ENVIRONMENT

Millions of spiders dropped from the sky in Australia, blanketing the countryside with their webs. “We see these falls of spiderwebs that look almost as if it’s snowing,” said one local resident. (Nat Geo News)

Use our resources to learn about slightly more terrifying arachnids from Down Under.

Teachers, scroll down for a quick list of key resources, including a link to today’s MapMaker Interactive map, in our Teachers’ Toolkit.

Discussion Ideas

• What is “ballooning”? Is it an Australian thing?
  • It’s a type of migration. According to Nat Geo News, “during a ballooning event, millions of spiders crawl to the highest points of their habitat—say a fence pole, or a tall plant—and send out silk strands that allow them to be lifted on air currents.”
  • Ballooning spiders are not limited to Australia. Check out this ballooning event in Texas.
    • Or, read Charlotte’s Web. (Who are we kidding: Take any excuse to read—or watch—Charlotte’s Web.) Pay attention to Charlotte’s daughters. Did you know the name of Charlotte’s daughter Aranea is a variation of the scientific name of some spider species that engage in ballooning? (Well-played, E.B. White, well-played.)

 

• Some reports say that it is “raining baby spiders” in Australia. What two things are inaccurate about that statement?
  • It isn’t raining. The spiders are being carried by wind, not precipitation.
  • The spiders aren’t babies. According to Nat Geo News, “the spiders are actually just ‘very, very small’ adults called sheet-web weavers or money spiders.”
    • FYI: The huge “money spider” family gets its nickname from a legend that says if you find a spider on you with a trail of silk, it must be trying to spin you a new set of expensive silken clothes!

 

• Take a look at our media spotlight on Australia’s deadliest spider, the fearsome funnel-web. Do you think the funnel-web could use the ballooning strategy to relocate?
  • No, thank goodness! Spiders that engage in ballooning events have to be light and aerodynamic enough to be carried by air currents. Most ballooning spiders weigh less than 2 milligrams (0.00007 ounce). It would take a strong wind to carry the heavy, chunky funnel-web very far.

 

• The excellent Nat Geo News article calls the ballooning spiders “aerial plankton.” What are aerial plankton? What are some other examples of aerial plankton?
  • Aerial plankton, or aeroplankton, are simply tiny organisms that have no means of moving on their own, but float and drift on air currents. (Oceanic plankton, of course, are tiny organisms that float and drift on ocean currents.)
  • Other examples of aerial plankton include pollen, plant spores, bacteria, and non-flying insects such as aphids and mites.
    • Use this great activity to identify “flying specks” of aerial plankton. Then submit your observation to the Great Nature Project’s “Global Snapshot”!

 

• According to Nat Geo News, most aerial plankton die before touching down. How do they die?
  • Weather: Precipitation and strong winds can crush and drown tiny “flying specks.”
  • Predators: Aerial plankton provide a nice “to-go meal” for predators such as birds and insects.

 

• Take a look at today’s MapMaker Interactive map of the Southern Tablelands region of Australia. How far do you think most “ballooning” spiders get?
  • Usually, not very far—rarely more than 10 meters (11 yards).
  • Sometimes, ballooning spiders can get caught in warm updrafts and even high-flying jet streams.
    • Following the formation of Anak Krakatau, ballooning money spiders were among the first animals to colonize the volcanic island.
    • This fascinating article details how one species of ballooning money spider—Orsonwelles!—successfully colonized the most isolated island group on Earth—Hawaii. (Whether they ballooned in from Australia, Asia, or North America, that’s a long way to drift!)

 

TEACHERS’ TOOLKIT

Nat Geo: Millions of Spiders Rain Down on Australia—Why?

Nat Geo: Angel Hair in New South Wales map

Journey North: Plankton in the Sky? Observing Aerial Plankton

(extra credit!) Invertebrate Systematics: Orsonwelles, a new genus of giant linyphiid spiders (Araneae) from the Hawaiian Islands