Bumblebees love dahlias

Dahlias might be the most perfect flowers — geometrically speaking.  Their symmetry is exquisite, and so is their vibrant color.

Purple Dahlia just opening

The camera doesn’t really do this flower justice — it was actually a deep purple. Something about those geometrically arranged spiral whorls of petals generates aesthetic appeal.

And the bumblebees really seem to love dahlia pollen — they have immersed themselves in it.

bumblebees and dahlias

One of my favorite dahlias is red with white frosting on the petals — a Mother’s Day present from last year I managed to save over the winter.

bumblebees and dahlias

The golden fuzz of the bumblebee highlighted by the golden glow of the pollen.

bumblebees and dahlias

There is so much pollen available, they don’t even mind sharing the riches of dahlia flowers.

Mirror, mirror on the wall

Well, actually on the mirrored sheet metal of the stove pipe around the buckeye tree — which turns out to be a difficult surface on which to photograph pale green insects.

tree cricket nymph

I think this is a Tree Cricket, most likely a late stage nymph since I don’t see any wings.  The reflection off the metal makes it look like the cricket has 12 legs instead of 6 and 4 antennae instead of 2.

Tree Crickets are related to grasshoppers and katydids, have long skinny bodies that usually match the vegetation in which they sit (it’s probably hard to match this sheet metal), and antennae almost twice as long as their bodies.  Usually they are nocturnally active and renown for the male’s musical chirping, which is amazingly temperature dependent — so well tuned to temperature in fact that you can use them like a thermometer (if you have already made the temperature calibration).

tree cricket nymph

This little (one inch) nymph doesn’t have much color except in the head region.  The legs and antennae look almost transparent, and its eyes are a striking white with one black fovea spot.

tree cricket nymph

Two sets of palps surround the mouth and assist in food manipulation. Apparently these crickets are omnivorous, feeding off plant, animal (insect), and fungal food sources.

What an odd-looking creature, but a most cooperative one for photography!

Specialists

Isn’t it strange that a plant that contains so many nasty chemicals (e.g., cardiac glycosides), as well as rubbery latex so alkaline that it can permanently scar the cornea of one’s eye, has so many insects that specialize on it?

But here they are — the amazing milkweed fauna:  lepidopterans, bugs, and beetles, consuming every part of the milkweed plant from its roots to its seeds — all seen in the backyard this summer.

milkweed-monarch butterfly larva

The familiar Monarch butterfly caterpillar, munches away happily undeterred by the milky latex exuding from the leaves and stems of the plant.

milkweed tussock moth larvae

The less familiar Milkweed Tussock Moth larvae — there were so many caterpillars on this particular milkweed plant, they completely defoliated it.

milkweed tussock moth larva

The tussock moth larvae grows some very long tufts and is not quite so gregarious when it’s older.

milkweed bug adults and nymphs

Milkweed bugs (true bugs — Hemiptera) are usually found on milkweed plants that have formed seed pods. They lay a clutch of bright yellow eggs on one of the pods, and the nymphs develop through five molts into adults by feeding through the pod wall on the seed endosperm.

aphis-nerii-cornicle-and-braconid-wasp

Yellow aphids collect on milkweed stems and pods, but feed on the sugars passing through the plant’s phloem vessels, not the seeds. Small wasps (left center) parasitize the aphids by laying their eggs on the host.  Aphids are actually true bugs (Hemiptera), although these non-winged individuals don’t appear very bug-like.

milkweed beetle-Tetraopes sp

The Red Milkweed Beetle is a member of the long-horned beetle family. They lay their eggs near the ground, and the larvae burrow into the roots and develop and overwinter there to emerge as adults the following spring.  Like the monarch butterfly larvae, milkweed beetles incorporate the milkweed’s poisonous chemicals into their own bodies, becoming distasteful to their predators.

milkweed-leaf-beetles-mating

Milkweed leaf beetles are members of the very large leaf-beetle family. They eat the leafy greenery, but the larvae are also known for consuming each other — their cannibalistic tendencies reduce competition for food in their local area!

Isn’t it ironic that in producing poisons to ward off herbivores, the plant becomes more attractive to specialist herbivores also trying to avoid predation?

tame birds

I have never encountered wildlife that are so inured to the threat of humans as I saw at Wood Lake Nature Center the other day.  Their innate responses to flee when approached by humans towering over them on a boardwalk seems to have been completely suppressed — amazingly.  The Barn Swallows featured on yesterday’s post were just one example.  Ducks and Grebes were equally unimpressed by our presence.

mallard hen and duckling

A Mallard hen and her one (remaining?) duckling were swimming by the boardwalk no more than 10 feet away.

mallard duckling

About half the size of his mom, this little one still has a lot of its natal fuzz. Mortality for ducklings is highest in their first two weeks of life — when about 70% of the total duckling mortality occurs.

wood duck hens

Wood Ducks were out in great numbers, casually sitting on logs next to shore or swimming quite close to the boardwalk. Most appeared to be hens or juveniles from this summer’s broods.  Female Wood Ducks are easily recognized by the large white patch of feathers behind the eye.

Male Wood Ducks molt out of their brilliant green, black, and brown breeding plumage in mid summer (June-July), but retain their bright red bill and eye, as well as some of the iridescent back feathers and white belly feathers.  During the time they exhibit this “eclipse” plumage, males molt a new set of wing feathers, and then finally begin the body molt back to breeding plumage in the fall just prior to migrating.

wood duck juvenile male

This bird had us confused, but looks like a juvenile male Wood Duck, with its white chin strap and throat coloration the same as the adult male. No red eye or bill coloration means it’s a juvenile though.

wood duck juvenile male

As he swam under the boardwalk, he created some interesting circular ripples in the water.  He is pretty now, but will be a striking when he molts into his full adult plumage.

juvenile pied-billed grebe

There were several juvenile Pied-billed Grebes foraging on the ponds. This one still has a tinge of its nestling plumage –black and white head feathers.

Once Pied-billed Grebes arrive in the spring from their wintering areas in southern South America, they tend to stay put and rarely fly.  They are adept swimmers and divers, snaring crustaceans, aquatic insects, and small fish for their large broods of chicks.  This marsh must have been great habitat for rearing Grebe chicks this year, because there were a lot of juveniles out on the water. Like loon chicks, young grebes ride around on their parents’ backs for the first couple of weeks of life — hanging on even during a dive.

pied-billed grebe adult

Next spring, juvenile birds will develop the silver and black-banding pattern for which the species is named.  

Barn Swallow hang-out

The Fall season is apparent now in the crisp, cool mornings and evenings we have had lately.  The sun rises later and sets earlier, and the birds have started to flock up in preparation for migration.  Barn Swallows always seem pretty gregarious — for birds, nesting together on any convenient man-made structure, but they stick even more closely together in their spring and fall migratory flocks.

barn swallow adults flock up before fall migration

Usually, swallows are hard to photograph as they swoop back and forth across the marsh land catching bugs.  I guess a mid-day rest was in order for these Barn Swallows, and they were carrying on a lively conversation, chirping vigorously with each other.  Males have rust-brown feathers on neck and abdomen; the breast and belly feathers of females are white under their rust-brown neck feathers.

The Barn Swallows are so used to humans walking up and down the boardwalk over this marsh at Wood Lake nature center, they hardly move in response to the traffic.  But just to make sure that two walkers behind me didn’t scare this particular bunch away, I asked them if they would pause for a moment in their rapid stroll that bounced the boardwalk up and down.  “Why?” asked one of the walkers.  “So I can take a photo”, I said — it being plainly obvious that I was carrying a huge camera bag and had out my long telephoto trained on the birds.

Even though it’s time to prepare for migration, some swallow parents are still feeding those chubby beggars from their second nesting of the summer.  I wrote about these birds just about exactly this time last year (see Feed me…still)

One lone juvenile perched, waiting to be fed, and provided some wonderful swallow poses for us.

baby barn swallow

This juvenile is fully feathered, but has a much shorter tail than the adults, and still bears the mouth markings of a chick — a yellow rimmed beak.

baby barn swallow

baby barn swallow

baby barn swallow

baby barn swallow

How close can I get?  Next spring, this little bird will molt new body feathers on its back and head that look blue-black instead of gray.

moth vs butterfly

Usually it’s easy to distinguish a moth from a butterfly. Moths are generally nocturnal; butterflies operate in the daytime.  Moths have furry, chunky bodies; butterflies are sleeker with less “hair”.

white-lined sphinx moth, Hyles lineata

A white-lined sphinx moth warmed itself on my outdoor light fixture late one night.

hummingbird clearwing moth

Hummingbird clearwing moths feed on flowers open in the daytime — so, the nocturnal-only attribute for moths has many exceptions.

leadplant flower moth, Schinia lucens (1)

How about this diurnally-active leadplant flower moth?  Easy to confuse with a butterfly, except that butterflies usually hold their wings vertically at rest while moths rest with their wings outspread or in a V-position, like the wings of a jet plane.

monarch on rough blazing star

A Monarch butterfly sips nectar from the flowers of a rough blazing star plant. On chilly days, butterflies might bask with their wings open, but usually they sit with the wings vertical at rest.

Butterflies generally have slender, clubbed antennae; moths sometimes have elaborate fringes on their antennae or have slender filamentous antennae without clubbed ends.

red admiral on coneflower

Ropy antennae with clubs on the end are characteristic of most butterflies, like this Red Admiral feasting on a coneflower.

male silkworm moth - Ash Bowie-Wikimedia Commons

The elaborate, feathery antennae of the male silkworm moth can detect the bombycol molecules released by a female moth from a mile away.  Photo by Ash Bowie from Wikimedia Commons.

As expected, the compound eye of moths differs from that of the butterfly — each being highly adapted to the light intensity of the environment in which the animal is most active.

red admiral eye and antennae

Butterflies generally have compound eyes adapted for color vision in bright light, with multiple darkened areas that probably represent clusters of ommatidia used as specific focal points.

leadplant flower moth, Schinia lucens (2)

The compound eyes of moths are specialized for visual acuity in dim light. They appear more uniform in color, lacking the dark spots seen in the butterfly eye.  Note the slender, filmentous antennae of this moth — very unlike a butterfly’s.

A final important difference between butterflies and moths is the pupal case, which may be a smooth chrysalis in butterflies but is a webby, textured cocoon in moths.

But then just to confuse things a little, we have the hairy-bodied skipper butterflies, with their densely haired bodies and their habit of sitting with wings spread rather than vertical.  But ropy antennae with clubs on the end means that these guys should be grouped with the butterflies.

arctic-skipper

You can read more about this group of butterflies here.

Infestation!

Each year about this time, the swamp milkweed acquires an infestation of yellow aphids.  I don’t know where they come from or how they find the plants (chemical cues?), but they regularly appear just as the pods are elongating and maturing seed.

Aphis nerii on swamp milkweed pods

Aphis nerii, the yellow milkweed aphid, is a specialist that only feeds on milkweed species. Winged adults settle on the plant and then produce hundreds of asexual (non-winged) clones of themselves.

Usually I find the aphids just on the terminal stems and pods, but one plant had a congestion of aphids from the ground level, up the stem, to the tip of the pods.

aphid infestation on milkweed stem

It’s hard to believe the aphids get much nutrition from the woody part of the milkweed stem.

Aphis nerii on swamp milkweed

Aphids feed on milkweed sap by inserting their slender proboscis into the vessels that carry the sugar manufactured by the plant. Swollen yellow abdomens stick upright from the plant surface while their heads are down near the surface. When threatened by a potential predator (or human), they wiggle their butts in unison.

For more information on this interesting phenomenon, see my earlier post on how predators control the aphid population.

 

Fruit trees?

Banana (trees?) hang over the fence in my sister’s backyard in Los Angeles.  While they are as big as some small trees, bananas are really just a very large herbaceous flowering plant.

bananas

The fence is about 5 1/2 feet tall, and the bananas approximately double that. You can just barely see an overly ripe bunch in the right-center of the photo above the fence.

Each stalk that arises from an underground corm produces one flowering stem that develop into the fingers of bananas we later purchase at the grocery store. When that stalk has ripened its fruit, it withers and falls, and a new “baby banana” shoot starts to grow up from the corm.  So banana plants are really herbaceous perennials.

banana fingers-very ripe

These bananas were beyond ripe and almost mushy, but very sweet tasting. The parent stalk behind the clump of bananas is already yellowing and will soon fall down.

Bananas originated in the Indomalayan-Australian region of the world. Varieities were selected that could develop fruits without seeds and without fertilization of the flowers for cultivation, so modern bananas develop directly from the first, female-only flowers on the flower stalk (i.e., parthenocarpic development).

banana fingers

Green (unripe) banana fingers grow in whorls around the flower stem. The lower part of that stem that would produce sterile and male-only flowers has been broken off.  The fleshy part that develops into the banana arises from the flower’s ovary; dried-up remnants of petals persist at the outer tips of the fruit. 

banana fingers and male flowers

When the female-only flowers have developed into banana fingers, the flower stalk elongates and produces additional sets of flowers in double rows — first, a set of sterile flowers with both stigma and anthers, and then lower down, rows of male-only flowers.

sterile banana flowers

I think these are the sterile banana flowers that contain both female and male reproductive organs, but no pollen or ovules in the flowers. The stigmas (female) are the whitish spoon-shaped structures, and the anthers are the yellowish, reflexed structures.

Plant breeders have so successfully messed with the sex life of the banana plant, there is no purpose for these sterile or male-only flowers, and they are usually removed.  Their slimy, sticky residues are a nuisance to clean up anyway.

The bananas in the Los Angeles backyards seem to be an untapped resource — there are no monkeys to harvest them, and the squirrels and birds seem to ignore them.

How dry it is…

In California for a brief visit with family, I strolled down to the local reservoir to try out a new point-and-shoot camera (Pentax MX-1), which I bought expressly for landscape shots while traveling.

silverlake resevoir, Los Angeles, CA

Severe drought over the past three years has lowered the water levels in Silverlake Reservoir markedly.  Photo taken with the camera setting on Auto — I didn’t have to tweak the contrast or the sharpening in Photoshop!

silverlake resevoir, Los Angeles CA

Across the street from the reservoir, hillsides are losing their vegetative cover, which increases the risk of dangerous erosion if and when the rain ever comes. Even the eucalpytus, native to dry areas of Australia, look like they are suffering from lack of moisture.

gulls on silverlake reservoir, Los Angeles CA

I have photographed this scene before, but I’m always amused to see how the gulls line up on the floating buoys in the morning sun.  No Photoshop touch-up employed with this shot either.

gulls on silverlake reservoir, Los Angeles CA

I changed the color cast to a warmer yellow from the blue in the original photo to make this shot more interesting (artistically).  This is a crop of the photo above with little loss of clarity and sharpness.

gulls on silverlake reservoir, Los Angeles CA

The 4X zoom brings in the subject with excellent clarity — I didn’t adjust anything but the color cast in this photo.

orchid tree, Bauhinia sp.

The orchid tree (symbol of Hong Kong) is blooming in southern California, and the hummingbirds are busy trying to defend this small patch of flowers.

orchid tree (Bauhinia sp.) flower

The camera does a great job with a macro shot of the orchid tree flowers.

With its fast, 18-112 mm lens, and wide-open f1.8-2.5 lens, it takes pretty sharp photos without any Photoshop tweaking.  It does a nice job on macros and gathers light well in dimly lit conditions, so I think it’s a keeper.

Turkey stroll

I haven’t seen much of the wild turkeys this year — it must not be a good year for acorns in my backyard.  But two young males checked out the weed patch in my neighbor’s yard the other day, and found it far more interesting than my wildflower garden.

turkey toms

Perhaps they are finding some good insects among the tall weeds. I dislike the way the weeds come through the fence between our yards, but am happy the weed patch brings in the wildlife.

turkey tom-old

The elder Tom (long beard hanging down his front) of the pair shows no interest in the bugs in the wildflower garden — perhaps he is not fond of bees.

turkey tom-young

The younger Tom (short beard) shows equal disdain for a different patch of wildflowers.  I wonder if this guy was hatched just this year, or if he is a year old.

turkey toms

Meeting up on the other side of the backyard, the two Toms decide to move on, to better foraging grounds.

Male and female turkeys flock up in the fall, like many other bird species, but are segregated by sex, and to some extent by age.  Young males (non-breeding jakes) will often hang out together all fall and winter, while a hen and her brood, or even multiple hens and broods form a flock of their own during fall and winter.  Adult (breeding) males also form flocks outside of the breeding season, rarely including the young Toms — kind of like an “old boys’ club”.