Passionflower-Bramble Katydid Infestation!

When we went down to El Cerrito's Ohlone Greenway at Lincoln Ave. to try to find Gulf Fritillaries on the passionflower vine, we we ending up getting much more than we were looking for!

---

Now that it is summer, starting on Tuesday 6/14 we have been going down to El Cerrito's Ohlone Greenway to look for stuff everyday, mainly Anise Swallowtails (Papilio zelicaon). Originally, we had also intended to look for Gulf Fritillaries (Augraulis vanillae) since there is an enormous passionflower (Passilflora) growing right at Lincoln Ave. While we were able to find a few of their caterpillars and an egg or two, the main highlight of the show was, without a doubt, the katydids.

Previously this year we had only found Mediterranean Katydids (Phaneroptera nana) on the Purple Morning Glory vine (Ipomoea purpurea) at Albany Middle School, starting on Memorial Day 5/30. And as for the native Mexican Bush Katydid (Scudderia mexicana), we have most often encountered them on random low trees and shrubs and rarely on vines. Two of the three we had found this year had been on our apple tree (Malus domestica) with the other being on a fennel plant (Foeniculum vulgare). But in these pass few days we had the lucky opportunity to collect not one but both species and more than doubled the number of each that we had at home.

As stated before, we originally started coming to the passionflower vine to search for Gulf Fritillaries as it is their caterpillar's host plant. But to our great amazement, immediately after we began looking on the noon of 6/14, we spotted a Mediterranean Katydid resting on the vine and basking in the sun. It was medium sized but compared to the ones that we had collected from the morning glory, it was quite big --  the same instar as the largest ones at home. At the time, we considered this an incredibly lucky find and didn't expect to find many more. I mean we had only really found them twice in the past in small numbers and we hadn't seen them at all since 2014 until just two weeks ago.

But soon we had spotted another a few feet away of the same size. Just like we had noticed before on the Morning Glory, it seemed that the Mediterranean Katydids are somewhat gregarious and like to hang out near each other. Unfortunately, since we had not all expected to find any katydids that day we had come unprepared equipment-wise. After frantically searching for something to catch the katydids with, we found a paper bag on the ground (it was actually this bag that we caught our Gulf Fritillary butterfly and Common Buckeye with). Soon after we successfully caught both the katydids that we had found, we discovered a third one also of the same size that we later spotted on a tall blade of grass growing directly under the passionflower. But during our scramble to catch it when the bag had already been filled with so many things just ready to escape at a moment's notice, we ended up dropping the passionflower leaf we had picked that had a newborn Gulf Fritillary caterpillar on it and it must have fell off in the impact! At this point we were starting to get a little overwhelmed and decided to take home what we had so far immediately. But as we were walking -- right when were only a few blocks from safety -- we realized the littered bag had holes in it. By the time we got home, one of the katydids that we caught had escaped. 

Two days later (yesterday, 6/16) when we got there at about 4:00 PM on a sunny afternoon (over 70 degrees), we were disappointed to find that there weren't any Gulf Fritillary butterflies fluttering around as we had seen two days ago when we had come near noon. We had been hoping to catch a few more and perhaps get them to lay eggs for us. Either way though, we still decided to scan the vine for caterpillars that we may have missed before or fresh eggs (this time we did manage to successfully collect two third instar caterpillars and one fresh egg).

But, just like before, we found Mediterranean Katydids after just a few minutes after laying our eyes on the passionflower. And soon after, we found a yellowish green, very mildly pinkish Mexican Bush Katydid camouflaged perfectly well with the pink and yellow flowers flowers. It was in the same instar as the big one we had at home -- the first wing bud instar -- and it was a female. Unfortunately, to our extraordinary lack of foresight, we had somehow forgot to bring proper equipment to catch with again and only had small petri dishes! At the time, we had somehow assumed that we wouldn't be able to find any more katydids and had already considered ourselves ridiculously lucky for having found them the previous day. Needless to say, it was a careless mistake and it cost us at least four of the nine Mediterranean Katydids that we found that day (one also died when we got home because it mismolted in the dish)  Some of them were quite large too, larger than any of the ones we had at home and with first-instar wing buds. Thankfully though, we did manage to snag the Mexican since they are typically larger and slower than the Mediterraneans. 

Today, 6/17, we came prepared. Well. . . kind of. When we went out again, this time around 4:45 on a somewhat gloomy day, we brought with us four cheap plastic cups and four small petri dishes -- the stuff we always use to catch these kinds of insects with and what we had used to catch them on the morning glory. If today had turned out like yesterday, it would have been no problem. But this time, the place was completely infested. 

Starting with the passionflower vine again, we were soon able to gather a hefty amount -- including huge ones with wing buds that we had missed before, successfully capturing most of them with our handy little cups. In a short amount of time, we began combining the contents of the cups to make empty ones to catch more. Then, we spotted a few on the bramble (wild blackberry Rubus ursinus, a California native) which was growing right under the passionflower. Trying as hard as we could to avoid getting poked to death by the spiky rose relative, we managed to catch most of these too. As we began moving farther and farther along the bramble to our left,  it became thicker to the point where it created a barrier between us and the passionflower. But I suppose the passionflower vine mattered little at this point because in a small corner just near the end of it, we found the bramble to be completely covered in Mediterranean Katydids. Everywhere we looked, we could see them, maybe six or seven at a time and more would show up as soon as you caught them. They were all roughly the same age -- either the same instar as the ones we had found earlier (instar right before wing buds) or newly molted ones with wing buds, but oddly enough we did somehow find a lone newborn. With only four flimsy cups that were filling up quickly, we weren't able to catch nearly as many of them that we saw, with more than ten of them escaping by the end. 

At the same time, their incredible numbers devalued them and we no longer jumped in excitement to see one (I think we would be downright terrified rather than enthusiastic to look closely at the bramble again the next the we come). The same cannot be said about the Mexican Bush Katydids though. Just to the left of this little corner, we found an enormous, thoroughly magnificent Mexican Bush Katydid that would very soon molt into adult (its wing buds were very thick and tight) although it was losing one of its hind legs. Regardless, we could have dropped all of Mediterranean Katydids for this guy because he was a male. All three of the Mexican Bush Katydids we had at home were females and we needed him if we wanted any hope of breeding them this year. Even more so because right under the passionflower on the bramble where we had found the Mediterraneans, we found another female Mexican in the first wing bud instar. And later today, we also found two more with one of them confirmed to be female (also first wing bud instar; the other one was the instar before this and could not be sexed) on the little citrus trees at the Alvarado School garden in Richmond. Lucky guy. . . 

In total we had collected 25 Mediterranean Katydids and 5 Mexican Bush Katydids over the three trips, bringing our totals up to 41 and 8 respectively. Through encountering these two katydid species we have definitely learned something about their habitat preferences. Mediterranean Katydids clearly seem to prefer a huge vine habitat in direct sunlight, away from the urban environment, where they can thrive in large numbers and have places to hide. We have never once found them on a tree. We had previously hypothesized that they were somewhat gregarious, but now it seems that it is simply aggregation (group but no social interaction between members) and not colonization (social). On the other hand, Mexican Bush Katydids are solitary and are much more flexible with where they live and what they eat. Evidently, they have different egg dispersal methods. Mediterranean Katydids lay their eggs in big rows on a single host plant which explains why finding some means finding a lot -- they are most likely groups of siblings. Solitary Mexican Bush Katydids lay their eggs singly and therefore have to choose more host plants to lay so many eggs. We are constantly learning about their behaviors and surely this information will come in handy in years to come. 

- Brian