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.

The mantis is greener on the other side of the fence

A few weeks ago, I found a praying mantis in my kitchen.  Since my kitchen isn't stocked with mantis food (i.e., live insects), I took the mantis back outside.  After that, I didn't see a mantis again until this weekend.  When I found the mantis pictured below, I thought it must be the same one that had made its way into the house.  It was considerably bigger than I remembered, but it was the same tan color that had worked so well as camouflage against the kitchen cabinets.

A tan colored European mantis (Mantis religiosa) female.

However, to my surprise, I soon encountered a second tan praying mantis in the backyard.  This one was sitting in the middle of the path, so I decided to move it to a safer spot.  Many years ago, I learned the hard way that a praying mantis can give a nasty pinch.  At least I learned that lesson well -- this time I put on my gardening gloves before picking up the mantis. 

A second European mantis (Mantis religiosa) female.  The spikes on the forelimbs can deliver a painful pinch to bare hands.

The second mantis wasn't my last surprise of the day.  When I started clearing dead plants from the front yard, I disturbed a third praying mantis from its hiding place.  This praying mantis was the same species as the two in the backyard, but bright green.

A green colored European mantis (Mantis religiosa) female.

This mantis quickly moved towards a bunch of dried plant stems and climbed up off the ground.  It was not very well camouflaged in its new spot; nevertheless, it soon began grooming itself, seemingly unaware of the large mammal hovering over it.

The green European mantis (Mantis religiosa) grooming itself.

New arrivals

This weekend, I went in search of the source of the woolly alder aphids (Paraprociphilus tessellatus) that have been swarming my neighborhood.  When on tree branches, these aphids form white, woolly masses that should be easy to spot.  I don't have their host plants (alders and maples) in my yard, but I thought some of those trees must be nearby.  I checked the alders in a nearby park, but their branches appeared clean.  If it hadn't been windy, I might have gotten a clue about where to look from the density of the aphid cloud.  As it was, I didn't see any aphids flying at all.

Wherever they had come from, the woolly alder aphids were still all over my backyard.  Some were sitting on foliage, presumably sheltering from the wind; quite a few others had been caught in spider webs.  While looking for the woolly aphids, I also discovered several more typical aphids -- ones that might be content with the plant selection in my yard.

A winged aphid on a morning glory leaf.

A winged aphid surrounded by her juvenile offspring on a rose leaf.

For much of the year, aphids reproduce asexually.  Without mating, the females can give birth to many live daughters, which are soon ready to produce their own daughters.  Therefore, a single aphid can quickly generate a large population. 

However, there is little chance that these new aphids will pose a threat to the plants in my backyard.  Starting tomorrow night, we are expected to have a series of hard freezes.  Even if the aphids survive the frost, there won't be much more damage that can be done to the plants this fall.