Cockroach as the Earliest Eusocial Animal

Abstract

A completely preserved cockroach Sociala perlucida gen. et sp. nov. (Blattida: Socialidae fam. nov.) is described from the Mesozoic (Albian Early Cretaceous) amber of Archingeay in France. It is categorized within the new family Socialidae, originating from the Mesozoic cockroach family Liberiblattinidae, and representing the sister group to the most basal known eutermite families. Numerous direct and indirect morphological evidence (such as a unique narrow body and pronotum with reduced coloration, legs without carination and with numerous sensillar pitts (forelegs) as adaptations to life in nests analogical to the living termitophillous species; enlarged head, long palps for communication, a general venation modified in a direction towards termites (subcosta and radial vein [R] approximated, R branches approximated, simplified, cross‐veins reduced), and possibly also the development of the breaking forewing sutura for detaching wings after marriage flight), suggest its eusocial mode of life. Thus, the first eusociality originated within cockroaches, prior to giving birth to termites; termites and Cryptocercus are not directly related. The group of eusocial cockroaches makes termite morphotaxon polyphyletic, but also in this case, the erection of a new order for mastotermites (including Cratomastotermitidae) and/or the inclusion of eusocial, morphological cockroaches within termites appears counterproductive, thus an example of such a general exception to the taxonomical procedure is provided.

Natural selection drives the evolution of ant life cycles

“…The number of known events that created obligatory eusociality in contemporary animals as a whole is only 18: three in synalpheid shrimps; two in the vespid wasps, scolytid beetles, and bathergid mole-rats; and one each in ants, termites, sphecid wasps, allodapine bees, augochlorine bees, corbiculate bees, halictine bees, thrips, and aphids (22,34). A cockroach species (Sociala perlucida) from the Early Cretaceous has been interpreted as being eusocial from a single specimen (35), but the claim needs additional evidence. On the other hand, a more immediately plausible case might be made for including human beings, because of the existence of the postmenopausal "caste" of grandmother helpers (36).…”

Afro-Asian cockroach from Chiapas amber and the lost Tertiary American entomofauna

“…The problem is that there are known "missing link" taxa in all cockroach families and we also know a half-cockroach-half termite (Vršanský 2010) and also half-cockroach-half mantodean. All studied living cockroach genera with fossil records have these transitional stages too, and the present taxon is no exception.…”

Low diversity cockroach assemblage from Chernovskie Kopi in Russia confirms wing deformities in insects at the Jurassic/Cretaceous boundary

“…About 100,000 collected specimens are known (Cifuentes et al 2006). During the Mesozoic both eusocial Isoptera (termites) and predatory Mantodea (mantises) evolved from the cockroach group Liberiblattinidae (Vršanský 2002(Vršanský , 2010Vršan-ský et al 2002;Vršanský & Aristov 2014). About 1,000 fossil species is known , while different authors state numbers of described living species of around 5,000 Roth 2003;Beccaloni & Eggleton 2013).…”

“…In advanced ecosystems they are important at the basic level of decomposition together with termites (Zherikhin 1993). During their evolution they adapted to various types of ecosystems and reached high levels of ecological and morphological diversity and disparity, including aquatic (Shelford 1909), pollinating (Nagamitsu and Inoue 1997), jumping (Bohn et al 2010;Picker et al 2012;Vršanský 2007), light-mimicking (Zompro & Fritzsche 1999;Vršanský et al 2012;Vršanský & Chorvát 2013), translucent (Vidlička et al 2003), predatory (Vishniakova 1973Liang et al 2009Liang et al , 2012, beetle-like (Vršan-ský 2003a), earwig-like Wei et al 2012aWei et al , b, 2013Guo & Dong 2011), semisocial (Steinmiller 2001Nalepa 2003;Grandcolas et al 2005) and eusocial (Vršanský 2010) forms.…”