Necrophagous flies that colonize human and animal corpses are extremely efficient at locating and utilizing carrion. Adult flies deposit eggs or larvae on the ephemeral food resource, which signals the beginning of intense inter- and intra-species competition. Within a short period of time after egg hatch, large larval aggregations or maggot masses form. A period of intense larval feeding ensues that will culminate with consumption/decomposition of all soft tissues associated with the corpse. Perhaps the most distinctive feature of these feeding aggregations is heat production; that is, the capacity to generate internal heat that can exceed ambient temperatures by 30°C or more. While observations of maggot mass formation and heat generation have been described in the research literature for more than 50 years, our understanding of maggot masses, particularly the physiological ecology of the aggregations as a whole, is rudimentary. In this review, an examination of what is known about the formation of maggot masses is presented, as well as arguments for the physiological benefits and limitations of developing in feeding aggregations that, at times, can represent regions of intense competition, overcrowded conditions, or a microclimate with elevated temperatures approaching or exceeding proteotoxic stress levels.

Adult females of Nasonia vitripennis inject a venomous mixture into its host flies prior to oviposition. Recently, the entire genome of this ectoparasitoid wasp was sequenced, enabling the identification of 79 venom proteins. The next challenge will be to unravel their specific functions, but based on homolog studies, some predictions already can be made. Parasitization has an enormous impact on hosts physiology of which five major effects are discussed in this review: the impact on immune responses, induction of developmental arrest, increases in lipid levels, apoptosis and nutrient releases. The value of deciphering this venom is also discussed.

The bases for forensic entomology are that insects and their arthropod relatives can serve as evidence in criminal, medical and civil legal matters. However, some of the very same species that provide utility to legal investigations can also complicate crime scenes by distorting existing body fluid evidence (e.g., bloodstains, semen, saliva) and/or depositing artifacts derived from the insect alimentary canal at primary or secondary crime scenes. The insect contaminants are referred to as insect stains, artifacts, specks or spots, and are most commonly associated with human bloodstains. This review will discuss the different types of insect artifacts that have been described from crime scenes and laboratory experiments, as well as examine insect contaminates (non-blood based artifacts, transfer patterns, meconium, and larval fluids) that have received little research or case attention. Methods currently used for distinguishing insect stains from human body fluids will also be discussed and compared to presumptive tests used for identification of human body fluids. Since all available methods have severe limitations, areas of new research will be identified for the purpose of development of diagnostic techniques for detection of insect artifacts.

Oviposition behavior was used to determine if handling time was a reliable indicator of host suitability for oviposition by the ectoparasitic wasps, Nasonia vitripennis (Walker) and Muscidifurax zaraptor Kogan & Legner, on pupae of Sarcophaga bullata Parker, the black blow fly, Phormia regina (Meigen), and the house fly, Musca domestica L. Oviposition behavior of both parasitoids was composed of a series of stereotypic and interdependent events or phases. The duration of behavioral events preceding puparium penetration was influenced by host species, indicating that host recognition depends on some external cue associated with the fly puparium. Total handling time was stereotypic regardless of host species or the number of eggs laid on a host, suggesting that the amount of time invested by N. vitripennis and M. zaraptor in oviposition does not predict clutch size or host preference. When N. vitripennis and M. zaraptor were held together at low host densities, females of N. vitripennis reacted aggressively and interfered with all oviposition attempts by M. zaraptor. Aggression by N. vitripennis toward M. zaraptor subsided when host density was increased, presumably because this was a less competitive situation.