Parasitism by Strepsiptera is termed stylopisation. Stylopisation lengthens the life of the host (Kathirithamby 1989) and causes loss or reduction of the external and internal genitalia in Delphacidae (Homoptera) (Kathirithamby 1978, 1979, 1989, 1998) (fig. 1, 2) as well as abnormality in the eggs of Segestidea novaeguineae (Bracsik) (Orthoptera: Tettigoniidae) (Kathirithamby 1998) (fig. 3). Salt (1927) reported that the colouration in the facial foveae, the pollen collecting apparatus and the anal fimbria in stylopised bees and wasps are all positive acquisitions of secondary sexual characters. Stylopization is also said to affect the behaviour of Hymenoptera (Pérez 1886, Hubbard 1892, Brues 1903, Pierce 1909, Smith and Hamm 1914, Schrader 1924, Salt 1927).
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Upper left: Fig. 1. Unstylopised male Sogetella furcifera Horváth with normal external genitalia (arrow) x 43. Lower left: Fig. 2. Stylopised male Sogetella furcifera Horváth with absence of external genitalia (arrow) indicating the presence of endoparasitic Elenchus japonicus Esaki & Hashimoto x 33. (Photographs taken in Professor Maeta’s lab in Matsue). Right: Fig. 3. SEM of (a) mature egg from unstylopised Segestidea novaeguineae (Brancsik) (b) egg from stylopised Segestidea novaeguineae with bulbous protrusion (arrow). Bar line = 1 mm. Images from Kathirithamby (1998), copyright © 1998 Elsevier Science.
The hosts of Stylopidia are:
- Blattodea (Blattidae, Blattellidae)
- Mantodea (Mantidae)
- Orthoptera (Gryllidae, Gryllotalpidae, Tettingoniidae, Tridactylidae) (fig. 4)
- Hemiptera (Homoptera - Lophopidae, Idioceridae, Ledridae and Typhlocybidae, Cercopidae, Cicadellidae [Deltocephalinae, Idocerinae, Ledrinae, Typholocybinae, Ulopinae], Delphacidae, Derbidae, Dictyopharidae, Eurybrachyidae, Flatidae, Fulgoridae, Issidae, Membracidae, Ricaniidae, Tettigometridae; Heteroptera - Coreidae, Cydnidae, Lygaeidae, Pentatomidae, Scutelleridae)
- Diptera (Platysomatidae, Tephritidae)
- Hymenoptera (Andrenidae, Eumenidae, Formicidae, Colletidae, Halictidae, Sphecidae, Vespidae) (fig. 5)
Top: Fig. 4. Female Stichotrema waterhousi Kathirithamby (arrow) parasitic in Paracaedicia sp. (Orthoptera: Tettigoniidae). Scale bar= 12mm. Image from Kathirithamby et al. (2001). Copyright © 2001 The Netherlands Entomological Society. Bottom: Fig. 5. SEM of stylopised minor worker of Pheidole sp. (arrow – broken cap of male cephalotheca). Image from Kathirithamby (1991). Copyright © 1991 Entomological Society of Southern Africa.
The most frequently collected hosts are Hemiptera and Hymenoptera. Some of the hosts of Strepsiptera are of economic importance such as:
Fig. 6. Sogatella furcifera Horváth stylopised by pupa of Elenchus japonicus Esaki & Hashimoto (arrow). Arrow head indicates the absence of external genitalia. Photograph taken in Professor Maeta’s lab in Matsue, copyright © 2002 J. Kathirithamby.
Fig. 7. Posterior view of abdomen of Proutista moesta (Westwood) stylopised by two empty male puparia (arrow) and a neotenic female (arrow head) of Halictophagus palmae Kathirithamby & Ponnamma. Scale bar= 0.4mm. From Kathirithamby and Ponnamma (2000). Copyright © 2000 Wildlife Heritage Trust of Sri Lanka.
- Homoptera
- Javesella pellucida (F.) (Delphacidae), a vector of pathogenic viruses on oats in the Palaearctic region (Raatikainen 1967)
- Nilaparvata lugens Stål and Sogatella furcifera Horváth (Delphacidae), vectors of pathogenic viruses on the rice plant in South and South East Asia (Kathirithamby 1979, 1982).
- Sogatella furcifera
- Nephotettix sp. (Cicadellidae), a vector of pathogenic viruses on rice in South and South East Asia (Kathirithamby 1980)
- Cofana spectra (Distant) (Cicadellidae), a vector of pathogenic viruses on rice in South and South East Asia and Africa (Kathirithamby 1992)
- Dalbulus maidis (Delong & Wolcott) (Cicadellidae), a vector of pathogenic viruses of corn in Mexico (Kathirithamby and Moya-Raygoza 2000)
- Proutista moesta (Westwood) (Derbidae), a vector of pathogenic viruses of oil palm, coconuts and araca nuts in India (Kathirithamby and Ponnamma 2000).
- Idioscopus clypealis (Lethierry) (Cicadellidae), a vector of pathogenic viruses of mangoes in the Philippines (Kathirithamby unpublished)
- Diptera
- Dacus sp. (Tephritidae), that damage fruits in Australia (Kathirithamby 1989, 1992)
- Hymenoptera
- Solenopsis invicta Buren, a nuisance pest in the southern United States (Kathirithamby and Johnston 1992, Kathirithamby and Hamilton 1992). Click on an image to view larger version & data in a new window
Fig. 8. SEM of abdomen of Solenopsis invicta Bruen with male cephalotheca. Top arrow – puparium with unemerged male within, bottom arrow- empty male puparia with broken cap. Photograph copyright © 2002 J. Kathirithamby.
- Solenopsis invicta Buren, a nuisance pest in the southern United States (Kathirithamby and Johnston 1992, Kathirithamby and Hamilton 1992).
- Orthoptera
- Segestidea novaeguineae (Brancsik) (Tettigoniidae) which severely defoliates oil palm in Papua New Guinea (Kathirithamby et al. 1998). Click on an image to view larger version & data in a new window
Left: Fig. 9. Female cephalothoraxes (arrows) in abdomen of Segestidea novaeguineae (Brancsik). Right: Fig. 10. Dissected Segestidea novaeguineae (Brancsik) showing two endoparasitc female Stichotrema dallatorreanum Hofeneder (arrows). Female with 1st instar larvae (black), with developing embryos (white). Images from Solulu (1996), copyright © 1996 T. M. Solulu.
- Segestidea novaeguineae (Brancsik) (Tettigoniidae) which severely defoliates oil palm in Papua New Guinea (Kathirithamby et al. 1998).
