Explores the use of insects and other arthropods in legal investigations, primarily for estimating the time since death.
Key Topics:
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Which of the following insect families is typically the first to arrive and colonize a corpse?
Calliphoridae (Blowflies)
Blowflies (Family Calliphoridae) have highly developed olfactory senses that allow them to detect the odors of putrescine and cadaverine from miles away, making them the first insects to arrive, often within minutes of death.
Based on standard terrestrial insect succession, which of the following represents the correct general order of arrival?
Blowflies -> Flesh flies -> Carrion beetles -> Dermestid beetles
Blowflies and flesh flies arrive early during the fresh and bloat stages. Carrion beetles arrive to feed on maggots during active decay, while Dermestid (skin) beetles arrive late to feed on dried tissue and hair during dry decay.
During which stage of decomposition are hide beetles (Trogidae) and skin beetles (Dermestidae) most likely to become the dominant insects on a corpse?
Advanced/Dry decay
These beetles have chewing mouthparts capable of consuming dried skin, cartilage, and hair, making them characteristic of the advanced or dry decay stage when moisture levels are too low to support blowfly maggots.
In the ecological categorization of carrion insects, ants and wasps that eat the blowfly maggots but may also feed on the body are classified as:
Omnivores
Omnivores, such as ants, wasps, and some beetles, feed on both the corpse itself and the maggots/other insects residing on it. This can complicate PMI calculations because they deplete the necrophage population.
How do insects belonging to the family Sarcophagidae (flesh flies) uniquely colonize a corpse compared to standard blowflies?
They deposit live first-instar maggots directly onto the body instead of laying eggs.
Sarcophagidae undergo internal egg hatching and larviposit, meaning they deposit live, motile larvae (maggots) directly onto the remains, giving them a slight head start over egg-laying blowflies.
Which category of forensic insects uses the corpse simply as an extension of their natural habitat rather than for direct feeding on tissues or necrophages?
Incidentals
Incidental insects (e.g., spiders, centipedes, and certain mites) use the corpse as an extension of their normal habitat for shelter or random wandering rather than specifically feeding on it.
Which insect behavior represents a significant challenge to forensic entomologists estimating a precise timeline, due to early-arriving populations being consumed?
Predation by early-arriving carrion beetles and ants
Predatory species like carrion beetles and omnivorous ants consume the oldest blowfly maggots. Since entomologists use the oldest maggots to estimate PMI, their consumption can lead to an artificially shortened PMI estimate.
Cheese skippers (Piophilidae) typically colonize a corpse during which transitional phase of decomposition?
From active decay to advanced decay
Cheese skippers typically arrive later than blowflies and flesh flies, most commonly peaking during late active decay and early advanced decay when the body begins to dry out and proteins ferment.
If only empty pupal casings of blowflies are found on a corpse alongside living dermestid beetles, an investigator can conclude that:
At least one complete generation of blowflies has finished its life cycle.
Empty puparial cases mean that the blowflies developed fully from egg to adult and the adult flies have emerged (eclosed) and left, signifying a minimum PMI of the duration of one entire life cycle.
What evolutionary advantage does a "maggot mass" provide to the developing larvae?
It produces significant metabolic heat, allowing continued rapid development even if ambient temperatures drop.
A maggot mass generates immense metabolic heat, sometimes elevating temperatures 5−15∘C above ambient. This heat allows rapid larval development even if the outside weather is cold.
