Why do thrips prefer 'jacks' in-the-pulpit?

By Chelsie Vandaveer

February 19, 2003

Sponsored By: Henry Fields Seed and Nursery!—>Click here.

Suggested Reading—>Click here.

Killer Picks: Jack-in-the-Pulpit, Arum italicum, & more—>Click here.

Jack-in-the-pulpits (Arisaema triphyllum (L.) Schott) are dioecious; staminate (male) and pistillate (female) flowers are borne on separate plants. Juvenile plants do not flower, the next growth stage are staminate plants. A few years growing under optimal conditions, the plants build up enough reserves and the sex changes from staminate to pistillate.

But pistillate plants may not remain 'Janes'. According to Paulette Bierzychudek (2001), heavy seed production, herbivory,

advertisement

A jack-in-the-pulpit George F. Mobley/National Geographic Buy this Framed Art Print at AllPosters.com

or drought will cause the plants to revert to males.

Jack-in-the-pulpits have few natural predators. The plants contain raphides, calcium oxalate needles. A single taste is a painfully memorable experience; most herbivores do not try a second time. Eastern white-tailed deer (Odocoileus virginianus Zimmerman) are one of the few mammals that can feed on Jack-in-the-pulpits and consequently change the sex ratios in a population.

Researchers at the Smithsonian Environmental Research Center (SERC newsletter, spring 1999) studied a specialist insect of jack-in-the-pulpits. The thrips' (Heterothrips arisaemae Hood) life-cycle appears dependent on male jack-in-the-pulpits.

According to Ilka Feller of SERC, winged adult thrips apparently feed on pollen. Female thrips lay their eggs, embedding them in the inner surface of spathe surrounding the spadix. When the first instar larvae (nymphs) emerge, they also feed on pollen. After shedding their exoskeleton, the now second instar nymphs leave the spathe and climb to the abaxial (under) side of a leaf.

The second instars feed by sucking fluids from the leaves. Areas where these nymphs have attached turn yellow, then brown, and by midsummer are holes in the leaves. Feller's group found that male plants have twice as many holes in the leaves as female plants and twenty times as many holes as juvenile plants.

Even though there was no nutritional difference between the leaves, most larval thrips remained on the plant where they hatched. With almost no damage, juvenile jack-in-the-pulpits are not affected in their ability to become male plants. Little damage to females may not impact the number of viable seeds she produces. But no one is yet certain whether the thrips-damage keeps males as males.

The International Aroid Society has a wonderful scanning electron micrograph taken by Ted Held of the pain-causing raphides found in Cryptocoryne, a genus related to Arisaema. To view the SEM, click on the link:

http://www.aroid.org/gallery/held/raphides.html

Ilka Feller's article, "A Pattern of Sex-Biased Herbivory in Jack-in-the-Pulpit", is posted on page 10 in the spring 1999, SERC newsletter. To read more or see photographs of thrips and thrips-damage, click on the link:

http://www.serc.si.edu/education/gallery/newsletters/spring1999.pdf

Suggested Reading:

Jack-in-the-pulpit (Arisaema triphyllum) Plant of the Week - February 17, 2003
Why does the lacewing lay her eggs on stalks? Renfield's Garden - March 6, 2002
Could a natural horror benefit sugar beet growers? Renfield's Garden - November 14, 2001
What is rotenone? What's in a Name? - June 6, 2003

Matsukaze Toad Lily

Springhill Nursery®

Tricyrtis hirta 'Matsukaze' – This unique Oriental import gives borders an exotic look for up to six weeks in late summer and early autumn. White, orchidlike blooms are covered with purple flecks. Easy-care perennial grows 18-24" high and spreads 12-18". Click here for $20 off your first order at Spring Hill Nursery! [More lilies...]

		Jack-in-the-Pulpit Henry Fields Seed and Nursery® Early spring color for moist, shady locations Exotic, hood-like spathe is royal purple with crisp white veining. Jack-in-the-Pulpit grows 24 in. tall and spreads just 12 inches. Bareroot.  Click here - $20 off at Henry Fields Seed and Nursery!
		Arum italicum Breck's Bulbs® A beautiful, three-season spectacle. Green blooms similar to jack-in-the-pulpits in early summer, followed by small clusters of orange-red berries. Arrow-shaped foliage becomes marbled and silver-veined in the fall. Add this jewel for variety in your garden. Arum italicum Zones 4-9. 4+ cm bulbs. Free $25 off any order of $50 or more at Brecks Bulbs  [View more Alliums...]
		Dracunculus vulgaris Breck's Bulbs® Large, exotic 10" dark red flowers with black pistils are enhanced by distinctive spotted leaves. A unique collector's plant to highlight a special bed. Dracunculus vulgaris Zones 5-10. 20-25 cm bulbs. Free $25 off any order of $50 or more at Brecks Bulbs  [View more Specialty Bulbs...]
		Henry Field's Annual Flower Garden Henry Fields Seed and Nursery® A spectacular selection of color for a super-low price! Get one packet each of Giant-crested Mixed Cockscomb, Sensation Mix Cosmos, Livingston Daisy Mix, Mixed Four O'Clocks, Boy O' Boy Mix Marigold, Double Mix Moss Rose, Twinkle Mix Phlox, California Poppy, Strawflower and Cactus-Flowered Zinnia, plus two packets of Thumbelina Zinnia.
Also includes a planting diagram, marker stakes and instructions. Attractive blend of heights, shapes and colors blooms all season, providing a constant supply for cutting. Click here for $20 off any order of $50 or more at Henry Fields Seed and Nursery Co! [More Flower Seed...]  [On Sale Today!...]
		Romeo Marigold Seeds Henry Fields Seed and Nursery® New! Flowers from late spring onward with beautifully rich colors. It is excellent at the front of your garden. Click here for $20 off any order of $50 or more at Henry Fields Seed and Nursery Co! [More Flower Seed...]  [On Sale Today!...]
		Cut Flower Collection Henry Fields Seed and Nursery® Bachelor Button Mix: Showy pink, blue and white flowers on 30 to 34-in. stems. Attracts butterflies and hummingbirds. Very easy to grow. Approx. 100 seeds per packet. Flamingo Feather Celosia: A profusion of rose-colored flower spikes all summer. Dense 2 to 3-ft. tall plants. Pretty in beds and everlasting arrangements. Approx. 75 seeds per packet.
Chimes Mixed Snapdragon: Traditional flower form, on low-growing 6 to 8-in. plants. Full and bushy. Approx. 75 seeds per packet. Bright Lights Mix Cosmos: Flowers early, continues all summer long in vibrant shades of orange, gold and yellow. Grows 18 in. tall. Approx. 50 seeds per packet. Senstaion Mix Cosmos: Daisy like all summer blooms 4-6 ft tall! Rose-pink white mix. Finely cut foliage. Very easy to grow. Approx. 50 seeds per packet. California Giant Mixed Zinnias: Fully double flowers measure 4-6 in. across, grows 30 in. tall. Blooms in early summer. Approx. 65 seeds per packet. Strawflowers: Summertime blooms, 30 in. tall, colorful dried. Cut before fully open, strip off leaves and hang upside down. Approx. 600 seeds per packet. Click here for $20 off any order of $50 or more at Henry Fields Seed and Nursery Co! [More Flower Seed...]  [On Sale Today!...]
killerplants Recommended Seed and Nursery Stores
BACK TO TOP