The art of deception of orchids: how orchids skillfully use insects to pollinate and reproduce.

When it comes to orchids, people can always think of "elegance, quietness and fragrance". In short, all the good things are stuck on its face. However, do you know that 1/3 of the more than 20,000 orchids in the world are cheating? They never abide by the management norms of animal and plant society, "I produce nectar and you pollinate". Instead, they attract insects with beautiful colors or sweet and attractive smells. These poor bugs not only help orchids spread pollen, but also get no money. What is even more surprising is that some deception tricks of orchids are very simple in our view, and can even be described as rough, but the effect is good, inducing countless insects to volunteer to serve orchids. Such a result is difficult to explain by general cooperation and competition, so that Mr. Darwin, the originator of our evolutionary biology, does not believe that cheaters are mixed in orchids. What tricks can orchids use to induce diseases and force insects to submit? Are these pollinators idiots with poor memory? Are those exotic plants that secretly pollinate just to give insects less food? If insects are not fooled, what should these deceptive plants do? With the deepening of research, the answers to these questions slowly surfaced. The food bait "entered Lan Zhi's room for a long time without smelling its fragrance". I don't think this room is definitely an orchid. No matter how long you smell that strong fragrance, it will still violently impact your olfactory nerve. I remember once traveling to Guizhou with my tutor, Mr. Luo Yibo. As soon as I arrived at the foot of Kishi Mountain, he said, "There are orchids on this mountain." But looking around, there are orchids. As a result, when we climbed to the top of the mountain, there was indeed a bunch of blooming orchids, holding their noses and smelling a sweet smell. However, this sweetness is obviously not prepared to please human beings. The fragrance of Cymbidium hybridum contains common components of flower fragrance such as ethyl acetate, which is a common signpost for China bees to find food, but only Cymbidium hybridum. In the subsequent observation, it is often found that the Chinese bees lured by the smell are swaying like drunkards lured by the smell of wine, heading for the flowers of cymbidium. However, fragrance is not an accurate signal. How to make the lured bees take the bait? Whelan also forged the signboard of the hotel. It's a chestnut red spot on the petals. In our opinion, the spots that affect the beauty of flowers are the favorite of insects such as bees, because they represent food. If you think that the spots on lilies hinder purity, you are wrong. It is no exaggeration to say that the existence of these spots attracts bees to collect nectar, completes the process of spreading pollen, and promotes the love and marriage of lily. Therefore, it is not too much to call them love points. As a result, this universal manna logo was stolen by Cymbidium hybridum. You might think, won't bees see such signs of theft? Usually, the life span of worker bees is only five or six months, and high-intensity pollen honey collection is completed every day. In this case, it is difficult to learn to recognize complex signals. Finding food quickly is the foundation of bees' survival. They don't even have time to tell the truth from the false. Fortunately, most plants provide some nectar and pollen to pollinators in return. Every time I see bees landing on the petals of orchids accurately, and then leave angrily, I really feel that orchids are very smart and it is not easy to sympathize with the life of bees. It's not just Chinese bees that are cheated. You will meet Paphiopedilum microphyllum, which is also stingy, on the karst rocky mountain in Guizhou. It has only one technique-color-bright yellow staminodes are particularly eye-catching, without fragrance and spots, yellow is enough. Just as we saw the capital "M" on the red billboard (recently changed to a black background), we knew there was food. Red and yellow are the main colors of human food, while yellow is the favorite of adult syrphids (larvae eat aphids), representing the color of pollen. In particular, female syrphids have a soft spot for yellow, because they need to get enough protein from pollen to have children. Even the experimental plates painted yellow are very attractive to them. Paphiopedilum is obviously dark, and it has achieved the ultimate in color deception, with only a huge yellow stamen and no redundant color and odor signs. Seeing this sign, syrphids naturally cling to the ground and willingly work as coolies for Paphiopedilum microphyllum. Compared with these simple food temptations, the temptation of sex seems stronger and more professional. After all, choosing a partner is more important than eating and drinking. Mei Lan disguised her flowers as a female wasp, and even the hair on the wasp was disguised on the petals. Not only that, Mei Lan also "smeared" the fragrance of the female bee on the flowers, which fascinated the guys who came to woo, and even contributed their semen to the petals. What's more, Mei Lan, who was successfully pollinated, directly turned into the smell that upset the wasp, from the girl's body fragrance to the grandmother's smell, and closed the door. Ophrys speculum tricked the coolie into coming, and it's not over yet. If you accidentally reveal the clues, the bugs will definitely fly away without looking back. Liar orchid has long thought of this, specially equipped with a device to force insects to pollinate coolies. Petal orchids have some longitudinal stripes on their petals that extend into the flowers. In the eyes of bees, these stripes are signposts that guide them to find nectar. Just follow the road signs. It's a pity that they didn't taste any sweetness in the end. Only when they left angrily did they find the problem coming. Originally, when they landed, their lips pressed down, and the entrance to the honey-seeking channel would become very loose. As the bee arches forward, the petals with changed center of gravity are slightly lifted, and the bee is tightly sandwiched between the lip and pistil. At this time, the pollen blocks will be tightly attached to their backs with the help of sticky plates. After some fierce twists and turns, the bee finally escaped from the narrow passage, but there was one more item on its back. In the flowering period of Phalaenopsis, we can often see coolies carrying pollen blocks flying between the flowers of this liar, looking for nothingness and sweetness. As long as they keep arching, orchids have nothing to steal. Compared with Cymbidium hybridum, the trap design of Paphiopedilum microphyllum is more delicate. It's no exaggeration to say it's a trap. This helmet-like lip is tailor-made for syrphids. It just can't spread its wings, just can't reach the edge of the trap. Fortunately, there is no digestive juice in this trap. Paphiopedilum microphyllum is not as open as Nepenthes. All it has to do is let the syrphids carry pollen. What would you think if you were locked in a room with a skylight? Of course, I escaped through the skylight. That's what syrphids think. This skylight is on the back of the trap. Of course, Paphiopedilum microphyllum will not let syrphids escape in vain. They installed pollen and stigma in the skylight passage. Every aphid who escapes from this place has to put the pollen loaded on the last flower on the stigma, and then put a new one on the stamen to be free. With these organs, even if the deception is a bit clumsy, the liar orchid can get the coolie of pollination. However, bad tricks will always be exposed. Insects are very clever, how should orchids deal with them? High risk and high return? ! Like many pollinators, I often wonder what benefits these deceptive orchids can get. Just to save the energy needed to produce nectar? In later observation, I gradually found that "saving" is not a good reason to explain the derailment of orchids. After all, derailment also comes at a price. This is entirely the behavior of gamblers, and insects always use nectar to identify those plants. And as mentioned above, some orchids are really low-level tricks, and insects are easy to identify. If you are fooled once, you will stay away from orchids and cherish your life. Every time I see those syrphids or bumblebees coming out of Paphiopedilum, I don't care to catch my breath. I just cleaned my wings and quickly fled this troublesome place. It is also for this reason that the seed setting rate of cheating Orchidaceae plants is very low, mostly around 10%, especially the seed setting rate of Cyperus sedge is only 2%. Some researchers in "Cypress Orchid" believe that in order to make up for the shortcomings of poor deception, deceptive orchids can only be opened more and more-if the trap is set more densely and eye-catching, it is always necessary for a fool to hit it. However, flowering is also a luxury. Take Paphiopedilum as an example. There may be thousands of plants on a mountain, but only 180 flowers can bloom a year. Even in the greenhouse, there is good water and good soil, and it is good to bloom every other year. For plants, flowering needs to consume a lot of nutrients, and it can even be said to be an activity that hurts the muscles and bones. On the other hand, for the sake of 2% firmness, it is too big to let the remaining 98% flowers go through the motions. After seeing the dense flower waterfalls with paphiopedilum in northern Guangxi, my doubts about the theory of "saving resources" deepened. It is unreasonable to waste so many flowers in order to save nectar. There seems to be something hidden behind these swindlers' orchids. Paphiopedilum hirsutum, you know, two-thirds of orchids still choose to provide benefits to pollinators. Yunnan Shixintong is such an orchid. They live next to Paphiopedilum with leaves and Phalaenopsis. Of course, bees prefer to spend a long time in Yunnan Shixintong, sucking the last drop of nectar as much as possible, and they will search back and forth on a bunch of flowers (an inflorescence). On the surface, it seems that "loyal" (loyal to nectar) busy bees can deliver more pollen to plants, and the nectar of Yunnan Shixintong is not in vain. However, things are not always so pleasant. These bees sucking back and forth on an inflorescence probably just moved pollen from one flower to another in the same inflorescence, resulting in the "inbreeding" of Xiantao. Just as human inbreeding increases the risk of producing deformed offspring, the offspring produced by inbreeding flowers are mostly weak. Liar orchid seems to be more shrewd at this point. If you can carefully observe that a syrphid or bumblebee has just cleaned its wings and quickly fled from this wrong place, you can realize that these orchids are more ambitious than preserving nectar. Those insects who flee with pollen may have to fly far to rest. If there is the possibility of being cheated again, pollen can only be contributed to orchids far away from the first time. Results Cunning orchids benefited a lot, and long-distance distant hybridization obtained high-quality offspring. Although the adaptability and viability of hybrid seeds need to be further tested, there is evidence that there is indeed a stronger gene exchange between the populations of deceptive orchids compared with those that provide benefits, and orchids with nectar face more pollination in the same plant, which can at least have more combination opportunities than orchids that pollinate themselves in one inflorescence. More combinations mean more hopeful choices. Seeing this, some readers will definitely ask, hybridization is good, but in the face of 2% seed setting rate, liar orchids also need to have a difficult choice, and a slight difference will not be wiped out. It is not worth the risk of losing children and grandchildren in order to improve the quality of future generations. Don't worry about this. Orchidaceae can choose to cheat because it has a special reproductive structure. First, pack the pollen into pieces, so that when the cheated insects move on the flowers, they will take away a lot of pollen, and the sperm inside will be enough to date the same amount of eggs. What's even more amazing is that orchids will firmly fix the pollen on the back and head of pollinators with mucus, sticky boards and the like, and these pollinators have no way to try to pat the pollen. Of course, waiting for these sperm is a considerable number of ovules in the ovary. The combination of the two will naturally produce a large number of seeds. Generally speaking, there are thousands of seeds in every mature orchid fruit. Seeing this, you probably understand that the liar Orchid is gambling a lot, and many of them fail, but once won the lottery, it is often a "five million prize". Evolution: Deception to upgrade or choose "kindness" From the pollinator's point of view, dealing with deceptive orchids is a high-risk behavior. In the field observation, I often see those syrphids that have strayed into the traps of Paphiopedilum macrophyllum and Paphiopedilum microphyllum are caught alive at the exit. Perhaps, at the last moment of their lives, like a little match girl, there are fragrant pollen and sweet nectar floating in front of their eyes. The existence of nature is cruel, we can't accurately identify the trap, but we are worried about our lives. As a result, stupid insects were stuck and eliminated by the power of natural selection, and the recognition ability of insect groups was improved. What should the liar orchid do? The simplest solution is to turn around in a friendly way and provide nectar to the pollinator. In the history of evolution, such a situation is not uncommon. For example, Disha in South Africa has many members who swing like this. Through the study of molecular systematics, it is found that there are both species from honey to non-honey, and species from non-honey to provide honey sources again. Some researchers believe that the poor deception of orchids is a kind of protection for themselves. A limited number of cheats will not make those stupid pollinators extinct. Only a few successful cheats are enough. So orchids like Cymbidium hybridum, Cymbidium hybridum and Paphiopedilum all choose to bloom in early spring or winter. Make out with small insects that have no flowers to harvest first, so as not to affect the reproduction of stupid insects. From this point of view, these liar orchids can be regarded as relaxed. Of course, there are also some swindlers, orchids, who are bent on going dark. Let's look at Paphiopedilum again. Species like Paphiopedilum rigidum and Paphiopedilum microphyllum, which rely on food signals to deceive insects, have limited chances of success after all, and generally do not bear more than 20% of fruits. As a result, some Paphiopedilum glabra have developed stronger destructive tactics, and those black protrusions that look like aphids even grow black hairs. The mother of syrphids can resist the temptation of pollen nectar, but can't resist the attraction of the next generation of food. Every mother of syrphids wants to prepare enough aphids for her children so that they can eat and chew enough aphids as soon as they hatch. Therefore, many mothers of syrphids are trapped by Paphiopedilum longipetalum. But Paphiopedilum longipetalum is better than Paphiopedilum microphyllum, with 90% seed setting rate. At this point, insects and flowers have not reconciled and their struggle will continue. If Paphiopedilum sends deceptive orchids to the evolutionary history for comment, I really don't know whether they are advanced or backward. After all, their risks and benefits are highly uncertain. Of course, I'm not saying that honest orchids are inferior cowards, and their survival skills are just as strong. Only one thing is certain, that is, in this nature, there is no perfect survival plan, only the winning tactics to adapt to the environment. (Shi Jun)