T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Fly (Hairy maggot blowfly) Chrysomya rufifacies

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Calliphoridae
Genus: Chrysomya
Species: C. rufifacies
Binomial name: Chrysomya rufifacies
Common name: Hairy maggot blow fly\

Chrysomya rufifacies is a species belonging to the blow fly family Calliphoridae. A mature adult is a shiny metallic blue-green colour and about 6 millimetres– 12 millimetres in length.
This fly is most significant in the field of forensic entomology due to its use in establishing or altering postmortem intervals. The common name for the species is the “Hairy maggot blow fly” and it belongs to the genus Chrysomya, which is commonly referred to as the Old World screw-worms. 
Chrysomya rufifacies prefers very warm weather and has a relatively short life cycle. It is widely distributed geographically and prefers to colonize large carcasses over small ones. The species is important medically, economically, and forensically.

The larvae of Chrysomya rufifacies are very easily identified with sharp fleshy tubercles running down their bodies, and the mature larva are about 14 millimetres (0.55 in) in length with a dirty yellowish color; hence the common name, hairy maggot blow fly.

Knowledge of the life cycle of Chrysomya rufifacies is crucial in determining the postmortem interval for applications related to medico criminal entomology. Accurate developmental and successional data for the species can significantly aid in legal investigations. Chrysomya rufifacies is especially important in postmortem interval determinations due to its highly predictable developmental time and low degree of variation in larval development. The life cycle of Chrysomya rufifacies is characterized by holometabolous development, consisting of egg, larval, pupal, and adult stages. The entire life cycle involving development from egg to adult takes from 190 to 598 hours depending on temperature.
The female lays an average of 210 eggs and a recorded maximum of 368 eggs near fresh corpses and often during daylight hours. After the eggs have been laid, the first instar larva of the insect emerges from the egg after approximately 26 hours at a temperature of 29° C. A total of three larval instars are involved in the life cycle of the species, and the entire larval development stage takes 2.5 days at a temperature of 29°C. The larvae are capable of regulating their body temperature by moving to a different position in the maggot mass in order to maintain a preferred developmental temperature. The maximal preferential temperature for the larvae of Chrysomya rufifacies is 35.1°C. The developmental time of the species is highly dependent upon temperature due to the cold-blooded nature of insects and the number of accumulated degree days. Any variability in developmental times can also be due to different rearing temperatures under different conditions such as varying humidity, rearing media, and larval density.
A pre-pupal stage is often present and characterized by larval dispersion and migration away from the food source in search of a pupation site. The body length of the larva decreases during this stage in preparation for pupation. If the larvae are restricted from movement and not allowed to disperse during the pre-pupal stage, a 24-hour delay in pupation will be observed. Thus, in medicocriminal investigations, if a corpse is wrapped and causes restriction of maggot migration, altered developmental times should be considered. The pre-pupal stage takes 1.5 days and the pupal stage takes 3 days at a temperature of 29°C. Pupation usually occurs near the soil surface or near decaying flesh and the skin of the larvae harden to form a dark brown puparium or outer casing. Adults emerge after pupation and mate 3–7 days after emergence in summer, and 9–10 days after emergence in autumn. Adults are capable of living for 23–30 days and oviposition occurs approximately five days after mating.

The larvae of Chrysomya rufifacies