An online resource based on the award-winning nature guide

July

A Butterfly’s Proboscis May Act More Like A Paper Towel Than A Straw

9-24-18 sulphur butterfly IMG_9736The chewing mouthparts of a butterfly larva, or caterpillar, undergo changes when the larva develops into an adult butterfly. They are turned into a tube consisting of two parts, or galeae, that when joined form a structure called a proboscis. The proboscis looks like a straw, and has long been thought to act like one. It is often referred to as a sipping tool through which nectar is obtained by butterflies. However, recent discoveries have scientists thinking that the proboscis works more like a paper towel than a straw.

The liquid that a butterfly feeds on in addition to nectar – animal tears, juice inside decomposed fruit, tree sap, sweat, liquid contained in scat – is so viscous that sipping or pumping it through the proboscis, or feeding tube, would require an enormous amount of pressure. It’s been suggested by entomologist Konstantin Kornev of Clemson University that butterflies draw liquid upwards using capillary action – the same force that pulls liquid into a paper towel. The proboscis actually resembles a rolled-up paper towel, with tiny grooves that pull the liquid upwards along the edges, carrying along the bead of liquid in the middle of the tube. (Photo: Sulphur Butterfly on New England Aster)

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Young Common Gartersnakes Appearing

8-3-18 garter snake 081Seventy percent of the world’s snakes lay eggs (oviparous). The rest give birth to live young (viviparous). Oviparous snakes tend to live in warmer climates, where the substrate they lay their eggs in is warm enough to incubate the eggs.  (Most egg-laying snakes deposit their eggs and then depart, relying on the substrate to incubate the eggs.)  Viviparous snakes tend to live in cooler regions, where the ground is too cold to provide incubation.

There is a distinction between egg-laying snakes.  The majority of snakes that lay eggs do so outside their body, in a protected area such as a rotting log.  These snakes are known as oviparous. There are also egg-laying snakes that retain their eggs inside their bodies until they’re ready to hatch. These snakes are called ovoviviparous. Ovoviviparous snakes, such as the Common Gartersnake, appear to give birth to live young, but they actually don’t. Unlike viviparous species, there is no placental connection, or transfer of fluids, between mothers and babies, because the developing young snakes feed on the substances contained in their individual eggs. The snakes emerge from the mother when they hatch from their eggs, giving them the appearance of “live” births. The gestation period for oviparous snakes is generally longer than those of ovoviviparous snakes and vary from a few weeks to a few months in length. (Photo: very young Common Gartersnake, Thamnophis sirtalis sirtalis, consuming an earthworm)

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Maybe A Great Year For Monarchs?

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I have no idea what the status of monarch caterpillars is in other parts of the country this year, but at least in parts of Vermont and New Hampshire, they are plentiful!  Two on one plant — just like the old days! (Thanks to Sadie Brown for NH input.)

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Bird’s Nest Fungus Fruiting Bodies Maturing

7-25-18 bird's nest fungus IMG_2701The observant eye may have spied what look like miniature bird nests filled with tiny eggs growing in gardens and wood chips this time of year.  They are a type of fungus that forms fruiting bodies that employ a “splash-cup dispersal” mechanism in order to disperse its spores.

The nests (peridia) serve as splash cups; when raindrops strike the nest, the eggs (peridioles) are projected into the air.  In some species, each peridiole is attached to the inner surface of the cup by a slender, hollow stalk which contains an inner, coiled, threadlike “funicular cord.” The fragile outer layer of the stalk is easily ruptured, thus releasing the inner, coiled cord. When wet, the cord elongates greatly and may reach a length of 6-8 inches. The base (hapteron) of this elongated cord is very sticky and adheres readily to solid objects after it is released from the cup. Like a wad of glue, the sticky cord base strikes a solid object, such as a nearby plant, adheres to a branch, and as the peridiole continues in flight the cord expands to its full length. Then the peridiole winds around the branch where the hapteron has become attached and is suspended in the air. Upon drying, the peridiole splits open, releasing its spores.

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Eastern Black Swallowtails Laying Eggs

7-23-18 black swallowtail female laying eggs_U1A2171Eastern Black Swallowtail (Papilio polyxenes) butterflies are mating and laying eggs.  The female Eastern Black Swallowtail can appear quite frantic as she visits multiple host plants just long enough to leave a very tiny, spherical, pale yellow egg before heading on to the next plant.  In the wild, Queen Anne’s Lace, Wild Parsnip, Golden Alexander and Poison Hemlock are favorite host plants; in vegetable gardens you frequently find larvae (if you should miss the eggs) on dill, fennel and parsley.  Entomologists have found that host plant odor is one of the cues involved in the Eastern Black Swallowtail’s choice of where to lay eggs.

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American Bur-reed Flowering

7-23-18 bur weedAmerican Bur-reed, Sparganium americanum, is an aquatic, perennial plant that grows two to four feet high and looks a lot like a grass due to its narrow leaves (but isn’t).  This member of the Cattail family grows in shallow water (up to a foot deep) in marshes and along muddy shorelines.  The flower stem forms a zig-zag pattern with flower clusters at each stem juncture.   The large, spherical female flowers are located on the lower part of the stem, with the smaller male flowers at the top.

Considered an important plant for conservation purposes, American Bur-reed has the ability to remove nitrogen and phosphorus from wetlands.  It can help prevent eutrophication by lessening the buildup of nitrogen (often from agricultural land) and phosphorus (households, industry) from runoff.

American Bur-reed spreads rapidly through its underground root systems of rhizomes, and is relied upon by many birds as an important source of food.  Waterfowl, including Mallards, Redheads, Ring-necked Ducks, Greater Scaup, Buffleheads, Canvasbacks, American Wigeons and Blue-winged Teal, consume the seeds, as do Soras, Virginia Rails and Wilson’s Snipe. Muskrats eat the entire plant. (Thanks to Kay Shumway for photo op.)

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Abbott’s Sphinx Moth Larvae Maturing

7-23-18 Abbott's sphinx moth_U1A2632The larvae of sphinx moths, commonly called hawk or hummingbird moths, are easily recognized by the horn, eye spot or hardened button that is near the tip of their abdomen.  Most readers are probably familiar with the larval stage of tobacco and tomato hornworms (Carolina Sphinx Moth and Five-spotted Hawk Moth, respectively) which are found on tomato plants. A less observed sphinx moth, Abbott’s Sphinx Moth (Sphecodina abbottii), can be found on grape and Virginia creeper vines.  As a larva it molts several times and assumes three different appearances by the time it pupates.

Abbott Sphinx Moth larvae start out green, with a horn near the tip of their abdomen, like most other sphinx moths. However, when they are about half-grown, they turn blue-green and the horn develops into an orange knob (see inset).  In the last stages before they pupate, the larvae molt and the knob turns into an “eye,” complete with a black pupil and encircling iris.  The finishing touch is a white reflection spot that makes the eye appear moist and shiny.  At this point, the larvae may be either brown with a “wood-grain” pattern (resembling grape vines, a host plant) or brown with ten pale green saddles along the back (thought to resemble grapes).  Pictured are the second and third stages of a brown “wood-grain” Abbot’s Sphinx Moth larva.

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