They're back, and pooping.

 As always at Oyster Bay, I stopped by the old apple tree. There will be a good crop this year.

Not ripe yet, but getting there.

And the tent caterpillars are back.

An abandoned branch, with only one caterpillar left. And lots of caterpillar poop.

Zooming in on that poop.

All the caterpillars were on the far side of the tree, clumped together in one dense mass. I couldn't get in a position to take a photo without clumping through the protected meadow.

The last time there were tent caterpillars on this tree was in 2019, 5 years ago. They come and go in cycles, one or two years of tents and up to 11 without. And they don't harm the tree; even with half the leaves gone that year, it still produced ripe apples.

Fall webworm caterpillar, Hyphantria cunea. Photo from 2019.

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Como siempre cuando estoy en Oyster Bay, pasé a mirar el viejo manzano. Y este año habrá una buena cosecha.

1. Manzanas, casi listas.
2. Y están de vuelta las orugas de la tienda, Hyphantria cunea. Esta es una rama donde ya comieron, pero ya se han ido al otro lado del árbol. Lo único que dejaron son sus feces. Y una oruga floja.
3. Las feces vistas de cerca.

Todas las orugas estaban en el lado opuesto del árbol cuando llegué, todas congregadas apretadamente en una rama cubierta de su "tienda". No pude acercarme a tomar una foto sin pisotear la pradera protegida.

La última vez que vi orugas en este manzano era en 2019, hace 5 años. Van y vienen en ciclos; uno o dos años con orugas, y hasta 11 años sin. Y no le hacen daño permanente al árbol. Hasta con la mitad de las hojas destrozadas en 2019, sin embargo produjo manzanas.

Foto #4: Una de las orugas que infestaron el manzano en 2019.

There will be apples

There's an old apple tree beside the shore at Oyster Bay. I drop by several times a year to look for apple blossoms and later, apples. Last year, what I found were tent caterpillars.

Western tent caterpillar, Malacosoma californicum, August 2019

Hundreds of caterpillars in their tent

I stopped by the other day. The branches are loaded with apples, still small.

Half red, but not ripe yet. It's still early.

Another branch

There were no signs of caterpillars. They usually infest a tree for a year or two, then disappear for several years. Last year, many trees were covered in their webs. I haven't seen any this year.

Last year's tented branch. No harm done.

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Cerca de la playa en Oyster Bay, hay un manzano viejo. Paso por allí varias veces al año para ver las flores, y luego las manzanas. El año pasado, lo encontré cubierto de una plaga de orugas de la tienda.

Lo fui a ver esta semana. Tiene muchas manzanas, todavía chiquitas. Y ni una oruga.

Estas orugas infestan un sitio por uno o dos años, y luego desaparecen por un tiempo. El año pasado, muchos árboles por aquí llevaban sus tiendas; este año no he visto ni una.

La última foto es de la misma rama de la segunda foto, que saqué el año pasado. Cuando hay una plaga, se ve horrible, pero no deja daño permanente.

Happy campers, tenting

There's an old apple tree beside the path at Oyster Bay. I stop there often, to look at lichen in the winter, and apples in the spring.

Little green apples, late June

I stopped again the other day. The apples should be ripe by now, and maybe I could pick a couple. But someone had been there before me.

Yes, the apples are ripe. And the tent caterpillars are busy.

The dark mass in the centre of that tent is made up of amassed caterpillars. If you click and zoom in, you can see their outlines.

Another branch; a feeding site, not used for overnight. The caterpillars huddle together for warmth, and this was a cool afternoon.

I pulled a couple of leaves away from this clump, exposing a few of the caterpillars inside.

Western tent caterpillar, Malacosoma californicum. Colours vary, from black to green to orange, and even pale blue, but all have that lengthwise stripe and long hairs. And all build the same webbed tents.

Another one. He seemed to be asleep until I touched him with a blade of grass. Then he hurried to get back under cover.

Caterpillar poop in a feeding site.

Leaves consist largely of nondigestible components, and it has been estimated that tent caterpillars void as fecal pellets nearly half of the energy they ingest. As a consequence, a colony of caterpillars produces large quantities of fecal pellets. (Wikipedia)

Skeletonized leaf, with webbing.

Western tent caterpillars build their tents on willow trees, cottonwood, apple, plum, cherry, and oak. This colony is on apple; later, I found another tent on a bitter cherry tree (Prunus emarginata).

Bitter cherry twig with feeding tent.

The trees are not really harmed. The caterpillar populations increase and decrease in cycles of from 6 to 11 years. In between, the leaves grow back and the tree thrives. The moths and their hosts are native species, and they are well adapted to each other.

I didn't get any apples. Somehow, all the apples on the trail side of the tree were missing, although the caterpillars hadn't touched those branches. On the far side, there were ripe apples, all too high, and too surrounded by webbing, to reach.