Traumatic Insemination in the plant bug genus

Coridromius

(Heteroptera: Miridae) Nik Tatarnic University of Sydney & Australian Museum

Q. What is Traumatic Insemination?

A. Male punctures female with hypodermic genitalia, injects sperm into body cavity

Q. Why Practice Traumatic Insemination?

A. Thought to be a means for males to circumvent female mating resistance

Q. Why Resist Mating?

A. Males and Females have differing reproductive optima = Sexual Conflict

Coercive mating in waterstriders Westlake Rowe & Currie (2000)

Genital Damage in Bean Weevils Crudgington, H.S. and Siva-Jothy, M.T. (2000)

Sexual Conflict Coevolutionary Arms Race • Males evolve structures and behaviours which increase their own fitness, but reduce female fitness • Females evolve structures and behaviours to mitigate costs

Sexual Conflict Coevolutionary Arms Race • Males evolve structures and behaviours which increase their own fitness, but reduce female fitness • Females evolve structures and behaviours to mitigate costs e.g. Traumatic Insemination & Paragenitalia

Who are the Traumatic Inseminators?

• Non-insect invertebrates: rotifers, acanthocephalans, pinworms, gastropod snails, free-living flatworms • Insects: Strepsiptera, Cimicomorpha (Heteroptera) e.g. Bedbugs

Who are the Traumatic Inseminators?

• Non-insect invertebrates: rotifers, acanthocephalans, pinworms, gastropod snails, free-living flatworms • Insects: Strepsiptera, Cimicomorpha (Heteroptera) e.g. Bedbugs

Heteroptera (True Bugs)

Heteroptera (True Bugs) Cimicimorpha

Schuh & Stys (1991)

Schuh & Stys (1991)

1 1 Genitalic TI

Genitalic Traumatic Insemination: Prostemmatinae • vaginal copulation • genital tract wall pierced with phallus • sperm travel through hemocoel to ovarioles C. Weisenböhler Deutschland / Baden-Württemberg, Vellberg III.2005

Schuh & Stys (1991)

1 2 1 Genitalic TI 2 Extragenitalic TI

Extragenitalic Traumatic Insemination (I) • Male punctures the female body wall with his genitalia – “Acus” in Plokiophilidae & Lyctocoridae – Aedeagus + left paramere in Anthocoridae*, Polyctenidae and Cimicidae *Not all Anthocoridae practice TI

Plokiophilidae Lyctocoridae Carayon (1972) Carpentiro & Dellapé (2005)

Schuh & Stys (1991)

1 3 2 1 Genitalic TI 2 Extragenitalic TI 3 Aedeagus & Paramere coupled

Extragenitalic Traumatic Insemination (II) • Male punctures the female body wall with his genitalia – “Acus” in Plokiophilidae & Lyctocoridae – Aedeagus + left paramere in Anthocoridae*, Polyctenidae and Cimicidae *Not all Anthocoridae

Anthocoridae, Polyctenidae & Cimicidae Stutt and Siva-Jothy (2001)

Female Response • Females have evolved paragenitalia to mitigate costs • Spermalege = External “Ectospermalege” & Internal “Mesospermalege”

Carayon (1974) Plokiophilidae Stutt and Siva-Jothy (2001) Cimicidae

A New Case of Traumatic Insemination • Family Miridae • Genus

Coridromius

• +32 species (11 described) • Pacific Islands, Australia, SE Asia, Africa • Extragenitalic TI with paramere & aedeagus coupled

*Tatarnic, N.J., Cassis G. & Hochuli D.F. 2006. Biology Letters 2: 58-61

The males

And the females?

Schuh & Stys (1991)

2,3 1 3 2 1 2 Extragenitalic TI 3 Aedeagus & Paramere coupled

Conclusions I • Traumatic Insemination has arisen multiple times • Coupling of paramere and aedeagus has arisen twice

Part 2 • Taxonomic descriptions • Phylogeny

75 98 85 92 59 63 50 86 96 68 56 55 54 86 72

Asia + Africa Pacific

86

Enough biogeography – back to the sex!

Conclusions II • Female paragenitalic evolution does not follow a simple transition series • Instead, multiple independent cases of elaborate paragenital development = Strong sexual selection

Summary • Traumatic Insemination has evolved at least 3 times in the Cimicomorpha • TI drives elaborate female morphology in

Coridromius

Question: What predisposes Cimicomorpha to such deviant sexual practices?

Acknowledgements

Gerry Cassis, AM Dieter Hochuli, U Sydney Michael Wall, AM/AMNH Locke Rowe, U Toronto Mike Siva-Jothy, U Sheffield NSF: Planetary Biodiversity Inventory