Fig wasp - Wikipedia
Fig wasps are wasps of the superfamily Chalcidoidea which spend their larval stage inside figs. . The fig–wasp mutualism originated between 70 and 90 million years ago as the product of a unique evolutionary event. . "Phylogenetic relationships, historical biogeography and character evolution of fig-pollinating wasps". Here begins the story of the relationship between figs and fig wasps. pouches have a responsibility to uphold in the mutualistic relationship. “Figs and the wasps that pollinate them present one of biologists' favorite examples of a beneficial relationship between two different species.
- New phase proposed in the relationship between figs and wasps | AGÊNCIA FAPESP
- A tale of loyalty and betrayal, starring figs and wasps
The study was published in the journal Acta Oecologica as part of a special volume compiled to commemorate the 50th anniversary of the original discovery of the fig-wasp mutualism. This is why fig-wasp mutualism is so interesting. The two species coexist and mutually adapt to survive. This mutualism is not confined to the interaction between the species that produces edible figs Ficus carica, the common fig and its specific pollinators, fig wasps of the species Blastophaga psenes.
The genus Ficus comprises more than species, and for each, there is a species of pollinating agaonid wasp. The mutualism is ancient, Palmieri explained.
The oldest fossils of fig wasps date from 34 million years ago. They closely resembled the species alive today, indicating that the symbiotic relationship evolved early and has not changed fundamentally since then. Molecular evidence shows that the relationship existed 65 million years ago, suggesting that it might be even older, perhaps going back to the age of dinosaurs.
The fig-wasp lifecycle begins when the female wasp enters the fig.
The flowers open inside it, so they need a special pollination process. They cannot rely on wind or bees to carry their pollen. Inside the fig, there are female and male flowers that develop at different times. The A phase occurs when the female flowers are not yet mature. They soon mature and are ready to be fertilized. They become receptive to the wasps and release a scent made up of a huge amount of volatile compounds, triggering the B phase.
Each fig receptacle is not entirely closed but has a small hole called an ostiole, through which the female wasp penetrates its interior. As it does so, it loses its wings and its antennae are broken, so that it cannot get out again. It lays its eggs and dies.
What Is the Symbiotic Relationship between Fig Wasps & Figs? | Animals - oculo-facial-surgery.info
Synchronized actions Once inside the fig, the female wasp lays eggs in many of the flowers but not all. At the same time, it fertilizes the flowers with pollen stored in a pouch on the underside of its thorax.
The flowers on which the eggs are laid now undergo a transformation to become hardened structures call galls. Now begins the C phase, which lasts two to three months. The flowers that receive pollen but no eggs develop into seeds. Flowers that receive eggs and harden into galls become nurseries with food and shelter for wasp larvae.
New phase proposed in the relationship between figs and wasps
The D phase occurs at the end of larval incubation. This is also when the male flowers start to mature, opening up to expose pollen containers known as anthers. These trees are far less cooperative.
Dioecious fig trees are subtly different to monoecious ones.
In particular, their flowers tend to have shorter stalks than those of monoecious species. The wasps can still nest in dioecious trees, but their young can only develop in male flowers The fig wasps have changed along with them.
Morphological data shows that wasps pollinating monoecious figs tend to have long ovipositors, while those that pollinate dioecious figs have short ovipositors. Dioecy evolved much more recently, as did the altered wasps. Fossil fig wasps have been found in England that date from 34 million years ago.
They have short ovipositors that are almost indistinguishable from those of modern species associated with dioecious figs. The nature of dioecious fig trees creates an evolutionary conflict, one that the fig wasps seem to be losing. View image of A Roxburgh fig Ficus auriculata Credit: Female flowers have comparatively long stalks, so the female wasps' short ovipositors cannot reach inside to lay eggs and turn the flowers into galls. A female wasp cannot lay its eggs in a female flower, so when it enters it commits reproductive suicide Despite this, some female wasps enter the female flowers anyway.
From the wasps' point of view this is utterly futile, as it means they cannot reproduce. At first scientists thought that they might be doing it because the male flowers were not yet receptive, leaving them no other option.
But in a study published in FebruaryRenee Borges at the Indian Institute of Science, Bangalore and her colleagues found that the wasps sometimes enter the female flowers even when the male flowers are receptive. It turns out that the female flowers attract the wasps by mimicking the scent of male flowers. The fig trees are deceiving the wasps, a Machiavellian strategy that furthers the reproductive goals of the fig tree but spells doom for the wasps.
A female wasp cannot lay its eggs in a female flower, so when it enters it commits reproductive suicide.
What Is the Symbiotic Relationship between Fig Wasps & Figs?
However, the female flower still gets pollinated and goes on to produce seeds. This raises an obvious question. If this strategy is harmful for the fig wasps, and the figs have been using it for tens of millions of years, why haven't the wasps bailed on the figs, or started fighting back?
Borges says it may all be down to genetics. The figs and the wasps are utterly dependent on each other, but that does not mean they are "loyal" Fig wasps are inbred, because they often mate with their own brothers or sisters inside a syconium. Forcing her way through the ostiole, she often loses her wings and most of her antennae.
To facilitate her passage through the ostiole, the underside of the female's head is covered with short spines that provide purchase on the walls of the ostiole. In depositing her eggs, the female also deposits pollen she picked up from her original host fig. This pollinates some of the female flowers on the inside surface of the fig and allows them to mature. After the female wasp lays her eggs and follows through with pollination, she dies.
After pollination, there are several species of non-pollinating wasps which deposit their eggs before the figs harden. These wasps act as parasites to either the fig or possibly the pollinating wasps.