I had a wonderful time at the 2018 SICB meeting in San Francisco. As usual, there were plenty of great presentations, and this year there was also a special Editors Challenge workshop on stress. This workshop was one of the highlights of the week for me, in the coming weeks you’ll be able to read a summary, find links to presentation slides, as well as video links to some of the presentations and discussions on the Integrative and Comparative Biology blog which I contribute to.
I had the opportunity to share some new insights on some old questions regarding territory defense in the cichlid fish Neolamprologus pulcher for my talk on Thursday. Additionally, along with recent Team Gambusia and UC Davis graduate Rechelle Viernes, I presented some new results on the behavioral and neuroendocrine impacts of pesticide exposure on the western mosquitofish during Saturday’s poster sessions. Look out for both papers in the not too distant future!
Team Gambusia alumni Rachel graduated this spring and has been hired by Pacific EcoRisk! Excellent work in the lab this past year, and best of luck in your future career!
The major goal of my postdoctoral fellowship project is investigating the impacts of human induced rapid environmental changes (HIREC) on natural selection in wild populations. To do so, I’m comparing modern populations of western mosquitofish (Gambusia affinis) to historical populations of fish collected at these same sites. These sites are unique from one another in the extent to which they’ve been influenced by human impacts they’ve faced.
Thus far, I’ve collected fish at each site twice, first in the spring, and again this summer. At each site, my amazing team and I caught fish, photographed them for morphometric analysis, and collected tissue samples from a subset of them for future molecular analysis (look for more info on that in future post!).
In the spring, we were delayed due to near-record rainfall we received this year in California. At one site, we literally couldn’t get within miles of the collection site because of flooded roadways. Eventually, the water receded enough that we could catch the fish in the parking lot at the site.
In spite of the amount of rain winter brought, it was a typical California summer and on our second visit to sites we were working in mid to high 90 degree heat. Finding fish was much easier however, and we only had to return to one site for a second day.
We’re looking forward to seeing and sharing the results of this work!
The rest of SICB was great, as was the rest of the time in New Orleans. The second day of the conference was rainy day, followed by a few unseasonably cold days, so it’s fitting that many of the talks I attended revolved around environmental stressors and measuring their impacts on organisms.
Behavioral and physiological responses to stress – Dr. Kimberly Rosvall, Indiana University
Dr. Rosvall described a study she performed on male Dark Eyed Juncos to understand how they responded to perceived territorial intrusions by other male birds. A common and well-accepted way to bird researchers trick birds into thinking another bird is intruding on their territory is to play audio samples of those birds singing. One experimental group had heard song clips the entire day before samples were taken (persistent social intrusion group), another heard 25 minutes of song before sampling took place (acute social intrusion group); both groups were compared to a control group which heard no songs.
Male birds in both experimental groups sang more than control group birds, indicating that they believed a competing male to be in the area. That males in the persistent social intrusion group sang frequently was interesting because they hadn’t heard a competitor’s song that day; it was a residual effect of the previous day’s songs. Physiologically, males that had heard songs were upregulating genes that indicated they were producing more sperm (a common response in many species to perceived competition over mates). These males that had heard songs also were upregulating particular genes in their brains associated with sending signals from the brain. Most interestingly, the spleens of birds in the persistent social intrusion group had shifted gene expression of genes associated with the immune system, suggesting that there is an actual cost to engaging in competition with other males.
Measuring Hormones in Whale Baleen – Dr. Kathleen Hunt, N. Arizona University
Dr. Hunt studies the hormone levels in baleen whales, but as you can imagine acquiring blood samples from whales can be a bit difficult. One method that is frequently used (but inherently difficult) is to follow whales in a boat and collect fecal samples as they float to the surface. Dr. Hunt described a new method she is utilizing to measure hormone levels in baleen whales – measuring the baleen itself.
Hair samples are used to measure hormones in many animals, and these samples are especially useful because as hair grows, it can give you a historical record of hormone levels over time. Because baleen is a modified hair, Dr. Hunt predicted she could measure hormone levels in baleen. She was correct, and her preliminary findings indicate that a number of hormones can be measured by examining baleen samples. This is especially useful because baleen can represent up to 10 years of the whale’s life, and there are abundant baleen samples in museums around the world!
Alternative Mating Strategies and Parasites – Dr. Susan Balenger, University of Mississippi
Many species have parasites that specialize on them, and often these species evolve adaptations to avoid succumbing to these parasites. A species of cricket that lives on Pacific Islands face a predicament because a parasitic fly that specializes on crickets is attracted to the chirp male crickets use to attract mates. If a male cricket tries to attract mates, he becomes more vulnerable to the parasitic fly laying eggs on him which will eventually hatch and eat his internal organs before erupting out of his body – killing him in the process.
On two Hawaiian Islands, a “flat wing” mutation has emerged in cricket populations leaving them unable to chirp. This mutation is advantageous in that males are less vulnerable to the parasitic fly, but they cannot attract mates. In order to breed, these males are more likely to wander in search of mates. On islands where the parasitic fly is abundant, these “flat wing” males have been very successful and have become more abundant (~95% of males on one Hawaiian Island).
Dr. Balenger raised some of these crickets in environments in which they heard other males chirp, and others without any chirping males. While all of the experimental crickets were capable of chirping, males from islands that had a large number of “flat wing” males were more likely to wander in search of mates if they had been raised without the sound of chirping males. Dr. Balenger attributed this plastic behavioral trait to the evolutionary pressure imposed by the parasitic flies – if there aren’t chirping males, there may be lots of flies and that male may be better off wandering rather than calling.
Lizards and Fire Ants: Effects of Maternal Stress – David Ensminger, Penn State University
Fire Ants are a problematic invasive species in many parts of the world, including the southeastern United States. There they share habitat with the Eastern Fence Lizard. Fire Ants are known to bite, kill, and eat fence lizards (as well as a number of other native species), and pose a real threat to ecosystems which they invade. It is clear that fire ant presence and bites are a stressor for these lizards, but David and his colleagues were interested in whether such stressful situations may have a lasting impact on the offspring of these individuals.
To test this, David collected gravid females and dosed half of them with the stress hormone corticosterone. These females then laid eggs, and David confirmed that indeed some of that corticosterone had transferred into the eggs by testing for its presence in the yolk (it was there). He then let these eggs develop and hatch, and found a number of differences between the experimental and control groups, including that those whose mothers had been stressed had lower corticosterone levels, and were longer than the control lizards. In future studies, David will be investigating whether these changes are beneficial to the offspring, or maladaptive and indicate that fire ants could be problematic for fence lizards.
Some amazing dinner at Gumbo Shop, and great music at Bourbon Maison!
Today was the first full day of The Society for Integrative and Comparative Biology (SICB) conference in New Orleans. It was a long day full of great talks and socializing with colleagues old and new over delicious food!
I spent most of the afternoon in the Division of Animal Behavior (DAB) Best Student Presentations, and I heard a number of excellent talks presented by graduate students from around the US and Canada. I’ll highlight a few of the most interesting talks and topics I heard:
Parasites controlling Stickleback behavior – Lucie Grecias, Université Laval
Threespine Stickleback often have a flatworm parasite that is known to influence the behavior of the stickleback to make it less risk averse and more likely to be eaten by wading bird predators (for more on this see THIS LINK). Such parasitic relationships have been described in a number of systems including MICE, and even hypothesized to occur in HUMANS.
These researchers were interested in understanding the mechanistic basis of this behavioral shift. Using a very interesting approach in which the researchers compared parasitized fish to those being dosed with pharmaceutical drugs (including fluoxetine – Prozac) to compare the behavioral responses as well as gene expression in the fish’s brains. While the drugs did replicate some of the behavioral shifts, they did not find similar patterns of gene expression.
Snail Personality and Response to Predation Risk – Chris Goodchild, Oklahoma State University
This was a very cool talk! This research group began by investigating whether snails differ consistently in their behavioral traits (what behavioral ecologists describe as animal personality). Indeed, snails vary consistently in boldness versus shyness, which was measured based on exploration of a novel habitat and latency to open their shell after a disturbance.
They exposed some of these snails to a predator cue to determine how life experience influences their behavior and physiology. After 28 days, the shy snails had developed stronger shells, the openings of which were differently shaped than shy control snails. The researchers hypothesized that when facing a real predator, bold snails move away quickly (by snail standards) after the interaction, while shy snails stay put and wait out the threat.
New Orleans Food Of The Day – Cochon Butcher
Pastrami Sandwich with Marinated Brussels Sprouts and Parish Brewing Farmhouse IPA.
This past year has consisted of a number of big events, each of which should have received the attention of its own post. While some certainly will, I wanted to post a brief summary of what is new.
Round Goby Research at Stone Laboratory
I had an outstanding REU student while at Stone Laboratory who completed a research project on resource holding potential in the round goby, Neogobius melanostomus. Alex Maytin, an undergraduate student attending Boston University did outstanding work collecting fish, setting up behavioral trials, and dissecting fish. We’re currently still rescoring videos of the behavioral trials, but the results will be presented at SICB this winter in New Orleans!
Field Behavioral Ecology at Stone Laboratory
This past summer I taught Field Behavioral Ecology (EEOB 3420) at Stone Laboratory on Gibraltar Island on Lake Erie. This was the first time Behavioral Ecology had been offered at Stone in quite some time, and it was a great opportunity to develop another course of my own. In addition to learning the fundamentals of behavioral ecology, students got a chance to visit a number of the islands of Lake Erie, performed a number of field experiments while learning field research techniques, and each developed their own independent research project and presented their findings in a manuscript and through a conference-style presentation.
I had an outstanding group of students, and they seemed to really enjoy the course. Additionally, I couldn’t have asked for a better TA – Destiny Palik. Destiny did excellent work, was great with the students, and took some awesome pictures while on the island too!
After leaving Stone Lab in July, I moved west from Ohio to begin my NSF Postdoctoral Research Fellowship in Biology at University of California, Davis. I’m working in the lab of Dr. Rebecca Calisi Rodríguez, and we’re doing some exciting work on how human impacts have influenced the introduced western mosquitofish, Gambusia affinis, living in the Central Valley of California. I’m especially excited about this work because it will make clear links between environmental impacts and behavior by investigating how these human impacts have influenced they physiology of organisms, and in turn how these shifts influence behavior. I’m learning a new suite of lab techniques, and I’m eager to put them into practice! This project has already become extremely collaborative, and I’m excited about working with students and faculty from across Davis and beyond. Museum collections will also be a key component of this project, and I’ve already had the opportunity to visit some since beginning the postdoc. These specimens are being photographed and morphometric analyses will be performed in order to make comparisons between current and historical populations.
As lab and field work continues in association with this project, I will no doubt have plenty to share here. I’ve greatly enjoyed being part of the intellectual community here at Davis, and my research and I have greatly benefitted from being a part of it. California isn’t too bad either…