It's not commonly known, but there is, in fact, more than one Darlus. Several versions of him exist, all working for the Dr Darlus Institute, and plenty of other researchers have written papers in his name.
On expeditions, he is usually accompanied by one or two assistants. The ever-present Carolus is a white bird which serves him as camerabeing, sample-gatherer and, occasionally, bait. (There are almost certainly more Caroluses than Darluses.)
The other companion changes from one trip to the next - generally an enthusiastic youngster. His companions are often Masks.
With the help of Beez?, Darlus recently [captured a butterfly] which seems to be able to exploit the so-called "butterfly effect" for its own gain. Other species have been known to affect local weather events (notably Papilio tempestae, described in [Pratchett] 1994), but Lephocodes lorenzii tinnaptera, as it's known, has tiny structures on its scales which create a tachyonic field, allowing its influence to spread back into the past.
While Darlus and a small audience in Puzzle Park watched, one specimen apparently caused a retroactive shift in the evolution of a particular species of plant in Charmwarp, rendering its nectar tastier and its flowers easier to drink from, then caused the flower to become popular among Victorian gardeners in Top, and finally, caused a planter full of them to be delivered right to the Park - all with a few careful flaps of its wings.
"The ramifications of a species having the power to shape not only the environment but also the past to its own ends are staggering," writes Dr Courbin in a recent bulletin. "L. lorenzii tinnaptera must be monitored to ensure that the butterfly's history-altering ability does not upset the balance of nature across the Mess and beyond."
On a sightseeing expedition to Elysium, Darlus discovered several large [eggs] buried in the sand, of unknown origin. These were swiftly confiscated by the Royal Brasstacean Guard.
While searching for the elusive Conkerdile Bird, Doctor Courbin passed through Puzzle Park, and encountered a corpse of Inhatti which contained the spiny egg of a Strangewarp Shatter-viper that had followed and attacked her there. After a bit of commentary and poking at it, he left it be and continued on his way.
The Institute publishes an irregular science bulletin, available at http://www.livejournal.com/users/doctordarlus/
Darlus is every science and nature show host rolled into one, from Sir David Attenborough and David Suzuki to Bill Nye and the Crocodile Hunter - as well as a high school science teacher of mine.