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."
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.
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.
Michael Engel has learned that his research, "The Earliest Known Holometabolous Insects" has been published in the Nov. 14 edition of Nature.
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:
Andrew Short of the Biodiversity Institute has research featured by the Discovery Channel, a video clip is available here: http://watch.discoverychannel.ca/#clip1017400
His work has also been featured by National Geographic, via a blog about an expedition: http://newswatch.nationalgeographic.com/author/andrewshort/
Caroline Chaboo of the Biodiversity Institute was recently interviewed by Wired magazine about insect collecting. Find the article here: http://www.wired.co.uk/magazine/archive/2013/10/how-to/collect-creepy-crawlies
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: http://news.ku.edu/2013/06/26/database-biodiversity-offers-peek-biologists%E2%80%99-field-notes-photographs
A portion of graduate student Mabel Alvarado's MA thesis work at KU (advised by Michael Engel and Caroline Chaboo) has been published in a new monograph that documents a significant diversity of large parasitoid wasps (43 new species in this one genus alone... from an originally known 6 species). These wasps have significant potential in the biological control of pest moth species in the region and some are from highly specialized habitats that are under threat from human-induced habitat homogenization as well as climate change. Mabel's thesis is available here through KU scholar works.
A recently discovered new species of insect larva with its specialized pack of plant remains indicates that a complex camouflage behavior used by insects today dates to at least 110 million years ago.
The discovery by a team of Spanish researchers and Michael S. Engel, a KU Biodiversity Institute entomologist and professor of ecology and evolutionary biology, was based on the study of an amber piece found in 2008 in the El Soplao outcrop (Cantabria, Northern Spain), the Mesozoic’s richest and largest amber site in Europe. The study is being published this week in the prestigious Proceedings of the National Academy of Sciences (PNAS).
The fossil, about four millimeters long, is a predatory larva of the order Neuroptera (lacewings and their relatives). It is covered by a tangle of plant filaments that it collected with its jaws to form a defensive shield and camouflage itself. This survival strategy, sometimes called “trash carrying,” is observed in current species to render them nearly undetectable to predators and prey.
Related to current green lacewings, the fossil represents a new genus and species designated Hallucinochrysa diogenesi. The name alludes to its “mind-blowing appearance,” the researchers said, and its resemblance to Diogenes syndrome, a human behavioral disorder characterized by compulsive hoarding of trash.
The research identified the filamentous plant remains composing the larval trash packet as trichomes, or plant hairs with diverse shapes and functions. The trichomes are thought to belong to a specific group of ancient ferns.
Today green lacewing larvae harvest plant materials or even detritus and arthropod remains and carry them on their backs, nestled among small tubercles with hairs. On the contrary, Hallucinochrysa diogenesi possessed a bizarre characteristic: it possessed extremely elongate tubercles, with hairs that had trumpet-shaped endings acting as anchoring points. All this structure, completely unknown until now, formed a dorsal basket that retained the trash and prevented it from sliding when the insect moved.
Hallucinochrysa diogenesi demonstrates that camouflage strategy and its necessary morphological adaptations appeared early and was well developed during the era of the dinosaurs. In the case of green lacewings, this complex behavior has been around for at least 110 million years. This is significant for evolutionary studies pertaining to animal behavior and the adaptative strategies of organisms throughout Earth’s history.
The study also shows an ancient and close plant-insect interaction — possibly an example of mutualism: the predatory larvae saved ferns from plagues, whereas ferns provided larvae with a habitat and protection. In a Cretaceous environment where resin forests in the ancient Iberian Peninsula were razed by wildfires, this larva collected remains from a fern that grew abundantly after wildfires.
The El Soplao outcrop, where the discovery was made, is one of the most important localities aiding researchers to unravel questions about Earth history, ancient forest ecosystems, and the evolution of major invertebrates lineages such as the insects.
In addition to Engel, the researchers who participated in the study are: Ricardo Pérez-de la Fuente and Xavier Delclòs, of the University of Barcelona (Spain); Enrique Peñalver, from the Geomineral Museum in Madrid; and Mariela Speranza, Carmen Ascaso and Jacek Wierzchos, from the National Museum of Natural Sciences of the Spanish National Research Council.