A few nights ago in Chitengo Camp, I caught a beautiful praying mantid Omomantis zebrata. A gorgeous species normally found in bushes and trees in savanna habitats, it is also attracted to lights. I photographed him, and then decided to lift up his wings to check for any coloration, as many mantids and grasshoppers have wild colors on their hind wings. I opened up his wings and was at first disappointed; they were mostly clear, with a slight pinkish tinge. But then I noticed a small dark object hunched in a fold of the right wing. It clearly was not a part of the mantid, and closer examination showed it to be a female parasitoid wasp in the family Torymidae! This animal parasitizes the egg cases (oothecae) of mantids. Many have developed elaborate ways of locating these oothecae, and this individual was a hitchhiker. When the mantid found a mate, the wasp would have jumped ship to the female mantid, and then parasitized the female mantid’s eggs as she laid them. A pretty sorry state of affairs for the mantid, but a very clever method of reproduction for the wasp, and also a reminder to always take a second look at everything.
A few photos from the past few days of several of the more spectacular animals found in Gorongosa National Park, in no particular order.
Yesterday I was flipping rocks in Chitengo Camp, and under one of them I saw a large black and white spotted insect that I recognized as a velvet ant (Mutillidae), a family of wingless wasps known for their extremely painful stings. I watched it race under the rock, and then decided to catch it. This proved to be an easy thing to do, as when I lifted the rock again, it ran right into my container. When I got a closer look at it, I was shocked – this was no velvet ant! It was a harmless carabid beetle that seemed exactly like a velvet ant. A super cool animal.
A few hours later, a very similar-looking insect came into my possession from the same area. When I looked at it, I realized that here was the model, the real velvet ant that could seriously sting me. Now I had a wonderful opportunity to shoot the model and mimic together. I placed both animals in my photo studio and placed a petri dish over them. The velvet ant raced around like crazy, while the carabid beetle sat quietly. Once the velvet ant calmed down a few minutes later, I gently herded the carabid over to the velvet ant, and took the shot. Below is the result. I was blown away by the unbelievable similarity between the velvet ant and the carabid beetle, how two insects so unrelated can seem so alike. The mimicry is almost perfect, right down to the positioning of the white spots and the dull red coloration of the thorax.
I arrived in Gorongosa National Park’s Chitengo Camp late Tuesday night. Around me pulsed the calls of thousands of crickets and katydids that I did not recognize. After getting my luggage put away and having a quick dinner at the restaurant here (which is very nice, I might add), I was out patrolling the grounds. Immediately I started seeing some awesome stuff. I found several grasshoppers which were familiar to me from my work on this group on dead specimens. Seeing them alive and in their natural habitats, they looked familiar, but also not. The lights around the camp swarmed with insects of all sorts; an occasional large katydid or grasshopper, small crickets jumping and flying everywhere, colorful assassin bugs and rhyparochromids scuttling under the leaves. Scores of the big-headed ant, Pheidole megacephala, were ever-present, ready to attack and take away any insect that paused too long. It was heaven.
The interesting thing about Gorongosa in July and August (which is their dry season) is that the abundance of many insects is not extremely high, but the diversity is. For example, I found a total of 5 individual katydids the other night, all very widely spaced around the camp, and each one was a different species. In comparison, Piotr has told me that in the wet season (January/February is the peak) you cannot even sit at the restaurant, because there are just clouds of giant preying mantids and katydids everywhere. Problem then is that most of the roads are flooded and you are basically trapped in Chitengo. Piotr arrived on Thursday morning from a collecting trip on Mt. Gorongosa, and I had dinner with him and several of the other researchers after we tried to locate a bat hawk in Chitengo (a very interesting bird of prey that only hunts bats for about 30 minutes every dusk) Learned quite a bit about all sorts of things. You cannot exit the camp unless you are on a safari or with someone affiliated with the park, because while the camp is fully fenced off, the rest of the park is not as safe with lions and elephants roaming the area. However, there are two gates. One is guarded and you are only allowed through with the guard’s OK. The other gate is open and you can just walk right though and go down to the river. As Piotr described it, the park has an agreement with the lions and elephants. They attack people at the first gate, and they don’t attack people at the second gate. But in all seriousness, the large mammals could be anywhere, but they usually avoid the area around the second gate because of the heavy foot traffic. These and many other interesting tidbits I have been picking up the last few days. I already have several cool stories of insects to post about, but that will have to be another day. I also have tons of photos and I will share a few below.
Tonight we are going collecting outside of the camp, at the “lion house”. Should be interesting…
In just over 18 hours, I will be in Gorongosa National Park, Mozambique, where I will be conducting research on the grasshopper fauna of the park with Dr. Piotr Naskrecki. We have internet at the Chitengo camp, so I plan to post one photo and/or story per day. At any rate, there will be lots of fantastic stuff, as the diversity of life within the park is off the charts. Piotr has posted many of these creatures on his blog, and I will hopefully be encountering these as well as many others. Stay tuned!
A few weeks ago my mom brought home a large snail shell that she had found at the foot of a city tree in South Boston. Usually neither she nor I had paid too much attention to snails and slugs, but this one was clearly unique. With its bright black and yellow stripes on a rounded shell with a width of about 2 cm, this was like no other snail shell I’d ever seen. I suspected that it was non-native, simply because of its large size and colorful markings. However, since my favorite identification website, BugGuide, covers only arthropods (and snails are gastropods), I figured that it might be well nigh impossible to find an ID for the critter. Since it was a dead, empty shell, I left it to my mom and went back to the insects.
Two days later, I had completely forgotten about the shell when my mom asked me if I had taken it. Of course I hadn’t, I replied. She hadn’t either, but it was missing from its spot on her dresser, where she had placed it, intending to draw and preserve it. Well, this was a mystery, as neither of us had moved it, and nobody else had been in the house. The thought popped into my head that perhaps it was not as dead as it had seemed. I checked behind the dresser, and lo and behold, there was the snail, attached to the wood frame of the dresser back! After peeling it off, there was no question that it was very much alive and well. What’s more, I discovered its slime trail on the top of the dresser, winding this way and that, and finally going behind the frame. I did wonder why it hadn’t moved for two days, but I am guessing that it was trying to hold out for water (houses are pretty dry places), and when none came, it decided to look around for itself but didn’t get far.
A habitat was quickly constructed for the obviously dehydrated animal, with some decaying wood, leaves, and of course plenty of water. Now that it had a backstory, I figured it was time to actually try for an identification. I posted a photo of it to BugGuide, asking if anyone knew of any good snail resources for the northeast. I was directed to the Terrestrial Mollusc Tool, and browsing through the photo galleries there, I spotted individuals from the genus Cepaea which looked awfully similar. Doing some additional research on other websites, including Wikipedia, I came to the conclusion that my snail was most likely Cepaea nemoralis, the Grove Snail, based on the dark brown color of the apertural lip (as opposed to a white lip in C. hortensis, a closely related species). Both species are European introductions established in the northeastern United States. They are highly polymorphic, with numerous color forms, and the genetics of this polymorphism have been very well studied. It is a slow growing species, usually requiring three years to fully mature, and it can live up to eight years.
So the end result of all this is that now I have a new pet snail.