A True Environmentalist – The Mantis

Among the vast array of insects that inhabit our world, few command as much attention and intrigue as the praying mantis. Characterized by its iconic folded front limbs that resemble a posture of prayer, the praying mantis stands out not only for its distinctive appearance but also for its exceptional predatory skills. Delving into the world of this remarkable insect unveils a realm of stealth, precision, and brilliance.

To begin with, the term “praying mantis” commonly refers to any of the insects within the order Mantodea, which comprises over 2,400 species spread across numerous families. These insects are predominantly found in tropical regions, but they are also native to temperate zones around the globe. Their size can vary considerably, with some species measuring just a few centimeters, while others reach up to 10 centimeters or more.

One of the most striking features of the praying mantis is its head. Equipped with large, well-developed compound eyes that grant them a wide field of vision, mantises have the unique ability among insects to turn their heads from side to side. This allows them to scan their surroundings with minimal movement, making them efficient ambush predators. Coupled with their keen eyesight, mantises have specialized elongated front limbs designed to rapidly extend and snatch their prey. These limbs, covered in sharp spines, hold the prey securely, rendering escape nearly impossible.

The compound eyes of the Mantis religiosa, or European mantis, are marvels of natural engineering, optimized for the predatory lifestyle of these insects. Here’s a closer look at the features and functions of these compound eyes:

Structure: Like other insects, the mantis has compound eyes, which means each eye is made up of numerous small visual units called ommatidia. Each ommatidium functions like a mini-eye, collecting light and forming a part of the overall image that the mantis sees.

Wide Field of Vision: Due to the prominent placement and large size of their eyes, mantises have a broad field of vision. This wide field allows them to spot potential prey or predators from various angles.

Binocular Vision: One of the most remarkable features of the mantis’s vision is its capacity for binocular vision, which is the ability to perceive depth by gauging the difference in the image seen by each eye. This is especially important for a predator like the mantis, as it allows them to accurately judge the distance to their prey. The forward-facing placement of their eyes gives them a region of overlap in their visual fields, enabling this depth perception.

Motion Detection: While the resolution of compound eyes is generally not as sharp as the single-lens eyes found in vertebrates, they are exceptionally good at detecting motion. This motion sensitivity is crucial for a predatory insect like the mantis, allowing them to react swiftly to moving prey or potential threats.

Polarized Light Sensing: Some studies suggest that certain insects, including mantises, can detect polarized light with their compound eyes. This ability can help them locate water sources or recognize different types of reflections in their environment.

Color Vision: Mantises are believed to have color vision, although it differs from human color perception. They can perceive some wavelengths of light that are vital for their hunting and environmental interactions.

Adaptation to Light Changes: The compound eyes of the mantis can adapt to varying light conditions. They have more light-sensitive cells for low-light conditions, allowing them to be active during dawn and dusk. In bright light, certain cells reduce their sensitivity to prevent overstimulation.

Pseudopupil: When observing a mantis closely, one might notice a dark spot in its eyes that appears to move. This is the pseudopupil, and it’s not an actual pupil but an optical effect. It represents the ommatidia that are oriented directly at the observer, and it appears dark because the light entering those ommatidia is absorbed and doesn’t reflect back.

The compound eyes of the Mantis religiosa, as with other mantis species, are integral to their predatory lifestyle. Their ability to detect motion, judge distances, and perceive their surroundings in various light conditions makes them efficient hunters and fascinating subjects of study in the world of entomology.

The praying mantis’s predatory nature doesn’t just stop at small insects. Astonishingly, larger mantis species have been observed catching and consuming small vertebrates, including frogs, lizards, and even birds. Their hunting strategy relies on camouflage and patience. Mantis species come in a range of colors and patterns, allowing them to blend seamlessly into their surroundings—be it on leaves, flowers, or tree trunks. Once an unsuspecting prey comes within reach, the mantis snatches the prey with lightning speed.

Reproduction in the mantis world is equally as fascinating, albeit with a dark twist. It’s well-documented that female mantises, in certain conditions, may consume their male counterparts after or even during mating—a phenomenon known as sexual cannibalism. This behavior, while gruesome, is thought to provide the female with necessary nutrients for successful egg production.

Eggs laid by female mantises are encased in a protective foam-like substance called an ootheca. This structure safeguards the developing nymphs inside from potential threats and environmental conditions. When the time is right, dozens, or even hundreds, of tiny mantis nymphs emerge, already resembling miniature versions of their adult counterparts.

The life cycle of a praying mantis in North America consists of three main stages: egg, nymph, and adult. Here is a detailed overview of the life cycle of mantises in North America:

Egg Stage (Ootheca):

• • Oviposition: In late summer or early fall, after mating, a female mantis lays her eggs. She produces a frothy protein substance that hardens quickly, forming a protective case called an ootheca. This structure can contain anywhere from several dozen to a few hundred eggs, depending on the species.
  • Overwintering: The eggs inside the ootheca go through a diapause, or period of dormancy, during the winter months. The tough ootheca protects the eggs from harsh environmental conditions, including the cold temperatures of North American winters.

1. • Hatching: As temperatures warm in the spring, the eggs inside the ootheca complete their development. After a few weeks to a few months, depending on the species and local conditions, tiny mantis nymphs emerge from the ootheca.

Nymph Stage:

• • First Instar: Upon emerging, mantis nymphs are in their first instar stage. They already resemble miniature versions of adult mantises but lack wings.

• • Molting: As nymphs grow, they undergo a series of molts, shedding their old exoskeleton to allow for growth. Each stage between molts is called an instar. Mantises usually go through 5 to 10 instars, depending on the species and environmental conditions.
  • Development: Throughout their nymphal stages, mantises actively hunt and consume prey, gradually increasing in size. With each molt, they look more and more like smaller versions of their adult form.

Adult Stage:

• • Maturation: After the final molt, mantises reach their adult form, now equipped with fully developed wings (though not all species are strong fliers). Adult mantises continue to be voracious predators.
  • Reproduction: In late summer, adult mantises engage in mating. Males often approach females cautiously, as there’s a known risk of cannibalism by the female during or after mating.

• • Lifespan: After mating and laying eggs, the adult mantises have completed their life cycle. They usually live for a few more weeks to a couple of months, but as winter approaches, most adult mantises in North America will die off. The next generation is left behind in the form of oothecae, ready to begin the cycle anew the following spring.

The praying mantis’s predatory nature doesn’t just stop at small insects. Astonishingly, larger mantis species have been observed catching and consuming small vertebrates, including frogs, lizards, and even birds. Their hunting strategy relies on camouflage and patience. Mantis species come in a range of colors and patterns, allowing them to blend seamlessly into their surroundings—be it on leaves, flowers, or tree trunks. Once an unsuspecting prey comes within reach, the mantis snatches the prey with lightning speed.

Reproduction in the mantis world is equally as fascinating, albeit with a dark twist. It’s well-documented that female mantises, in certain conditions, may consume their male counterparts after or even during mating—a phenomenon known as sexual cannibalism. This behavior, while gruesome, is thought to provide the female with necessary nutrients for successful egg production.

Eggs laid by female mantises are encased in a protective foam-like substance called an ootheca. This structure safeguards the developing nymphs inside from potential threats and environmental conditions. When the time is right, dozens, or even hundreds, of tiny mantis nymphs emerge, already resembling miniature versions of their adult counterparts.

Perhaps the greatest threat, not considering birds, bats, spiders, frogs, and lizards is people.  More specifically, people with pesticides/insecticides.

Praying mantises, like many other beneficial insects, are affected by insecticides. Insecticides are designed to control or kill insect pests, but they often do not discriminate between pests and beneficial insects. When mantises come into contact with these chemicals, either directly or through their prey, they can be harmed or killed.

There are several ways in which mantises can be affected by insecticides:

Direct Contact: If insecticides are sprayed and mantises are directly hit by the spray, they can absorb the toxic chemicals through their exoskeleton or ingest them while grooming. This can lead to immediate death or chronic effects, such as reduced ability to hunt, reproduce, or avoid predators.

Residual Contact: Even after the insecticide has dried or settled, residues remain on surfaces like plants, soil, or other structures. Mantises that walk or rest on these surfaces can absorb the toxicants, leading to similar negative effects as direct exposure.

Prey Consumption: If a mantis consumes an insect that has ingested or come into contact with insecticides, the toxicants can be transferred through the food chain, a phenomenon known as secondary poisoning. For example, if a mantis eats a bug that has consumed insecticide-treated plants, the chemicals can affect the mantis.

Reproductive Effects: Some insecticides may impact the reproductive capabilities of mantises, either by affecting adults directly or by affecting their eggs or nymphs. For instance, a female mantis exposed to certain insecticides might lay fewer eggs, or the eggs she lays might have reduced viability.

Disruption of Ecosystem Balance: Broad-spectrum insecticides can significantly reduce the number of available prey insects in an area. This can starve mantises or force them to move to new areas in search of food, exposing them to new risks.

Given these potential harms, it’s crucial for gardeners and farmers to consider the broader ecological impacts when using insecticides. Opting for targeted treatments, natural alternatives, or integrated pest management (IPM) practices can help minimize harm to beneficial insects like the praying mantis.

Mantis religiosa, commonly known as the European mantis, is one of the most well-known species of praying mantises. Its dietary consumption, like other mantises, varies based on factors such as size, gender, and reproductive status. However, for a rough estimate:

An adult Mantis religiosa can consume insects roughly equal to its body size daily, especially when active or gravid. In terms of weight, it might eat prey amounting to 20-30% of its body weight in a day, though this can vary.

For a tangible example, an adult female Mantis religiosa, which can reach lengths of about 7-9 cm, might consume 2-3 medium-sized crickets, several moths, or a comparable volume of other insects daily. However, it’s essential to note that consumption can be sporadic; a mantis might eat a significant volume of insects one day and then eat very little or nothing the next, depending on the availability of prey and its energy requirements.

In general, Mantis religiosa is a voracious predator and will consume a variety of insects throughout its life, helping regulate pest populations in environments where it is present.  Since the lifecycle is a full year, gardeners and farmers wanting to use the mantis for pest control should allow a full year for the mantis to lay ootheca’s and increase their population.

For those wanting to increase the mantis population immediately, Oothecas can be purchased in bulks and deposited in the fields as needed for the spring hatching.

The cultural significance of the praying mantis is also noteworthy. These insects have been revered, symbolized, and even emulated in various societies. In ancient China, the mantis was a symbol of courage and fearlessness. Its poised and efficient hunting techniques inspired martial arts forms that sought to mimic its movements. Elsewhere, it has been seen as a symbol of stillness, meditation, and mindfulness.

The praying mantis, with its arresting appearance and impressive predatory prowess, is a testament to great design and ingenuity. The mantis is a master of ambush, camouflage, and precision, it serves as a compelling reminder of the natural controls and the wonders that the insect world. From its unique physical characteristics to its role in cultural mythologies, the praying mantis stands as a captivating emblem of the intricate dance of life on Earth.