Each species of wasp pollinates only one species of fig, and each fig species has its own wasp species to pollinate it. This extraordinary diversity of coevolution between figs and wasps has become so profound that neither organism can exist without the other. Wasps mature from eggs deposited inside the flowering structure of the fig, called the syconium, which looks very much like a fruit. Inside the completely enclosed syconium are the individual flowers themselves. When a wasp egg is deposited in one of the flowers, that flower develops a gall-like structure instead of a seed. The blind, wingless male wasps emerge from the galls and search out one or more galls containing a female, and upon finding one, he chews a hole in the gall and mates with her before she has even hatched.
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The origin of mutualism is also the beginning of the fig wasp phylogeny. In the phylogenetic tree, the genus of Blastophaga and Wiebesia are very similar.
Both of these genera pollinate Ficus species of figs. These wasps lay fertilized eggs in the syconium of a F. When the larvae hatch, they develop in the fig ovaries , creating a gall. The larvae become adults around the same time male fig flowers are ready to produce pollen. When an adult wasp is mature, it mates with another wasp within the syconium. After mating, females emerge from the fig and search for a new nearby fig in which to lay their eggs. The female then oviposits into a new syconium.
From there, the short life cycle of a B. This idea leads to the concept of fig-fig wasp mutualism. As previously stated, B. This fig can only be pollinated by the symbiotic wasp who has retrieved pollen from another syconium. Female wasps oviposit into the syconium for hatching. When these larvae emerge as adults, they carry pollen that they accumulated in the syconium out of the fig.
Wasps usually oviposit into a nearby syconium. When they oviposit, they are also pollinating that syconium. There is a major difference between male and female fig trees. Due to the fact that wasps do not have very long ovipositors, they can only parasitize ovaries of these female flowers with short styles which are only found on male trees.
All female flowers on male trees with parasitized ovaries with wasp eggs produce larva and no seeds. All female flowers on male tree with ovaries that are not parasitized with wasp eggs will produce seeds and will help pollination and reproduction of that flower. Because of this lack of depositing eggs in these female flowers, all female flowers on female trees produce seeds and none produce larva. Also, it is near impossible for wasps to emerge from a fig if they cannot perform oviposition.
This leads to the trend that female trees are lethal since wasps are stuck in that syconium. This also implies that the fig wasp population is much more active and larger in the spring. The spring and winter caprifigs have a cycle related to each other as to maximize resources and output of figs and wasps. Winter, or delayed, caprifigs usually occur on male trees. Spring, or undelayed, caprifigs usually occur on female trees. Because female trees are lethal, wasps prefer these delayed caprifigs of male trees.
In the case of B. Figs emit compounds that the wasps can sense. Pentane extracts from figs which are in their receptive-phase will attract B.
Upon sensing these signals from a specific syconium, the wasp will approach that fig. The wasps assess the figs before entrance.
They do this by holding up their heads and antennae next to the opening of the syconium the ostiole. The actual attractive substances come from the ostiole.
If a wasp detects the signal, it will lower its antennae and will search for the entrance to the fig. Both smell and taste also help actual entrance into a fig once the desired fig has been located.
If the wasp does not detect a signal, it will not enter the fig. Instead, it will move on and search for another receptive fig. Because these wasps have such short lives, selection has favored this attraction towards receptive plants to be easily distinguishable from a few meters. Due to the difference in male and female trees, male tree figs are more attractive than female tree figs as caused by selection.
Sometimes mating occurs before the female has finished emerging from its cocoon. Some fall from the fig to the ground. They have no wings and die shortly after. The enlarged opening enables the females to leave the syconium in search of a new one where to oviposit.
Mating occurs within the syconium and laying eggs occurs in a syconium different than the one where mating occurred. This can lead to some flowers not being pollinated because some styles are too long. Each larva from a deposited egg destroys a female flower when it feeds on its growing seed. When wasps emerge from the syconium, they rush to the nearest syconia. This rush creates a large number of wasps all competing to enter an adjacent syconium.
Due to this rush, pollination will become less effective as more pollen falls off of the wasp bodies. The number of offspring is low when the entry number of wasps in a syconium is high. The mother produces this hyperplastic tissue when she lays the eggs in the syconium.
The ants use the fig-fig wasp mutualism to find the fig wasps by detecting an odor that comes from the figs of the male trees. They know that most fig wasps are located on male fig trees, so they use that relationship to prey on wasps. This concept is called associative learning of odor because the ants are indirectly finding these wasps by associating the smell of the fig with the wasps.
However, some ants do not respond to the odor of figs for different reasons. For instance, the fig could be a non-pollinator and therefore not release any chemical substance. In the case where the ants cannot detect odors, the wasps will not be predated upon. When a B. These nematodes then invade, feed, and reproduce inside the floret tissues. Larvae finish development with nematode still inside the hemocoel.
After fertilization, females emerge from a syconium with nematodes still in hemocoel along with pollen flakes along her body. Because this nematode is primarily found in the hemocoel of a female wasp, males are not associated with nematodes. The specific problem is: Caution: Mostly incorrect. Needs expert revision. WikiProject Biology may be able to help recruit an expert. February B. By being a cleptoparasite, P. This layering of ovipositing causes the larvae of P. While the nematodes as parasites are not lethal to B.
The wasps carry this disease on their wings and body. Fig endosepsis is not transmitted transovarily by the fig wasp. The wasps become contaminated with spores of the fungus as they contact plant surfaces upon emergence. Studies show that wasps on upper surfaces of the leaves were infected with this fungus in higher levels than other wasps. Wasps who were higher up in the tree or further out on a branch also showed more fungus on their wings and bodies.
This led to the conclusion that contamination increases as the wasps walk on leaves, petioles, and fruits before they reach the opening to the syconium.
This fungus affects both males and females. The fungus shows to be more evident in spring caprifigs that are pollinated with 5 to 10 winter caprifigs than when spring caprifigs are pollinated with only one winter caprifig. Also, the incidences of this fungus are higher when there is a high population of wasps with limited figs. The more wasps that pass through one ostiole, the more likely the wasp will contract F.