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Archive for July, 2011

Cecropia Moth Caterpillar Molting

The caterpillar, or larval, stage of a butterfly or moth is the only stage in which the insect has chewing mouth parts.  Hence, it is the stage during which a great deal of eating takes place.  As the caterpillar eats, it grows larger, and eventually molts its skin, revealing a new, larger skin underneath the old.  A cecropia caterpillar molts four times before spinning its cocoon and pupating. The cecropia caterpillar in this photograph has just molted its skin, which is attached to the plant just above the caterpillar’s head. If you look closely, you can see where the colored tubercles were.  Within an hour of when this photograph was taken, the caterpillar had eaten its skin.

 


Monarch Caterpillar’s Spinneret

Unlike spiders, whose spinnerets, or silk-spinning  spigots, are located at the tips of their abdomens, caterpillars’ spinnerets are located underneath their heads.  The most prominent white structure with a black band around it is the monarch caterpillar’s spinneret, in which its silk glands are located.  The smaller structures are called maxillary palps and are antennae-like sensory devices.  Prior to metamorphosing into a chrysalis/pupa, the monarch caterpillar draws silk through its spinneret, and forms a small, well-anchored button of silk. The caterpillar clasps this button with a structure called a cremaster, located at the tip of its abdomen, from which it suspends itself upside down.  Soon thereafter its skin splits, revealing a gold-dotted, green chrysalis from which an adult monarch butterfly will emerge in two weeks.


Decomposition

It’s a well-known fact that fungi, along with invertebrates and bacteria, are responsible for the majority of plant and animal decomposition that occurs.  They are very efficient at breaking down organic material into simpler forms of matter that can then be recycled.  Seeing  this mushroom, the fruiting body of a fungus, undergoing  the same process  with which it is associated reminds me of the porcupine with a face full of quills it received from its relative.


Rattlesnake Plantains

Rattlesnake plantains get their name from their rosette of broad, egg-shaped leaves, which are similar in shape to those of plantain, a common lawn weed. Although they are called plantains, they are actually orchids.  There are four species of rattlesnake plantains in New England, and the differences between them are subtle.  The pictured checkered rattlesnake plantain (Goodyera tesselata) has leaves with soft green markings, whereas the other three species have silver-white central stripes and/or markings.  Sometimes the species hybridize, making identification challenging.

 


Monarch Butterfly

This 15-minute-old monarch butterfly that emerged yesterday will live for 2 to 5 weeks, long enough to mate and produce the next generation of monarchs.  The generation of monarchs that emerges a month or more from now will live six to nine months, and not mate until next March or so – after flying  to one of about a dozen locations in the Transvolcanic Mountains of central Mexico (a flight of up to 3,000 miles) and spending  the winter.  Late summer-emerging monarchs live longer than monarchs that emerge earlier in the summer because they do not immediately expend energy on breeding and the cool winter temperature in Mexico slows their metabolism, allowing them a longer life.

 


Cecropia Moth Caterpillar

The larval stage of the Cecropia Moth ( Hyalophora cecropia), a giant silk moth, is a sight to behold.  The yellow, blue and red knobs that adorn its 4″ pale green body are striking.  Look for this caterpillar on apple, ash, box elder, cherry, lilac , birch, maple and poplar trees, whose leaves it consumes with relish.  The larva spins a brown, spindle-shaped, 3” cocoon in the fall, and overwinters as a pupa inside it.  In the spring, the adult Cecropia Moth , North America’s largest native moth, emerges.  Brown, with a 4” to 5” wingspread, it has no mouthparts, and lives only about a week to ten days, during which time the males mate numerous times, and the females lay eggs. Unfortunately, this species of moth seems to be declining in number, in part because it suffers from parasitism by a fly that was introduced to control the Gypsy Moth.

 


Dragonflies and Temperature Control

Often on hot, sunny days you will see dragonflies perched facing away from the sun, with their abdomens raised high in the air above them.  This position actually has a name – the obelisk posture – and some dragonflies and damselflies assume this position to prevent overheating.  They raise their abdomen  until its tip points at the sun, minimizing the surface area exposed to it.  The name given this posture comes from the fact that when the sun is directly overhead, the vertical alignment of the insect’s body suggests an obelisk. The meadowhawk dragonfly in the photograph  assumed  the obelisk posture several seconds after the sun came out from behind  the clouds.  As soon as the sun was obscured by clouds again, the dragonfly would lower its abdomen to a horizontal position. It continued doing this for a considerable amount of time.  Sometimes abdomens are raised for reasons other than temperature control, including threat displays during conflicts.


Ruby-throated Hummingbird

Ruby-throated Hummingbirds, New England’s only species of hummingbird, are a major pollinator of flowers.  As they hover at flowers, often red like the pictured bee-balm, hummingbirds probe their bill down into the flower’s nectaries in order to reach the nectar. As they do so, the anthers of the flower brush against the hummingbird, often on top of its head or on its face, depositing pollen.  Some of this pollen is likely to fall off on the strategically placed stigma of the next flower it visits  (often the same species). Research in Illinois and Missouri confirms that ruby-throated hummingbirds deposit ten times as much pollen (per stigma per visit) as do bumble bees and honey bees!  The diet of hummingbirds is not limited to nectar, however.  Insects, including caterpillars, mosquitoes, spiders, gnats, fruit flies and small bees, are gleaned from leaves and bark, as well as captured in air.  The sap holes drilled in trees by yellow-bellied sapsuckers attract insects which hummingbirds consume along with the sap.


Beavers

If there’s any species that knows how to survive a heat wave, it’s beavers! More at home in water than on land, the beaver can hold its breath for up to 15 minutes, and swim up to half a mile under water. Beavers also have valves in their nose and ears that automatically close when beavers are submerged, and transparent nictitating membranes that act as a third eyelid, covering and protecting  their  eyes under water.


Leafhoppers

Leafhoppers belong to the family Cicadellidae — one of the largest families of plant-feeding insects.  There are more leafhopper species worldwide than all species of birds, mammals, reptiles, and amphibians combined.  Certain species, including the pictured red-banded leafhopper,Graphocephala coccinea, drink the watery sap from the plant’s xylem tissue, and secrete honeydew, a sugar-rich solution which ants love.  The ants protect the leafhoppers against predators in return for this sweet treat (an arrangement they also have with aphids).


Wild Turkeys

 

In the heat wave we’re having, humans aren’t  the only creatures looking for relief.  In the middle of the day this hen turkey and her poults sought cooler temperature in the only shade this pasture offered – a small clump of sugar maples and white pines.  They settled in and did some serious preening before ambling off in search of grasshoppers and other insects to eat. The young males will disperse in the fall, while the female poults will remain with their mother until next spring.


Chanterelles

The Chanterelle family of fungi includes some of the best known edible wild mushrooms.  The chanterelle pictured, Cantharellus cibarius, is considered a delicacy, but there are poisonous mushrooms that look very much like this chanterelle, so you should only consume one if someone you trust has identified it.  Most chanterelles are either convex or vase-shaped, and instead of true gills, these mushrooms often produce spores on ridges or folds.  Most chanterelles grow on the ground and appear at this time of year.

 


Dragonflies Mating

7-19-11  Mating Dragonflies

Dragonflies (and damselflies) form what is called a “mating wheel” when they mate.  The male (top) grasps the female at the back of her head with the appendages at the tip of his abdomen. The female then curls her abdomen forward so that its tip reaches his sex organs and receives his sperm.  After mating, the male may continue to grasp the female and accompany her while she lays her eggs, to prevent another male from removing his sperm from the female and then mating with her.

 


Snails and Slugs

Snails and slugs are grouped together as gastropods – a class of Mollusks that includes land, freshwater and sea snails and slugs.  The term “snail” is used for species with an external shell large enough for the soft parts to withdraw completely into it. Those gastropods without a shell, and those with only a very reduced or internal shell, are usually known as “slugs.” We refer to many marine gastropods as seashells, including whelks, conchs, cowries, olives, cone shells, figs and tulips.  While many gastropods are herbivorous grazers, several groups are carnivores, capable of drilling through the skeleton of their prey.


Robber Flies

Robber flies often perch on the leaves or stems of low plants waiting until suitable prey flies by, and then attack it in the air.  They have long, strong, spiny legs for grabbing prey, and piercing-sucking mouthparts for consuming it.  Robber flies prey on a variety of insects, including bees, beetles, bugs, dragonflies, grasshoppers, flies, leafhoppers and wasps. Once they capture an insect, they pierce it with their short, strong proboscis, or mouthpart, and inject  their saliva into it.  The saliva of robber flies contains enzymes that paralyze the insect and digest its insides, which the robber fly then drinks. The pictured robber fly is feasting on the innards of a stink bug it just captured.


Fecal Sacs

A smelly nest is a dead give-a-way to would-be predators, so most birds make an effort to keep their nest fairly clean. (In addition, if the nestlings’ down feathers get matted, they cannot assist in keeping the young birds warm.)  While the young of some birds, such as raptors and herons, defecate at or over the edge of the nest as they age, the waste of  many young songbirds is excreted in what is called a fecal sac – a nice, tidy bundle which the parents carry off and drop at some distance from the nest.  Some species of birds actually eat their nestlings’ fecal sacs when the nestlings are very young, as the sacs still contain some nourishment.


Millipede

Millipedes and centipedes, along with other arthropods (insects, arachnids and crustaceans), possess an exoskeleton, a segmented body and jointed appendages.  All but a few of a millipede’s body segments have two pairs of legs whereas centipedes have one pair of legs per body segment.  Most species of millipedes consume decaying  vegetation, though a few are omnivorous or carnivorous.  Millipedes do not move very fast, and cannot bite or sting; they defend themselves by coiling up tightly so as not to expose  their underside and legs, or by emitting a toxic secretion or gas.

 


Indian Pipe

The very first Indian pipes are starting to poke up through the forest floor.  Lacking chlorophyll, this flowering plant cannot make its own food, but instead is parasitic and relies on  getting energy from fungi  under the ground that , in turn, derive their energy from the  trees they are connected to. You can tell if a flower has been pollinated by Indian pipe’s position.   Prior to pollination, the flower head bends down towards the ground; after pollination, its stem straightens, and the flower faces skyward.


Mating Milkweed Longhorn Beetles

This is what I call a win-win situation.  The female milkweed longhorn beetle feasts on a milkweed flower bud while the male milkweed longhorn beetle satisfies his appetite as well.

 


Great Golden Digger Wasp

Great golden digger wasps are solitary wasps that dig vertical tunnels in the earth with cells off of them into which they put an insect (often a cricket or katydid) that they have stung and paralyzed, but not killed.  They then lay an egg on the insect and seal the cell.  When the egg hatches, the wasp larva consumes the insect before developing into an adult wasp and digging its way out of the cell.  In this photograph, the great golden digger wasp has curled its abdomen under itself and has just inserted its stinger into a caterpillar.  While larval wasps eat insects, adults consume nectar. 


Red Baneberry

Red baneberry, Actaea rubra, can be found growing in moist, shady woodlands, or even roadsides, where it is often not noticed until its red berries have formed in mid-summer.  Although the berries are poisonous to humans, they are not to birds, which are the primary disperser of baneberry seeds.  In addition to robins, brown thrashers, catbirds, sapsuckers and grouse, small mammals such as chipmunks, voles, squirrels and nice eat the fruit.  Several species of birds that consume baneberry eat the fruit but void the seeds, while some of the small mammals remove and eat the seeds leaving  the pulp.  You may be familiar with a common relative, white baneberry, which produces white berries that are referred to as “doll’s eyes.” Native Americans used the juice from the fruits of various baneberry species to poison their arrows. 

 


Crambid Snout Moth

Crambid snout moths are certainly distinctive, and quite unusual looking.  What I thought was the abdomen of this insect turned out to be the head!  Crambid snout moths typically rest in this position, with their head down and abdomen and wings up, looking like a bit of bark or twig.   When they land on a branch or the trunk of a tree, they are extremely well camouflaged.  If you look closely you can see this moth’s long  antennae laying against its body, as well as the brush-like appendage in front of  its head.


Bald Eagle Nest Update

The bald eagle previously photographed on  its nest in May has successfully raised two nestlings, both of which may fledge in the near future.  The young eagles are all brown — it will be four years before they attain the white head and tail of an adult.  As they near their two-month-old date, the young eagles are flapping their wings and lifting themselves up several inches in the air and onto nearby branches as they develop their flight muscles and practice landing.  Research indicates that up to half of all eagle nest departures are unsuccessful, and the young may remain on the ground for weeks before regaining flight ability.  While the parents do continue to feed them, the fledglings are very vulnerable to predators.


Monarch Butterflies

The third and fourth generations of the monarchs that migrated from New England to central Mexico last fall are arriving in New England, mating and laying eggs.  The eggs are hatching, and some of the larvae, or caterpillars, are well on their way to adulthood.  This larval stage of their metamorphosis lasts about two weeks, and is the only stage during which monarchs have chewing mouth parts. The caterpillars take advantage of this by consuming both the leaves and flower buds (see photograph) of common milkweed practically non-stop, increasing their body mass up to 2,000 times.