoptera

C. Collecting and preserving

1. Collection of hosts and rearing parasites
2. Parasitized (stylopized) hosts can be recognized by the distorted abdomen and one end of the parasite sometimes protrudes between segments.
3. 80% alcohol
4. Slide mount

 



Prepared by: E. R. Day, VPI & SU
Last modified: 9/3/96