by Samantha Smith, Ph.D. Student
Twitter: @samijoe_smith

Assassin bugs (Reduviidae) are incredible predators, some using unique behaviors and morphology to specialize on specific prey such as millipedes, spiders and bees, while others act as generalists, feeding on whatever they can. Their diverse predatory behavior reaches its peak in the tropics. Gabon, a country in western Africa, has preserved much of its jungle, making it an ideal country to collect and study these amazing insects.

As a PhD student at UC Riverside, I am fascinated by the evolution of unique characters such as behavior and morphology. Insects are a perfect study system for evolution: they are amazingly diverse and understudied, leaving an abundance of questions ready to be answered. Though much of my research is done in the lab, collecting insects in the field for DNA work and to better understand their behavior and habitat is a crucial first step. Using their DNA, we can build phylogenetic trees that estimate relationships between different species, allowing us to further predict how unique behaviors and morphologies may have evolved over time.
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In February I traveled to Gabon to collect assassin bugs (Reduviidae), focusing mainly on species found under bark that were missing from our lab’s DNA ‘bank’. We spent two weeks collecting at three different sites throughout the country, using light trapping, general collecting and yellow pan traps.

Using insects collected during this trip, our lab is building a phylogeny of assassin bugs that will resolve relationships between species that are currently unknown. As we understand these relationships, we will also be able to better understand how the wide variety of behaviors evolved across the family, and which behaviors may have led to increased diversity within the family.
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I’ll be returning to western Africa, this time to Cameroon, to study thread legged assassin bugs (Emesinae) and their association with spiders and spiderwebs this summer. Spiders are some of the best predators in the world, and their spiderwebs act as an extension of their sensory system. Surprisingly, Emesinae can manipulate spiderwebs and either feed on the host spider or on prey caught in the spiderweb. Though this behavior is seen in several species of Emesinae, it has only been closely studied in two. I will be collecting and studying four different species of Emesinae in Cameroon to compare with the behavioral work already done. Together with a phylogeny resolving relationships within Emesinae, this study will open a window into better understanding how such unique behaviors may have evolved.

Driving through Southern California, it's hard to miss the plethora of trees that zoom by on the side of the road. It's a little bit easier, though, not to notice just exactly how many of those trees are alien invaders. In fact, most of our decorative trees used in parks and around houses are non-native ornamental trees. One recognizable example of these foreign trees is the genus Eucalyptus. These are the tall, evergreen trees that can usually be seen on the side of the freeway or scattered throughout neighborhoods. Eucalyptus trees have a long history in California, first being planted in 1856, to fulfill the shade-desiring inhabitants of the tree-starved landscape. They grew hardily and fast, supposedly up to 40 feet in 6 years, not hindered by any of their natural pests.

 These primarily Australian  trees are often known as "gum trees" because of the sticky "gum" that they release when damaged. They can also be distinguished by their bark, which can often be pulled off in long strips and flakes, and by their distinctive flowers and fruits. There are about 600 species in the Eucalyptus genus and they can all be distinguished by these features. 

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.

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?