subfamily:
Phaneropterinae (Burmeister, 1838)
tribe:
Insarini (Rehn & Hebard, 1914)
genus:
Arethaea (Stål, 1876)
adult female:
Arethaea genus katydids are spectacularly beautiful animals and are easy to care for.
Adult male and adult female:
Introduction
I only have experience from a single season of raising Arethaea from nymphs to adults. Unfortunately, I did not get to raise these guys from eggs, so my discussion here is very limited. Of all the katydid species I have raised, Arethaea are the only ones that I never heard sing. Perhaps their singing was just too soft and drowned out by my many other katydids in the rearing room, or perhaps they sang in a range that I could not hear.
It seems that there is not much accessible online information regarding this genus. I found the most thorough discussion to be by orthopterist Morgan Hebard (1887-1946). Entomologist Philip Edward Bragg wrote an interesting
biography of Hebard, available on ResearchGate. Bragg (2009) describes Hebard's initial interest in Lepidoptera. Hebard met Abram Garfield Rehn, then a student of Orthoptera, at Philadelphia Museum. Through Rehn's influence, Hebard's interests expanded to include Orthoptera and other orders, and Rehn and Hebard collaborated on Orthoptera research beginning in 1905 (Bragg, 2009). The Bragg biography of Hebard is quite compelling reading, and I would encourage anyone interested to have a look at this fully accessible article.
The Morgan Hebard 1936 treatment of Arethaea is the most recent work I could find on this genus through my online searching. Hebard describes the species of this genus as "small and slender, light green in coloration, with organs of flight very narrow when fully developed and limbs amazingly thin and elongate" (Hebard 1936). In his paper, Hebard expands on his collaborative 1914 Rehn and Hebard research to add clarity in light of his more recent findings, noting that much more work is to be done.
This short discussion on rearing Arethaea will include the following sections: 1) Habitat, 2) What Species?, 3)Housing (cage and food), 4) Life Cycle, 5) Mating Mystery, and 6) Observations.
Adult female:
Habitat
Regarding habitat, Hebard (1936) says that Arethaea prefer narrow-leaved grasses where their camouflage is remarkable. He describes their flying as "feebly fluttering." In my brief experience of seeing them in the field, I thought that they flew quite gracefully, but generally for short distances, which made it quite easy for me to catch several adults as well as some young nymphs for the purpose of rearing.
In my time in the field, I found Arethaea in grassy meadows where wildflowers were blooming. I collected mine mostly during mid-morning hours in early June of 2021. The Arethaea were often fairly still or gently rocking, but would flush when I walked too close to them.
Arethaea in natural habitat:
This adult blends in well with the environment:
What Species?
The
SINA site lists 14 species under the genus Arethaea. Unfortunately, I do not know what species I collected and raised. However, I suspect that I had two different species, likely among these three possibilities:
• Arethaea grallator
• Arethaea gracilipes
• Arethaea constricta
Hebard (1936) notes the "pronotum with a fine medio-longitudinal buffy line" of A. grallator, but that might be true to other species, as well?
Perhaps a BugGuiding Orthopterist can offer some insight.
These are some adult male cerci images, perhaps of two different species?
adult male, showing cerci:
Possibly a different species? adult male:
This adult male does not have the pink abdominal markings down the center:
This female also looks different to me based on abdominal markings and wing length/shape:
But I suppose that it's possible that the female of the same species might look different.
male, female, male:
This female was smaller than the others:
Housing
As with my other katydids, I use large mesh butterfly cages measuring 36" x 24" x 24" for housing.
Cages for rearing Arethaea:
For this genus, it's very important to include flowering plants inside the cage. My Arethaea's first dining choice was flowers.
Interestingly, these guys would often chew the stem at the base of a flower, leaving the blossom leaning over. Here is a Rudbeckia hirta (Denver Daisy) victim:
(Perhaps they watched some Monarchs engaging in their signature stem notching behaviour and deemed it a fun idea?)
FOOD
Quite surprisingly, these skinny, lithe, delicate katydids can put away a remarkable amount of nosh. To keep my Arethaea happy, I served organic romaine lettuce and apple slices, rolled oats, cricket powder, butterfly sponges (nectar), and fresh water. And, of course, they always had access to native plants in their cage.
A plate full of large lettuce leaves and apple is reduced to this by morning:
Arethaea (five here) munching on lettuce:
Arethaea adult munching on cricket powder:
Adult male on butterfly sponge:
Adult female and male on butterfly sponge:
VIDEO of Arethaea final-instar nymph female munching on apple.
Life Cycle
EGG
I do not know where females lay eggs, but it is possible that they use stems of plants, leaves of plants, and/or soil. The size and shape of the ovipositor makes me think they would use relatively thin stems of plants or even leaves. However, the only time I actually saw a female laying eggs was this instance where she laid an egg in one of the soil substrate dishes that I always provide for katydids:
Eggs are dark and kidney-bean shaped, measuring 2.5 to 3.0 mm. I believe females generally deposit eggs in stems of plants.
Arethaea eggs:
NYMPH
Many of the youngest nymphs are pink and gradually become green after a couple of instars.
Note the difference in colouration here:
young nymph pinkies:
This nymph is beginning to transition from pink to green:
middle instars:
later instars:
final-instar nymph female:
final-instar males:
final-instar nymphs munching on leaf:
Arethaea exuvia (female):
ADULT
This is an adult female with a young pink nymph:
And here is an adult male next to a final-instar nymph:
Adults generally hold their long, slender wings up like dancer damselflies. Note the frass in this image: small, grey, roundish pellets.
adult males:
Most adults are green with beautiful pink markings; however, I also had pink/brown forms.
adult males, pink form:
adult females:
adult female ovipositor:
adult female ovipositor and cerci (dorsal view):
OLD AGE
After moulting to full adult, my Arethaea generally lived 8 to 12 more weeks.
Very old adults at the end of their lives are moved to assisted living and hospice cages (with other species) where they can easily access their food and water. At this stage, they especially appreciate butterfly sponges (nectar) and apple.
Hospice cage for Arethaea and other species:
This very old female is laying eggs in the butterfly sponge after she is too weak to crawl onto plants:
Old adult male on butterfly sponge:
My very last male died on 11.13.2021 (from the nymphs and adults collected early June 2021).
This is my final male on 10.23.2021:
Mating Mystery
Unfortunately, I never once saw this mysterious species mating. However, it is highly likely that they do in fact mate.
I did on a couple of occasions see a female with an attached spermatophylax. My guess is that this species practices brief copulation with the transfer of a full spermatophylax.
female with spermatophylax:
Interestingly, on one occasion, I found a discarded spermatophylax. While this practice was common with the Amblycorypha species that I reared, it was rare in the other genera I have cared for.
discarded spermatophylaces:
Observations
In my area it appears that Arethaea occur irregularly, often absent for a few years at a time. In 2021, they happened to be quite abundant, but they were absent in the same locations during the preceding and following years. Is it possible that these guys, as with Amblycorypha, can overwinter as eggs for two or more years?
I found Arethaea to be graceful flyers in the field, but only for short distances. As such, it was easy for me to capture a few adults for rearing. They do not fly out of the cage, so opening the cage daily in order to clean, water their plants, and refresh their food was easy.
Both nymphs and adults are strikingly beautiful with markings of varying shades of green, pink, white, and brown.
Arethaea, like some other genera of katydids such as Amblycorypha, will rock side-to-side when nervous.
My Arethaea were mostly crepuscular eaters and were generally inactive during daylight hours.
I was surprised to find that these guys are voracious eaters, but, of course, that always makes them more fun to feed. They especially love flowers.
Arethaea genus katydids are a joy to raise with their exquisite and graceful design and their intriguing air of mystery that always kept me in a state of wonder.
References
Bragg, Philip. (2009). Biographies of Phasmatologists – 9. Morgan Hebard.. 17. 51-58. https://www.researchgate.net/publication/348512364_Biographies_of_Phasmatologists_-_9_Morgan_Hebard
Hebard, M. (1936). Studies in Orthoptera Which Occur in North America North of the Mexican Boundary. VI. A Revision of the Genus Arethaea (Tettigoniidae, Phaneropterinae). Transactions of the American Entomological Society (1890-), 62(3), 231–256. http://www.jstor.org/stable/25077375
Singing Insects of North America. (2023). Checklist of Katydids North of Mexico. https://orthsoc.org/sina/katylist.htm#Arethaea
.