On the safe side

When feeding in a large group, caterpillars may be more noticeable to predators -- but they may also be better able to defend themselves.  Groups of tent caterpillars and webworms can consist of hundreds of individuals, which makes them easily spotted (and probably smelled) even from a distance. To thwart their many enemies, these caterpillars surround themselves and their feeding zones with a protective netting of silk.

A nest of fall webworms (Hyphantria cunea) on a mulberry branch.

The caterpillars then proceed to devour nearly everything within their tightly woven nest.  As they move along a branch, all that they leave behind are leaf skeletons wrapped in silk.

The larvae can completely skeletonize large leaves.

Meanwhile, any predators that locate the caterpillars are likely to depart without obtaining a meal. Watch a wasp get foiled by the silk enclosure in the video below:

More than an itch, part two

Compared to the assassin bugs, stink bugs (Pentatomidae) may seem to be unlikely predators. While most stink bugs do stick to feeding on plants, some supplement their diets with insects. Others are pure predators.

A leaf beetle (Ophraella sexvittata) being attacked by a predatory stink bug (Perillus sp.) on a goldenrod (Solidago sp.) leaf.

A few of the predatory stink bugs are even used to control agricultural pests. However, the stink bug shown here had trouble controlling just one small beetle.

The beetle struggles to get away.

The stink bug appeared to have pierced the beetle with its mouthparts, yet the beetle showed no sign of giving up.

The bug continues to pull away.

I did not see whether the beetle escaped in the end. Yet, what I saw when I came back several days later convinced me that neither the stink bug nor any other predators had been very successful in reducing the beetle population.

The goldenrod plants later that week.

The host with the most, part two

The mining flies and galling mites inflicted peculiar injuries to the lantanas, but last year I saw plenty of ordinary herbivory of lantanas too.  Of course, after finding evidence of herbivory, I sought out the herbivores themselves.

A lantana leaf fastened in half by silk.

When the damage was fresh, I did not have to look far before finding the herbivore.  One type of caterpillar, the lantana leaftier moth, made pouches out of the lantana leaves by tying them with silk.  It then consumed the leaf down to a membrane while remaining concealed within the folded leaf (until I came along and pulled the leaf open).

A lantana leaftier moth (Salbia haemorrhoidalis) caterpillar eating the leaf from within.

Another, much larger caterpillar made an even more complete meal of the lantana leaves.  After it had finished with a leaf, there was often not much left besides the tough central vein.

A lantana after a visit from a very hungry caterpillar.

Looking for the first relatively intact leaf adjacent to the consumed leaves, it was easy to find the lantana moth caterpillars that were responsible for the devastation.

A lantana moth (Diastema tigris) caterpillar underneath a lantana leaf.

Eager for lily pads

A few days after my surprise encounter with a swimming beaver, I went on another walk around the beaver ponds.  I had hoped that the beaver I had seen before might be back patrolling its pond, so I was disappointed to find the pond empty (at least of visible beavers).  However, I did not give up, and in a pond a short way down the path, I found two beavers.

A beaver eating a rolled up lily pad.

These beavers were busy with the important task of rolling up and eating lily pads.  One after another, the lily pads disappeared into the beavers.  Fortunately for the beavers, the pond was so full of lily pads that an imminent shortage seemed unlikely.

* To see this video in high definition (1080p), you may need to: 

(1) click "YouTube" to watch on the YouTube website

(2) change the settings at the bottom of the video screen

Home sweet home

Inside a leaf, an insect can gain food and shelter simultaneously.  The challenge is that leaves are nearly flat.  It seems like it should be very difficult for insects to live inside them -- at least not without making a gall.  Yet, the larvae of numerous species of moths, flies and other insects have overcome this challenge.

These larvae are known as 'leaf miners' and they leave distinctive marks on the leaves they inhabit.  Some leaf miners take long, winding paths through their leaves.  The resulting 'serpentine' trails are often filled with the frass (droppings) of the larvae, which turns the trails black behind the leaf miners.  To me, this seems like a big drawback of living inside your food.

The trail left in a rose leaf by a leaf miner, possibly a larva of the moth Stigmella rosaefoliella.

Other leaf miners consume large patches of leaves, creating opaque 'windows'.  Sometimes, as in the picture below, the leaf miner can be seen through the window.

A leaf miner is visible through a 'window' in a common morning glory (Ipomoea purpurea) leaf.

To get a better look at the leaf miner pictured above, I flipped the leaf over.  I found that this morning-glory leaf miner (Bedellia somnulentella) was keeping its feeding area clean by expelling its frass through a hole in the leaf surface.  It would seem that, in the case of leaf miners, outdoor plumbing is the significant innovation.

A morning-glory leaf miner (Bedellia somnulentella) in a common morning glory (Ipomoea purpurea) leaf.

We only come out at night

Recently, I have been seeing less and less green in the garden.  The weather has been very dry and is now getting cooler -- but these aren't the only problems that the plants have been facing.  They are also losing large portions of their leaves to hungry herbivores.

A rose leaf that has been damaged by an insect, possibly a leafcutting bee.

I wanted to know what was altering the leaves, often in quite interesting and aesthetically pleasing ways; however, during the day, the "artists" remained anonymous.  Searching again after dark, I found a very different garden.  Wherever I looked, there were earwigs (Forficula auricularia).  I may have seen over a hundred earwigs during a single tour of the garden -- and wherever I saw them, they were eating.

A European earwig (Forficula auricularia) eating the edge of a leaf.

Although by far the most numerous, the earwigs were not the only insects busy chewing up leaves.  I also found a couple of black vine weevils (Otiorhynchus sulcatus) feeding under the cover of darkness.

A black vine weevil (Otiorhynchus sulcatus) eating the edge of a leaf.

The weevil above was just getting started on its leaf when I found it.  It was startled by the camera and dropped to the ground (these weevils cannot fly).  However, other leaves nearby had not been so lucky.

Surprise inside

Earlier in the year, the crabapple (Malus sp.) tree in the backyard was buzzing with bees.  Now, it is covered in small, sour fruits.  I keep checking the fruits to see if anything will eat them, but so far they have been left alone.  Instead, I have noticed that many of the crabapple leaves are getting rolled up and eaten.

A rolled crabapple (Malus sp.) leaf.

Curious to know what was inside, I began carefully unrolling the leaves.  Within the first few leaves I found white silk, insect frass (the black droppings in the picture below), and ladybugs.

A convergent ladybug (Hippodamia convergens) in a rolled crabapple leaf.

However, most ladybugs are predators, not herbivores.  Something else must have been rolling and eating the leaves -- and then been eaten by the ladybugs.  I kept looking.  On about the fifth leaf, I finally found a leaf roller caterpillar.

A leaf roller caterpillar inside a crabapple leaf.

Having found only harmless (to me) insects inside the leaves, I started unrolling the other leaves with less caution.  However, I soon discovered that the leaf roller caterpillars were not the only ones rolling leaves.  As I peeled open another leaf, I saw long, spindly legs -- and I immediately released the leaf.  I brought a flashlight down to the garden so that I could peek inside through the narrow opening without further disturbing the leaf.  With the aid of the flashlight, I found that the legs belonged to a spider guarding its egg sac.

A spider and egg sac inside a rolled crabapple leaf.

The pincer attack

Despite the fact that they have never done me any harm, I have always had a strong dislike of earwigs.  Their large pincers are threatening enough without the suggestion that they could be brought into my ears.  My insect field guide asserts that though earwigs do seek refuge in enclosed spaces, those spaces do not include human ears. 

A European earwig (Forficula auricularia) deep inside a hollyhock (Alcea rosea) flower.

Whether earwigs really do crawl into ears is not something I am willing to test for myself.  However, I was willing to test how much of a pinch the pincers can give -- as long as I wasn't the one getting pinched.  Watch the video below to find out what happened.

* To see this video in high definition (1080p), you may need to (1) click "YouTube" to watch on the YouTube website and (2) change the settings at the bottom of the video screen.

I was somewhat disappointed with the response of this European earwig (Forficula auricularia).  Although the earwig did use its pincers to grapple with the grass stem, it did not seem to do any serious pinching.  What was more impressive was that the earwig barely paused chewing on the hollyhock (Alcea rosea) leaf as it fended off the attack.