FINAL COLLECTIONS

We have officially completed our collections from the bear and the pig. The animals were well-skeletonized, although the thick hide of the bear remained in large part. The bear still supported some invertebrates in some number (Omosita, Necrobia, misc. staphylinids, Stearibia nigriceps). Interestingly, the soldier fly Ptecticus sp. (recorded earlier in the summer) was also present in the adult stage. Its forensic importance is still unknown.

Our conclusions are that 1) a similar fauna attacks large mammals and humans alike, and 2) the decomposition of the bear may be slowed by a variety of factors including the thick hide and fat layer. Further, Lucilia illustris was the first arriver followed quickly by Phormia regina, which is expected. There were three distinct waves of maggot movement off the bear, one off the pig.



13 Sept. 2007: Graduate student Krystal Hans assists with invertebrate collections off the bear carcass.

13 Sept. 2007: The final stage of decomposition in the pig - dry remains.

A tale of two carcasses...

2 July 2007: We are still keeping an eye on the bear periodically. We lift the legs, head, and torso to accumulate a collection of cryptic beetles and their larvae. This will allow us to document relatively long-term succession of insects on the carcass. During this phase of deep dessication, we collect beetles and sweep for flies approximately weekly.

2 July 2007: The pig, like the bear, is also in the dry phase of decomposition. The underside is still moist, and maggots are present (see below).

2 July 2007: This morning, just a few hours short of exactly 1 week into decomposition, we had a mass exodus of maggots from underneath the carcass. The grasses and weeds obscure the view, but in the photo above you can make out the larvae clearly. The smaller carcass supported fewer numbers than the large bear (a 119 pound difference), but there were thousands of maggots moving into the undergrowth to burrow into the soil for pupariation.

3 July 2007: After the movement of maggots off the body yesterday, little activity is observable.

3 July 2007: The effects of maggot feeding... The larvae consume the carcass down to the bone, exposing the drying internal organs and pave the way for a dry phase of decomposition. This is where beetles, sepsid flies, and piophilid flies become the dominant players.

4 July 2007: We're pretty much in a phase where, like the bear, decomposition will progress very slowly. We'll continue to collect, but not daily. We will collect beetles on our under the carcass and sweep for flies 1-2 times per week. It is very overcast today, and rain appears to be iminent. That being so, we may see a resurgence in fly activity. If it does indeed rain, I'll head out check again today. The moisture will make some of the tissue soft again, and perhaps we'll have a second wave of blow flies. It really depends on how much rain we get, if any...

Week 2: 2-3 June 2007: Huge Maggot Exodus

An incredible sequence of maggot migration...

3 June 2007: Rain has created a situation where maggots are creating large amounts of 'froth' around the edge of the bear.

3 June 2007: Maggots are moving in an enormous exodus from the bear. We began to see this to a smaller degree several days ago, but now they are grouping together in a virtual maggot swarm.

3 June 2007: A close-up of maggots on the trail...

3 June 2007: A maggot's-eye view of the exodus of the carcass. The maggots remaining on the bear are probably somewhat younger. Many early instars of blow flies are still present on the carcass. There will probably be another substantial mass movement of maggots of the carcass in upcoming days.

3 June 2007: During the study, we have been keeping track of maggot development. At the bottom is a mature maggot. Above that is a newly formed pupa (hours old), followed by a darker puparium a day or so old, followed by progressively darker (and older) puparia.

2 June 2007: In the morning, many maggots are mature and actively moving. This appears to be in preparation for a mass migration off the carcass. The stench is still horrendous, and the vegetation is dying around the bear.

2 June 2007: The first real "wave" of maggots leaving the carcass. Many maggots continue to grow an develop on the carcass. Adult flies (Calliphoridae, Muscidae, Sepsidae, Piophilidae) are still active on and around the bear.

2 June 2007: A maggot's- eye view of the trail...

BLACK BEAR DECOMPOSITION - WEEK 1

We have been observing the bear, collecting insects, and rearing maggots for a week now. We have watched the bear and the insects change through time.
The bear has gone through phases of being very stiff and rigid to becoming more 'relaxed' as decompostion progresses. The stench is overwhelming. The skin has begun to slough off the body due to the action of the 10's of thousands of maggots present.

The insects have changed as well. The first arriver was a green bottle fly (Phaenicia sericata), a very common blow fly. They laid eggs quickly. The black blow fly (Phormia regina) came next, followed by cheese-skipper (Piophilidae) and black scavenger (Sepsidae) flies.

See our Forensic Insect Photo Atlas for some pictures of these flies:
http://www.cmnh.org/site/ResearchandCollections_InvertebrateZoology_Research_ForensicEnt_ForensicPhotoAtlas.aspx


We have hundreds of maggots being reared on beef in a small enclosure about 100 feet from the bear. We keep the insects there so the stench of decaying meat doesn't foul our lab and generate protests from colleagues. We also keep them in an outdoor enclosure so we can easily follow their growth and development at the same temperatures the bear and its insect community are exposed to.



HERE ARE SOME PHOTOS OF THE FIRST WEEK OF DECOMPOSITION:



22 May 2007: Laura Bock, a student of the Cleveland Institute of Art and a Museum summer intern, erects an exclosure around the bear to deter large scavengers. We thank the Kirtlandia Adopt-A-Student program for providing funds for Laura and her work!

22 May 2007: The bear during its first hours exposed to insect activity. Note that it is in a cage (or exclosure) to prevent large scavengers such as coyote from disturbing the study.

22 May 2007: The bear in its exclosure. It is positioned at the edge (or ecotone) between an open goldenrod field and a forest fragment composed mainly of wild black cherry. This is fairly typical habitat for black bear.

24 May 2007: The first colonizers... Blow flies arrived quickly and laid eggs. Within two days, we noted these maggot masses in the nostrils. There were also maggots in the mouth and around the anus. Openings to bodies and carcasses are the first places flies lay eggs. The tissue is soft, and there is moisture there that prevents the soft-bodied maggots from desiccating...

25 May 2007: The debris on the bear is just leaf-fall. Note the sticky trap next to the paw. It is just a cardboard sheet with a sticky material on it to capture flies. Each of those dots on the sticky trap is a fly! Hundreds were attracted to the bear. The sticky trap gives us an idea of what fly species are attracted to the bear. New traps are placed out daily...

26 May 2007: It doesn't look like much has changed since yesterday, but note the slight change in postion of the head to the photo above. Most of the action is taking place within the head and anus, out of view. The head is shifting because the decomposition of the musculature, as well as its consumption by maggots, will cause the animal to "relax" somewhat.

28 May 2007: Again, not much looks too different, but note the tail is pulling back from the body due to maggot action. The whitish material seen under the chin is frass, or insect excrement (yes, maggots poop) from those feeding in the nostrils and inside the mouth.

28 May 2007: Six days into decomposition, things are really moving... The skin is sloughing from the body. A huge maggot mass has accumulated around the anus/genitalia/abdomen. The nostrils, mouth, and ears are stuffed with blow fly maggots. Hundreds of flies (families Calliphoridae, Muscidae, Piophilidae, Sepsidae, and Phoridae) are still active. Many of the maggots are approaching full growth. See our blow fly life cycle diagram at:

http://www.cmnh.org/site/ResearchandCollections_InvertebrateZoology_Research_ForensicEnt_ForensicBlowfly.aspx

Note that the daytime temperatures are reaching the high 70s to mid 80s F, while night temps have dropped as low as 50F.

28 May 2007: Note that the skin is sloughing off the body below the chin.

28 May 2007: This is the maggot mass that was generated around the abdomen at day six. A blow fly can lay 100 eggs or more. When these maggots mature in a few days, they will wander off the carcass to find a safe place in the soil to form the pupal stage. Once they do that, we suspect it will take some 5-7 days before an adult fly is liberated from the pupal skin (or more technically, the puparium).