A Choresine beetle, or "nanisani."  Full image

Scientists at the National Zoo's Conservation and Research Center have found a little-studied, tiny beetle to be a source for the poison in New Guinea's poisonous birds and possibly the Colombian poison-dart frog. According to John Dumbacher (now at the California Academy of Sciences) and Scott Derrickson and colleagues, the poisons are batrachotoxins, which are among the most toxic natural substances known (250-fold more toxic than strychnine). Batrachotoxins were isolated and identified from Phyllobates frogs over 25 years ago. It was known that the frogs did not produce the toxins, but despite years of searching, their toxin source remained unknown.

Choresine beetles recently found in the stomach contents of toxic birds in New Guinea are a probable source of toxins for the birds. Scientists hypothesize that their relatives in Colombia may similarly supply the frogs.

The breakthrough was provided by local naturalists from Herowana Village, which is in the Crater Mountain Wildlife Management Area in the Eastern Highlands Province of Papua New Guinea. They recognized that both the birds and the beetles caused the same burning and tingling sensation when tasted.

The irritating sensation is called nanisani in the local language, which is also the local name for the toxic Ifrita bird and the Choresine beetle (family Melyridae). It is believed that such toxins provide these birds and beetles some protection against their natural enemies, including humans.

Doug Owsley receives a skull for field analysis.  Full image

Physical anthropologists Doug Owsley and Kari Bruwelheide, historical archaeologist Laurie Burgess, several Smithsonian volunteers, and selected students and teachers from Talbot County high schools excavated human burials believed to be those of 17th-century colonists. The excavations took place in a rural landscape on Maryland’s Eastern Shore that has remained unchanged for the past 300 years. Non-native occupation of the site occurred as early as the mid- to late 1600s. The burials were recently discovered during an archaeological survey of the private property, which is being restored to waterfowl habitat. The Washington Post’s devoted front-page coverage to the work in its Metro section.

SCMRE Conservation Fellow Katharina Geier, volunteer Gordon Lee, and SCMRE conservator Mel...  Full image

A Hawaiian outrigger canoe given to the Smithsonian by Queen Kapi'olani in 1887 is the centerpiece of the current National Museum of Natural History’s "Hawaiian Treasures" exhibit. Thought to be the oldest Hawaiian canoe in any collection, it had a number of renovations in the past that made proper interpretation difficult. In addition, some areas of the canoe were lost or damaged, and structural materials were degraded to the point that they were no longer functional.

At the request of curator Adrienne Kaeppler and the Anthropology Conservation Laboratory (ACL) of the Department of Anthropology, the canoe was conserved and restored by a team of conservators and scientists at the Smithsonian Center for Materials Research and Education (SCMRE). Conservation treatment was designed and supervised by Mel Wachowiak, SCMRE Senior Furniture Conservator, and was carried out by SCMRE conservation fellow Katharina Geier and interns Akiko Wanikawa and Susie Seborg. The team was aided by a group of volunteers led by Gordon Lee of Hawaii, and canoe builders in Hawaii supplied much-needed advice and materials.

Working on a tight 60-day schedule, the SCMRE/ACL team restored the bow and stern, one outrigger boom (iako), and the float (ama). They also removed or inpainted modern paint spattered over the surface. One outrigger boom and two new cross-braces (wae) were made of Hawaiian woods, and the new lashing for the outrigger was handmade of coconut fiber by the Hawaiian Maritime Center.

In addition to the conservation, SCMRE organic chemist Walter Hopwood analyzed several samples of paint, and SCMRE microscopist Harry Alden identified the lashing materials. Nora Lockshin of SI Archives provided advice and training in preserving the 19th-century paper labels.

An optical photograph of the Horsehead Nebula in Orion, showing the dramatic effects of the...  Full image

The spaces between stars are far from empty, containing copious amounts of gas and dust. (Astronomers estimate that about 5–10 percent of the total mass of our Milky Way galaxy is contained in the interstellar gas and dust). About 1 percent of the mass of this interstellar material—quite a lot in astronomical terms—is in the form of tiny dust grains made predominantly of silicates, rather like fine sand; some grains are also composed of carbon and other elements.

The dust is important: it blocks visible light while emitting infrared light, and thus helps determine what astronomers can see; it controls much of the energy balance in the interstellar medium (ISM) by virtue of its absorption and subsequent re-emission of light from stars; it is essential to the chemistry that takes place in the ISM because it provides gas molecules with a surface on which to react with other molecules; and, not least, it contains a large fraction of many important elements in the universe like silicon, carbon, or iron. Furthermore, astronomers suspect that at some stage in the evolution of new stars, the dust around them can coagulate into large clumps—one step toward forming planets.
Despite the importance of dust, its abundance remains a mystery. At least according to traditional models, dust is easily destroyed (by shock waves, for example, that can be produced by supernovae), but takes a long time to be made (in the atmospheres of old stars). Why, then, is the dust relatively so abundant?

Smithsonian Astrophysical Observatory astronomer Jonathan Slavin and two colleagues of his have now published a new set of calculations on the evolution of dust grains in the ISM that, for the first time, does not treat the dust and gas as a collective unit, but instead calculates the evolution of the dust separately and explicitly. The scientists find that sizes of the grains, and to some extent their compositions, affect their fates critically. Many grains thus escape violent shocks without being destroyed. The authors speculate that these escaped dust grains may act as a reservoir of material for future coalescence. The grains that are destroyed, on the other hand, can be accelerated by the shocks to extremely high speeds and could become the seeds for cosmic rays—ultra-energetic atomic particles that bombard the Earth. The results go a long way toward resolving an unsolved puzzle about dust, while shedding light on the origins of both planets and cosmic rays.

Reconstruction by Mary Parrish. From Willard, Phillips, Lesnikowska and DiMichele....  Full image

The "behavior" of ecosystems has been a topic of ecological debate since early in the 20th century. Broadly speaking, two schools of thought predominate. One views assemblages of plants and animals as a happenstance of local conditions and the local climate of the moment—a snapshot of an ever-changing world. The other sees an assemblage as the result of long-term interactions on evolutionary time scales, in which it has properties not present in any of its individual component species. The result is ecosystems that should have staying power in the face of environmental changes. Perhaps the truth lies somewhere between these views, which have been argued mainly from models and short-term ecological studies, and the fossil record may be the best place to find the answer.
 
Recognizing the potential to examine ecosystem dynamics on long time scales, from hundreds of thousands to millions of years, the National Museum of Natural History looked at the fossil record of the terrestrial and marine realms to determine if there was credible evidence for long-term persistent assemblages or if the world of organisms was a constantly changing "boiling pot." Depending on the spatial scale examined, the scientists found evidence for both kinds of behavior, but certainly for a significant amount of assemblage persistence, especially when ecosystems were examined on larger geographic scales.
 
The fossil record suggests that ecosystems have a certain level of resilience—an ability to tolerate environmental change and still retain their species composition and ecological order. However, the record also suggests that catastrophic changes may occur when some threshold of disturbance and species extinction is crossed. Just where that threshold lies is not certain for most systems, given the coarse resolution of much of the fossil data. Nevertheless, the basic pattern is seen in both marine and terrestrial systems. Such patterns should lead humans to move with caution when planning how we fit into nature.

Dumbacher, J.P.; Wako, A.; Derrickson, S.R.; Samuelson, A.; Spande, T.F.; and Daly, J.W. Melyride beetles (Choresine): A putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds. Proceedings of the National Academy of Sciences, 101(45): 15857-15860.

DiMichele, W.A.; Behrensmeyer, A.K.; Olszewski, T.D.; Labandeira, C.C.; Pandolfi, J.M.; Wing, S.L.; and Bobe, R. 2004. “Long-term Stasis in Ecological Assemblages: Evidence from the Fossil Record.” Annual Review of Ecology, Evolution, and Systems 35: 285-322. (e-posted; article appears in December).

Slavin, J.; Jones, A.; and Tielens, A. 2004 "Shock Processing of Large Grains in the Interstellar Medium," The Astrophysical Journal Letters, pp. 614, 796.