The orchid mantis, Hymenopus coronatus, is known for its resemblance to a flower, a form of camouflage it uses to ambush prey. Native to the tropical forests of Southeast Asia, this insect has delicate, petal-like legs and vibrant coloration that can shift between white and pink. The orchid mantis exhibits extreme sexual dimorphism, meaning males and females have distinctly different characteristics. These differences extend to their physical form, behavior, and life history, shaping their roles in survival and reproduction.
Key Physical Distinctions
The most apparent difference between the sexes is their size. Female orchid mantises are substantially larger, reaching lengths of up to 7 centimeters. In contrast, males are considerably smaller and more slender, measuring only about 2.5 to 3 centimeters. This size disparity is directly linked to their different life strategies.
A definitive method for distinguishing between them is by examining the underside of their abdomen and counting the segments. An adult female will have six visible abdominal segments, whereas an adult male possesses eight. This method is accurate and can be used to identify the sex in younger mantises, known as nymphs, though it becomes easier as they mature.
Other physical markers also set the sexes apart. The male’s antennae are longer and more feathery compared to the female’s, which helps them detect chemical signals, or pheromones, released by females. Another indicator is the “neck shield” or crown on the thorax; females may display a prominent green or brown marking that is much smaller or absent in males. The petal-like lobes on the legs are also more pronounced on the larger females.
Behavior and Lifespan Differences
The physical dimorphism between male and female orchid mantises influences their behavior, especially their mobility. Adult males are nimble and capable fliers, spending much of their time actively searching for mates. Their small, lightweight bodies are well-suited for flight, allowing them to cover more ground.
Conversely, adult females are largely sedentary. Their greater size and weight make them incapable of flight, so they adopt a “sit-and-wait” predatory strategy. They remain motionless among flowers, waiting for pollinating insects to come within reach, which conserves energy needed for egg production.
These lifestyles are mirrored in their development and lifespan. Males mature much more quickly than females and their overall lifespan is briefer, lasting only a few months. Females take longer to mature and can live for up to a year, which is necessary to support the development and laying of large egg cases. Males tend to be more skittish, while the larger females are often calmer but can be aggressive hunters.
Implications for Mating
The differences between the sexes are evolutionary adaptations tied to their reproductive roles. The male’s small size, keen senses, and ability to fly are traits that enhance his objective of locating a female. Since females are stationary, an active male has a better chance of finding a partner.
The female’s large body size allows her to hunt larger prey and accumulate the resources to produce a substantial egg case, known as an ootheca. After mating, she can lay a foamy pouch containing up to 100 eggs, and her larger body provides the energy reserves to guard them.
This dynamic also introduces the risk of sexual cannibalism. The larger female may view the approaching male as prey, and he risks being eaten before, during, or after mating. The male’s agility and cautious approach are important for his survival. He may approach the female carefully, sometimes tapping her back to signal his intentions or waiting until she is distracted with a meal before mating. His ability to fly provides a quick escape route if the encounter turns aggressive.