Question

A corpse discovered in the desert at 5:00 PM was found to have larvae from the blow fly species Phormia regina that had just developed into the first instar stage. Controlled experiments show that this species requires 16.0 hours at 26.7 ∘ C to develop from an egg to the first instar stage. The average nighttime temperature in the desert was 22.4 ∘ C , and the average daytime temperature was 37.8 ∘ C . If the sunset occurred at 9:00 PM and the sunrise occurred at 7:00 AM, how many hours prior to discovery was the corpse placed in the desert?

Answer 1

Answer:

12.19 hours prior to discovery was the corpse placed in the desert.

Explanation:

Heat required for fly eggs to develop into first instar larvae = $Exposure\,time\times temperature$

From the given,

Exposure time = 16 hrs

Temperature = 27 C

$=16\times 27 = 427.2^{o}C$

The day time exposed hours is 10 hrs.-(7.00am-5.00pm)

$=10\times 37.8 = 378^{o}C$

So, the extra heat  = 427.2-378= 49.2

The addition heat divided by average temperature.

Average temperature = 22.4 C

$=\frac{49.2}{22.4}= 2.19 hrs$

So, the total time exposed is night time hours to day time hours.

= 10+2.19 = 12.19 hrs.

Therefore, 12.19 hours prior to discovery was the corpse placed in the desert.