Meet the New Orb-Weaver…

This weekend I received texted photo of a spider, with the question: “Friend or Foe?”  What she meant, of course, is whether the arachnid posed a danger to her.  The picture she sent was that of a Joro spider (Trichonephila clavate). I told her it wasn’t dangerous, but in truth it requires a more complex answer. 

Fat and Happy Joro

Until recently, I could comfortably identify the big spiders around my house as either the garden or writing spider (Argiope aurantia) or the golden silk orb weaver (Trichonephila clavipes).  When late-summer spider season hit and webs were being spun in every available tree and porch pillar, the usual suspects aren’t in attendance.  Instead, the Joro spider, an Asian native, has set up shop all over Athens and throughout our woods in a neighboring county. 

In the Fall of 2014, a fellow in Madison County, Georgia, sent photos of a strange spider to the Department of Entomology at the University of Georgia.  This is the first record of the Joro spider in North America. They probably arrived, as so many invasives do, in packing material for goods shipped across the ocean. Since then, they have expanded their range across the Piedmont of Georgia and South Carolina.  Given that the spiders lay egg sacks with hundreds of eggs (up to 1500!), it is easy to see how they overwhelm the other large orb weavers in the ecosystem.

My ecologically-aware friend was incensed.  “…are we just meant to let them naturalize, or are we supposed to be coming up with ways to get rid of them?”

Golden Silk Orb Weaver

Good question.  If one species takes over a niche from another species, that is cause for a naturalist’s concern.  Unfortunately, unless the usurper causes some economic harm, you aren’t likely to have any of the Powers That Be care enough to devote resources to it.  Not that there is likely to be a way to combat this species that doesn’t threaten all other spider species. 

No, I think we will see the Joro continue to spread and naturalize.  They will capture insects with as much efficiency as their predecessors, and their bites are just as harmless to humans. Whether the transition of arachnid power will impact the ecosystem beyond displacing some species remains to be seen. 

Links:

Spiders in Georgia: Identify the spiders you find.

Curse of the Starling

If I became governor of Hell I would reserve a special room for Eugene Schieffelin and his minions in the North American Acclimatization Society, the idiots who thought it would be nice for all the birds mentioned in Shakespeare’s works to be represented in America. In the 1890’s he released around 60 starlings into Central Park. Because of one single line in Henry IV, an estimated 200 million of the aggressive little bastards currently occupy North America, wreaking havoc on native bird populations.

Why such antipathy for these morons? Why not put in Etienne Trouvelot (who introduced Gypsy Moths) or whoever shipped the wood that contained the fungus that annihilated the American Chestnut?  Because Schiefflin and his cronies went out of their way to perpetrate their crime, and for a silly reason.

Humans have been bringing pests from one land to another since they first commenced to roam, and many native species and a few ecosystems have paid the price.  Many are completely unintentional, from fire ants to zebra mussels.  Some seemed like a good idea at the time, like kudzu or cogon grass.  But Schieffelin’s crowd were whimsically Anglophilic.

Dreamers are fine.  But sometimes their dreams can become nightmares.

Rogue Pears

As I write this, white blossoms are popping out behind my house — an old nemesis sneers at me. The Rogue Pear.

The callery pear (Pyrus calleryana) is an Asian native brought to the US in the 1960s.  Why?  The pears are small, round, and inedible.  The flowers fill the air with a sickly-sweet odor.  The trees are densely limby and prone to splitting in bad weather.  Like many fast-growing trees, the callery pear is short-lived, lasting only a couple of decades or so.   So why has it turned up in every doctor’s office park and subdivision?  Three things: beautiful foliage– deep green in summer, leaves turning blood-red or wine-dark in the autumn; an explosion of flowers late in winter; quick growth to a bushy, symmetrical silhouette.

Horticulturalists created a number of cultivars, the best-known being the ‘Bradford’.  We removed the thorns, we straightened the forms.  As a useful biproduct, these cultivars couldn’t reproduce.  You plant Bradfords, and they stay where you put them. 

But, in our great and unmatched wisdom, we kept tinkering.  Each cultivar had slightly different properties.  Different colors, stronger limbs.  And then it happens. One cultivar is used to landscape a new strip mall, and a different one dresses up an office park down the street.  Some local bees visit one and then the other.  It turns out that different cultivars can fertilize each other. And these new seedlings exhibit the attributes of the original, wild pear: able to grow on a wild range of soils, able to seed prolifically, and armed with thorns that can punch through a truck tire.  I call them rogue pears, when I don’t use stronger adjectives for them.

It’s a contagion the scope of which you aren’t likely to notice until late winter.  Come February until April, these innocuous green trees suddenly blaze white in floral profusion.  My corner of the county is pretty well infested; a mere 10 years after being fallow, the neighbor’s field is a young forest, with 8 out of 10 trees being pears. But I didn’t have any inking of realize how widespread the problem was until I was a couple of hours away, driving on  a highway skirting the Fall Line.  In the pine plantations on either side, the midstory was packed with pears bedecked with their white blossoms.  Some quick research showed the rogue pear has popped up in most states east of the Mississippi, and it has a foothold in several western states as well.

Everyone knows about kudzu.  You may have heard of Chinaberry or privet or tree-of-heaven.  Now that pear is on your radar, maybe you’ll start seeing it come the end of winter. 

Maybe, hopefully, you’ll choose native trees for your next landscaping project.