Foliage holes in a variety of plants. Right to left and top to bottom: 1) black-eyed Susan, 2) Vitis, 3) rebud, 4) cherry, 5) arrowwood, 6) ash, 7) chestnut, 8) eupatorium, 9) wild ginger. © Beatriz Moisset
If you are like me, you probably never paid much attention to the countless little holes in the foliage all around you, unless the damage was serious enough to make you take notice. I became aware of them only after reading Doug Tallamy’s “Bringing Nature Home.”
Sawfly larvae (Periclista) on oak. © Beatriz Moisset
I invite you to look around next time that you take a walk in a nature area. The more I look, the more I see the abundant signs of insect-feeding everywhere. In many cases, perhaps most, the leaf damage is infrequent enough that it fails to detract from the luxury and freshness of the foliage. This is particularly true of landscapes dominated by native vegetation and free from non-native invasive pests. Things may take a turn for the worse in the case of crops, ornamental gardens, and ecologically disturbed areas. This can also be the case when an introduced pest, free from biological controls, spreads through the native landscape.
Black-headed sawfly (Tethida barda) on ash. © Beatriz Moisset
Sawfly larvae (Macremphytus testaceus) on dogwood. © Beatriz Moisset
Sometimes, it is possible to deduce who left their signature on the leaves by the shape of the holes, the time of the year, and, perhaps more significantly, by the plant species. Moths and butterflies, sawflies, leaf beetles, katydids and grasshoppers are the main suspects. Often, it is their young, not the adults, which do most of the eating. Caterpillars chew plant material. Adult moths and butterflies prefer nectar, and perhaps pollen; in some cases they eat nothing at all.
A caterpillar of Funerary dagger moth (Acronicta funeralis) on unrecorded plant (perhaps hickory). © Beatriz Moisset
Plant eaters exhibit a variety of styles; some chew up the edges of leaves, while others nibble between veins, skeletonizing the leaf. Others dispose of the entire leaf before moving on to the next one. Some are specialists that stick to only one species of plant or a few related species. Others help themselves to a wide variety of plants.
So far, I only mentioned the ones that make holes in leaves. But then, there are leaf-rollers, leaf-miners, gall-makers, sap-suckers … not to mention the ones that feed on all the remaining plant parts, above and below ground; all of them worthy of other posts. For now, I will stick to insects that make holes in leaves. All of them combined eat considerably more foliage than all the larger vertebrates.
Milkweed tussock moth (Euchaetes egle) caterpillar on milkweed. © Beatriz Moisset
Monarch caterpillar on milkweed. © Beatriz Moisset
I made my peace with all this plant feeding when I realized what an important part of the food chain insects are. Birds, lizards, frogs, small mammals… many of them depend on those herbivorous insects or on the spiders that feed on insects. Even some large mammals value insect food; bears gorge themselves on countless fat caterpillars in preparation for winter. Many carnivores, in turn, depend on the animals that feed on insects.
Golden tortoise beetle (Charidotella sexpunctata) larva on morning glory carrying a protective “umbrella” of its own feces. © Beatriz Moisset
Golden tortoise beetle (Charidotella sexpunctata). The adult is as pretty as the larva is ugly. © Beatriz Moisset
Nowadays, I look at the traces of leaf eating with joy and curiosity. I visualize that hole converted into a piece of living protein going up the food chain, first a caterpillar, then a song bird and finally a hawk. I wonder about the identity of the ones who stamped their signature in the foliage.
Longhorn milkweed beetle on milkweed. © Beatriz Moisset
Here are a few which I was fortunate to catch in the act. In these cases I can tell who done it, but there are so many mysteries! Have you solved some of them?
© 2012, Beatriz Moisset. All rights reserved. This article is the property of Native Plants and Wildlife Gardens. If you are reading this at another site, please report that to us
About Beatriz Moisset
Beatriz, Like you, I didn’t pay too much attention to the holes in my leaves untl I read Bringing Nature Home, either. Now when I see holes I always wonder if they were made by a ‘good’ bug or a ‘bad’ one. And on some day, between the insects, the deer, rabbits & gophers that also feed on foliage I’m amazed that there’s any green at all in the garden!
Debbie recently posted..Buttercup Winterhazel – You Can Grow That!
You have to keep telling yourself: “think food chain” or “think ecosystem”. It is a huge mental shift from the way we used to think.
Beatriz Moisset recently posted..Cast of Characters
I also love to see leaf holes cut by Leafcutter Bees!
Love this! “I visualize that hole converted into a piece of living protein going up the food chain, first a caterpillar, then a song bird and finally a hawk.”
Here is another area for me to explore..thank you..Michelle
Rambling Woods recently posted..I CRIED over beautiful things knowing no beautiful thing lasts….
Beatriz, yes, let’s hear it for insects! They are such a hard sell, but so critical to the all the working systems that keep ecosystems functioning. I recommend Thomas Eisner’s ‘For the Love of Insects,’ with a forward by E.O.Wilson, for enlightenment illuminated with entertainment. A great book. Appreciating insects makes life so much more interesting. Loved the composite photo!
Sue Dingwell recently posted..Bear-y Delight
“Let’s hear it for insects” should be our rallying cry. We must make sure that we are doing more than just paying lip service to their role in the ecosystem. Fortunately, in a healthy ecosystem the checks and balances are all in place and the plant eaters rarely get out of hand.
Another great book is Eric Grissell’s “Insects and Gardens”. It is fittingly dedicated to Rachel Carson.
Thanks everybody for the nice comments.
Beatriz Moisset recently posted..Moths as Pollinators
Like you, I have celebrated leaf-damage due to insects since reading Tallamy. I was very excited the other day to finally spot evidence of leaf-cutter bees on a flower petal and Virginia Creeper.
I envy you and Denise for seeing signs of leaf-cutter bees. I haven’t had the pleasure. The Japanese Osmia cornifrons have taken over my bee houses and I don’t get to see Megachile bees in my garden. I wasn’t planning on raising non-native bees. Sigh!
Beatriz Moisset recently posted..Gardening for Honorary Butterflies (Mint Moths)
I am always curious as to who may be eating the leaves…it gives me an opportunity to learn from these critters…
Donna@Gardens Eye View recently posted..Gardens Eye Journal-October 2012
Beatriz, thank you for another terrific post! Doug Tallamy’s excellent book (and lectures) has helped those he’s reached make such important connections (healthy migrant and breeding birds survive on butterfly and moth caterpillars, among other things, found on native vegetation). Great for all of us to continue to share this fact in different ways
I loved Vincent Vizachero post too and have directed many to it, “Native Cultivars – Good, Bad, and Ugly,” where he shared that he’s not happy if something isn’t eating his native plants (because that’s what is meant to be):
http://nativeplantwildlifegarden.com/native-cultivars-good-bad-and-ugly/
Now, I’ll happily direct folks to your great post as well. Well said and portrayed in your terrific photos. Thanks!
Pat Sutton recently posted..Monarch Migration at Cape May — Fall 2012
Another thought provoking article Beatriz – thanks.
After reading Tallamy, I now look at plants in my landscape with no “herbivation” (that’s a word, right?) suspicously. When I was ready to replace a cultivar Witch hazel with the real deal native version, we decided to test the wildlife value of each. We planted the native right next to the cultivar. At the end of season, we saw obvious but not excessive predation on the native, with hardly any leaf damage on the cultivar. So my assumption is the expensive cultivar isn’t providing wood for the wildlife while the less expensive native is. So next year the old nursery plant is coming out and a native is going in.
-Hal
Hal Mann recently posted..It was Dead – but Now….
Nice to see that your observations confirm these principles and that you are putting into practice.
“Herbivory” is the word, but I think that I like “herbivation” better. Very descriptive.
Beatriz Moisset recently posted..Gardening for Honorary Butterflies (Mint Moths)
Great Post Beatriz! Important too! I also love to explore under leaves and marvel at the intelligence insects have in selecting and consuming plants . . . especially when they contain slightly toxic sap in their veins. I love to watch the Monarch caterpillar as they chew off parts of the node attached to the main stem of a milkweed plant . . . cutting off the flow of sap to the leaf. This way they will not become ill from an overdose of Cardiac glycosides as they munch the leaf to nothingness . . . very clever.
Carol Duke recently posted..Monarch Butterfly Life Cycle: A Metamorphosis ~ Part Four ~ Lift Off Towards Migration
Thanks. Yes, monarch caterpillars do that. Longhorn milkweed beetles and milkweed weevils also do that. The slashed veins and dripping milkweed are easy to see. On the other hand, milkweed bugs drink juices from intercellular spaces and avoid the milkweed sap altogether, so they don’t need to drain the leaf or stem first.
Other insects have an assortment of techniques. A very common one is skeletonizing the leaves, eating between veins. I wish there was a guide to holes in the foliage. My friend, Charley Eismeman published a book with Noah Charney called “Tracks and Sign of Insects and Other Invertebrates”. Fascinating, but it doesn’t deal with holes. Let us hope that somebody does this sometime.
Beatriz Moisset recently posted..Plume Moths: More Little Known Pollinators
What an excellent article Beatriz and a great idea for a book, as you just said…a field guide to leaf eaters! Why not start working on that in your spare time Beatriz! I would buy that for sure…
Ellen Sousa recently posted..Vegetable Gardening the Natural Way
I once heard a statistic that in general, less than 1 in 10 caterpillars ever survive to adulthood. That’s a compelling reason for gardeners to not panic when they see something eating their plants. Chances are, it’s not going to be around for long if you’ve got birds and a healthy beneficial insect population. OK – If it’s a vegetable or container plant, it’s probably worth hand picking (or exclusion by row covers) but if it’s a perennial, shrub or tree, as long as it’s a healthy plant, most plants can withstand quite a bit of leaf defoliation without affecting its health too much.
Ellen Sousa recently posted..Vegetable Gardening the Natural Way
Thanks for the nice comments. I would be willing to contribute to a guide of leaf eaters if somebody else were willing to take the lion’s share of it. That is all I can do.
Very few caterpillars make it to adulthood. In some instances it is 1 in a thousand for those species that lay huge numbers of eggs.
Most plants do fine and look fine despite caterpillar’s attacks. Vegetables are more vulnerable in part because they have lost some of their natural defenses through cultivation. The other serious problem for all plants is introduced pests. There are no biological controls for many of them and the populations can grow exponentially each year. Another reason for not using non-native plants. Many times they are the carriers of non-native insects. Japanese beetles illustrate these points.
Beatriz Moisset recently posted..Invisible Bird Food in the Foliage
Ahhhh, Beatriz……thank you so much.
You know I LOVE a good bug tale!
phabulous photos as always!
Loret recently posted..New Life List Dragonfly