“Actually, Spiderman’s powers have nothing to do with radioactivity,” Dr. Julie Dunning Hotopp clarified to the roomful of entomologists. “It was the transfer of spider DNA into his genome.” While the ability to climb walls or shoot webs out your wrists (or worse) is pure science fiction, the transfer of DNA between two different species does actually occur. Dr. Dunning Hotopp explained that this process, known as lateral gene transfer (LGT), is quite widespread and the advent of genome sequencing (determining the chemical code that make an organism unique) in the last decade has greatly expanded our knowledge on the prevalence and role of foreign DNA in animals

Insects lay eggs, right? Well, in aphids, a speciose family of the Sternorrhyncha, females actually have the option of laying eggs or producing live young from embryos (instead of laying eggs). This is an example of reproductive polyphenism. Polyphenism is the ability of some organisms to adapt their phenotypes in response to environmental cues (Figure 1, from Ogawa and Miura 2014).  In aphids the two reproductive strategies are a response to changes in photoperiod (day length) and this polyphenism is observed ubiquitously in these insects.  In their life cycle, after having survived the winter as frost-resistant eggs, founder females reproduce asexually birthing live young that will produce further asexual females. Asexual females are all about high reproductive rates and dispersion. Those asexual females actually exhibit a second type of polyphenism in that some of them can develop wings promoting dispersion when its current location is experiencing crowded conditions. As day length gets shorter, indicating the coming of winter, sexual egg-laying females are produced (Figure 1). But how are those changes mediated by the environmental signals and how does the system switch from sexual to asexual reproduction?

In last week’s colloquium, Gregory Davis illustrated the complexity of deciphering the mechanisms behind reproductive polyphenism using aphids as his model. Much of this work is available in his most recent review paper (Davis, 2012). He believes that such a novelty may have developed because an initial, slight change in morphology may have stimulated a modification of life history, with changes in life history feeding back to further changes in morphology, continuously playing off each other until obvious changes in body structure and development evolve. 

Ecological theories and models that attempt to explain interactions between plant, herbivore, and predator are innumerable. But just how accurate can these theories be? How many factors can be feasibly fitted to a model without making it cumbersome? What major variables are missing from these interaction evaluations? Dr. Rodriguez-Saona cites one key aspect of agro-ecosystems that has often been ignored: anthropogenic effects of crop selection. 

In terms of biological control, there are numerous top-down and bottom-up factors that play a role in the dynamic balance between plants and herbivores. Top-down factors are regulating mechanisms in which herbivore population numbers are controlled through upper trophic level organisms such as predators, natural enemies and parasitoids. In response to a lack of mobility, plants have developed an array of bottom-up mechanisms with which they can resist attack. Bottom-up controls are synergistically balanced with top-down controls in natural systems for overall suppression of herbivore populations. Plants utilize bottom-up mechanisms directly, through chemical and physical features used to resist damage and indirectly, by signaling to predators of an ongoing attack. These cries for help are in the form of volatiles (herbivore-induced plant volatiles, or HIPVs) that predators and parasitoids can respond to, finding food and reproductive hosts while simultaneously defending the plant. The HIPVs influence both bottom-up and top-down controls in this tri-trophic interaction. 

Dr. Ted Schultz has trekked the Americas in search of precious buried treasure; fungus-farming ants. Although these anthropomorphic creatures are not typically what we consider to be of monetary importance, they reveal a wealth of information about coevolution and symbiotic relationships. Fungus farming ants, like human farmers, cultivate their own food in gardens that are remarkably well cared for (Schultz, et al. 2015). However, unlike humans, fungus-farming ants have an obligate mutualism with their species-specific fungus. Imagine if we could only cultivate one type of food and that food could only survive via human agriculture. Dinner as we know it would be an entirely different experience.

Tracking these ants to their colony requires patience and dedication.  To start, Dr. Shultz baits the ants with Cream of Rice and waits for an ant of interest to approach and take a bit of bait to bring back to the colony. Using a white food source makes it easier to spot the ants as they travel through the leaf litter, but it is still a difficult task.  Once the ant leads him to a colony entrance, the digging starts.  Fungus-farming ant colonies may be over 3 meters deep and digging requires several determined entomologists. Walls that cave in and sandy soils are no deterrents when the prize is a sample of the fungus garden and the ants that tend to it. 

The devastation malaria has wrought on humanity cannot be overstated. On the wings of mosquitoes, this disease has long evaded eradication while preying disproportionately on our developing world. Malaria relentlessly suppresses societies in arid environments by exploiting the interplay of human behavior and ecological dynamics that drives poverty in these areas. Dr. Andres Baeza intimately understands the challenges to sustainability in these regions because he spent his formative years basking in the Chilean sun. Visiting from SESYNC, Dr. Baeza described to the Entomology department colloquium how he’s using his expertise to understand and empower disease intervention in the Northwest region of India.

            Dr. Baeza was quick to point out the precedent of his work in Gujarat and Rajasthan, India, with a graph (figure 1) representing fever (malaria) cases as they correlate with rainfall from a 1911 study by Sir Rickard Christophers. 

Some of the most charismatic and recognizable features in the animal kingdom are the impressive weapons they wield when competing with each other. Porcupine quills, the chelae of crayfish, and the antlers of elk all require an enormous amount of energy dedicated primarily to fighting their fellows for resources and mates. Most species get by with a modest arsenal; mockingbirds will pick fights over the best territory, but their beaks are hardly fearsome. For centuries scientists have studied and debated the evolutionary pressures that guide the creation of extreme biological weaponry we see in mastodons, kudu, and stalk-eyed flies1. Why do a few species develop these exaggerated armaments when most get by with beaks and jaws that can crack seeds not bones?Some of the most charismatic and recognizable features in the animal kingdom are the impressive weapons they wield when competing with each other. Porcupine quills, the chelae of crayfish, and the antlers of elk all require an enormous amount of energy dedicated primarily to fighting their fellows for resources and mates. Most species get by with a modest arsenal; mockingbirds will pick fights over the best territory, but their beaks are hardly fearsome. For centuries scientists have studied and debated the evolutionary pressures that guide the creation of extreme biological weaponry we see in mastodons, kudu, and stalk-eyed flies1. Why do a few species develop these exaggerated armaments when most get by with beaks and jaws that can crack seeds not bones? 

In his experiments, Rob uses a synergistic combination of BMSB aggregation pheromone (Khrimian et al., 2014) and methyl (E,E,Z)-2,4,6-decatrienoate (MDT) (Weber et al., 2014) to lure BMSB into his traps. The advantage of this technique lies in its specificity for BMSB. By using the male-produced aggregation pheromone, Dr. Morrison and his colleagues are able to selectively attract and kill the BMSB without catching other insects (such as bees present in those same orchards) in the crossfire. Since this method only targets the BMSB, the ecosystem will remain largely uninterrupted, allowing for seamless integration of these traps without fear of large-scale ecosystem repercussions. The availability of these attractants in conjunction with research looking into convenient trap designs for growers means that these strategies have real field potential.

Tired of blanketing your entire orchard with gallons of pesticides in order to combat the stink bug menace? Imagine drawing the bugs to a smaller spray area in order to deliver them to an untimely, yet well deserved, end while reducing your environmental impact. Dr. Rob Morrison at the USDA definitely thinks this is possible!