March of the larvae, continued

The masses of beetle larvae were not the first to infest the grey alders (Alnus incana) this year.  Nearly as soon as the leaves had appeared in April, large numbers of bluish black beetles appeared on them.

Alder leaf beetles (Agelastica alni) feeding on grey alder (Alnus incana) leaves in April.

These alder leaf beetles (Agelastica alni) spent their time consuming large portions of the leaves -- and mating.

Alder leaf beetles mating.

By mid May, some of the female beetles had eaten so much that their elytra (wing covers) no longer fit over their abdomens.

A female alder leaf beetle in May.

These greatly enlarged females must have then gone on to lay numerous eggs, producing the legions of larvae that would be responsible for even more damage to the grey alder leaves.

March of the larvae

Although I encountered one moth larva crossing the sidewalk, the hundreds of other insect larvae that I have seen recently have been (not very surprisingly) on leaves.  What is surprising is that nearly all those larvae have been on the same few leaves. 

A group of alder leaf beetle (Agelastica alni) larvae eating a grey alder (Alnus incana) leaf.

These unfortunate leaves belonged to grey alders (Alnus incana) and hosted groups of 20+ beetle larvae.  The larvae not only shared the leaves, but also kept in tight formations as they ate their way across the leaves...

The beetle larvae on another leaf leaving a sinuous trail.

...leaving behind them trails of small holes.  However, some of the grey alder leaves were riddled with considerably larger holes.  To be continued...

The better to smell you with

As I walked through one of the small parks in my neighborhood, I noticed a small moth flying along the path.  Holding my breath, I hoped fervently that it would land somewhere nearby.  Why did I care so much about getting a better look at a little moth?  The answer is that I had never seen one like it -- and that it had seemingly impossibly long antennae.

A male fairy longhorn moth (Nemophora sp.).

Luckily for me, the moth did land right beside the path.  Approaching cautiously, I was surprised to see that it had stunning wings, with iridescent yellow, blue and purple markings and a fuzzy fringe.  I was still more impressed by the antennae, though, which were so long that they had made the moth's flight appear somewhat awkward.

Another view of the fairy longhorn moth (Nemophora sp.).

Moths use their antennae for smelling.  They can use their acute sense of smell to locate nectar to drink, host plants where they can lay their eggs, and mates.  Although both male and female fairy longhorn moths (Adelidae) have long antennae, those of the males are significantly longer and can be several times the length of their wings.  The males may use their long antennae to detect pheromones released by the females, or perhaps to locate other males, since male fairy longhorn moths are known to swarm in large groups.

Yet another view of this amazing little moth.

A sticky situation

Recently, my neighborhood has been filled with profusions of pink and white -- the rhododendrons are blooming.  Whenever it hasn't been raining, wasps and bees have been flying among the flowers, collecting nectar and pollen.

A bumble bee (Bombus sp.) hovers in front of a rhododendron flower.

The flowers have also been attracting ants, and in great numbers.  Many of the flowers have several ants busily gathering nectar even when the rain keeps other flower visitors away.  However, unlike the wasps and bees, the ants do not contribute to pollination of the flowers.

Ants gathering nectar in a rhododendron flower.

As I observed the ants, I noticed that the white rhododendron outside my building had an abundance of dead ants on its flower stems in addition to the live ants in the flowers.

One of the many dead ants on the white rhododendron flower stems.

At first, I thought there must be a predator roaming the rhododendron and taking advantage of the plentiful supply of ants.  I inspected the stems, but could not find any sign of a predator.  Instead, I found an ant that was in a different sort of trouble.

An ant at the base of a rhododendron flower.

Its legs had become trapped.  They seemed to be entangled in the fine hairs of the flower stem, which may also have been sticky.  Despite the ant's struggles, it was unable to free itself and eventually expired without making any further progress down the stem.

The ant trying to free itself from the flower stem.

Although I have not found a description of sticky flower stems in rhododendrons, it has been suggested that such stems can help keep nectar robbers and thieves (such as ants) out of the flowers of other plant species, thereby reserving the nectar for pollinators.

Ladies in waiting

A little over two weeks ago, I found a cluster of bright yellow eggs underneath a linden (Tilia sp.) leaf.

A cluster of lady beetle eggs on the underside of a linden leaf.

Although I did not need to wait for the eggs to hatch to know what was inside -- developing lady beetle larvae -- I hoped to see the larvae before they dispersed.  Therefore, I made a mental note of where the leaf was and occasionally checked on the eggs.  Finally, after two weeks, there was a change.

The lady beetles shortly after hatching.

The lady beetle larvae had emerged from their eggs.  Soon, they would spread out in search of food.  Checking the surrounding leaves, I saw that the lady beetle larvae would not have to go far to find a plentiful supply of aphids.  However, they would have competitors, as more batches of lady beetle larvae were hatching nearby.

A linden aphid (Eucallipterus tiliae) on a nearby leaf.

Color-coded for freshness

Many of the streets here in Berlin are lined with large horse chestnut (Aesculus spp.) trees, and for the last few weeks, these trees have been adorned by large clusters of flowers, or "candles".  Some of the trees have white flowers with yellow, orange, or dark pink markings...

A "candle" of horse chestnut (Aesculus hippocastanum) flowers.

... while other trees have pink flowers with the same yellow, orange, or dark pink markings.

A "candle" of red horse chestnut (Aesculus × carnea) flowers.

Meanwhile, the sidewalks beneath the trees have become littered with white and pink flowers.  Interestingly, though, all the fallen flowers have dark pink markings.  A closer look at the flowers still on the trees reveals that those with yellow markings have fresher petals and anthers (the structures that hold the pollen).

New flowers have yellow markings, which then turn orange and pink as the flowers age.

It is also only those young flowers that produce nectar to reward pollinators.  Thus, the different color markings enable visitors such as bees to quickly discriminate between rewarding and unrewarding flowers.  Nevertheless, the older flowers may help attract bees and other potential pollinators from a distance by contributing to the overall size of the floral display.

More than meets the eye

As I was on my way to the grocery store, I noticed that I shared the sidewalk with a much slower walker... one that was just inching along.

A geometrid caterpillar (Geometridae) inching its way across the sidewalk.

I crouched down to watch this geometrid caterpillar, more commonly known as an inchworm, as it crossed the sidewalk.  However, other pedestrians, who seemed intent on ignoring both me and whatever I was looking at, nearly stepped on the caterpillar.  Therefore, I decided to aid the caterpillar in its journey and gingerly picked it up.  Suddenly, something unexpected happened: the caterpillar went rigid and transformed into a twig.

The same caterpillar doing an impressive imitation of a twig.

Or, at least, the caterpillar took on the appearance and texture of a twig -- which might have been very helpful for the caterpillar had I been a bird looking for its next meal.

Ants in my pants, continued

Before I was chased away by the wood ants, I caught a glimpse of something metallic and blue pushing up through the sand about a foot away from the stump where the ants had their nest.

Something begins to emerge from the burrow.

This neighbor of the ants was a dor beetle (a.k.a. an earth-boring dung beetle).  Nearly as soon as the beetle had breached the surface, wood ants came running up to inspect their neighbor.

A wood ant (Formica sp.) inspects the dor beetle (Geotrupidae).

Although I thought that the ants might attack the beetle, each one ran off again after a short pause.

Another ant comes and inspects the beetle.

Then, once the beetle had finally emerged from its burrow, it simply turned around and backed down the hole again. 

The beetle safe (?) in its burrow.

Meanwhile, some of the ants were taking more interest in me than they had in the beetle, and so it was time for me to move on.

Ants in my pants

Unlike the ant-hills between the cracks in the sidewalk, the ant-hills that I came across in a nearby park presented real obstacles -- due to their size, the number of ants defending them, and the logs that had been placed around them. 

A wood ant (Formica sp.) nest.

Disregarding the implicit warning of the log barrier, I came closer for a better look at the ants.  The ants were swarming in and out of crevices in the stump where the colony had made its nest. 

A close-up of the wood ants.

Although not quite as apparent in the top picture, the ants had also spread out over the logs and throughout the surrounding area (including where I was standing).  Some of the ants, such as the one pictured below, were returning with captured prey.

A wood ant carries its prey back to the nest.

Meanwhile, a few others were crawling over my shoes, and at least one made it into the leg of my pants before I decided it was time to continue my walk.

Natural Current Microevents

Of the thousands of photographs that I take, only a few become featured on this blog.  However, now you can see some of the "microevents" that did not make it into larger narratives, along with other updates, at the new Facebook page for Natural Current Events!

A maple seedling just coming out from under the wing.

Spring cleaning, continued

In between some of the sidewalk cobbles, I found sand piles that were mountains compared to the ant-hills.  There were no ants around these sand piles, nor could I see anything inside when I peered directly down the large, round entrances.  However, as I explored a nearby forested park, I came to the top of a (real) hill that was littered with similar sand piles.

One of the many nests on the hill.

Here, the holes were not all empty.  As I walked along the path, I noticed a quick movement as something disappeared down one of the tunnels.  I crouched nearby and waited -- and after a moment a fuzzy head re-emerged.

A fuzzy head peeks out of the nest.

The occupant of the nest was a mining bee.  Unlike some other bee species (such as honey bees and bumble bees), mining bees are not social.  Each female has her own nest that she provisions with food for her offspring.  Nevertheless, these bees often nest in close proximity to each other.

Two of the mining bees crawling out of their holes.

The two bees pictured above seemed to live too close for their comfort.  Repeatedly, they would crawl forward to inspect each other, then rapidly retreat back into their nests before returning to the surface for another round.

Spring cleaning

Ever since the snow melted off the sidewalks, piles of sand have been appearing between the cobbles. 

Entrances to an ant nest.

Some of these sand piles are ant-hills, produced by ants as they expand their underground tunnels.  Though miniscule to us, some of the sand particles are larger and heavier than the ants.  Nevertheless, the ants are able to carry these particles up and out of the nest, utilizing both their surprising physical strength and teamwork.

Ant workers moving sand out of the nest.

In addition to the ant nests, I found a few sand piles with much larger entrances -- and occupants.  To be continued...

Game over

Sometimes, it is the flower that gets bitten by the visitor.  Other times, it is the visitor that gets bitten.

A small crab spider eats a fly on a wood anemone (Anemone nemorosa) flower.

After searching hundreds of flowers, I was excited not only to see my first crab spider in Germany, but also to find it complete with prey.  However, since I realize that not everyone feels that a spider improves a flower, here is a view of some of those that were spider-free.

A patch of wood anemones (Anemone nemorosa) where just a few days ago I had only seen dry leaves.

Spring training, continued

As spring advances, the flowers quickly change.  The crocuses have already been replaced by daffodils, hyacinths, forsythia, common daisies, and many more.  Each flower has a different shape, and it can take some experimentation before a bee learns to handle the flowers efficiently.  For example, this bumble bee made an awkward attempt to drink nectar upside down...

A bumble bee (Bombus sp., likely pascuorum) visits a glory of the snow (Chionodoxa sp.) flower.

... before switching to a more conventional approach at the next flower.

The bumble bee tries a different approach.

For another bumble bee, it was not the approach -- but the flower -- that posed a problem.  Corydalis flowers (pictured below) have their nectar at the end of a long spur.  To get the nectar, it is necessary to have a tongue long enough to reach deep into the spur.

A  bumble bee (Bombus sp., either lucorum or terrestris) trying to drink nectar from a Corydalis sp. flower.

This bumble bee's tongue was not long enough, yet it did not give up.  The opening of the flower was too far from the nectar, so the bee made a new opening closer to the end of the spur.

The bumble bee chewing a hole through the spur of the flower.

Although the bee gets the nectar this way, it fails to provide a benefit to the plant: either by pollinating the flower or by picking up pollen to carry to the next flower.  Therefore, this behavior is known as "nectar robbing".  Not all potential pollinators are capable of chewing through flowers.  However, once a flower has been robbed, all subsequent visitors have the option of using the shortcut to any nectar that remains and to any new nectar that is produced.

A hole in another flower is visible above the bumble bee's foot.

Spring training

Although Sommerzeit did not begin auspiciously, a string of sunny days has quickly faded winter into a distant memory.  Instead of snow, the ground is now covered with early-spring flowers: snowdrops (Galanthus spp.), winter aconite (Eranthis hyemalis), glory of the snow (Chionodoxa sp.), and crocuses (Crocus spp.).

A purple crocus (Crocus sp.) blooming outside my building.

The crocuses especially are popping up in almost every green space -- yards, city parks, and even road medians -- enlivening the city with bright splashes of white, yellow, and many shades of purple. 

One of the many crocuses (Crocus sp.) blooming in a nearby park.

In some places, the crocuses are so dense that their flowers nearly carpet the ground.  In these areas, there is a steady traffic of honey bees and bumble bees collecting nectar and pollen from the blossoms.

A European honey bee (Apis mellifera) foraging at a cluster of crocuses.

However, on these first days of the foraging season, not all of the bees have been living up to their reputation as indefatigable workers.

A European honey bee (Apis mellifera) taking a break from foraging on the crocuses.

Sommerzeit

Leaving France, I traveled east to Berlin, Germany -- and even deeper into winter.  There were several inches of snow on the ground, with more falling almost every day.  After a few days, I received an email reminder that sommerzeit (literally, 'summer time') was about to start.  Looking out the window, I felt that sommerzeit was a cruel name for daylight savings time.

A snowy view from my window.

In my apartment, I was not the only one at the window waiting for spring.  When I opened one of the windows to check how cold it really was outside (very cold!), I found a lacewing that had been hiding in the crevice between the window and the windowsill.  Although the lacewing was brown in color, it was most likely a common green lacewing (Chrysoperla carnea), which fades to brown when it hibernates.

The lacewing I found hibernating in between the window and the windowsill.

At another window, I found a small beetle as it tried to climb the glass, fell, and rolled around on its back on the windowsill.  I helped the beetle back onto its feet, but decided to wait until it was warmer before letting the beetle out through the window.

A small beetle on the windowsill.

When the first day of sommerzeit arrived, I pulled open the curtains...

A snowy start to sommerzeit.

... only to see yet more snow falling.  Feeling disappointed but not at all surprised, I adjusted my clocks forward and left my short sleeve shirts at the bottom of the drawer.