Death Du Jour

“So what can you tell me?”

“You want the whole rundown?”

“Sure.”

“First of all, I think your vics were killed during the day. Or at least the bodies were exposed during daylight hours for a while before burial. I found larviposition by Sarcophaga bullata.”

“Give that to me in English.”

“It’s a species of flesh fly. You collected empty Sarcophaga bullata puparial cases and intact puparia from both bodies.”

“And?”

“The Sarcophagidae aren’t too spunky after sundown. If you drop a body right next to them they might larviposit, but they’re not very active at night.”

“Larviposit?”

“Insects use larviposition or oviposition. Some lay eggs, some lay larvae.”

“Insects lay larvae?”

“First instar larvae. That’s the very first larval stage. The Sarcophagidae as a group larviposit. It’s a strategy that gives them a head start on the rest of the maggots, and also provides some protection against predators that feed on eggs.”

“Then why don’t all these insects larviposit?”

“There’s a downside. The females can’t produce nearly as many larvae as they can eggs. It’s a trade- off.”

“Life is compromise.”

“Indeed. I also suspect the bodies were exposed outside, at least for a short period. The Sarcophagidae aren’t quite as willing to enter buildings as some other groups. The Calliphoridae, for example.”

“That makes sense. They were either killed on the island or the bodies were transported there by boat.”

“In any event, I’d guess they were killed during the day, then spent some time outside and aboveground before being buried.”

“What about the other species?”

“You want the whole party?”

“Definitely.”

“For both corpses burial would have delayed the normal insect invasion. Once the top body was exposed by the scavengers, however, the Calliphoridae would have found it irresistible for egg laying.”

“Calliphoridae?”

“Blowflies. They usually arrive within minutes of death, along with their friends the flesh flies. They’re both strong fliers.”

“Bully.”

“You collected at least two species of blowflies, Cochliomyia . . .”

“Maybe we should stick to common names.”

“O.K. You collected first, second, and third instar larvae and intact and empty puparial cases for at least two species of blowflies.”

“Which means what?”

“O.K., class. Let’s review the life cycle of the fly. Like us, adult flies are concerned with finding suitable places to rear their young. A dead body is perfect. Protected environment. Lots to eat. The perfect neighborhood to raise the kids. Corpses are so attractive, blowflies and flesh flies may arrive within minutes after death. The female will either oviposit immediately, or feed for a while on the fluids seeping from the remains, and then lay her eggs.”

“Nice.”

“Hey, the stuff is very rich in protein. If there’s trauma to the corpse, they’ll go for that, if not they’ll settle for orifices—eyes, nose, mouth, anus . . .”

“I get the picture.”

“Blowflies lay huge clusters of eggs that can completely fill natural body openings and wound sites. You say it’s been cool there, so there may not have been quite as many in your grave.”

“When the eggs hatch, the maggots take center stage.”

“Exactly. Act two. Maggots are really pretty cool. On the front end they have a pair of mouth hooks that they use for feeding and locomotion. They breathe through little flat structures on the back end.”

“They breathe through their asses.”

“In a sense. Anyway, eggs laid at the same time hatch at the same time and the maggots mature together. They also feed together, so you can get these enormous maggot masses moving around the body. The group feeding behavior results in the dissemination of bacteria and the production of digestive enzymes which permit maggots to consume most of the soft tissues of a corpse. It’s all highly efficient.