Question Mantodean oothecae

An ootheca (plural oothecae) is a Latinized version from the Greek terms ōon (egg) and theke (receptacle). Ootheca are also referred to as egg cases or pods. Oothecae can be produced within the female (Blattodea), or the protective shell constructed by the female and the eggs are then deposited within (As in Mantodea). These egg masses are a basal character of the Dictyopterans (Mantodea, Blattodea, Isoptera), but have also convergently developed in other invertebrates such as; Molluscs, Spiders, Caelifera(Orthoptera), Mantophasmatodea, Cassidinae, Hydrophilidae & Chrysomelidae(Coleoptera) and Korinninae(Phasmatodea). 

Mantis oothecae are a complex structure formed by the genitalia of the female mantis during oviposition. They are made up of structural proteins and tanning agents that cause the protein to harden around the eggs. Oothecae appear to have evolved convergently across several invertebrate groups as a successful reproductive strategy, protecting their occupants from the extremes of weather, predation, and parasitisation. The casing of a mantis ootheca is so impenetrable that most parasitization seems to occur during oviposition, as once the shell hardens it becomes inaccessible. 

The composition varies depending upon species and environment; with porous structures to prevent desiccation in dry environments, and smooth waterproofing to protect from over-saturation in wetter climates. Many ootheca seem to be insulated enough to protect their charges over winter, even in sub-zero temperatures and snow, as univoltine Mantodeans overwinter within the ootheca, when an individual would be unable to survive the conditions outside. This seems of particular importance in regions where it snows over the winter months.

Breland noticed during a study on the parasitisation of Mantis oothecae that there was considerable variation between the egg masses produced by different species. Later, Breland, together with Dobson was one of the first to write a paper concerning the specificity of Mantodean oothecae with descriptions for individual species. It is a fantastic paper that very comprehensively describes both differences between species and some variation within species, and describes the multiple differences between the oothecae of the limbata complex, which up until that point was thought to be a single species due to an inability to determine any differences between the adults.

Substrate and point of attachment tend to be diagnostic at various taxonomic levels and can demonstrate considerable variation from the traditional “attachment along the ventral surface”. They can be attached to bark, twigs, leaves, rocks, grasses, or even buried in the ground (some females have evolved digging apparatus on their abdomen for this specific purpose).

The external wall exhibits remarkable variation; smooth to corrugated, pliable to completely unyielding. Colouration tends to be cryptic, anything from dark brown to white, with occasional yellow, green or reddish tones. The external wall can sometimes be coated in a spongy material which wears away with time, so oothecae that were collected when they had been in the environment for a lengthy duration may differ from those that are freshly deposited. A good example of this is the recently described Carrikerella simpira; whose ootheca when freshly deposited is covered in a pale-brown, air-bubble filled spongy layer, but when this has worn away; “the ootheca itself has a thick, yet flexible, external wall that is carmine red in colour” Rivera & Callohuari (2019).

Multiple researchers have concluded that mantis oothecae are taxonomically relevant, morphological characters were found to be consistent and characteristic of the species that produced them. It is expected that they now be included where possible in species descriptions and the information they can provide appropriately utilized; especially since oothecae may be the only evidence that can be found of certain species (especially in temperate regions) all through the year.

This is a project I have been working on for a few years now and intend to turn into an Honours project, which will involve some work with DNA Barcoding to verify samples (both collected by me and museum specimens on loan) followed by a full description of the morphology of as many species oothecae as humanly possible. We’ll also be doing a photographic record and a systematic key which should help people to identify any oothecae they find in the wild.

I highly appreciate contributions made to my work, so if anyone spots a mantis or an ootheca please do contain it and get in touch! My email is This email address is being protected from spambots. You need JavaScript enabled to view it. and is the best way to contact me. Don’t forget to include details like collection date, your full name and the location you found the specimen, as I’ll need to include those on the specimen label. 

References 
Brannoch, S. K. Wieland, F. Rivera, J. Klass, K-D. Béthoux, O. Svenson, G. J. 2017. Manual of praying mantis morphology, nomenclature and practices. 2017. ZooKeys 696:1-100. 
Breland, O. P. “Podagrion mantis (Ashmead) and other parasites of praying mantid egg cases”. 1941. Annals Entomological Society of America Vol. XXXIV, Pages 99-113. 
Breland, O. P. Dobson, J. W. 1947. “Specificity of Mantid Oothecae (Orthoptera: Mantidae)”, Annals of the Entomological Society of America, Volume 40, Issue 4, Pages: 557–575, doi.org/10.1093/aesa/40.4.557  
BRUNET, P. C.J. (1951-06-01). "The Formation of the Ootheca by Periplaneta americana : I. The Micro-anatomy and Histology of the posterior part of the Abdomen". Journal of Cell Science. S3-92 (18). ISSN 0021-9533.  
Goldberg, J. Bresseel, J. Constant, J. Kneubühler, B. Leubner, F. Michalik, P. Bradler, S. (2015). “Extreme convergence in egg-laying strategy across insect orders”. Scientific Reports 5:7825 
Grimaldi, David; Engel, Michael S. (2005-05-16). Evolution of the Insects. Cambridge University Press. p.230. ISBN 9780521821490.  
Keller, Laurent (1998-03-01). "The Evolution of Social Behavior in Insects and Arachnids. Jae C. Choe, Bernard J. Crespi". The Quarterly Review of Biology. 73(1): 110–111. doi:10.1086/420149. ISSN 0033-5770  
Matthews-Cascon, Helena; Rocha-Barreira, Cristina de Almeida; Meirelles, Carlos; Bigatti, Gregorio; Penchaszadeh, Pablo (April 2009). "Description of the ootheca of Turbinella laevigata (Mollusca, Gastropoda)". Brazilian Archives of Biology and Technology. 52(2): 359–364. 
Rivera, J. Callohuari, Y. (2019). “A new species of praying mantis from Peru reveals impaling as a novel hunting strategy in Mantodea [Thespidae: Thespini]”. Neotropical Entomology. doi.org/10.1007/s13744-019-00744-y

Images (left to right); Othrodera ministralis female with ootheca and nymphs.
Archimantis sobrina, ootheca and nymphs.
Archimantis latistyla male, female and oothecae.
Pseudomantis albofimbriata female, nymphs and oothecae.