Pseudocopulation

Pseudocopulation occurs when a flower mimics a female of a certain insect species, the males of which try to copulate with it. This is much like the aggressive mimicry in fireflies described above, but with a much more benign outcome for the pollinator. This form of mimicry has been called Pouyannian mimicry,[7] after Pouyanne, who first described the phenomenon.[63][64] It is most common in orchids which mimic females of the order Hymenoptera (generally bees and wasps), and may account for around 60% of pollinations.[65] Depending on the morphology of the flower, a pollen sac called a pollinia is attached to the head or abdomen of the male. This is then transferred to the stigma of the next flower the male tries to inseminate, resulting in pollination. Visual mimicry is the most obvious sign of this deception for humans, but the visual aspect may be minor or non-existent. It is the senses of touch and olfaction that are most important. The Hymenoptera are one of the largest orders of insects, comprising the sawflies, wasps, bees and ants. Over 130,000 species are recognized, with many more remaining to be described. The name refers to the wings of the insects, and is derived from the Ancient Greek (hymen): membrane and (pteron): wing. The hindwings are connected to the forewings by a series of hooks called hamuli. Females typically have a special ovipositor for inserting eggs into hosts or otherwise inaccessible places. The ovipositor is often modified into a stinger. The young develop through complete metamorphosis that is, they have a worm-like larval stage and an inactive pupal stage before they mature (See holometabolism). Pseudocopulation describes behaviors similar

to copulation that serve a reproductive function for one or both participants but do not involve actual sexual union between the individuals. It is most generally applied to a pollinator attempting to copulate with a flower. Some flowers mimic a potential female mate visually, but the key stimuli are often chemical and tactile.[1] This form of mimicry in plants has been titled Pouyannian mimicry.[2] Orchids commonly achieve reproduction in this manner, secreting chemicals from glands called osmophores located in the sepals, petals, or labellum, that are indistinguishable from the insect's natural pheromones. The pollinator then has a pollinium attached to its body, which it transfers to the stigma of another flower when it attempts another 'copulation'. Pollinators are often bees and wasps of the order Hymenoptera, and flies. The cost to the pollinating insects might be seen as negligible, but study of Cryptostylis (an Australian orchid) pollinators shows that they may waste large amounts of sperm by ejaculating onto the flower. Thus there could be antagonistic coevolution such that pollinators become better at identifying their own species correctly and orchids become better mimics.[3] African Dwarf Frogs (Hymenochirus boettgeri) in amplexus (more photos) Pseudocopulation is also used to describe close physical contact between mating animals which have their eggs externally fertilized. Frogs provide one such case, with the male releasing sperm as the female discharges her eggs, a process called amplexus.[4] Pseudocopulation is also used as a term to describe behaviours of birds that appear to be copulating but may merely involve mounting and could involve pairs of the same sex.