Tuesday, July 28, 2015

A new true bug: Cystococcus campanidorsalis

Bush coconuts, also known as bloodwood apples, are a type of gall. Such galls are abnormal outgrowths of plant tissues. They can be caused by various parasites, from fungi and bacteria, to insects and mites. A researcher investigated the insect responsible for these bush coconuts and found that they were caused by a new species.

And a strange one it is:  These insects display sexual dichronism, with females giving birth first to males, and then to females once the males almost matured inside the gall. The wingless female nymphs cling to their winged adult brothers, hitching a ride out of the maternal gall when the males fly to find mates. This bizarre behaviour is called intersexual phoresy.

The new species was named Cystococcus campanidorsalis for the insect's bell-shaped back that plugs the entrance to the gall.

For the experts: Australia houses some unusual biota (insects included), much of which is undescribed. Cystococcus Fuller (Hemiptera : Sternorrhyncha : Coccoidea : Eriococcidae) currently comprises two species, both of which induce galls exclusively on bloodwoods (Myrtaceae: Corymbia Hill & Johnson). These insects display sexual dichronism, whereby females give birth first to sons and then to daughters. Wingless first-instar females cling to their winged adult brothers and are carried out of the maternal gall when the males fly to find mates – a behaviour called intersexual phoresy. Here, we use data from two gene regions, as well as morphology and host-use of the insects, to assess the status of a previously undescribed species. We describe this newly recognised species as Cystococcus campanidorsalis, sp. nov. Semple, Cook & Hodgson, redescribe the two existing species – C. echiniformis Fuller and C. pomiformis (Froggatt), designate a lectotype for C. echiniformis, and provide the first descriptions of adult males, and nymphal males and females for the genus. We have also reinterpreted a key morphological character of the adult females. This paper provides a foundation for further work on the genus, which is widespread across northern Australia and could prove to be useful for studies on biogeography and bloodwood ecosystems.

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