Friday, October 31, 2014

Happy Halloween!

This fall, I found some natural Halloween decorations hanging in the park by my apartment.  There were spooky, spiky jack-o'-lanterns...

A spinybacked orbweaver (Gasteracantha cancriformis) spider.
...and spooky, spiky skulls...

Another color form of the spinybacked orbweaver.
...all appropriately surrounded by spooky spider webs!

Wednesday, October 29, 2014

Adding eggs to the basket

Around the time that the tortoise beetles were leaving their eggs on the bindweed, I found two small cabbage white butterflies laying lots of their own eggs in the garden.  Small cabbage whites are native to Europe, Asia, and north Africa -- and so too are the garlic mustard plants that they chose as hosts for their offspring.

A female small cabbage white butterfly (Pieris rapae) on a garlic mustard (Alliaria petiolata) leaf.
The butterflies fluttered from leaf to leaf, sometimes moving on quickly and sometimes pausing to lay a single egg before going off in search of the next suitable leaf.

A small cabbage white butterfly (Pieris rapae) egg.
The butterflies appeared to be spreading their eggs out amongst the available leaves, which made sense to me as a way of reducing the risks of predation, parasitism, and competition.  Therefore, I was surprised by what I found when I went to check on the eggs again later.

Now there are two small cabbage white butterfly eggs!
Where there had been just one egg, there were two eggs.  Even more surprisingly, where there had been two eggs...

Two small cabbage white butterfly eggs underneath a garlic mustard leaf.
...there were seven eggs!

Now there are seven small cabbage white butterfly eggs under the leaf.

Wednesday, October 22, 2014

The ugly larvae, part two

As larvae, tortoise beetles are made distinctly unattractive by the amalgamation of frass and shed skins that they hide beneath.

A green tortoise beetle larva with its fecal shield.
Yet, the beetles undergo a remarkable change when they metamorphose into adults.

A golden tortoise beetle (Charidotella sexpunctata).

Even having seen pictures of the adults beforehand, I was stunned when I saw the shining beetles in the backyard one evening.

A golden tortoise beetle (Charidotella sexpunctata) showing some orange coloration.
That evening, there were many tortoise beetles on the bindweed around the garden and they were from at least two different species.

A mottled tortoise beetle (Deloyala guttata).
However, by the next day, all the adults were gone.  I thought that they might just have gone into hiding for the daytime, but they had not returned to the bindweed by the time I checked again in the evening -- or any time later.  They had left something of themselves behind, though!

Tortoise beetle eggs attached to the underside of a bindweed leaf.
A few days later, the larvae began appearing and were soon devouring all the bindweed.

Wednesday, October 15, 2014

The ugly larvae, part one

Like spittlebugs, tortoise beetle larvae conceal themselves underneath an excretion of the plant material that they eat.  However, since the beetle larvae feed on leaves rather than sap, the end product is not nearly as elegant as the spittlebugs'...

A tortoise beetle larva with its fecal shield raised.
...nor is the process of making their coverings.

A tortoise beetle adding to its shield.
Yet regardless of aesthetic objections, the fecal shields seemed to be quite adequate for the purpose of protecting the larvae, which thoroughly infested the bindweed in the garden without attracting any predators or parasites (as far as I could see).

Three tortoise beetle larvae on a mostly eaten bindweed (Convolvulaceae) leaf.

Monday, October 13, 2014

Growing up in bubbles, part two

After feeding on lots of plant sap from within its blanket of bubbles, the spittlebug nymph sheds its skin...

The exuviae of a spittlebug nymph.
...and emerges as an adult froghopper.

An adult froghopper (Aphrophora sp.).
In addition to discarding its old exoskeleton, the adult froghopper abandons the bubbly shelter that kept it safe as a nymph.  It no longer needs to hide from its enemies, since it can easily escape them.  True to their name, froghoppers are very adept at hopping.  In fact, they are among the best hoppers in the world (especially when accounting for their size).

Explore some more: Guinness world record: highest jump by an insect and Jumping performance of froghopper insects

Friday, October 10, 2014

Growing up in bubbles, part one

Caterpillars are not the only animals that are resourceful in using their food plants to hide themselves from danger.  While hiding inside the plants' leaves and stems is relatively common, one group literally forms protective bubbles by blowing air into an excretion of the plants' sap.

Bubbles on a goldenrod (Solidago sp.) stem.
The result is a blob of bubbles, commonly referred to as frog spit, snake spit, or cuckoo spit.  However, the "spit" does not come from any frog, snake, or cuckoo; it comes from a small insect concealed underneath the bubbles.

Something is visible underneath the bubbles.
When the bubbles are brushed away, the bubble-blower -- a spittlebug -- is revealed.

A spittlebug (a.k.a. froghopper) nymph.
Although the bubbles were easy enough for me move aside, they apparently form an effective barrier against smaller enemies, as well as the elements.

Explore some more: "The frothblower"

Monday, October 6, 2014

A stitch too late

The hydrangea leaftiers wrapped themselves in multiple layers of protection, but what did they need to be shielded against?  Another group of caterpillars that I encountered over the summer illustrated a potential danger.  These caterpillars were also busy tying leaves.

Woven together leaves.
However, as they built their shelters, they were exposed on the exterior of the leaves.

A caterpillar, probably of a tortricid moth (Tortricidae). 
One of the vulnerable caterpillars exhibited evidence of a recent attack: two parasitoid eggs attached to its body.

A caterpillar with two parasitoid eggs on it.
Even if this caterpillar escaped the attention of predators and hid itself within the leaves, it was probably the parasitoid larvae that benefited from the shelter in the end.

Wednesday, October 1, 2014

All sewn up, part three

After sealing itself up inside the hydrangea leaves, what did the hydrangea leaftier caterpillar do?  From the outside, there was no obvious sign that the caterpillar was feeding on the leaves.

Hydrangea leaves after an encounter with a hydrangea leaftier (Olethreutes ferriferana) caterpillar.
Pulling apart one of the older leaf capsules to see what was happening inside, I found something that did not look very much like a caterpillar.

Nested inside the sealed leaves was a sealed bundle.
It looked a lot like a clump of moldy frass, but I tried separating it anyway -- and out popped a twitching pupa.

Inside the cocoon was a hydrangea leaftier (Olethreutes ferriferana) pupa.
By tying the hydrangea leaves together and then forming a cocoon inside, the caterpillar had made a snug refuge with multiple layers of security to protect it during its metamorphosis into a moth.