Part 1: Mechanism
34 Comments
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. 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. 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.
It’s been a busy few weeks for the UC Riverside Entomology Outreach Program! The city of Riverside recently held two large public events to promote science engagement in our community: The Long Night of Arts and Innovation, and the first everRiverside Citizen Science BioBlitz. UC Riverside Entomology graduate students showed up in force at both events.
The annual music festival, Burning Man, in Black Rock Desert, Nevada has been overtaken by swarms of noxious insects. Reports have stated these bugs can and will bite people causing painful welts. So just what are these bugs, what are they doing and why is this infestation occurring now when it has never happened before?
This week I got to spend a few days in Anza-Borrego Desert State Park, and at the Steele-Burnand Desert Research Center (a fantastic field station!). In Anza-Borrego, one of the park’s botanists, Larry Hendrickson, has been leading a weeding effort at a popular wildflower viewing site. For more than 10 years, he has led a team of volunteers in carefully removing all of the Brassica tournefortii individuals from within delineated removal plots. Brassica tournefortii, commonly known as Sahara mustard, is a noxious invasive plant throughout the southwest U.S. that negatively impacts native annual plants. The effect is striking – where Brassica tournefortii is removed, native annual plants thrive and the landscape is a lush mixture of native wildflowers. Where Brassica tournefortii is left intact, it is nearly the only plant species present! We know that Brassica tournefortii has negative effects on many native plants, but we know less about how it affects our native arthropods. It’s important to know which organisms are impacted by invasive species, because this information helps biologists to protect the most vulnerable species. As arthropods are amazingly diverse in form, function and ecology, different groups of animals are likely to be affected differently.
We are happy to announce the opening of the EGSA's regular blog! Stay tuned for posts from our graduate students on a wide variety of topics. . .
|
Show posts about...
All
Show posts from...
December 2020
|