Australian and new Zealand scientists have found that orchids of the genus Cryptostylis markedly reduce the reproductive success of pollinating their riders. The flower of these plants mimics the female wasp and the male trying to mate with him, spend an average of ten percent of the total stock of sperm. This can not only negatively affect the success of reproduction, but also affect the demographic structure of the whole population, argues in an article published in the journal Functional Ecology.
The flowers are approximately four hundred species of orchids in the evolution of acquired similarity with the female insects. The purpose of this simulation, sometimes very skilled, is pollination. False females are attracted to males that try to mate with them and carry pollen from flower to flower. The most famous example of this Orchid, which pchelovodny (Ophrys apifera).
It may seem that deceived the insect does not lose anything, except time. However, if pseudocopulation often spent cum, the production of which is energy-costly. In some species of insects, primarily parasitoids riders, and its supply is limited and not replenished during life. This means that overly promiscuous, the male runs the risk of significantly reduce its reproductive success.
A team of researchers headed by Amy Branton Martin (Amy L. Brunton Martin) evaluated the harm done to males ichneumonid riders Lissopimpla excels Australian orchids liars of the genus Cryptostylis. The flowers mimic females of the riders, not only appearance, but also smell.
The researchers conducted a series of field experiments, which showed male riders flowers Orchid C. subulata or C. erecta. The work took place on six different sites, three of which have natural populations of these plants and the other three not. The authors allowed the part of males to mate with orchids and compared the remaining the stock of sperm that had individuals in contact with orchids.
It turned out that pseudocopulation with a fake female reduces sperm have deceived male L. excels in an average of ten percent. While individuals from areas where they grew orchids, each pairing spent less sperm than their relatives from the areas where these plants were not. The authors believe that this may be an adaptation to offset damages from fraud. However, there is an alternative explanation: it is possible that males produce less sperm at each mating, if you meet more females, both real and fake.
Like most Hymenoptera, L. excels haplodiploid, that is, in females there is a double set of chromosomes, and males have a single. Fertilized eggs appear new females, and unfertilized males. This means that spending sperm on orchids, little liars can not only reduce the reproductive success of individual males, but also to shift the sex ratio in the entire population in favor of the insidious plants. The more sperm will spend males into fake females, the more males will be born in the next generation and the higher the chance for the pollination of orchids.
Most animal pollinated plants rely on insects, however, this rule has many exceptions. For example, recently it was foundthat the parasitic plant Scybalium fungiforme from Brazilian forests attracts for pollination Bolshevik of opossums (Didelphis aurita).