Behavior And Ecology

The mating behavior of archaeognathans is unique. There are three different modes of sperm transfer. In the most widespread and unique mating behavior, a carrier thread is used. In Machilis germanica, for example, the male approaches the female and drums on her with his long maxillary palps. The female shows "willingness" to mate by moving toward the male and bending up the tip of her abdomen. The male then attaches a secreted thread to the ground with his parameres. While the thread is being drawn out, the male secretes three to five sperm droplets onto the thread (Fig. 4). The male curves simultaneously around the female, preventing her from moving forward. Finally, the male places the sperm droplets onto the ovipositor of the female. The indirect transmission of sperm droplets, which are deposited on a thread stretched between parameres and the ground, is unique within the animal kingdom. At least two other possibilities of indirect sperm transfer are known. In Petrobius (Machilidae), the sperm are moved directly from the penis onto the ovipositor of the female and in all Meinertellidae sperm are transferred by stalked spermatophores deposited on the ground.

Archaeognatha are found in habitats with very different climates. Representatives of the genus Allopsontus (Machilidae) are found up to 5000 m in the Himalayan region. In contrast, two meinertellid species live in the Amazonian forest. Some genera (e.g., Petrobius) are found near the seacoast. In tropical forests, meinertellid genera are found on the leaves of bushes and trees. Most Archaeognatha feed on green algae, lichens, and dead leaves. Several species of spiders probably are their principal predators.

Their protection against enemies is probably provided by three main factors: (1) the presence of long appendages with sensilla (filum terminale, cerci, antennae); (2) a dense scale cover on the relatively thin and flexible tergites and coxites; and (3) their ability to jump, which is fully developed in all free-living stages and in all recent representatives, and probably is their most effective defense.

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