BBC - Earth - A tale of loyalty and betrayal, starring figs and wasps
The pollination mutualism between figs and fig wasps provides an excellent to an Excel Spreadsheet or Access Database, Converting QUAL2K to WASP. Fig trees and fig wasps are partners in life, but sometimes the trees betray their closest allies. Read the relationships on each card. Paste it on the sheet under one of the symbiotic relationships: Predator-Prey, Parasitism, Mutualism or Figs+; Fig Wasps+.
The carpet of tiny flowers in the interior of the synconium consists of both male and female flowers, which cannot pollinate eachother as they mature at different times, and also sterile "gall flowers" Kricher The strangler figs have a symbiotic relationship with their sole pollinator: This is an advanced form of mutualism where both organisms benefit from interacting: Each has very specific needs that the other is precisely adapted to fill.
This is the result of a long path of co-evolution, which has made the lives of these organisms inextricable; to explain the pollination of the fig's strange flower is to explain the life cycle of the fig wasp Kricher The gall flowers in the fig synconium contain fig wasp eggs, laid by the previous generation.
The male wasps hatch first, and inseminate the female wasps while they are still unborn. The females then hatch, already pregnant, at the exact same time that the male flowers mature Kricher How this timing is managed, especially given that different fig trees flower at different times Thomson et al,has not been explained by any source that I have found. The female wasps get covered with pollen from the male flowers before digging their way out of the synconium, and flying off in search of other fig trees.
When a female wasp finds a synconium on another tree, she burrows in and lays her eggs, then dies. In the process, the pollen she has carried with her is brushed off onto female fig flowers, which are thus pollinated Kricher How the wasp locates a synconium in the right stage of development, with mature female flowers, is another question that my research has not answered.
She certainly cannot try multiple flowers; the female wasp is often injured by the process of burrowing into the synconium Kricher The females only live for about a day outside the synconiums Kricher Yet a genetic analysis study of fig paternity ie, which trees donated pollen for which fruits has shown that the wasps, despite their extremely short lives, are "efficient agents of long-distance dispersal, routinely moving up to 10 km between flowering trees" Nason et al, !
Implications for Conservation Numerous studies have been done regarding various aspects of strangler fig ecology. Some have focused on the conditions for strangler fig seed germination: Putz and Holbrook showed that humus from decaying leaves available to epiphytic figs in palm tree canopies was higher in nitrogen, magnesium, and potassium than soil on the ground, suggesting that nutient levels may be a factor in the germination and growth of figs, and possibly other epiphytes as well.
Swagel et al demonstrated that Ficus aurea seeds require high substrate water levels for germination, and suggested this as another reason that stranglers typically germinate only in the canopy, and, in drier areas, mostly on palm trees. Other studies have focused on factors affecting genetic diversity among seemingly small populations of strangler fig trees. Thomson et al examined cases of allofusion fusion of multiple individuals into one tree, as discussed above and found that while the trees produced flowers of multiple genotypes, all of the flowers in a given "mosaic" tree flowered in synchrony, preventing those separate genotypes from pollinating eachother since the male and female flowers do not mature at the same time on a given tree.
This means that the gene pool may be larger than the number of trees since there can be multiple genotypes per treebut a certain population size of whole trees is still needed to meet pollination requirements and sustain wasp populations. Nason and Hamrick asserted that the wide dispersal range of fig wasps allows strangler figs to be pollinated even in otherwise isolated forest fragments.
Moreover, conservation of strangler figs, and by implication all of the species that the figs support, "may be dependent on the preservation of forest elements in a surrounding fragmented landscape.
Laman, Timothy G Allen; Hamrick, James L Before she dies, like any good mother, she ensures the survival of her babies.
She injects the flowers with a chemical that transforms them into fat, rounded structures called galls. When the eggs hatch, these galls will provide food and shelter for the young offspring.
They are fig wasp nurseries.
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The young wasps will grow to adulthood, and even mate with each other, within the syconium. Then the males and females face very different fates. View image of A male Waterstoniella masii emerging from Ficus stupenda Credit: They bite through the syconium, creating an opening for the winged females to fly out.
Their purpose completed, the wingless male wasps die, and the syconium ripens into mature, fruit-containing seeds. Meanwhile the female wasps collect pollen from the male flowers, which have just matured. They stuff the pollen into specialised pollen pockets, located above the abdomen.
A tale of loyalty and betrayal, starring figs and wasps
The nature of dioecious fig trees creates an evolutionary conflict, one that the fig wasps seem to be losing They then leave in search of another fig syconium. There they will deposit their cargo of pollen, lay eggs, and start another life cycle. Thanks to their short life cycle of just two months, the fig wasps ensure that the fig trees produce fruit all year round.
As a result, in rainforests many birds and animals depend on figs for food, making them keystone species that support the entire ecosystem. By nesting in the figs, the fig wasps indirectly help in maintaining biodiversity and population density. It is a stable partnership that benefits both members, and the wider ecosystem. But in the case of dioecious fig trees, all bets are off. These trees are far less cooperative.
What Is the Symbiotic Relationship between Fig Wasps & Figs? | Animals - pugliablog.info
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.
Growth and Ecology of Strangler Figs [Final]
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.