The story of the fig and its wasp

Inside the rounded fruit of a fig tree is a maze of flowers. That is, a fig is not actually a fruit; it is an inflorescence—a cluster of many flowers and seeds contained inside a bulbous stem. Because of this unusual arrangement, the seeds—technically the ovaries of the fig—require a specialized pollinator that is adapted to navigate within these confined quarters. Here begins the story of the relationship between figs and fig wasps. The queen of the fig wasp is almost the perfect size for the job—except, despite her tiny body, she often times will lose her wings and antennae as she enters through a tight opening in the fig. “The only link the fig cavity has to the outside world is through a tiny bract-lined opening at the apex of the fig, called the ostiole, and it is by means of this passage that the pollinating fig wasp gains access to the florets,” as described in Figweb, a site by Iziko Museums of Cape Town. Once inside, the queen travels within the chamber, depositing her eggs and simultaneously shedding the pollen she carried with her from another fig. This last task, while not the queen’s primary goal, is an important one: She is fertilizing the fig’s ovaries. After the queen has laid her eggs, she dies and is digested by the fig, providing nourishment. Once the queen’s eggs hatch, male and female wasps assume very different roles. They first mate with each other (yes, brothers and sisters), and then the females collect pollen—in some species, actively gathering it in a specialized pouch and in others, accumulating it inadvertently—while the wingless males begin carving a path to the fig’s exterior. This activity is not for their own escape but rather to create an opening for the females to exit. The females will pollinate another fig as queens. The males will spend their entire lifecycle within a single fruit. While this tree-wasp relationship may not be common knowledge to all fig-eaters, it is well-known to biologists as one of the most solid examples of coevolution. “One of the best activities to do with an introductory biology class is to pass around Fig Newtons, let them take a bite and then tell them the story of the fig wasp life cycle,” said tropical plant ecologist Greg Goldsmith as we recently hiked through a cloud forest in Monteverde, Costa Rica. “It’s a fascinating story.” After learning the story of the fig and its wasp, the most common question is, “Do we eat wasps when we eat figs?” The short answer is that it depends—that is, some figs are parthenocarpic, meaning they are...

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Immersed in the clouds: Interview with tropical cloud forest researcher

There is a world within the canopy of a tropical cloud forest that not many people get to see. In this unique ecosystem—maintained by the exceptionally wet microclimate of cloud cover—orchids, moss, lichens and other epiphytes grow in every crease and pocket of the supporting tree branches. Here, hundreds of species of birds, along with monkeys and other mammals navigate the aerial landscape, scattering seeds along the way (see below video). (Resplendent Quetzal Canopy in the Clouds from Colin Witherill on Vimeo.) Greg Goldsmith, tropical plant ecologist from the University of California, Berkeley, spends his days harnessed in this “canopy in the clouds”—also the name of the interactive, educational website he is currently working on with photographer Drew Fulton and cinematographer Colin Witherill. The website, which explores the topical montane cloud forest in Monteverde, Costa Rica, will be launching a Spanish version called “Dosel en las Nubes” in the next couple of weeks. Goldsmith, who is the host in the Canopy in the Clouds videos, explains the microclimates, landscape, plants, pollinators, insects and the many other fascinating aspects of the forest. “I am still absolutely blown away by the sheer quantity of green that you see when you first walk into one of these forests,” said Goldsmith in a recent Ecological Society of America Field Talk podcast. “I am still amazed and still totally enthralled by the idea of seeing something I have never seen before, every single day. And that is a function of the incredible biodiversity that exists in this part of the world.” Thanks to the many hours of work from the crew, Canopy in the Clouds has numerous panoramic photographs embedded with short videos that describe a specific process or aspect of the forest. According to Drew Fulton’s photography website, “This group spent over 200 days in the field, bringing together [their] passions in pursuit of a new generation of science education media…” It was the first time Fulton and Witherill worked in the tropics. With the website completed, Goldsmith can guide visitors to experience a unique perspective within and above the canopy at the highest elevation—an area that is largely inaccessible without careful training. So, instead of telling a student that “the canopy is almost always immersed in this beautiful layer of clouds,” as Goldsmith said in the podcast, he is able to show them firsthand. Photo Credit: All photos copyright of Drew...

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