Friday, December 13, 2013

The admiral defends his territory, continued

The red admiral butterfly seemed very bold when defending his territory against intruders (including me).  Yet at other moments, the red admiral was considerably more subdued and would sit motionless at various locations around his territory.

The red admiral (Vanessa atalanta) sitting on a branch by the boardwalk that he defended.
The day was cool enough that after sitting still, the red admiral would need to warm its wings again before taking flight.  To warm up, the butterfly would "shiver" its wings (as can be seen in the video below).  The red admiral certainly was not trembling in fear!

* 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

Another thing that can be seen in the video is how conspicuous the red admiral is with its wings spread open.  Nevertheless, whenever the red admiral fluttered down onto the boardwalk and closed its wings, it would nearly disappear against the wood grain.

Can you find the red admiral?

Monday, December 9, 2013

The admiral defends his territory

Most butterflies, including the shy common buckeyes, tend to maintain a safe distance from me and my camera.  However, I recently encountered a very different sort of butterfly.  This one flew directly towards me -- and only stopped when its wings were brushing my face. It continued to fly around my face and hands for several more seconds before alighting on a nearby leaf.  We had reached a stalemate: I wasn't about to move on and neither was the butterfly.

A male red admiral (Vanessa atalanta) butterfly perched on a leaf.
The butterfly was a male red admiral (Vanessa atalanta) and I had encroached into its territory, a sunny stretch of boardwalk winding through the woods.  During the minutes that I stayed to watch it, the red admiral aggressively chased all newcomer butterflies out of its territory.  It did not forget about me either, and would occasionally return to tickle me with its wings some more.

The red admiral briefly opens its wings, revealing a flash of color.
Explore some more: Red admiral territorial behavior

Monday, December 2, 2013

Behind closed petals

Hibiscus flowers are stunning while they last, but that is not for very long.  After just a few hours, or at most a couple of days, the petals shrivel up and the flowers drop to the ground. 

A blooming Texas star, a.k.a. scarlet rose mallow (Hibiscus coccineus).
Once the flowers wilt, they are unlikely to be pollinated or to transfer any more of their own pollen.  Yet, they may still have some nectar left inside.  Though the conventional route to the nectar is closed off, the nectar is not out of the reach of all visitors.

A carpenter bee (Xylocopa sp.) chewing through a closed hibiscus flower.
Large carpenter bees, such as the one shown in the pictures above and below, can chew through the expired flowers to reach any remaining nectar.

The carpenter bee starts to work on another flower.
Although this behavior is technically nectar robbing, the salvaging of left-over nectar by carpenter bees should not have any cost for the plant -- as long as the bees do not damage the flowers' ovaries in the process.

Thursday, November 28, 2013

Happy Thanksgiving!

Have a Happy Thanksgiving...

An eastern chipmunk (Tamias striatus) nibbling on an unidentified something.
 ... and enjoy your feast (whatever it is)!

Rose hips partially eaten by a chipmunk.

Monday, November 25, 2013

Gotta find them all! continued

My brief field guide for the park continues with the lizards, which means skipping both the fish and frogs.  Fish are easy enough to see in some of the larger ponds, but not so easy to photograph.  Meanwhile, the frogs were simply too fast for me.  Each time I walked up to a pond, I heard them plop into the water before I spotted them.  I will also be skipping the rabbit at the end for the same reason; the only rabbit that I have seen so far darted off into the bushes before I could get my camera ready.

Lizard: Anoles are the most abundant vertebrates I have seen in the park.  In particular, I find Carolina (a.k.a. green) anoles perched on many of the herbaceous plants and bushes.

A juvenile Carolina anole (Anolis carolinensis) shortly before it disappeared into the vegetation.
However, anoles are not the only lizards in the park.  I recently, and very briefly, saw a skink as it buried itself under the leaf litter.

Butterflies: Butterflies of quite a few different species are also very common in the park.  The most striking butterfly I have seen is the common buckeye, which I have now spent quite a bit of time chasing back and forth across the meadow.

This common buckeye (Junonia coenia) kept fluttering a few more feet away each time I approached it.
Follow the links if you are interested in seeing three more of the butterflies I have identified in the park: a tawny emperor (Asterocampa clyton), a gray hairstreak (Strymon melinus), and a dusky-blue groundstreak (Calycopis isobeon).

Heron: The ponds and the bayou -- or rather, the fish and other prey in the ponds and the bayou -- attract a number of heron and egret species.  Especially along the bayou, all I have to do is look up and down the embankment, and I can usually spot one standing in wait near the edge of the water.

A juvenile yellow-crowned night-heron (Nyctanassa violacea) out in the rain.
Lastly, why did I skip over the beetle?  I considered the generic "beetle" on the sign to be somewhat redundant, since ladybugs (featured last week) are beetles -- not bugs.  For contrast, you can see some true bugs (again) by clicking here.  There are other beetles in the park besides ladybugs, but they will have to wait until another post.

Friday, November 22, 2013

Gotta find them all!

The park across the street has a sign advertising some of the organisms that are likely to be found by visitors to the park. (Note that the sign does not include the organisms most likely to find visitors to the park, namely the mosquitoes and chiggers).

Which one of these doesn't quite belong?
I have already made considerable progress in documenting each of the organisms on the sign (and have either seen or heard all but one of them).  Here is a quick guide to each organism, starting from the top left of the sign:

Ladybug: I have found at least three species of ladybugs (a.k.a. lady beetles) in the park.  However, since the drawing was specifically of a seven-spotted lady beetle, I will show that species too.  This species was an interesting choice for the sign, given that it is not native to North America.

Two seven-spotted lady beetles (Coccinella septempunctata).
Dragonfly: I was absorbed in watching a bee (notably omitted from the sign) when I was startled by the sound of the dragonflies pictured below.  They were making a violent clattering as they beat their wings against the vegetation in their struggle.

A male (left) attempting to mate with a female (right) variegated meadowhawk (Sympetrum corruptum).
Turtle: I didn't even have to cross the street to find a turtle.  The one pictured below was on the grass along the sidewalk outside my apartment.

Probably a red-eared slider (Trachemys scripta elegans), but it was hiding its "ears" along with much of the rest of its head.
Squirrel: You may have noticed that I skipped over the acorn.  I don't remember seeing any in the park, but they may have been there (I was not looking specifically for them) or they may have all been hidden by the many squirrels, most of which appear quite well fed.

A fox squirrel (Sciurus niger), but still no acorn.
To be continued...

Friday, November 15, 2013

Looking for a new backyard

One of the challenges of moving to an apartment was that I would no longer have my own backyard.  Although I could observe the animals and plants in the apartment complex's landscaped areas, it might cause some misunderstandings if I started photographing and videotaping directly outside the ground floor residents' patio doors!  After some thought, I came to the conclusion that if I couldn't have my own backyard, I would find something even better -- and now my new "backyard" (just across the street) is a park complete with woods, meadows, a bayou, and a chain of ponds. 

A view of part of my new "backyard".
When first exploring this new backyard, I was quickly tempted off the trail and into the tall grass to chase a butterfly that turned out to be quite adept at eluding me.

A common buckeye (Junonia coenia) butterfly perched on grass.
Once off the trail, I found that the meadow, which looked quite plain from a distance, was in fact full of wildflowers...

A blanket flower (Gaillardia sp.).
... and insects feeding at those flowers...

A skipper (Hesperiidae) visiting a flower.
... and also a surprising number of insects and mites that preferred to feed on me.  Therefore, in subsequent visits to the park, I made a slight adjustment to my wardrobe.

My new boots are not just for the rain!

Monday, November 11, 2013

Assassins all around, part two

The lone assassin bug that I found in Maine did not seem to have many food options available as winter approached.  In contrast, back here in Houston, the thriving insect community is still supporting a large and diverse population of assassin bugs.  I've found these assassin bugs lurking in the park across the street...

A milkweed assassin bug (Zelus longipes), not on milkweed.

... poising to strike from the flowers along the road...

Another assassin bug on goldenrod (Solidago sp.).
... and even coming in through the hallway window at work.  Since I did not have my camera with me at the time, I captured this last assassin bug and brought it home for further observation.

A leafhopper assassin bug (Zelus renardii) that I caught and brought home.
Just like the nymph that I described previously, this related species of assassin bug keeps its front legs sticky, presumably to aid in capturing prey.  Having sticky legs does come with a significant drawback though, as I noted when I put this assassin bug into a container with some dirt.  Almost immediately, its legs were coated in the dirt.  When given a choice, however, the assassin bug appeared careful to avoid walking directly on dirt -- and by the next morning, it had managed to clean off all the debris.

Friday, November 8, 2013

Assassins all around, part one

In the yard in Maine, the most stunning transformation that occurred during the transition from summer to fall was of the burning bushes.  These small trees went from rather modest plants to the most ostentatious ones in the garden, with vividly pink leaves...

Fall foliage of the burning bush (Euonymus alatus).
... and multitudes of brilliantly red fruits.

Burning bush branches loaded with dehisced fruits.
 As I was admiring the burning bushes, one leaf with a bit more green on it stood out from the others.

A pale green assassin bug (Zelus luridus) nymph on the burning bush.
Hanging on to the leaf was an immature pale green assassin bug (Zelus luridus) waiting to grab prey with its sticky forelegs and then stab the prey with its sharp beak.

The assassin bug nymph raising its sticky forelegs in defense, or maybe in preparation for attack!
Though the assassin bug initially seemed disturbed by my attention, I kept seeing it on the same leaf over the next couple of days.  Then, the leaf fell from the tree and the assassin bug disappeared with it.

Monday, November 4, 2013

Don't try this at home

In the summer, when it is warm and the flowers are plentiful, the vast majority of bumble bees out and about are female workers.  Instead of reproducing themselves, these workers collect nectar and pollen to feed to their mother (the queen) and their many younger siblings.  However, the workers are not all completely sterile.  After the queen dies towards the end of the season, some of the workers may begin laying eggs of their own.  Even though these eggs are unfertilized (since the workers never mated), they are still viable -- and they will all develop into males.

A male orange-belted bumble bee (Bombus ternarius) visiting a flower.
In bumble bees, as well as other Hymenoptera, the females are diploid (having two sets of chromosomes and developing from fertilized eggs) and the males are haploid (having only one set of chromosomes and developing from unfertilized eggs).  A consequence is that as bumble bee colonies begin to decline in the fall, more and more of the bumble bees visible on flowers will be males.

A male common eastern bumble bee (Bombus impatiens) visiting a cosmos inflorescence.
Male bumble bees differ from females in the number of their antennal and abdominal segments, the structure of their hind legs, and, in some species, the size of their eyes and the length and color of their hairs (especially on the head).  For example, notice the yellow fuzz on the face of the male bee below.  In the females of this species, the hairs on the face are black.

A very fuzzy male Bombus ternarius resting on a rock.
An important, and potentially less subtle, difference between male and female bumble bees is that only the females sting.  Bee stingers are modified ovipositors, which bees' ancestors used to lay eggs.  Since only the females had ovipositors, only female bees now have stingers.  Not only are male bumble bees unable to sting, they are also quite docile; many of the male bumble bees I found would tolerate being petted gently without flying away.

The bee was very fuzzy indeed!
Please note that I do not recommend trying this yourself (unless you have also worked extensively with bumble bees and are confident that (a) you can correctly identify the males and (b) you are not allergic to bumble bee stings).  Although less common in the fall, female bumble bees are still present and they may sting -- repeatedly -- with little provocation.

A male (above) and much larger female (below) Bombus impatiens.
Explore some more: Bumble bee identification and see more pictures of male bumble bees at the Natural Current Events Facebook Page.

Thursday, October 31, 2013

Happy Halloween!

Is your Halloween costume ready?  The females of the dragonfly species known as the "Halloween penant" stay "dressed" in orange and black their entire adult lives.  Yet, they are only likely to be seen on Halloween in the southernmost (and warmest) part of their range -- Florida.

A female Halloween pennant (Celithemis eponina).

Monday, October 28, 2013

Mild and woolly

During a walk through the woods in the fall, it can be tempting to gaze at the trees and their marvelous array of colors, sparing little attention to the ground below.

The woods on a quintessential autumn day.
However, it is still important to look down every once in a while -- and not just to avoid tripping.  Paths through the woods are often shared with animals that are an unfortunate combination of small, slow moving, and easily squished. 

A banded woolly bear caterpillar (Pyrrharctia isabella).
Moreover, while the trees in their autumn foliage emanate a certain serenity, finding a fuzzy caterpillar is much more exciting (at least for me)!  Finding this caterpillar was particularly exciting, as when I got close to see its face...

Facing down the woolly bear. suddenly whipped around into a ball (reminding me of another caterpillar's surprising reaction).

The banded woolly bear in a defensive posture.
Though curling up is unlikely to be a good defense against shoes or wheels, the caterpillar's response did make it easy for me to roll it off the road and out of harm's way.

Tuesday, October 22, 2013

What's that bug? continued

After identifying the lobate lac scale, I thought I would try to identify another of the unusual looking bugs in the "Hemiptera" folder.  The larva pictured below seemed like it ought to be easy to identify due to its distinctive appearance, including branched spikes and secreted covering.

A strange, spiky larva on a leaf.
However, the closer that I looked at the picture, the more I began to doubt that it really was a hemipteran.  But if it wasn't a bug, what was it?  Browsing through the various orders of insects, I stumbled across a picture that looked both strange and familiar -- a match for one of the insects in my "Unknown" folder.

An adult male narrow bark louse (Graphopsocus cruciatus) on a rose hip.
The tiny mystery insect was a narrow bark louse, a distant relative of parasitic lice with a much more agreeable diet of plants, lichens, and fungi.  Returning from this lucky digression to the problem of the spiky larva, I eventually came across a surprising answer.

A tortoise beetle larva with its "fecal shield".
The larva was an immature tortoise beetle and possibly a golden tortoise beetle (Cassida sexpunctata), which is considerably more attractive as an adult.

Friday, October 18, 2013

What's that bug?

While I immediately recognize a few of the arthropods in my photographs, I have to file away many of my pictures for later identification.  Most of these can initially be filed to family or at least order, but a few remain complete mysteries.  The strange, butterfly shaped scale insects pictured below lingered anonymously in my "Hemiptera" folder until I serendipitously came across a similar picture when looking for images of invasive species.

Lobate lac scales (Paratachardina pseudolobata) in South Florida last December.
Further research on the internet confirmed that these scales do belong to an introduced species, the lobate lac scale (Paratachardina pseudolobata).  However, learning more about this insect just raised more mysteries.  Although the lobate lac scale is not thought to be native to Florida (or the Bahamas or Christmas Island, where it is also found), it is not clear where this species came from.  A related species (P. lobata) is known from India and Sri Lanka, so this species is likely to be Asian as well.  The spread of this species -- from wherever its native range is -- is somewhat surprising, given its lack of wings and the fact that adults remain relatively sessile.  Also unusual is the absence of males; unlike its relative P. lobata, this scale reproduces parthenogenetically (asexually), developing from unfertilized eggs.

Explore some more: Featured Creature: lobate lac scale

Monday, October 14, 2013

A problem for roots

The invasive Japanese beetle (Popillia japonica) is notorious for the damage that it causes both above and below ground.  Above ground, adult beetles can be seen voraciously consuming foliage and flowers.  Below ground, beetle larvae feed so extensively on the roots of grasses that conspicuous dead patches form on the lawn above.  However, not all dead patches of grass should be blamed on Japanese beetles; some may be due to another Asian beetle with a large appetite for roots: the oriental beetle (Anomala orientalis).

An oriental beetle (Anomala orientalis) sitting on a daisy.
Like the Japanese beetle, the oriental beetle was also accidentally introduced to North America from Japan in the early 20th century and has been gradually expanding its range.  In contrast to the Japanese beetle, though, adult oriental beetles are not very destructive (I have seen several but never observed one feeding).

Another brown oriental beetle sitting on, but not eating, a fern.
A particularly interestingly aspect of oriental beetles is that they come in several color variations.  Can you spot the slight differences in the patterns of the two beetles above?  I've put a hint below the next picture, which illustrates a more extreme example of color variation.

The less common, black form of the oriental beetle (Anomala orientalis).
Hint: The biggest difference is on the thorax (the segment between the head and the abdomen).  The first beetle has a solid brown patch, whereas the second beetle has a white line dividing the brown patch.  The patterns of white and brown on the elytra (the wing converings on the top of the abdomen) are also not quite the same.  See even more examples on the Natural Current Events Facebook page.

Friday, October 11, 2013

Going for a ride? Take a Beetle or a Vespid!

Since I am sitting in an airport, it seems like a good time to write about travel.  Though insects seem small from our perspective, many of them are able travelers.  They can cover long distances by walking, jumping, swimming, digging, and flying.  Additionally, they can use their sensitive antennae to detect faraway food (such as carrion, in the case of the burying beetle shown below).

A tomentose burying beetle (Nicrophorus tomentosus) attempting to scurry away from the camera.
These characteristics make insects an attractive mode of transport for a group of much less mobile arthropods: mites.  If you look closely at the burying beetle below, you can see the mite that had crawled out from some hidden spot onto one of the beetle's wing covers (elytra).

A mite (Poecilochirus sp.) riding on the back of the tomentose burying beetle.
Poecilochirus mites are commonly found riding on burying beetles, since these mites also need to get to carrion in order to feed.  Some Poecilochirus mites consume fly eggs and larvae on the carrion, while some are predators of the burying beetles' own eggs.  Meanwhile, other mites prefer foods unrelated to carrion and, correspondingly, take different forms of transport in search of those foods.

A group of mites rides on the back of the thorax of a mason wasp (Vespidae).
Are mites at best hitchhikers or free riders?  Perhaps not, as some evidence suggests that insects can benefit from the mites too.

Explore some more: Parasitic mites as part-time bodyguards of a host wasp

Monday, October 7, 2013

More than a pain in the neck, continued

After noticing the pattern in how candy stripe spiders tackle their prey, I decided to look back at my many pictures of crab spiders for comparison.  As I had thought, the crab spiders also frequently bit their prey just behind the head.

A female Misumena vatia crab spider eating a tricolored bumble bee (Bombus ternarius) in 2012.
The crab spiders took a different approach, however, when their prey was a hover fly (Syrphidae). 

A juvenile crab spider eating a hover fly (Syrphidae) in 2012.
In these cases, as illustrated in the pictures above and below, the crab spider bit right into its victim's abdomen.

Another crab spider eating a hover fly, this time on a snapdragon.
In addition to having a soft abdomen, hover flies are relatively easy for crab spiders to catch.  One way for hover flies to compensate for their vulnerability is to spend more time inspecting landing sites for potential danger; indeed, hover flies can often be seen seemingly suspended in the air above flowers before touching down to feed or darting quickly away.

Two hover flies inspecting a flower before landing.