On a warm Spring morning, wandering around a grove of American Sycamore, I became curious about these magnificent trees: where in the US are they native; why are some leaves larger than the palm of my hand and some half the size; what about those odd pingpong sized seedballs lying on the ground everywhere you look ….. why don’t they roll away in search of an ideal spot to pop open so the seeds can germinate …… when the seedballs are kicked, stepped on or crushed beneath a car tire, do the 1,000’s of seeds inside blow away to sprout ….. are the seeds (all or some of them) even viable ….. do the seedballs make a good ink or dye or maybe they’re edible or even medicinal……. what, if any wildlife species eat the seedballs or seeds; and ooooohhhhhhh, sycamore bark! Why does this tree’s bark flaunt a pastel palette of greens, yellows and pinks. These and many more questions came to mind that it seemed about time the American Sycamore became a subject for my nature journal, until ……………..
There! In the tree above my head, I spotted a most curious thing. Parting a few of that sycamore’s beautiful Spring green palmate-shaped leaves was a bundle of dead brown and beige leafy bits and sticks all haphazardly glued together. Wishing to get a closer look at that elongated ornament shaped “thing,” I found it was securely suspended from a branch. Trying to puzzle out this fascinating mystery while searching for my pen knife, a stiff breeze blew through the tree. It was then a I noticed hundreds of those 2-3” long bundles all over the tree; from the base to its crown!
Curiosity is the Essence of Nature Journaling
What continues to draw me to nature and nature journaling after so many years are the surprises in the familiar and in the unknown. I know well enough that new encounters in nature are infinite; you just have to open your eyes and look. Having learned by carefully observing what appears to be familiar, often leads to new discoveries. That’s when my curiosity kicks into high gear ….. when it’s time to engage in some serious poking around to figure something out; to learn what the “thing” is.
Curiosity, for me, is the very heart and soul of nature journaling. The ‘art’ of curiosity even precedes skill in observation. It’s what drives me out the door in the morning and fuels my exploration. Curiosity fills the mind with countless questions if for no other reason but to develop a deeper understanding of the natural world.
But I “wax philosophical.” Needless to say, my curious discovery on that warm and breezy Spring morning prompted an abrupt change of mind for my next blog post (this post). Anxious to learn about the “thing” suspended from a tree branch, probably minding its own business, I proceeded to cut it down (along with two more) and popped them in a bag along with a few sycamore leaves and seedballs.
Later that same day …….
Upon completing my journal sketches of sycamore leaves and seedballs, and posting a few photos to iNaturalist for an initial ID, it was time to take a closer look at my discovery. Reaching into the bag for one of the “things” (wiping my hand free of spider webbing?), I placed it on my examination table surrounded by several hand lenses, a larger magnifying glass, a penknife, and 2 pairs of tweezers. Before beginning the dissection, I noticed about a dozen black pepper-sized bits moving about the “thing.” Thinking tiny spiders had come from the bag, I didn’t give them a second thought (should’ve been curious!).
This bagworm bag was the subject of my dissection. Notice the pepper-sized black dots next to the bag ….. those are wiggling 1st instar larva.
iNaturalist ID Pick :::::::::::::: BAGWORM MOTH ::::::::::::::: iNaturalist ID Pick
(awaiting genus/species ID)
A Bagworm Moth!
How cool is that!?!
The opened bag of a female Bagworm moth. She’s very dead, but her progeny are escaping as fast as they can.
Dissection resumes ……
After finding out the “thing” I’ve been pondering over is the Bag of a bagwormmoth, I learned the Bag was built during last Spring, Summer and Fall by either a male or female bagworm moth. If a male, the Bag would be empty; if a female, the Bag would contain her remains …. she would’ve died last fall after a male fertilized 500-1,000+ eggs she overwintered inside her body until Spring when newly-hatched larvae would emerge from the bottom of the Bag and begin the species’ life cycle all over again.
The Bag, that took about 10 minutes and all my dissection tools to open, contained the black and mushy remains of a female and 100’s of wiggling/dancing larvae! They were on the move; escaping from the now wide open Bag, and quickly covering my examination table like a pepper grinder out of control.
And my effort to open the Bag? This made sense after reading about the high tensile strength of the silk they produce. These thin strands of silk, 10x stronger than that produced by silkworms, is used in abundance to construct their Bags.
The coolest thing ever! Notice the either late 2nd or early 3rd instar larva, no longer naked, but swaddled in very chewed up leafy bits glued together with strong silk. This dude was hiking up a sycamore branch, continually chewing, wiggling, and gluing.
After disposing of all the naked 1st instar larvae waggling and dancing across my examination table, I placed the dissected Bag, the two whole Bags, and collected leaf material into a clear plastic ziplock to observe what would happen. Over 10 days, the number of larvae multiplied and the naked 1st instar caterpillars grew in size (at least to 2nd instar) while building their individual Bags from tiny bits of leaf litter! Their wiggling dance seemed to be the way their silk strands wrapped and secured leafy bits around their bodies. It’s been fun to watch all the activity.
Have you ever encountered one or more of the 1,350+ species of bagworm moths? What materials were their Bags made from? Please share your experience with these fascinating members of the butterfly/moth family of insects.
Webster’s had it “right on” when describing the Ubiquitous Plant Gall!
gall /ga:l/ 1. something irritating; rude. 2. not able to understand a behavior is unacceptable.
—-the boldness of these guys; the sheer gall and effrontery; the chutzpah; the unmitigated gall; What gall!
“Yeah ….. What Gall is This?!”
That was the question uppermost on my mind when a slight breeze wafting down the trail lifted a fresh oak leaf revealing four slightly wonky vase-shaped growths. One was squatty and pale; three were colored with alternating bands of cadmium yellow and deep vermillion. All four galls were attached to the underside of the leaf, hanging upside down, so whatever might’ve been inside is out.
After 5 minutes of inspection ….. poking and prodding, and peering inside the tiny vases ….. I took some photos to post on iNaturalist to figure out this little mystery. It didn’t take long before my discovery was identified! These are galls of the parasitic cynipid wasp called Feroncaepula, formedthis Spring on a new leaf of Shrub Live Oak (Quercusturbinella).
Originally identified in a 1926 field report as a new species, Diplolepisundulata, this species’ name was reestablished as Feron caepula in a report published in 2023. Ordinarily I choose to only cite a field report, but decided to make an exception in this case for several reasons…… the description of this new species was helpful in better understanding my specimens, and……. one of the paratypes used to describe the new species came from Tijeras, NM (which happens to be my home!). So the entire 1926 field report* (surprisingly short) by LH Weld is added below.
Supplement to the Nature Journal Pages
A Curiosity of Oak Galls, Revisited …… Part III
Curious about plant galls for decades, I finally began reading and experimenting to learn a bit about the inner world of oak galls. Throughout the winter of 2020-2021, I enlisted Roy’s help to collect about 100 nickel diameter, reddish-brown galls hanging on oak leaves like holiday decorations. Not knowing what to expect, I cut into a bunch of these galls and found tiny squirming grubs (larvae) – one/gall. The grubs seemed to be suspended by a complex network of stringy plant tissue radiating from each larva at the center to the inner gall shell. It reminded me of a snow globe frozen in time! Of course I had to know what these guys would become. So I placed about half of the galls into glass jars, and the other half went into jars without their protective gall home. In a few weeks the jars were full of the smallest wasps ever! Wasps! Little parasitic cynipid gall wasps active and ready to be released back into the wild to do what these wasps do! (Rest assured, they were releases in the same area where the galls were collected.)
A few years later, I was once again smitten by these tiny wasps and their galls, and learned more about their life cycle and other facts about galls in general. You can read all about my earlier experiences (and my efforts with experiments) in 2021 and 2023 at this post “No Small Galls this Fall! Oak galls, then and now, the sequel”.
Back to the Present
Here it is 2024, and while hiking the Albuquerque foothills, a new (to me) and colorful gall form appeared hanging beneath an oak leaf. My curiosity piqued. It was high time I gained some insight about the life cycle of cynipid gall wasps. Paraphrasing numerous expert sources, my attempt to interpret and understand what has been described the one of the most complicated life cycles known in the animal kingdom, still seems confusing. Maybe it’s been hard to wrap my mind around Parthenogenesis (asexual reproduction)***….. a key component of a cynipid gall wasp’s life cycle. By taking my time (over a month), and after many written and diagrammatic iterations, I stitched together a description that works. If you’re curious, read on!
One of the oak galls collected late 2020 …. On Shrub Live Oak (aka Sonoran Live Oak)
Where do Oak Galls Come From, and Why?
Every year in late-Spring and through early Summer our shrub live oaks (Quercusturbinella) are a-buzz with a cloud of nearly microscopic cynipid gall wasps that have emerged from a hundreds and hundreds of leaf galls. These often weird looking abnormalities begin forming during an oaks’ accelerated growth period in the Spring. “But where do galls come from and why?”
It’s Complicated!
In the case of cynipid gall wasps, the majority of more than 1400 known species* parasitize oaks, while a much smaller number favor rose and chestnut as host plants. Where and how a gall forms on a host plant, along with the gall’s size, shape and coloring is vector-specific. This gall uniqueness makes it possible to identify what species of insect, such as a cynipid gall wasp (or other external vector like a mite or virus or nematode or fungus or virus or bacteria) was responsible for each gall.
The life cycle of cynipid gall wasps alternate between asexual and sexual generations. This process, called Cyclical Parthenogenesis, is both fascinating and baffling. Typically, the gall formed by the females of the sexual generation (sexgen) shows itself in late winter/early spring, and is on a different part of the oak (such as a twig or stem) than the later asexual (or agamic) generation (agamic galls usually appear on actively growing plant tissues). The following is what appears to happen during the ………………
Photo of Cynipid gall wasp (courtesy Pixabay)
Lifecycle of a Cynipid Gall Wasp
The Asexual (Agamic) Generation
When the weather warms in late winter, an all-female generation of cynipid gall wasps emerge from galls which developed and became dormant the previous year, well before the cold and snow set in. This asexual generation of wasps initiates late Spring/early Summer gall development by inserting (with its ovipositor) an egg along with a maternal secretion from the venom gland, into a swollen leaf bud of the host oak. Egg laying takes place as the growing (meristematic) tissues inside the bud rapidly develop. The egg quickly hatches, and the larva begins feeding, all the while exuding specialized growth hormones that stimulate exaggerated tissue growth resulting in structures (the galls) that are visibly different from normal plant tissues. It’s during the Spring/Summer that developing galls are readily seen, often on the undersides of new leaves.
Portion of journal page from 2021
The safely hidden larva continues to eat the nutrient-rich plant tissues forming inside the gall and grows quickly until it develops into a pupa. After a few weeks in this pupal stage, an adult cynipid gall wasp has formed. Still tucked away, the adult (which is either a male or female) chews a small hole in the gall and emerges to mate.
Another journal page from 2021
The Sexual Generation (aka “Sexgen”)
With the business of mating taken care of, and with no mouth parts to eat, the males quickly die, followed soon by the females. However, before the females die, they deposit one or more eggs on a leaf or within a twig or stem of the host plant. Before the plant’s growing season concludes, the eggs have hatched, larvae have eaten and grown within their individual galls, and have pupated in preparation for over-wintering. Depending on the length and/or severity of winter where these cynipid gall wasps live (and they can live nearly anywhere worldwide), the dormancy period may last from three-five months.
And now …. back to the emergence of the Asexual or agamic generation (the females), in an on-going cyclic loop that is the life cycle of the cynipid gall wasp.
A Supplement to the Supplement!
Types of Galls
Leaf galls
Form on leaf blades or petioles (leaf stems)
Most common galls appear on the upper or lower leaf surface, on or between leaf veins.
Galls may look like leaf curls, blisters, nipples or hairy, felt-like growths.
Oak galls on Gambel Oak
Stem and Twig Galls
Deformed growth on stems and twigs.
Range from slight swelling to large knot-like growth.
When seen, may be peppered with many tiny holes where the adult gall wasps have emerged.
Bud or Flower Galls
Deformed size and shape of buds or flowers.
Fun Facts
Galls are growing plant parts and require nutrients just like other plant parts.
A gall keeps growing as the gall former feeds and grows inside the gall.
Once galls start to form, they continue to grow even if larvae die.
Most galls remain on plants for more than one season.
Galls are usually not numerous enough to harm the plant and control is not warranted.
Gall numbers vary from season to season.
Typically, plant galls become noticeable only after they are fully formed.
The asexual generation (agamic) galls are reported more often because they are larger and persist longer than the sexual generation (sexgen) galls.
Mature plant tissues are usually not affected by gall-inducing organisms.
Iron gall ink, which was the most common ink used from the Middle Ages to the 19th century, was used in line drawings by DaVinci, Van Gogh, and Rembrandt, and in the writing of many historical documents like the US Declaration of Independence.
It’s been so helpful to study the life cycle of these tiny parasitic cynipid wasps, if for no other reason than to admit my understanding remains basically rudimentary, and I must keep my Curiosity alive!
As always, thanks for stopping by!
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*Field report from 1926 by LH Weld
Diplolepis caepula, new species
Host. — Quercus undulata [Wavyleaf oak, Quercus x undulata]
Gall. — Shaped like a small onion, tan-colored, single or scattered in small numbers on under side of leaf in the fall, persisting on the leaf through the winter. The basal third of the sessile gall is beset with long straight single-celled hairs which are mostly reflexed toward the leaf surface. The conical apex is often lop sided and an opening at the end leads into a thin-walled cavity in which are a few scattered hairs and in the base of which is the transversely placed thin-walled larval cell in the very base of the gall. Inside the larval cell at the pedicel is a thin white disk.
Habitat. — The type is selected from a series from galls collected November 14, 1921, near Hillsboro, N. Mex., the flies emerging April 5-25, 1922. Paratypes are from Tijeras, N. Mex., and of the adults cut out of the galls on November 1 some lived in a pill box until December 28. Other paratypes are from Blue Canyon west of Socorro, adults being cut out of the galls on January 2. ….. Similar galls were seen on Q. grisea at Magdalena, N. Mex.
LH Weld: (1926) Field notes on gall-inhabiting cynipid wasps with descriptions of new species”
**The 1400 known species of cynipid gall wasps have been identified worldwide, with an estimated total of more than 6,000 species. In the U.S. there are over 2,000 known species of gall-inducing insects, including 750+ cynipid wasps (500 of which are found in just the West). Worldwide, entomologists have estimated that there are over 210,000 gall-inducing insects yet to be identified!
*** Parthenogenesis is a form of asexual reproduction where an egg develops into a complete individual without being fertilized. The resulting offspring can be either haploid or diploid, depending on the process and the species. Parthenogenesis occurs in invertebrates such as water fleas, rotifers, aphids, stick insects, some ants, wasps, and bees. Bees use parthenogenesis to produce haploid males (drones) and diploid females (workers).
Some vertebrate animals, such as certain reptiles, amphibians, and fish, also reproduce through parthenogenesis. Although more common in plants, parthenogenesis has been observed in animal species that were segregated by sex in terrestrial or marine zoos. Two Komodo dragons, a bonnethead shark, and a blacktip shark have produced parthenogenic young when the females have been isolated from males.
a curious nature 