Posts Tagged ‘invasive species’

How to Photograph Really Large Spiders (If You’re an Arachnophobe)


Monday, November 26th, 2012

Huntsman Spider © Jungle Pete

How to Photograph Really Large Spiders (If You’re an Arachnophobe) by Jungle Pete Corradino

This is a Huntsman Spider.

The Huntsman Spider is a very large spider. This is not a good photograph of a spider.

1)    If the spider is in your home, make sure you have created an escape/panic/freak out route. Open a sliding glass door. Blow out candles. Pick babies up off the floor.

2)    If you intend to dispatch the subject after the shoot, make sure your method of destruction is suitable for your enclosure. Baseball bats, whether aluminum or wood are inappropriate.

3)    Use a tripod with a remote to avoid violent, nervous shaking.

4)    Consider a fast shutter speed and a zoom lens to stay as far away as possible.

5)    Kill first, ID later is not an option with spiders. They curl up or even disintegrate. Respect nature. Escort the natives outdoors. Humanely dispatch the invasive species.

The Huntsman is an invasive species, native to Asia and now found throughout the Gulf States and California. Their colloquial name is “Banana Spider”, having most likely arrived in the U.S. with banana imports. They are often confused with Nursery Web Spiders (Pisaurina mira) and the infamous Brown Recluse (Loxosceles recluse) which can inflect a seriously harmful bite. The Huntsman is distinguished from similar spiders by brown “false eyes” on the cephalothorax.

Huntsman Spider © Jungle Pete

The female Huntsman Spider (Heteropoda venatoria) has a body nearly an inch long and carries a white egg sack underneath the body. Both males and females have hairy legs that make the arachnid the size of an average man’s hand. They are ruthless hunters and are valued for their appetite for roaches. The preference is to have them as the first line of defense on the outside of your house.

This one must have hitched a ride down from the attic with the Christmas ornaments. My wife came into my home office, held up eight fingers and pantomimed tiptoeing. I interpreted this to be “it’s eight o’clock, be quiet and don’t wake the baby.” Nope. Eight-legger in the ceiling corner of the bathroom.

The Huntsman has been known to inflict humans with a bite that resembles a harsh bee sting. It’s better if they’re outdoors. This one had three strikes against it. I don’t like hairy-legged spiders. It’s an invasive species. It’s in my house.

The Huntsman is a speedy little devil and any time wasted on photographic endeavors could result in its escape. I have no interest in allowing a hand-sized, biting spider free in my home with my child. So I snapped a quick picture of the beast gobbling the half dollar-sized “good” house spiders before “capturing” it with a web broom. In this case the Huntsman became the hunted.

Gypsy Moths


Thursday, August 23rd, 2012

Gypsy Moths in Manitoba by Gene Walz

Gypsy Moths

Gypsy Moths © E. R. Degginger/Color-Pic, Inc.

My yard was supposed to be sprayed overnight. I live in one of the two areas of Winnipeg where Gypsy Moths (Lymantria dispar) have recently been found. How they got here is anybody’s guess.

We’re proud of our motto, “Friendly Manitoba”, but we’re treating these newcomers in a most hostile manner. A crop-duster full of the insecticide Btk (Bacillus thuringiensis) was supposed to douse my neighborhood. A thunderstorm, heavy winds, and rain gave us a temporary reprieve from last night’s scheduled spraying. The crop-duster never showed up. By the time you read this, it will have given my yard a bacterium bath.  Ah, well.

Btk is said to be “a naturally occurring bacterium that only kills caterpillars.”  I hope so. Since the city started wholesale spraying for mosquito and inchworm prevention, many of the formerly common birds here have disappeared. No more orioles, wrens, or mourning doves in my yard. I miss their songs.

The Gypsy Moth is one of North America’s worst introduced pests. We can thank a misguided scientist named Leopold Trouvelot of Medford, Massachusetts for importing the moths from their native Asia in 1868. Since then the caterpillars have wreaked havoc on forests across the continent, defoliating trees at alarming rates.

I hope this regime of treatments is effective. I don’t want Gypsy Moths in my world. I want my trees to thrive. I don’t want a second round of spraying next year or a third. I want more birds around. They’ve got enough to cope with already.

Invader, Meet Invader


Friday, August 3rd, 2012

Invader, Meet Invader – Garlic Mustard by Julie Craves

The non-native, invasive plant Garlic Mustard (Alliaria petiolata), is such an abundant part of my urban landscape that I often don’t even notice it. So I surprised myself one day walking through my field site because, although my thoughts were elsewhere, I stopped in my tracks when I saw a Garlic Mustard plant with chewed leaves. Part of the success of many invasive, non-native plants is that they flourish in regions where they have no natural enemies. Not much eats Garlic Mustard in North America. Apparently I was so used to seeing intact leaves that these obviously browsed ones triggered a response in my subconscious.

Garlic Mustard Wildflowers

Garlic Mustard © K. P. McFarland

When I stopped to take a look, I saw two small Cabbage White (Pieris rapae) butterfly larvae feeding on the leaves. That’s another non-native, widespread species that’s so ubiquitous I hardly register their ever-presence. I found two more Garlic Mustard plants nearby that each had a Cabbage White caterpillar feeding on it.

Here, the plot thickens.

Cabbage White larvae feed on many species of plants in the mustard family (Brassicaceae). This includes crop species introduced into North America, including Brassica oleracea (from which cabbage, broccoli, kale, and other vegetables are derived), mustard greens, and turnips. In Europe, Cabbage Whites also use Garlic Mustard as a host plant.

Cabbage White Butterflies

Cabbage White © Rick Cech

Both Cabbage Whites and Garlic Mustard were first recorded in North America in the mid-1800s, in Quebec and New York, respectively. Despite long association in both their native and introduced ranges, there are relatively few reports of Cabbage Whites using Garlic Mustard as a host plant in North America.

Studies have suggested this may be due to the fact that the butterflies have so many delicious choices of host plants here that they can choose those that they prefer (mustard greens are a favorite), and don’t need to resort to Garlic Mustard. There is an organic garden and lots of “preferred” choices within 100 yards of where I found these caterpillars. Why Garlic Mustard was chosen instead in this case is a mystery.

I brought the four Cabbage White caterpillars indoors and successfully raised them to adulthood on wild Garlic Mustard. I released the adults, hoping that perhaps they might go on to begin a population with a taste for a host from the homeland that wasn’t also destined for own our dinner plates.

Stop It – The Burmese Python – Part I


Monday, February 13th, 2012

Everglades Guide Jason with a Burmese Python

We must do everything we can to rid the Everglades of all invasive plant and animal species. That’s a seemingly impossible task at this point for the supposed invasive species capitol of the world. We must also prevent the importation and introduction of any new species to protect the currently out of whack balance of South Florida’s ecosystem. Having said that, I am enraged by the ignorant media coverage regarding the “big snakes” in the Everglades. In December of 2011 an article titled “Severe mammal declines coincide with proliferation of invasive Burmese pythons in Everglades National Park” was published and the media-led hysteria that followed offered tabloid style headlines that fed into people’s natural fears.

“Pythons Rule Florida’s Everglades”
“Pythons and Anacondas Dominate Food Chain”
“Burmese Pythons Picking Florida’s Everglades Clean”
“Pythons have stranglehold on Everglades”

A local NBC anchor suggested without a trace of skepticism that the population of the invasive giants was well over 200,000. This is a stunning climb up the food chain from a few years ago when the estimate was 9,000, then 15,000, 30,000 and then inexplicably 150,000. Now 200,000 plus? Stop it.

Burmese Pythons (Python molurus bivittatus) are endangered in their native Southeast Asian range, thanks to poaching and exportation for the pet trade. People buy them as pets because they’re cuddly or they’re constricting. Sometimes it’s hard to tell the difference. They get to be big, growing to lengths over 20 feet. Eventually they’re the ideal pet they once were and owners dump them in the Everglades. Many were thought to have escaped into the swamp in 1992 when Hurricane Andrew devastated Homestead, Florida, home of many reptile breeders and importers.

Northern Raccoon

The scientific paper that has flamed the frenzy claimed that Northern Raccoons (Procyon lotor), Virginia Opossums (Didelphis virginiana) and bobcat sightings (both live and road kill) are down about 99% from a period of time that predated the python infestation. Now one of the co-authors is distancing himself from the suggestion that pythons are to blame. He says it’s possible, but he blames the media for drawing a correlation between the two.

Virginia Opossum with young © Jack Dermid

They did note that top predators like the Florida Panther (Puma concolor coryi) and Coyote (Canis latrans) (an Everglades new comer), populations had increased but did not suggest that they could be culprits in the population declines of prey species such as raccoons and opossums. Nor did they mention the severe drought the Everglades National Park has experienced and what effect that might have on the need for certain species to seek out better habitat.

Florida Panther © Brian Kenney

The analysis of the scientific paper was lacking and the media did not do their due diligence to understand the entire issue. The shocking headline was enough to craft an exciting tale of reptile Armageddon. I’ll explain more about the biology of the pythons, the threat they pose and what we need to do to stop it. Next week.

Invasive Charm


Friday, May 6th, 2011

I thought it was a rose as soon as I set eyes on it. How could I have overlooked a rose in my wanderings through these woods? This three ft tall plant is growing on the edge of the red mangroves and wasn’t here last year. As pink buds opening in the warm sun, this plant is beautiful with the exception of the mealy bugs that appear to be lining the stems. Its’ beauty is the reason this plant was brought to Florida from south Asia in the first place. It is now listed as a category 1 invasive by FLEPPC, the Florida Exotic Pest Plant Council. Not a rose at all but a member of the myrtaceae family and native to southern and southeastern Asia, The Downy rose myrtle Rhodomyrtus tomentosa is an evergreen shrub that usually grows to 6 ft tall and occasionally to 12 ft. “Downy” is the common name that describes the tomentum, the soft hairy undersides of the leaf which are light green while the upper leaf is dark green and glossy. It produces a popular fruit for birds and humans like to make jam from them. Invasive exotics displace native plants and change the ecosystem. We have seen this happen with so many plants already like the melaleuca and the Brazilian pepper. Beautiful as it may be I will be pulling them up as I see them so I can continue to see the flora of Florida.

Zebra Mussels


Friday, June 25th, 2010

Location: Zumbro River near Rochester, Minnesota

Last week, I spent a rainy morning fishing on the Zumbro River. As I waded upstream, my water shoes crunched on a carpet of shells. Zebra mussels (Dreissena polymorpha), an invasive freshwater species, covered the river bottom. Zebra mussels originated in the Balkans, Poland and Russia. In 1988, a ship unknowingly carried them in ballast water across the Atlantic, and then discharged them in Lake St. Clair, between Lake Huron and Lake Erie.
These inch-long mollusks get their name from the striped pattern on their shells, and like their namesake mammal, the shell patterns vary greatly and are sometimes not present. Young zebra mussels swim in water currents. Older ones spread by attaching themselves to boats and wildlife such as turtles and crayfish.
So what’s the problem? Hydro-power plants spend millions each year to keep zebra mussels out of intake pipes, the cost of which gets passed on to you and me. These prolific mollusks anchor on native mussels, killing them. They eat algae, which makes water seem cleaner, though all it really does is steal food from bottom-of-the-food-chain creatures. The water may look clearer, but they do not remove pollutants.
You can help prevent the spread of zebra mussels by not transporting aquatic plants and wildlife to other water sources. Wash your boat. If you go fishing, clean your gear, empty water wells and bait buckets on dry land and throw your leftover bait in the trash.