xx - The Hybrid Problem

Hybridization is the mixing of two closely related species to create offspring of unnatural heritage. (Hybrids do happen in nature but are rarely viable) Most (but not all) of the hybrids available to the hobby are the result of unintentional cross-breeding. Lucky for most hobbyists a majority of pet cockroaches cannot hybridize and do not even try to court their close relatives. Unfortunately there are several major dealers selling hybrids to the feeder community as a high yield, larger alternative to true-bred roaches (Nearly all are Blaberus hybrids). Economically this does make sense but many mistakes have been made in recent years resulting in multiple strains of hybridized Blaberus species and has further muddied the already murky waters of their heritage.

Some of the well known pet roaches such as Blaberus fusca are still contested as a pure species. It's possible they are some form of cross of Blaberus peruvianus and another Blaberus species but personally I feel they are morphologically dissimilar and of their own unique pure species. The best known and readily available hybrids are Blaberus fuscaXcraniifer, fuscaXperuvianus, and Blaberus discoidalisXboliviensis. 

The myth of a Blaberus giganteus hybrid is just that, a myth. The B. giganteus is related to B. craniifer and fusca but cannot produce viable ootheca together and would rarely attempt breeding. 

The larger fuscaXcraniifer or fuscaXperuvianus hyrbids may be responsible for the European "brown wing" craniifer, but like most other Blaberus, that is still up for study. (You must remember that hybridization gives rise to traits of both species, including the "wing hairs" of Blaberus craniifer BW) These hybrids (both fuscaX???) are also easily identified as such as they are smaller than Blaberus fusca and have a partial to full jack-o-lantern pronotum marking. They are also highly variable in coloration ranging from nearly black to the brown of B. fusca. This highly variable hybrid is only a danger to uneducated first time buyers and breeders, once a little experience is collected they are easily seen as hybrids. 

The smaller discoidalisXboliviensis hybrids pose a much more difficult issue. These hybrids are often sold as pure-stock Blaberus discoidalis because of their smaller size and relatively normal markings. However once your colony gets large enough you will start to notice "freaks" molting out. These "freaks" are unlike Blaberus discoidalis because of their unusual pronotum markings, various pronotum sizes, various wing sizes. and the occasional freakishly large specimen. I myself currently have a colony of these hybrids; they were sold to me as pure stock. After about a year with them I noticed too many variations in size and structure and finally sought confirmation of their illegitimate heritage. I am currently culling this hybrid colony as I have no use for hybrids. My pure bred stock looks exactly like 90% of the hybrids, but that other 10% is proof enough of their muddied blood. 

The moral here is please be sure of the heritage of your animals. Feeders or pets, know what you have. Say someone wants to revitalize their colony with new stock. Then you sell your hybrids as pure stock because you were told they were pure. In the end you never got confirmation of their purity because you "just thought" they were pure and resulted in completely ruining someone's pure-stock colony. The American Cockroach Societies forum is http://www.roachforum.com and is your best source for confirmation. Contact the moderators or myself and we will try our best to figure it out. 

Blaberus species hybrid comparison

Additional reading:
http://nsrdec.natick.army.mil/LIBRARY/70-79/R70-102.pdf (Probably the most important study in Blaberus hybridization ever done)