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Insect Signs

Praying Mantis Egg Case

12-9-13 praying mantis egg case 057In the fall, after mating, the female praying mantis lays up to 400 eggs in a frothy liquid produced by glands in her abdomen. This one to two-inch long mass is attached to vegetation, often grasses and goldenrod stalks, about a foot or two off the ground. The frothy structure hardens, providing a protective case for the eggs. In the spring, miniature (wingless) mantises, called nymphs, will hatch from this egg case. When hatching, the nymphs appear all at once, crawling from between tiny flaps in the case and then hanging from silk threads about two inches below the case. Within an hour or two, after drying out, they disappear into nearby vegetation.

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Cecropia Moths Pupating

11-11-13 cecropia cocoon dissected  056Our largest North American native moth, the Cecropia Moth, Hyalophora cecropia, spends the winter as a pupa inside a cleverly-crafted 3” – 4”-long shelter, or cocoon, which it creates and attaches lengthwise to a branch while still in its larval stage. The Cecropia caterpillar, with the silk glands located near its mouthparts, spins not one, but two silk cases, one inside the other. In between the two cases, it spins many loose strands of very soft silk, presumably to enhance the insulating properties of the cocoon. Inside the inner case, the caterpillar splits its skin and transforms into a pupa. Come spring, an adult moth will emerge from the pupal case and exit the cocoon through one end which was intentionally spun more loosely, allowing the moth to crawl out the somewhat flexible tip. (Note: dissected cocoon was not viable.)

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Jewelweed Gall Midges

10-4-13 jewelweed gall  277Abnormal plant growths called galls come in all sizes and shapes, are found on leaves, buds and stems, and are caused by a number of agents, including insects. A majority of insect galls are caused by the eggs and developing larvae of flies, wasps and midges. Jewelweed, or Touch-Me-Not (Impatiens capensis), has a very distinctive looking aborted bud gall that is produced by a midge (Schizomyia impatientis). While some galls provide shelter and food for a lone resident, the Jewelweed Gall Midge is colonial, and several orange larvae can be found residing in separate cavities within the gall. These midge larvae are now emerging and will overwinter as adults.

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Apple Scat

10-4-13 woolly bear scat 028At this time of year it’s not unusual to find the scat of various mammals consisting mostly of apple. Red Foxes, White-tailed Deer, Cottontail Rabbits, Porcupines and Black Bears, in particular, are all avid consumers of this appetizing fruit. Birds, including Purple Finches, Cedar Waxwings and Northern Mockingbirds, also include apples in their diets . While many insects drink the juice of apples, it’s not that often you see an insect like this Woolly Bear caterpillar (the larval stage of the Isabella Tiger Moth) consuming a sizable chunk of a McIntosh apple and leaving behind tell-tale scat. (Discovery by Sadie Richards)

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The Give and Take of Food in a Paper Wasp Nest

8-7-13  paper wasp nest 011Like all adult wasps, bees, and ants, adult paper wasps are limited to liquid diets – they have no chewing mouthparts, and the passageway between their head and abdomen, where food is digested, is so narrow that pieces of food wouldn’t fit through it. Wasp larvae (the white grub-like organisms in the upper third of the pictured wasp nest cells) are able to eat a wider range of food, due to mouthparts and their body structure. Adult paper wasps capture and feed caterpillars and other insects to their larvae. The larvae then digest their food and produce saliva rich in nutrients. The adult wasp proceeds to scrape her abdomen across the nest, producing a vibration that signals to the larvae to release some of their carbohydrate-rich saliva which the adult then drinks. (Cells covered with white paper nest material contain wasp pupae.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Goldenrod Ball Gall Fly Larva

3-22-13 goldenrod ball gall fly larva IMG_6182The round “ball” that is often present on the stem of goldenrod plants contains the overwintering larva of a fly (Eurosta solidaginis). A year ago an adult female fly laid an egg in the stem of the goldenrod plant. The egg hatched and the larva proceeded to eat the interior of the stem. As it did so, the larva excreted chemicals which caused the plant to grow abnormally, creating a ball-shaped “gall.” If you were to open a goldenrod ball gall today, you would probably find an overwintering larva (if a downy woodpecker or parasitic wasp hadn’t gotten there before you). Within the next few weeks the larva will pupate, and as early as April the adult fly will emerge from the gall, having crawled out the passageway that it chewed last fall. An inflatable “balloon” on its forehead allows the fly to burst through the remaining outermost layer of tissue at the end of the passageway. The adult fly lives about two weeks, just long enough to mate and begin the process all over again.


Hibernating Queen Wasps

2-7-13 hibernating wasp queen2 IMG_2680The queen is the only wasp in a colony to live through the winter (the others all die), and she usually does so in a sheltered spot such as a rotting log or under the loose bark of a tree (pictured). I wasn’t aware, until discovering this wasp, that queens actually chew a cavity in which to hibernate, but that appears to be the case in some instances. You can see the woody bits of fiber under the wasp that accumulated from her excavating the chamber. The cavity is roughly one inch long and ¼-inch deep. As a rule, hibernating queen wasps protect their wings and antennae by tucking them under their bodies. Some species produce glycerol, which acts as an antifreeze, while others allow ice to form around their cell walls and simply freeze solid. Most queen wasps die over the winter, primarily from predation by other insects and spiders, not the cold. (The pictured wasp had succumbed.) Warm winters are more likely to affect queens, as they emerge from hibernation too soon and starve due to lack of food.


Blueberry Stem Gall

12-20-12  blueberry stem gall IMG_7405If you happen to notice a ¾” to 1 ¼”- long, brown kidney-bean-shaped or round structure on a blueberry bush this time of year, you’ve come upon the blueberry stem gall – a summer and winter home for a dozen or so wasp larvae that will pupate and emerge in the spring as very small (less than 1/8”) black wasps (Hemadas nubilipennis). Last summer a female wasp laid her eggs in a tender, developing blueberry shoot. She then climbed to the tip of the shoot and stabbed it repeatedly, causing considerable damage. Within two weeks the eggs hatched, and the larvae began feeding, which, along with the egg-laying, stimulated the formation of the gall. Initially a blueberry stem gall is green and spongy; by fall it turns red, and by late autumn, it is brown and woody. Next summer, look for multiple holes in these galls that were chewed by the exiting wasps.


A Great Christmas Present!

If you’re looking for a present for someone that will be used year round, year after year, Naturally Curious may just fit the bill.  A relative, a friend, your child’s school teacher – it’s the gift that keeps on giving to both young and old!

One reader wrote, “This is a unique book as far as I know. I have several naturalists’ books covering Vermont and the Northeast, and have seen nothing of this breadth, covered to this depth. So much interesting information about birds, amphibians, mammals, insects, plants. This would be useful to those in the mid-Atlantic, New York, and even wider geographic regions. The author gives a month-by-month look at what’s going on in the natural world, and so much of the information would simply be moved forward or back a month in other regions, but would still be relevant because of the wide overlap of species. Very readable. Couldn’t put it down. I consider myself pretty knowledgeable about the natural world, but there was much that was new to me in this book. I would have loved to have this to use as a text when I was teaching. Suitable for a wide range of ages.”

In a recent email to me a parent wrote, “Naturally Curious is our five year old’s unqualified f-a-v-o-r-I-t-e  book. He spends hours regularly returning to it to study it’s vivid pictures and have us read to him about all the different creatures. It is a ‘must have’ for any family with children living in New England…or for anyone that simply shares a love of the outdoors.”

I am a firm believer in fostering a love of nature in young children – the younger the better — but I admit that when I wrote Naturally Curious, I was writing it with adults in mind. It delights me no end to know that children don’t even need a grown-up middleman to enjoy it!


Cecropia Moth Cocoon

This past summer there seemed to be more giant silkmoths than usual, including Cecropia Moths (Hylaphora cecropia).  (see http://naturallycuriouswithmaryholland.wordpress.com/2012/06/04/cecropia-moth-2/ ). Assuming many of these moths bred and laid eggs, and that most of the larvae survived, there are probably a large number of Cecropia cocoons in our woods.  Even so, it is not an easy task to find them, as they are so well camouflaged, and are often mistaken for a dead leaf.  Cecropia caterpillars spin silk and fashion it into a three-inch long, tan cocoon (giant silkmoths make the largest cocoons in North America) which they attach lengthwise to a branch or stem.  There is a tough but thin layer of silk on the outside, which protects an inner, thicker and softer layer of silk on the inside.  The caterpillar enters the cocoon through loose valves it makes in both layers, which are located at the tip of the cocoon’s pointed end.  Shortly after the larva crawls inside both of these layers, it pupates.  Its skin splits, revealing a dark brown pupa. For the rest of the winter and most of the spring, it remains a pupa.  In early summer it metamorphoses into an adult moth and exits the cocoon through the same valves  through which it entered.

 


Sawfly Cocoon

Sawflies are often mistaken for wasps, but there are subtle differences in appearance, including the thick “waist” of a sawfly compared to the threadlike waist of a wasp.  Their common name comes from the females’ sawlike ovipositor which they use to cut into plants and lay their eggs.  Certain species of sawflies overwinter as pupae inside cocoons that they attach lengthwise to twigs.  These cocoons are fairly small (the pictured cocoon is just over ¼” long).  Sawfly cocoons persist even after the adults emerge in the spring, as they are made of very tough material.   Look for capped cocoons during late fall and winter, and empty cocoons, sometimes with the cap still attached, the rest of the year.


Goldenrod Spindle Gall

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There are three fairly well-known galls (abnormal plant growths caused by a variety of organisms) on goldenrod – the goldenrod ball gall (round swelling in stem caused by a gall fly), the goldenrod bunch gall (leaves at top of plant are bunched up into a mass caused by a gall midge) and the goldenrod spindle gall (elliptical stem swelling caused by a moth).  The amazing thing about insect galls is that not only do they provide shelter for the insect, but they are nutritious and serve as the insect’s food supply as well.    The spindle-shaped galls are home to the larval stage of the goldenrod gall moth (Gnorimoschema gallaesolidaginis).  In the late fall the adult female moth lays an egg on a low goldenrod leaf, where it overwinters. The larva, or caterpillar, hatches out the following spring and makes its way from the now dead leaf to a newly sprouted goldenrod, where it eats its way through a bud and into the stem.  The goldenrod plant reacts to this activity by forming an elliptical swelling, or gall, around the area where the larva took up residence. The larva feeds and develops all summer.  Prior to pupating, it chews a tunnel all the way through the gall (this is the only stage in which the moth has chewing mouthparts), and then spins a silk cover for it.  The larva then returns to the cavity in the middle of the gall and pupates.  In the fall the adult moth crawls down the tunnel,  bursts through the thin layer of silk and then mates and lays eggs.


Signs of Striped Skunks

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If you are finding small, conical pits in your lawn, you probably have a striped skunk to thank for reducing your grub population.  During the spring and summer, invertebrates make up a large percentage of this nocturnal omnivore’s diet.  With the help of their well-developed sense of smell and their long nails (which make them excellent diggers), they locate, gain access to and consume subterranean insect larvae with relative ease.   Another sign of skunk activity, in addition to lawn divots, are the excavated ground nests of yellowjackets.  If they’ve met with success, skunks will often leave sections of empty, paper cells scattered about the nest site.  Apparently, even though yellowjackets can sting multiple times, they’re not very effective at discouraging foraging skunks.  Should you be so inclined, a close examination of skunk scat will reveal bits of insect exoskeletons, as well as the bones and hair of small rodents.  The pictured scat (next to the divot) contained, in addition to insect parts, the fur of another nocturnal animal, a flying squirrel.  (Thanks to Emily and Joe Silver for photo op.)


Pine Cone Willow Gall

Galls are abnormal plant growths that can be caused by insects, fungi, bacteria, nematode worms and mites.  Insects cause the greatest number of galls and induce the greatest variety of structures.  Galls provide both food and shelter for the organisms living within them.  Galls develop during the growing season, often in buds and on leaves.  Pine Cone Willow Galls, named for their resemblance to small pine cones, are found on willows, typically in terminal buds.  A gall midge (Rhabdophaga strobiloides) is responsible for the willow bud going haywire and developing  abnormally. (No-one has determined exactly how insects cause galls, whether it’s the act of laying eggs in or on the plant, or if it’s somehow connected to the chewing of the larvae into the plant.)    Each gall-making insect has a specific host plant, or small group of related plant.  The galls that each insect species induces and lives in while developing into an adult has a recognizable shape and size.  When you think you’re seeing pines cones on willow trees, you’re not hallucinating, you’ve just discovered the temporary home and food supply of a tiny fly, known as a midge.


American Lady Larva

The American Lady larva is very distinctive with its branched spines and white bands across its abdomen.  One of its favorite foods is Pussytoes, a member of the Aster family.  The larva feeds inside a shelter it makes by tying up several leaves with silk.  In the photograph, the larva has incorporated the flower heads of Pussytoes into its shelter.  Not only is the larva feeding and growing inside this 1 ½ ”-long  cavity, it also shed its skin.  To see an adult American Lady butterfly, go to http://naturallycuriouswithmaryholland.wordpress.com/2012/07/08/american-lady-common-milkweed-pollinia/ .  Soon after the larva forms a chrysalis and pupates, a butterfly emerges and starts its migration south for the winter.


Tobacco Hornworms & Brachonid Wasps

Tobacco Hornworms, Manduca sexta (often found feeding on tomato plants and confused with Tomato Hornworms, Manduca quinquemaculata) are often the target of a species of Brachonid wasp that parasitizes beetle, moth, fly and sawfly larvae. The adult wasp lays her eggs inside the hornworm with her long ovipositor. The eggs hatch and the wasp larvae feed on the caterpillar. Eventually the wasp larvae emerge and form white pupa cases on the skin of the dying hornworm larva, inside of which they transform into winged adults. Braconid wasps are extremely good at locating hornworms, even when there are very few to find. Because they parasitize hornworm, cabbage worm, aphid and gypsy moth larvae, Braconid wasps are considered important biological control agents. If you want to discourage Tobacco Hornworms in your tomato patch, allow the wasps to complete their metamorphosis – this accomplishes both the demise of the hornworm, as well as an increased population of Braconid wasps.


Common Aerial Yellowjackets

Common Aerial Yellowjackets derive their common name from the fact that their nests are often aerially constructed, unlike the underground yellowjackets we’re more familiar with. Being in the same genus, it’s not surprising that Bald-faced Hornets and Common Aerial Yellowjackets build nests that are almost identical. The nests of both species have two to six horizontally-arranged layers of comb (for eggs and larvae) inside several layers of protective paper envelopes. The easiest way to tell which species made a nest is to see if there are yellow (yellowjacket) or white ( hornet) markings on the residents. The yellowjackets on the outside of the nest in the photograph are all busy making paper-mache out of wood fiber and applying it to their nest in order to enlarge it.


Monarch Butterfly Chrysalis

Of the multitude of discoveries that every summer offers us, one of the most magical is that of  a Monarch Butterfly chrysalis.  While locating a Monarch larva is not all that difficult, especially when they are as prolific as they are this summer, finding a chrysalis doesn’t happen all that often. Most butterfly chrysalises are a rather drab brown, but the Monarch’s is a beautiful green which serves to camouflage it in fields where the caterpillars feed on milkweed and eventually pupate (form a chrysalis).  The Monarch caterpillar, when mature, usually seeks a sheltered spot under a leaf or branch where rain will not cause the silk button by which it hangs to disintegrate.  The chrysalis in the photograph is attached to a blade of grass which was anchored with silk to another blade of grass in order to make it more secure.  No matter how many I’ve seen, each one still takes my breath away.


Botfly Puparium

Congratulations on some very creative guesses!  Yesterday’s post  was a botfly puparium – a hard case made from an insect’s larval exoskeleton (skin) that covers and protects the pupa.  Most insects that go through complete metamorphosis (egg, larva, pupa, adult) don’t have this added protection for their pupal stage, but certain flies, including botflies, do.  Botflies are fairly large, hairy flies that resemble bumblebees and are internal parasites of many species of mammals, including humans. Depending on the species, the botfly deposits its eggs on or near the host animal, or on another insect, such as a mosquitoe or housefly, which carries them to their host. The eggs of some species of botflies are ingested or inhaled; those of other species hatch and the larvae bore into their host. After entering and crawling around inside of the host animal for a week or so, most species of botfly larvae settle in a spot just under the host’s skin and remain there for three to ten weeks, consuming the flesh of its host.  The lump, or “warble,” that forms just under the host’s skin where the botfly resides increases in size as the larva grows. A tiny hole chewed in the skin allows the larva to breathe, and eventually it exits through this hole.  The larva falls to the ground, where it pupates in the soil and later emerges as an adult botfly. (The two yellow bumps at one end of the puparium are spiracles, through which the pupa breathes.) The whole story of this particular puparium is that Jeannie Killam  found it in her old farmhouse’s kitchen cupboard, where it probably popped out of a visiting mouse.  (Illustration is of a human botfly.)


Monarch Butterfly Eggs Hatching

It appears that this may be a good year for monarchs in the Northeast, as with very little looking, you can find their eggs as well as young monarch caterpillars. Look on the underside of the top leaf or two on young milkweed plants – these leaves are tender and monarchs often lay their tiny, ribbed eggs there (usually one per plant) as they (leaves) are ideal food for young larvae. The first meal a monarch larva eats is its egg shell. It then moves on to nearby milkweed leaf hairs, and then the leaf itself. Often the first holes it chews are U-shaped, which are thought to help prevent sticky sap (which can glue a monarch caterpillar’s mandibles shut) from pouring into the section of leaf being eaten.


Close-up of Entire Organ Pipe Mud Dauber Nest

The images in a slideshow are smaller than if they were posted individually, so I thought I would include a single shot of the first image, showing all of the cells in the nest’s three tubes.


Inside Look at Organ Pipe Mud Dauber Wasp Cells

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Each “pipe” of the Organ Pipe Mud Dauber nest consists of several sealed cells (four, in this photograph), each stuffed with spiders (typically orb-spinning spider species) and one wasp egg. When the egg hatches, the white wasp larva consumes the paralyzed spiders, which are still fresh because they are still alive. Eventually, upon finishing the spiders, the larva will form a pupa case, and spend the winter inside it. In the spring the adult wasp will emerge from the case and chew its way out of the mud cell. If you look closely at the open, back side of these three “pipes” you can see that the oldest pipe is on the left, and contains cells with wasp larvae, whereas you can see mud dauber eggs lying on top of the spiders in two of the cells on the far right, in the most recently built pipe.


Organ Pipe Mud Dauber Wasps

There are basically two groups of wasps: 1) social wasps, such as hornets, yellowjackets and paper wasps and 2) solitary wasps, species that live solitary lives and typically hunt prey for their larvae (the adults consume nectar). Mud daubers are a type of solitary wasp.   Organ Pipe Mud Daubers builds cell out of mud in which they put prey (usually spiders) that they have stung and paralyzed, but not killed. They then lay an egg on top of the spiders, and seal the cell. After the egg hatches, the larval wasp consumes the still-fresh spiders, pupates, emerges as an adult wasp and chews its way out of the cell. In this picture a female Organ Pipe Mud Dauber wasp has collected a ball of mud and is applying it to the most recent cell she is making. The name “organ pipe” comes from the shape of the “pipes”, which consist of several cells, placed end-to-end, with the most recent cell at the bottom. (Notice the new, wet mud is darker in color.)


Leafcutter Bee Cell Leaf Sections

At the risk of boring readers, I wanted to include one final Leafcutter Bee post, showing the two basic shapes that these bees chew out of leaves in order to make their incubator/nursery cells.  There are oblong pieces, roughly an inch long, as well as perfectly round, ¼-inch diameter pieces.  Each cell consists of several layers of oblong pieces rolled lengthwise which are sealed at one end with a round piece of leaf.  The round end pieces appear to be glued into place (perhaps with the pollen/nectar mixture?) at one end of the cell, leaving the opposite end open.  The cells are arranged end-to-end, with the open end of the cell placed against the sealed end of the next cell.  Together they form a nest that is somewhat cigar-shaped and is typically located a few inches down in the soil, or in a cavity.


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