Today we found a Mexican bush katydid (Scudderia mexicana) nymph at Albany Hill (Albany, California).

Every year in late Spring and early Summer we are bound to encounter a few wild Mexican bush katydids (Scudderia mexicana) nymphs randomly hanging out on herbivore-friendly shrubs, vines, or trees. We have already captured a number of very young nymphs earlier this year on top of having some of our eggs from last year hatch so we now are rearing a number of them. 

Today we found another one on the bramble growing near the playground at Albany Hill. It looks to be L4. After taking a few shots, we captured it with a petri dish and brought it home.  

Its good to know that the Mexican bush katydid population is still going strong in the wild. It isn't that they aren't common; each year during the fall we can hear males chirping on every block. The problem is that the introduced Mediterranean katydids (Phaneroptera nana), an extremely similar species, seem to have become increasingly common over the years and now we are finding them in places that used to only be inhabited by the mexicana​. We have nothing against the introduced species but it would be a shame if the pushed out the native species. 

​Authors
Brian Liang

Our Mexican bush katydids (Scudderia mexicana) eggs from last year have begun to hatch.

Last year in late summer we collected over a hundred Mexican bush katydids (Scudderia mexicana) eggs laid by a handful of females that we had painstakingly captured, reared, and mated from nymphal stages. Many of the eggs were inserted into leaves or flower petals, probably the most natural location for oviposition in the wild, but it seems that many of these eggs had desiccated along with the leaf over the months sitting a petri dish. A number of eggs were, however, deposited in plastic tape that were apart of the mesh cage that the females were housed in that didn't seem to face this problem. 

A few weeks ago, we noticed that the eggs in the tape were becoming noticeably plumper and pinkish in color. On this 5/13 post, we got a few shots of the eggs that show the developing katydids and it was quite evident that they were going to hatch very soon. 

The first of the eggs finally hatched today - three of them. They hatch by breaking the egg (which is very flat) with a sharp horn on their heads some place where the two disk-shaped halves of the eggshell come together. The newly emerged katydids are a pale pink which is the same color as the developing eggs (the eggs are probably translucent). After a few hours, they eventually tan into a dirty brownish pink. 

After we consolidated the newborns with the two nymphs (one first instar and one second instar) we have, we noticed that the newborns were unwilling to settle down. Whereas the older nymphs rarely stray from the food source, the newborns consistently crawled to the lid of the container. Like most newborn caterpillar that take a day before settling down on host plant, this behavior is probably designed to get them to find a suitable living place considering that eggs in the wild are probably located in all kinds of obscure places on the ground. 

Rearing notes for our Mexican bush katydids (Scudderia mexicana). These were collected as nymphs in northern California, May 2017.

Rearing Notes 5/14/17-5/??/17:

See Found a Newborn Scudderia Mexicana

​Authors
Alan Liang

We have found a newborn Mexican bush katydid (Scudderia mexicana).

Well this is quite odd. Just yesterday we were looking at our Scudderia mexicana eggs that we had collected from our captive females lasts summer in a petri dish, and had observed that they were near hatching. Well, today we found a newborn nymph, but it wasn't from these eggs. The katydid was inside the cage we had used to house the captive females last year and are currently using for our lineatas and achemons. It was resting on the grape cuttings we had put in for the moths and could've only gotten in the cage by hatching out of an egg lodged in some corner of the cage by the captive females last year. It seems, then, that the wild and captive eggs in the petri dish are quite in synch, as they are hatching around the same time. Also, historically, May has always been when have begun finding the young katydid nymphs of this species. 

The newborn katydid is very small and orangish brown, decorated in many black spots and other colors. The antennae are very long and have alternating white and black sections. The hind legs are very long and thin. We remember seeing nymphs like this in past years, but were never quite sure if it was the first instar or not, but apparently it is; they can't possibly get smaller than this when given the size of the egg.

For now, we haven't done anything with the katydid and plan to just leave it in the cage and feed on the grapes. Maybe when it gets larger we'll have to get some larger plants for it.

Some of our Mexican bush katydid (Scudderia mexicana) eggs have begun showing visible signs of development and are near hatching. These were laid by captive raised females collected in northern California, Summer 2016.

It's been many months since we obtained Scudderia mexicana eggs from our captive reared females last summer. We had collected the many dozens of eggs in a small petri dish and neglected it over the months, not giving it any special care whatsoever. Well, unfortunately it looks like we should have took better care as upon checking on them recently, it appears many are probably dried out. However, looking closer, however, it became clear that a few were developing and going to hatch soon!

The developing eggs are pinkish and have a groove on the side between the katydid's head and leg. The katydid can already be clearly seen through egg shell when inspected up close, and it is quite interesting how compactly it is positioned in the egg. The body is curled, with the large hind legs folded up and meeting the head. Opening one revealed a yellow katydid that was probably close to fully developed, as it was quite solid already.

​Authors
Alan Liang

Today we discovered our first Mediterranean Katydid (Phaneroptera nana) eggs; also an update on our Mexican Bush Katydid (Scudderia mexicana) eggs.

Today while we were moving our Mediterranean Katydids (Phaneroptera nana) our of their enclosure, we discovered three eggs laid in the potted blue morning glory (Ipomoea acuminata) inside. A little sad that there were only three, actually, considering that there are over ten females in there and at least one of them gets mated every day for many weeks now (I'd imagine that every single one is fertile by now!). Like the related Phaneropterinae Mexican Bush Katydid (Scuderria mexicana), the eggs were inserted between the epidermal layers of the leaf. They are slightly smaller than the Mexican Bush Katydid eggs (shown side by side in the right image with the Mediterranean eggs on the right), proportional to the size of the ovipositer, which, in turn, is related to the significantly smaller body of the Mediterranean Katydid. 

As an update on our Mexican Bush Katydid eggs, we collected another 21 of them today, making a total of 101 eggs so far. And this is all by the work of four females at the most. If they all hatch next spring, we shall be swamped!

- Brian

The sixth installment of our rearing notes for the native Mexican Bush Katydids (Scudderia mexicana) from 8/11-8/19.

​Rearing Notes and Stats 8/11-8/19:

- Brian

Today we have finally found a good way to get our fertilized Mexican Bush Katydid females (Scudderia mexicana) to oviposit!

For weeks now since our first Mexican Bush Katydid female (Scudderia mexicana) got mated we have been struggling to find a way to get them to lay eggs. Yesterday, we made a post about how we actually found a group of six eggs layed by our first female in a slit created by a piece of tape and a paper towel in our glass aquarium tank. While it was surely a great discovery for us, what puzzled us is why the katydid insisted on ovipositing only in the tank and not anywhere in the actual breeding enclosure that we provided it -- a 2 x 2 x 4 feet screened box with a live potted passionflower vine (Passiflora) in it. The leaves of the passionflower vine looked as excellent as any leaf for ovipositing; they were large and thick, easily enough room for the katydid to insert her scimitar shaped ovipositer in.

It has been weeks now and not a single egg that we know have in the enclosure. While, SINA recommends depriving the female for a few days of suitable ovipositing sites, this is quite ironic. We had put the female who laid the six eggs into the tank in an attempt to deprive of proper sites (obviously that unexpectedly failed, in a good way) and yet she chooses not to lay in the enclosure where there should be plenty of places.

Starting from yesterday, we noticed two of our females, presumably fertile, struggling with all of their might to oviposit in a small tag sticking out from the top of the enclosure. The tag was basically a thin strip of plastic (only one layer) so there was no possible way that the females could oviposit in it, but they kept obsessing over it, biting at the edges with their jaws and stabbing it with their ovipositers as if their life depended on it. Why, oh why were they so interested by this tag when there is a live plant in there? 

Well, the make a long explanation short, the only thing we could come up with is that the females require a very specific position for laying eggs. Actually, specific ovipositing position is something that can be seen in a lot of insects. Simply put, the female can't lay unless her ovipositor (whatever shape it may be) is not in a convenient angle or location on the substrate to do so. In the case of these katydids, we noticed that unlike the leaves on the passionflower, the tag was sticking in just the right way such that the female could crawl directly onto the edge and position her ovipositer comfortably, without falling off. In nature, they probably search all day for suitable places, which isn't terribly difficult with the enormous diversity of the plants growing around but in our enclosure the passionflower vine probably just didn't cut it.

To test our prediction, we took one of the females inside and put her on an orchid flower (the ornamental plants kind you can find in most grocery stores). Like mentioned before, being able to crawl directly along the edge of the substrate is critical. An orchid flower is unique in that the petals are very flat, rigid, and thick (roomy for ovipositing) like a disc which allows the katydid to have a firm grip crawling on it without wobbling (like on a flimsy leaf or flower). The clincher is the orientation: the orchid flower was growing vertically and not somewhat horizontally like most flowers (the latter, I imagine, would be awkward to crawl on the edge of). But even with the convenient morphology of the orchid flower, we had to help her a bit sometimes, allowing her to crawl on our hand while ovipositing on the edge.

Within a few minutes, she had laid four eggs, methodically feeling around with her mouth-parts for the edge and then nibbling at it when she found it so she could insert her ovipositer into it. Once in, there is a short pause as she prepares to lay. The egg is actually laid when she slowly withdraws the ovipositer; it is left within is slit created by the ovipositer. The entire process only takes a few minutes (shown in the videos below). After each egg, she would thoroughly clean her ovipositer with her mouth.  

Eventually, we brought in the three other females to lay. One of them, our first fertilized katydid (who also laid the eggs in the tank) seemed even more enthusiastic and laid immediately. However, the other two seemed to have no reaction whatsoever; one of them even started to eat the orchid. We assumed that they weren't fertile and took them away. By the time the two fertile females were done, we had collected 20 or so. At last, we have found a successful technique to get them to lay the eggs!

- Brian

​Stats:
Encounters this year: 10
Locations:

• Ohlone Greenway at Lincoln Ave., El Cerrito, CA (4)
• Home, Albany, CA (3)
• Alvarado School, Richmond, CA (3)
• Ohlone Greenway at Gilman St., Berkeley, CA (1)                                                     

Host plants:

• ​Blackberry Rubus ursinus (3)
• Lemon Citrus limon (3)
• Apple Malus domestica (2)
• Passionflower Passiflora (1)
• Willow Salix (1)​

Months:

• May (2)
  • L3 nymphs (2)
• June (8)
  • L3 nymphs (1)
  • L4 nymphs (2)
  • L5 nymphs (4)
  • L6 nymphs (1)
• July (1)
  • Adults (1); starting to hear the chirping of male adults in the wild

Sex:

• Male (4)
• Female (5)
• Unidentified (2)

Adult Molt Log:
6/20 (overnight): oldest male; has a missing hind leg
7/8 (noon): one of four similar aged females​
7/11 (overnight): two of the three remaining females; both have cannibalized middle legs
7/15: found an adult male in the wild; not sure when it molted to adult
7/20 (overnight)​: last female
7/26 (around 9 AM)​: male with a missing hind leg due to mismolting in to sixth instar
7/27 (early morning)​: last male

- Brian