Entomology Graduate Student Association at University of California, Riverside
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A Whole New World (of Wasps)

1/13/2016

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Most of my day is spent thinking about invisible things. Well, not quite invisible, just reeeeally small. The tiny things I spend every waking hour (and most sleeping ones) obsessing over are the following: bacteria, DNA, and impossibly small wasps. And yes, I think of them all at the same time. I study symbiosis. Here is what The Oxford English Dictionary has to say about symbiosis:

noun (plural symbioses ˌsɪmbɪˈəʊsiːzˌsɪmbʌɪˈəʊsiːz)
[mass noun] Biology
1. Interaction between two different organisms living in close physical association, typically to the advantage of both.

Symbioses are common. We are in a symbiotic relationship with all the bacteria in our guts, for example. My favorite symbiotic relationship is between a bacterium known as Wolbachia, and a very small wasp known as Trichogramma.
Picture
Two Trichogramma wasps sitting upon a bed of moth eggs. The wasp on the left is a female, and the wasp on the right is a male.
The image that often comes to mind upon hearing the word "wasp" is that of a large, black and yellow insect that stings and lives in a nest with others of its kind. Trichogramma don't fall into this category: they are less than half of a millimeter in length, they prefer the solitary life, and they wont sting you. In fact, most wasps are more like Trichogramma, we just don't notice them. And while they may not sting you, the females will sting something. That something might be a tree, another insect, or even another wasp. When a small Trichogramma stings its preferred sting-ee (moth and butterfly eggs) it is in fact laying an egg. Once Trichogramma inserts an egg, the wasp will develop inside of the moth egg, eating what would have hatched into a caterpillar. A week or two later, instead of a wee caterpillar, an adult wasp hatches out of the egg shell. This is known as parasitism; Trichogramma is a parasitoid wasp. Other species of parasitoid wasps will lay their eggs in or on caterpillars, spiders, grubs, maggots, eggs of other insects, you name it. There are estimated to be more than half a million species of parasitoid wasps, each with their own particular preferences of where to lay eggs. There is a whole world of these tiny creatures out there that most are not aware of.

In the laboratory, we can watch all this happen.

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In search of natural history...Cameroon field expedition & beyond

1/11/2016

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By: Eric Gordon, Graduate Student Researcher, University of California, Riverside

I work on a groups of bugs that aren't very common or well known. Not only are they cryptically colored but you can only find them in the tropics where they're not particularly abundant. This combination means they happen to be pretty infrequently collected and observed even less often. Even if you did spot one, you’d probably have no idea that these cryptic bugs can possess such interesting biology and behavior

The insects I’m talking about are assassin bugs in the subfamily Salyavatinae. At least one species, Salyavata mcmahanae, has been comparatively well studied. Check out this amazing documentary clip below.
That moving amalgam of dust is actually a nymph (or immature) of one of these assassin bugs and that dust is made up from the same material as the termite colony and seems to chemically disguise it from the termites. These specialist bugs can “fish” for termites over and over up to 31 times in a row and go unnoticed by termite soldiers. Scientists have only ever recorded this species feeding on one particular species of nasute termite, Nasutitermes corniger.

The genus Salyavata is the only salyavatine that you can find in the New World, but there’s a whole group of other genera in Africa and Asia; check out the diversity of the group in the pictures below. You can see that some have strange enlarged fore legs often covered with unique hairs, and that sometimes the females possess larger forelegs than males by quite a bit. Intriguing right? Unfortunately, we have no idea why (in an evolutionary sense) and no one has ever observed these bugs “use” their uniquely modified legs. Like S. mcmahanae, a meager handful of species in Africa and Asia have literature reports recording them as being observed near or feeding on termites, but unlike S. mcmahanae, none has ever had any special study devoted to it. Another subfamily, Sphaeridopinae (also pictured), is thought to be a close relative of this family and might specialize on termites, as one species has been caught near a termite nest and fed on those termites in captivity (P. Wygodzinsky pers. comm. in McMahan [1982]).
Recently I traveled to Cameroon in an attempt to collect some of these assassin bugs. Cameroon hosts an exceptional diversity of these bugs in a relatively small area and I hoped to collect quite a few species along with conducting some behavioral observations to see if I could confirm whether or not at least some Old World members of the group were also termite specialists.

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