Tuesday, September 15, 2015

beetle brood
Many scientists believe the very same dynamics that have shaped conflict between nations since the early 20th century also may govern how species evolve on Earth.

“The term ‘arms race’ originated with tense and competitive relationships that developed among European nations before World War I as they built up stockpiles of conventional weapons,” said Caroline Chaboo, assistant professor of ecology and evolutionary biology at the University of Kansas and assistant curator with KU’s Natural History Museum and Biodiversity Institute. “The term has become widely used to describe competitive relationships.”

She said biologists have adopted the term for another kind of escalation — defenses, countertactics and one-upmanship among rivals in the natural world. 

“We know these evolutionary interactions can be fast, as in medicine where medical professionals and drug companies have a tense relationship with fast-evolving and drug-resistant pathogens, and they must design new and different cocktails to keep up with this enemy,” Chaboo said. “Other examples of tense relationships that drive evolution, counterevolutionary responses and one-upmanship include parasites and their hosts, seeds and seed-eating bugs, hunters and prey.”

According to Chaboo, such arms races influence the mechanics of evolution, as traits developed for defense over time result in entirely new species.

“One member of the relationship is attacking or resisting while the other is evolving to overcome defenses or avoid attack,” she said. “The competition can be at the level of genes, sexes or individuals. Ultimately, the one-upmanship drives diversity in a certain direction. Enemies make the population better. Thus, the more fit individuals — those with better escape responses, more effective offenses, better weapons to fight — avoid elimination and live on to reproduce and contribute their genes to subsequent populations.”

While the arms-race model is popular in evolutionary studies, it needs more validation from field research, Chaboo said.

Now, she and colleagues Ken Keefover-Ring of the University of Wisconsin-Madison and Paula “Alex” Trillo of Gettysburg College have been awarded a two-year, $150,00 National Science Foundation EAGER grant to study questions from the arms-race model of defenses in leaf beetles. The fieldwork will take place at the Smithsonian Tropical Research Institute in Panama next summer.

Chaboo and her team will focus in part on the evolving defenses and tactics of tortoise beetles.

“In the larval stage, tortoise beetles exhibit a very different array of physical, behavioral and chemical traits,” she said. “Baby insects lack wings, and their first reaction to interference is to walk away. A large group of tortoise beetles has lateral projections which function in different ways — these break up the body outline, making the larva ‘disappear’ against its background, and they are armed with pointed hairs that may act as lances.”

Chaboo said many tortoise beetle species also show gregarious behaviors, living in groups. Working together, they diffuse plant toxic chemicals as each member ingests a small amount, and they also present a more intimidating herd to an “interloper.”

Also, the beetles expertly defend themselves with the ick factor.

“By far, the most peculiar defense is the recycling of their own feces and cast skins — exoskeletons of earlier larval stages — into a shield that is worn like an umbrella over the body,” she said. “This shield can ‘hide’ the larva, making it look like a damaged leaf to an aerial enemy, or form a nasty physical barrier to probing enemy mouthparts.” 

One arms-race strategy researchers will study in depth is the “escape and radiation” tactic, found in tortoise beetles, whereby new traits that better deter attack arise in a species. That species flourishes, free of enemy attack —to radiate or split into two or more species, giving rise to richer biodiversity.

“Individuals that survive day-to-day conflicts grow to adulthood, reproduce and leave more of their offspring with refined traits in successive generations,” Chaboo said. “Over evolutionary time, new traits and new trait combinations result in more diversity. We can compare lineages in our new evolutionary trees to determine how they diverged and radiated and identify which traits or suites of traits may be influencing radiations.”

Chaboo said the grant would present different challenges at each stage.

“The experimental work requires us raise up large populations of beetles in a greenhouse, and we have just one field season,” she said. “The sequence-phylogenies have bioinformatics issues. Integrating the phylogeny, behavioral and chemical datasets is a challenge, which is why we were invited to submit our proposal to the NSF EAGER program in the first place as a high-risk, high pay-off study.”

But with high risk comes high reward: A better understanding of arms-race theory derived from studying the beetles could help us better grasp our own evolution, Chaboo said.

“The work on beetles might demonstrate fundamental principles about how antagonistic and competitive relationships drive evolution and generate diversity,” she said. “This can explain partly how our world looks and even explain human evolution. What aspects of human morphology and behavior can be traced back to the impact of our ancestors trying to avoid being prey or becoming more adept hunters?”

Chaboo said the research team would develop an online educational resource in both English and Spanish about subsocial insects like beetles.  “Subsociality is far lesser known than true sociality. Our content with images and movies should fill a knowledge gap,” she said.

Along the way, the biologist and her colleagues will continue to mentor U.S. undergraduates alongside Panamanian students in international field research.

“We anticipate involving Panamanian schoolteachers as well through existing outreach programs at the Smithsonian Tropical Research Institute,” she said. 

Article by Brendan Lynch.
Photo above: Beetle mom with brood of larvae in French Guiana (Credit: Pascal Bonin) 

News Type:
Research News
Thursday, March 5, 2015

The National Science Foundation has awarded entomology curator Andrew Short a grant of $700,000 for his proposal “CAREER: Teaching Modern Biodiversity Science from Fieldwork to Phylogeny: Diversity, Systematics, & Evolution of Ecologically Promiscuous Aquatic Beetles.” The grant includes resources for undergraduate and graduate student opportunities, including fieldwork in Suriname and Guyana.

Freshwater and terrestrial habitats demand dramatically different sets of morphological, physiological, and behavioral traits. Consequently, animals at each end of this habitat continuum exhibit starkly different morphologies and life histories, and lineages must overcome numerous challenges to transition between these divergent ways of life. Nevertheless, insects have repeatedly crossed the freshwater-terrestrial boundary in many independent groups. Despite this diversity and abundance, little is known about how insects evolve across this seemingly formidable aquatic-terrestrial boundary and how this affects the evolutionary trajectories of these lineages. Using the beetle family Hydrophilidae, a lineage which has diversified in a range of fully aquatic, terrestrial, and intermediate habitats and has transitioned between them repeatedly, Short and the students will examine (1) the ecological and morphological transitions associated with aquatic-terrestrial habitat shifts, and (2) both the macroevolutionary (e.g., changes in diversification rate) and intraspecific (e.g., differences in genetic structuring) consequencesof these shifts. By combining fieldwork, revisionary taxonomy, RAD-seq phylogeography and phylogenetics with immersive undergraduate coursework and graduate student training, this team will disentangle the evolutionary history of habitat transitions in water beetles.


News Type:
Award Grant News
Thursday, June 26, 2014

LAWRENCE — The instinct for mothers to protect and nurture offspring is rooted in more species than scientists have understood before now.

In a new study published in the Journal of Natural History, University of Kansas researcher Caroline Chaboo details how some leaf beetles — a huge group of about 40,000 separate species that usually are solitary insects — show self-sacrificing maternal care for their young.

"Maternal care is a phenomenal behavior, whether it's a beetle, a shark or a monkey," Chaboo said. "The investment of mothers with their time, their vigilance, their grooming and cleaning, finding and providing food, putting their own lives at risk, often not eating for themselves — it's remarkable that parental care is so one-sided."

Dubbed by scientists as "subsociality," active parenting among leaf beetles is notable because the insects usually live out their lives alone, without the more complex social behavior seen in bees, ants, wasps and termites — which scientists call "eusociality."

But the exception to the loner's life of a beetle is motherhood, where the solitary insects become more like "helicopter moms."

"A leaf beetle mother will keep an eye on the eggs, grooming and guarding them," Chaboo said. "She will oversee her herd of larvae as they eat, while she keeps watch for flying attackers, like wasps, and also pedestrian attackers, like ants. She moves between the attacker and the babies, and will stamp her foot and try to shoo off the intruder."

The leaf beetle's active mothering is critical to the survivability of the next generation, according to Chaboo.

"If she is removed or lost, all the babies die," she said. "It’s pretty crucial that she is around to ensure some of the offspring survive and reach adulthood."

After a century of research focus on eusociality by William Morton Wheeler, Susan Batra, Edward O. Wilson and KU's own Charles Michener, James Costa brought focus to the poorly known phenomenon of beetle subsociality with his 2006 book, "The Other Insect Societies." Chaboo worked to expand knowledge of leaf beetle parenting with her own fieldwork and an extensive review of literature.

"Leaf beetles have fascinated me since I first looked at these extremely colorful beautiful beetles in a museum drawer," said the KU researcher. "During fieldwork in my native country, Trinidad, I found female leaf beetles guarding their babies. This discovery led me to start pulling on the thread. I was already writing this new paper when Costa's book appeared. To make a truly paradigmatic shift in research on leaf beetle subsociality, I needed to make the paper synthetic by pursuing every bit of what we may already know about parental care in leaf beetles, more comprehensive by pursuing more fieldwork to discover species I suspected were subsocial, and more paradigmatic by developing evolutionary models to organize the information we have and to accelerate future research."

Indeed, Chaboo's paper on leaf beetle subsociality has received praise from fellow scientists for its comprehensiveness and new insights into how insects' social lives have contributed to their evolution.

"It’s an important paper, because it extends the records of subsociality in insects and in particular in the Coleoptera," said Bert Hölldobler, the Pulitzer Prize-winning evolutionary biologist at Arizona State University, using the scientific name for beetles. "Subsociality is generally considered the evolutionary precursor of eusociality, which is so prevalent in ants, and some bee and wasp species and termites. But there are also some beetle species known that have evolved eusociality. The kind of work Caroline has just published is extremely important for all of us who want to understand the evolution of social life on this planet.” In addition to the extensive literature review, Chaboo and her colleagues spent countless hours in the field, discovering many species with subsociality.

"We're searching for species in tropical forest habitats — the needle in the haystack," Chaboo said. "Even though we had educated guesses on the host plants, it is still serendipitous when a subsocial species is discovered. My co-authors, Rob Westerduijn in northern Peru and Fernando Frieiro-Costa in Brazil, have more frequent access to the habitats and are walking the trails a lot. Each new species we report represents tenacious work — to search out the plants, turn over leaves, scan vegetation for mothers and babies, and keep returning to study the behaviors."

Chaboo’s own fieldwork took her to Panama, Costa Rica, Nicaragua, Trinidad and Peru. She says that in the midst of the research she gained even more understanding of the maternal instinct common to so many species by becoming a mother herself. "During the course of writing this paper, my co-author Jesus Gómez-Zurita in Spain and I each had a child," she said. "I think our respect for these leaf beetle mothers grew enormously with our own experience as first-time parents."

News Type:
Research News
Friday, May 23, 2014

Scientists from the University of Kansas and more than 60 other international research institutions spanning six continents have responded to a recent paper in Science, which questioned the practice of collecting and preserving scientific specimens.

KU biologists Rafe Brown and Andrew Short, along with other researchers, argued that the value of scientific collections is vast and their effect on natural populations is minimal. The response also stresses the immense value of scientific collections – such as those held by the KU Biodiversity Institute and Natural History Museum – across a wide range of disciplines.

In the original paper, "Avoiding (Re)extinction," the authors had argued that the collection of scientific specimens has played a significant role in species extinction, pointing to examples of now-extinct birds, frogs and plants to support this claim.

Today’s response paper, led by Luiz Rocha, a fish biologist from the California Academy of Sciences, emphasizes the minimal effect that research-based specimen collecting actually has on populations. Rocha, Brown and Short, and other scientists, argued that the value of scientific collections is vast and their effect on natural populations is minimal.

“This is a delicate topic because none of us like to think about the death of a beautiful bird or colorful frog,” said Brown, curator of herpetology at the Biodiversity Institute.  “But as conservation scientists, we are primarily concerned with species preservation and the long-term viability of populations.  It’s not the several individual frogs that are sacrificed humanely for the global good that make me sad…I get emotional about the many hundreds of thousands that will die this year en masse as we cut down forests and pave over the last of their habitat; we know that many of those individuals will be the last of their species."

The authors point to several examples that illustrate the role scientific collections have played in understanding such things as the effects of climate change on populations and the spread of disease. In one such analysis, scientists looked at specimens from a wide range of taxa, collected over the past several decades or more, and found a significant correlation between an increase in daily temperatures and a decrease in body size — a response that might limit the ability of some species to tolerate more dramatic swings in future temperature extremes.

Scientists have also analyzed amphibian specimens collected over the past five decades or more, including many hundreds of specimens in KU’s herpetology collections, to track the origin and spread of the frog-killing chytrid fungus in hopes of preventing its further spread.

It is only by investigating information about specimens collected across time that scientists can answer questions about species and the environment in a changing world, said Short, entomology curator at the Biodiversity Institute. Such collections are not the cause of extinctions.

“Responsible collecting of scientific specimens is the only way to identify most of the world’s species,” Short said. “These collections are critical to assessing water quality, habitat degradation and the impact of climate change. It is not a conservation threat and treating it as such distracts from the real drivers that are imperiling our biodiversity, such as habitat loss and invasive species.”

In the original paper, the authors went on to recommend alternatives to standardized collection methods used today, namely photography, audio recordings and non-lethal tissue collection. Although in many cases these methods are employed in species identification, scientists point out that they will often fall far short of the wealth of information that scientific specimens provide. Species identification, they write, is not the only — and is often not the most important — reason to collect voucher specimens.

In other cases, genetic data from decades-old scientific specimens has even been used to identify current species that were thought to be extinct.


News Type:
Research News
Thursday, April 24, 2014

While there is wide agreement on the importance of a complete inventory of all organisms on Earth, the public is partly unaware of the amount of known and unknown biodiversity. A recent study co-authored by entomology graduate student Laura Breitkreuz asked 300 visitors to vote on a name for a new species and out of four preselected options, Ampulex dementor Ohl n. sp. was selected. The name, derived from the ‘soul sucking’ dementor from the popular Harry Potter books, is an allusion to the wasps’ behavior to selectively paralyze its cockroach prey. In this example, public voting on a scientific name has been shown to be an appropriate way to link museum visitors emotionally to biodiversity and its discovery.
Full Article

News Type:
Research News
Wednesday, March 5, 2014

Jewel Beetle & Weevil

Entomology Curator Michael Engel is among researchers quoted in an article in Wired magazine about determining the color of fossil insects; see article here.

News Type:
In the News
Thursday, November 14, 2013

Michael Engel has learned that his research, "The Earliest Known Holometabolous Insects" has been published in the Nov. 14 edition of Nature.

News Type:
In the News
Friday, October 4, 2013

Andrew Short of the Biodiversity Institute has research featured by the Discovery Channel, a video clip is available here: 

His work has also been featured by National Geographic, via a blog about an expedition:

Caroline Chaboo of the Biodiversity Institute was recently interviewed by Wired magazine about insect collecting. Find the article here:

News Type:
In the News
Friday, October 4, 2013

Andrew Short of the Biodiversity Institute has research featured by the Discovery Channel, a video clip is available here:

His work has also been featured by National Geographic, via a blog about an expedition:

Caroline Chaboo of the Biodiversity Institute was recently interviewed by Wired magazine about insect collecting. Find the article here:

News Type:
In the News
Thursday, June 27, 2013

Andrew Short, Entomology curator, was elected this month to a 2-year term on the executive committee of the Coleopterists Society. More information on the entomology digitization project can be found here:

News Type:
Award Grant News