It’s a common question: are there really dead wasps inside your figs? This stems from a unique biological partnership between fig trees and a specific type of wasp. Understanding this intricate relationship reveals how figs come to be, and the role these tiny insects play.
The Unique Partnership Between Figs and Wasps
Figs are not fruits, but rather an inverted flower structure known as a syconium. This fleshy, hollow receptacle contains hundreds of tiny flowers lining its inner surface. A small opening, called the ostiole, provides access to these hidden flowers. This structure necessitates a specialized pollinator: the fig wasp (family Agaonidae).
The relationship between figs and fig wasps is an example of obligate mutualism, meaning both species rely on each other for survival and reproduction. The fig tree needs the wasp to pollinate its concealed flowers to produce seeds. In return, the fig provides a protected environment and nourishment for developing wasp larvae. Each of the over 750 fig species typically has its own dedicated fig wasp species, highlighting their deep co-evolution over 60 to 100 million years.
The Fig Wasp’s Life Cycle Inside the Fig
The life cycle of a fig wasp begins when a mated female, carrying pollen from her birth fig, locates a receptive fig syconium, often guided by its scent. She then squeezes through the narrow ostiole, a passage so tight that she often loses her wings and parts of her antennae in the process. Once inside, the female wasp crawls around the interior, pollinating some of the female flowers as she deposits her eggs into the ovaries of others.
After laying her eggs and pollinating the fig, the female wasp dies within the fig’s cavity. Her eggs hatch into larvae, which feed on the fig’s tissues, specifically within the flowers where they were laid. Male wasps typically emerge first; they are wingless and will mate with the female wasps while still inside the fig. These male wasps then create an exit tunnel for the fertilized females before dying themselves, never leaving the fig. The newly fertilized female wasps collect pollen from the now-mature male flowers before exiting the fig through the tunnel created by the males, flying off to find a new fig to continue the cycle.
Not All Figs Are Created Equal
While the fig-wasp mutualism is widespread in nature, not all figs consumed by humans require wasp pollination. Many commercially cultivated fig varieties, such as some common figs, are parthenocarpic, meaning they can produce fruit without pollination or viable seeds. These figs develop their fruit through vegetative means and do not host fig wasps.
For other cultivated varieties, like the Smyrna fig, pollination by the fig wasp is necessary for fruit development. However, the “caprifig,” a wild type of fig that produces pollen, specifically hosts the fig wasps and is not typically consumed. This distinction ensures that many of the figs found in grocery stores have not been part of the wasp’s life cycle. The long history of fig cultivation has led to the development of varieties suitable for human consumption that bypass the need for wasp involvement.
What Happens to the Wasp’s Remains?
For figs that rely on wasp pollination, the fig itself plays a role in breaking down the female wasp’s remains after she dies inside. The fig produces an enzyme, ficin, which is a proteolytic enzyme. This enzyme effectively digests the soft tissues of the wasp’s body.
Through this enzymatic process, the wasp’s body is largely absorbed and integrated into the developing fig. What remains are the tougher, indigestible parts of the wasp’s exoskeleton, primarily made of chitin. These chitinous fragments are minuscule and typically imperceptible to human consumers. Therefore, while a wasp may have been involved in the fig’s development, the fig’s natural processes ensure that any remnants are broken down and not noticeable when the fruit is eaten.