Mantodea

Mantodea (commonly known as praying mantises, from the Ancient Greek mantis, "prophet / diviner," referring to the prayer-like resting posture of their folded raptorial forelegs) is an order of hemimetabolous, exclusively predatory insects comprising approximately 2,500 described species across ~30 families and 430 genera. Together with their sister order Blattodea (cockroaches and termites), Mantodea forms the superorder Dictyoptera, having diverged from cockroach-like ancestors during the Late Jurassic to Early Cretaceous (~145–135 million years ago, with early stem fossils such as Santanmantis armed with spiny raptorial forelegs preserved in Crato Formation limestone).

Every praying mantis is an ambush or pursuit carnivore engineered around three neurobiological and biomechanical specializations:

1. Raptorial Prothoracic Forelegs: Greatly elongated prothoracic coxae, femora, and tibiae armed along their opposing ventral margins with interlocking rows of sharp femoral and tibial spines (plus a specialized basomedial discoidal spine battery) that snap closed around insect, arachnid, or small vertebrate prey in 50 to 70 milliseconds.
2. True Binocular 3D Stereopsis: Forward-facing, high-acuity compound eyes mounted on a triangular head capable of 180° azimuth rotation on a flexible prothoracic neck; mantises are the only invertebrates experimentally proven to possess true stereopsis (computing 3D target distance from binocular retinal disparity).
3. A Single Midline "Cyclopean" Ultrasonic Ear: In the ~70% of mantis species with flying males, a single unpaired tympanal auditory organ is recessed inside a deep longitudinal groove in the ventral midline of the metathorax between the hind coxae, detecting 25–100 kHz bat echolocation calls and triggering an immediate aerial power dive.

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` Superorder Dictyoptera (Carboniferous–Jurassic divergence) ├── Order Blattodea (Cockroaches & Termites [Isoptera]: ~7,600 detritivorous/wood-feeding spp.) └── Order Mantodea (Praying Mantises: ~2,500 obligate predatory spp.) ├── Basal Relict Families (Cockroach-like runners with short prothorax & unspecialized raptorial spines) │ ├── Family Chaeteessidae (Chaeteessa: Neotropical bark runners; lack terminal tibial claw) │ ├── Family Mantoididae (Mantoida: small Neotropical ant/wasp mimics) │ └── Family Metallyticidae (Metallyticus splendidus: brilliant iridescent metallic blue-green bark hunters of SE Asia) │ └── Core Eumantodea (Elongated prothorax, full tibial terminal hook, & cyclopean metathoracic ear) ├── Superfamily Eremiaphiloidea (Eremiaphilidae: wingless high-speed desert sand-runners of North Africa/Middle East) ├── Superfamily Hymenopoidea ("Flower Mantises": Hymenopodidae & Empusidae) │ ├── Hymenopus coronatus (Malaysian Orchid Mantis: petal-lobed femora & UV-absorbing floral aggressive mimicry!) │ ├── Idolomantis diabolica (Devil's Flower Mantis) & Gongylus gongylodes (Violin Mantis) │ └── Phyllocrania paradoxa (Ghost Mantis: crinkled dead-leaf crypsis) ├── Superfamily Acanthopoidea & Gonypetoidea (Dead-leaf mimics: Acanthops, Deroplatys) └── Superfamily Mantoidea (Typical Mantises: Mantidae, Hierodulidae, Tenoderidae, Toxoderidae) └── Mantis religiosa, Tenodera sinensis (Chinese mantis), Stagmomantis carolina, Sphodromantis, Hierodula

A striking mantis (Tenodera sinensis or Stagmomantis) does not use a passive elastic catapult like a grasshopper (Orthoptera) or mantis shrimp; instead, it executes a visually guided, two-phase muscular strike that continuously adjusts to prey distance and elevation:

1. Preparatory Stalking and Peering Parallax: While approaching prey, the mantis sways its head and prothorax rhythmically from side to side (peering behavior), using motion parallax to calibrate rough target distance before locking the prey image onto the central fovea of both compound eyes.
2. Phase 1 — Coxal Promotion and Tibial Extension (0–30 ms): Simultaneously, the elongated fore-coxa swings forward at the prothoracic joint while the tibia extends partway open relative to the femur, positioning the open spined trap just below and behind the prey.
3. Phase 2 — Body Lunge and Femoro-Tibial Snap Closure (30–65 ms): The middle and hind legs rapidly extend to lunge the entire prothorax forward while the powerful tibial flexor muscle snaps the sharp terminal tibial hook and ventral tibial spines shut against the opposing femoral and discoidal spines, locking the prey inside a serrated mechanical vice. Because the strike is driven by direct synchronous muscle contraction rather than a pre-cocked spring, the mantis can scale its lunge amplitude and strike duration (50 to 80 ms) to match the exact 3D coordinates computed by its visual system!

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Each compound eye of a praying mantis contains 8,000 to 10,000 ommatidia with a broad 70° binocular overlap field directly in front of the head. Within the frontal-central region lies a depressed fovea (acute zone) where enlarged flat facets and long rhabdoms achieve an inter-ommatidial angular resolution of 0.5° to 0.6°.

In a landmark series of experiments beginning with Samuel Rossel (1983) and expanded by Vivek Nityananda and Jenny Read (2016, 2018), researchers fitted praying mantises (Sphodromantis lineola) with miniature red–blue/green 3D anaglyph glasses affixed to the forehead with beeswax and presented virtual computer-generated prey on an LCD monitor:

• When the virtual prey was displayed at a simulated 3D binocular disparity corresponding to the mantis's natural strike range (2.5 cm in front of the face, even though the physical monitor screen was 10 cm away!), the mantis struck repeatedly into empty space at 2.5 cm.
• Crucially, mantis stereopsis operates via a fundamentally different computational algorithm than human/primate stereopsis:
  • Human Cortical Stereopsis (Cross-Correlation of Static Contrast): Human V1 binocular neurons cross-correlate static luminance patterns between the left and right retinas, allowing humans to see 3D depth in stationary random-dot stereograms; if one eye's dots are contrast-inverted (black dots in the left eye, white dots in the right eye: anti-correlated stereograms), human stereopsis completely breaks down.
  • Mantis Lobula Stereopsis (Kinetic Temporal-Change Disparity): Mantises are completely blind to static random-dot stereograms. Instead, binocular neurons (T5 and wide-field lobula complex neurons connected across the brain hemispheres by a commissural feedback loop) compute disparity strictly between locations where luminance is actively changing over time (temporal kinetic contrast)—allowing a mantis with only ~1 million total brain neurons (vs. 86 billion in humans) to solve the stereo correspondence problem and even strike accurately at anti-correlated moving targets that baffle the human visual cortex!

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1. The Single Midline Metathoracic Ear (Yager & Hoy, 1986)

For centuries, praying mantises were assumed to be completely deaf because they never produce acoustic mating calls and lack tympana on their legs or abdomen. In 1986, David Yager and Ronald Hoy discovered that flying mantises possess a single, midline "cyclopean" ear located inside a narrow vertical slit between the metathoracic coxae:

• Inside the deep cuticular cleft, two opposing tympanal membranes face each other less than 0.1–0.2 mm apart, backed by tracheal air sacs and innervated by a pair of auditory organs containing ~30–45 scolopidial neurons.
• Because the two eardrums are separated by less than a fifth of a millimeter (far smaller than the ~7–14 mm wavelength of 25–50 kHz ultrasound), the cyclopean ear cannot determine the left-versus-right direction of an approaching bat. Instead, it acts as an omnidirectional ultrasonic warning detector: a single interneuron (501-T3) fires a high-frequency burst when a hunting bat approaches within 5–10 meters, triggering full extension of the forelegs, dorsal abdominal curling, and a steep spiral power dive at 2× normal flight speed that reduces bat capture success from 80% (in experimentally deafened mantises) to <20%.
• Remarkably, in the 60+ independent lineages of mantises where females evolved flightlessness (brachyptery or aptery), the female's metathoracic ear became anatomically degenerate and ultrasonically deaf, while the flying conspecific male of the exact same species retains a fully functional ultrasonic ear!

2. Aggressive Floral Mimicry (Hymenopus coronatus) and Sexual Cannibalism

• The Malaysian Orchid Mantis (Hymenopus coronatus): Rather than hiding among flowers to ambush pollinators, juvenile female Hymenopus coronatus expand their Meso- and Metathoracic femora into four flattened, pink-and-white petal-like lobes while synthesizing epidermal pigments (3-hydroxykynurenine and ommochromes) that reflect visible wavelengths while absorbing ultraviolet (UV) light at the body core—creating an optical floral bullseye that attracts foraging hymenopteran pollinators (bees and hoverflies) at rates exceeding those of real tropical flowers (O'Hanlon et al., 2014), representing the only verified case of a whole-body flower-mimicking aggressive lure in animals.
• Foam Oothecae and Sexual Cannibalism: Female mantises deposit 50 to 400 eggs inside a frothy ootheca whipped from accessory-gland silk-like proteins (*fibroin-like` coiled-coil proteins cross-linked by catecholamine quinone tanning) that hardens into a rigid, multi-chambered polyurethane-like insulating foam able to survive sub-zero winter temperatures. During or immediately prior to copulation in ~15–30% of natural encounters (in genera such as Mantis, Tenodera, and Pseudomantis), nutrient-limited females practice sexual cannibalism—consuming the smaller male from the head downward. Because the subesophageal ganglion in the mantis head normally exerts tonic neural inhibition over the copulatory central pattern generator in the terminal abdominal ganglion (A8/A9), decapitation actually releases the male's abdomen into vigorous, autonomous copulatory flexion and spermatophore transfer, while radio-isotope labeling (Tenodera sinensis and Pseudomantis albofimbriata) demonstrates that amino acids from the cannibalized male's body are directly incorporated into the female's developing eggs, increasing oothecal mass and offspring count by 30–40%.

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1. Svenson, G. J., & Whiting, M. F. (2009). Reconstructing the origins of praying mantises (Dictyoptera, Mantodea): the roles of Gondwanan vicariance and morphological convergence. Cladistics, 25(5), 468–514. Google Scholar%3A%20the%20roles%20of%20Gondwanan%20vicariance%20and%20morphological%20convergence)
2. Nityananda, V., Tarawneh, G., Henriksen, S., Umeton, D., Simmons, A., & Read, J. C. (2018). A novel form of stereo vision in the praying mantis. Current Biology, 28(4), 588–593. Google Scholar
3. Yager, D. D., & Hoy, R. R. (1986). The cyclopean ear: a new sense for the praying mantis. Science, 231(4739), 727–729. Google Scholar
4. O'Hanlon, J. C., Holwell, G. I., & Herberstein, M. E. (2014). Pollinator deception in the orchid mantis. American Naturalist, 183(1), 126–132. Google Scholar

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• Insecta
• Blattodea
• Orthoptera
• Sensory Transduction
• Natural Selection