First off, let me say how impressed I am with all the intelligent and thought-provoking questions and observations I've received. I'll spend the rest of this entry addressing these very insightful comments.Charlesatta,
Hello! I'm having a blast up here and there's wildlife everywhere. Since I know you guys are into sparrows, here's a little natural history about one of the sparrows around here, the white-crowned sparrow (Zonotrichia leucophrys
The white-crowned sparrow's song is made up of long whistles followed by shorter trills. Females select which males to mate with based on their songs. Males learn their song at a young age by listening to the songs sung around them. Because males learn to sing from their environment and migrate to the same location each spring, lots of regional "dialects" exist in the white-crowned sparrow song. In fact, some people can tell which valley of the Rockies they're in just by listening to the white-crowned sparrow's song! Another cool tidbit, both males and females of this species get pretty territorial during the breeding season and will readily challenge invaders to of all things, singing contests!
Opportunities abound for you to do biology fieldwork. And lots of them don't involve insects (well, at least not as the study organism). For example, here at RMBL, scientists are studying marmots, ground squirrels, woodpeckers, plant communities, climate change, and the list goes on. And as a side note, RMBL offers on-site summer college courses in subjects like ornithology, animal behavior, field ecology, etc. They also have a NSF program called Research Experience for Undergraduates (aka REU), where undergrads spend 10 weeks working with a scientist mentor on their own field research project here at Gothic. If you'd like to learn more about these programs, here's the link to RMBL's homepage: rmbl.org
. These are opportunities you guys should keep in mind as you begin your college careers.Brittney,
Hi! While I'm slowly adjusting to the altitude, I'm also coming to terms with the fact that I'm not as fit as I previously thought! Oh well...I'm sure the mountains will whip me into shape soon enough. Here's a photo of our high altitude field site, Belleview Mountain. We work about halfway up it:
And here's a photo of me, exhausted and collecting data, after hiking up Belleview:
One of the many things that interests me about our burying beetles is their complex reproductive behaviors (see June 20th post). We tend to associate parental care with vertebrates or the social hymenoptera (ants, bees, wasps). Burying beetles are a fascinating exception to this generalization. And last, but not least, the burying beetle research being conducted at RMBL has wider implications. For example, Dr. Smith has discovered if the larval sizes (small, medium, or large) of a brood is known, then by applying probabilities one can reasonably predict how many larvae will emerge as adults (vs. how many will die during winter). The ability to predict how many adults will emerge from a given brood may be useful for programs aimed at the conservation of another species of burying beetle, the critically endangered American burying beetle (Nicrophorus americanus
). In fact, the St. Louis Zoo's Insectarium runs both a breeding and reintroduction program for the American burying beetle (which, by the way, is native to, but has been extirpated from, Missouri). If you'd like to learn more about the Zoo's program and see some cool burying beetle pictures, click here
Oh and one more cool thing about our burying beetles....they share a symbiotic relationship with a species of mite (the mites are the little brown things on the burying beetle's head- I know, ewww!!):
Symbiosis is a close relationship between individuals of two different species. In this case, the relationship is termed mutualistic symbiosis because both the beetle and the mites benefit from associating with each other. The mites live on the beetle till the beetle locates and buries a carcass. Then the mites leap off and eat any fly eggs that have been deposited on the carcass. No fly eggs translates into no maggots which means more food for the burying beetle larvae. The mites also help to keep the beetles clean while they do their dirty work.
We thought for sure we had outwitted the fox, but this is what we encountered when we went to check the beetle traps this afternoon:
So we've tried reinforcing the traps with heavier stones. If she can get to the meat now, she's either got super fox powers or a backhoe. I can't be too upset with her though, she's scavenging in part for her litter of pups. They're living in a drain pipe in the middle of town:
We do check the beetle traps everyday. We haven't gotten beetles yet, but in the past they've emerged around June 29th (only a couple of days away!). However, we still check and record the absence of beetles in our log books. This is important negative data for us because when the beetles do emerge, we'll be able to give a specific date. Conversely, if we were only checking the traps every once in awhile, we wouldn't be able to say with certainty when the beetles emerge.
The beetles we trap at our high and low elevation field sites are weighed, sexed, marked, and released. This data will be used in a population census. We also have 5 traps set up around Gothic; these beetles will be kept and used in behavioral and reproduction experiments. I'm not sure what the details of these experiments are yet, but when I find out I'll let you know!
Thanks for the great comments! There are some pretty marked differences between the beetle populations at high and low elevations. Here's a run-through:
- Population Density: While beetle populations fluctuate yearly at both sites, there are always significantly more beetles at lower elevations.
- Morphology: Beetles at higher elevations tend to be larger than the beetles found at lower elevations. This may be in part due to:
- Differences in Reproductive Behavior: At the high elevation site, females lay about the same number of eggs, regardless of the size of the carcass. This means that if the eggs are on a large carcass, the hatched larvae will have more to eat, and eventually emerge as larger adult beetles. On the other hand, at the low elevation site, the number of eggs increases with increasing carcass size. This means, there will be more larvae on a larger carcass. As a result, larvae at lower elevations tend to be of a more uniform size.
You might ask why these differences between high and low populations exist? Well, that's one of the things we'd like to know too! Perhaps it's caused by environmental cues or maybe it's genetic. One of Dr. Smith's graduate students, Kira Pontius, is delving into this question. She plans to breed high elevation beetles at low elevation sites and low elevation beetles at high elevation sites. If the high elevation beetles bred at low elevation sites still produce offspring with characteristics of high elevation beetles, we can infer that environmental cues do not play a large part in the differences seen between the two populations. Instead, there may be a genetic component. However, it the high altitude beetles bred at low altitudes suddenly produce smaller babies whose larval numbers are dependent upon carcass size, we can infer that there must be some environmental cue that is dictating these differences.
As for abiotic differences between the two sites, let's see...there is less air pressure at the high elevation site. It is definitely a harsher environment- it is consistently colder, with higher winds, later snowmelt, etc. The soil types also differ, with the high elevation site being more rocky. As for biotic factors, past yearly censuses have shown there are less rodents at the high elevation site (by the way, great observation on the rodent-beetle population correlation). There may also be differences in the amount and type of competition at the two sites. Burying beetles experience two types of competition over their food resource, interspecific, which is competition with other species (think carrion flies, ants, and fungi) and intraspecific competition, which is competition between members of the same species. Intraspecific competition occurs when the burying beetles fight over who gets the deed to the rodent carcass.
And switching gears, on to the ground-nesting birds...yes, raccoons could definitely threaten populations of ground-nesting birds. Furthermore, raccoons are one of the highly adaptable species that have thrived in the midst of human encroachment and development. Surprisingly, we don't have raccoons in this area of the Rockies. Another species that's greatly contributed to the decline in numbers of ground-nesting and flightless bird species is none other that the domesticated house cat. While cats make sweet and affectionate pets, we must remeber they are skilled and effective predators. Case in point:
These are specimens of the Stephens Island Wren, a small flightless bird that was once endemic to St. Stephens Island in New Zealand. In the late 1800s, a lighthouse keeper brought his cat, Tibbles, to the island. Killing and bringing home several individuals each day, Tibbles hunted the Stephens Island Wren into extinction within the span of just one year.Click here
for an interesting article about cat predation in Missouri.
Once again, I want to say thanks for all your questions and comments. Keep them coming!