Hymenopteran Parasitoids of Forensic Importance: Host Associations, Seasonality, and Prevalence of Parasitoids of Carrion Flies in Western Australia

Abstract

A 2-yr survey of hymenopteran parasitoids associated with carrion-breeding flies was conducted to establish the parasitoid species of potential forensic significance in Western Australia. Host associations, seasonality, and rates of parasitism in the field were examined to assess the value of the identified parasitoids as forensic indicators of time since death. Four species of parasitoid emerged from dipteran specimens collected from carcasses: Tachinaephagus zealandicus Ashmead (Encryptidae), Nasonia vitripennis Walker (Pteromalidae), Spilomicrus sp. (Diapriidae), and Aphaereta sp. (Braconidae). Overall parasitism of carrion-breeding flies was 11.8%. T. zealandicus and N. vitripennis were the predominant species, accounting for 86.3 and 11.5% of parasitism observed, respectively. In contrast, Aphaereta sp. and Spilomicrus sp. were intermittently collected from carcasses throughout the study and the parasitism rates of both species were low (< or = 3.0%). Our findings provide forensically important biological and behavioral data of parasitoid-host interactions within carcass environments. The cosmopolitan parasitoids T. zealandicus and N. vitripennis have the greatest potential as indicators of time since death in forensic investigations based on their broad host ranges, rates of parasitism, and seasonal prevalence. In combination, these two species are present throughout the year and they parasitized nearly all of the dipteran species that colonize carcasses. Because both are cosmopolitan species, the data presented here are applicable to regions experiencing a similar Mediterranean climate. This work reports the first incidence of T. zealandicus and N. vitripennis parasitizing the dipteran species Calliphora albifrontalis Malloch (Calliphoridae), Calliphora dubia Macquart (Calliphoridae), and Hydrotaea rostrata Robineau-Desvoidy (Muscidae).

Intraspecific variability in associative learning in the parasitic wasp Nasonia vitripennis

“…Slow learners on the other hand need several experiences to make lasting associations, but are less likely to learn irrelevant or wrong information (Chittka et al 2009;Hoedjes et al 2011). Such variation might be important in a species like N. vitripennis, which attacks hosts in diverse microhabitats, from bird's nests to animal carcasses (Abraham 1985;Voss et al 2009). Differences in the environment and hence slight differences in the ecology between populations can cause variability in learning behavior.…”

Oviposition Restraint and Developmental Alterations in the Ectoparasitic Wasp,Nasonia vitripennis, When Utilizing Puparia Resulting From Different Size Maggot Masses ofLucilia illustris,Protophormia terraenovae, andSarcophaga bullata

“…Use of parasitoids to determine periods of insect activity or the minimum postmortem interval is infrequent for a variety of reasons (Amendt et al 2000, Disney and Munk 2004, Turchetto and Vanin 2004, Voss et al 2009). However, N. vitripennis offers advantages over many other parasitic species in that ßy hosts cannot be parasitized until after pupation is complete but before the onset of eclosion behavior, providing a window into the minimum length of host development on a corpse.…”

“…In the latter scenario, accelerated larval growth rates as a function of elevated mass temperatures leads to smaller puparia (Ullyett 1950, Kamal 1958, Rivers et al 2010, which is predicted to represent a diminished nutritive food source for parasitoids, particularly those relying on a gregarious reproductive strategy (Rivers and Denlinger 1995, Rivers 2007, Voss et al 2009). Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) is an example of a gregarious ectoparasitoid of synanthropic ßies that frequently rejects hosts deemed too small Denlinger 1995, Rivers 2004); or if oviposition on such ßies does occur, clutch sizes are smaller, sex ratios are increasingly male biased, larval development is extended, and adult body sizes (particularly female) are truncated (Rivers and Denlinger 1995).…”

Comparison of Host-Seeking Behavior of the Filth Fly Pupal Parasitoids, Spalangia cameroni and Muscidifurax raptor (Hymenoptera: Pteromalidae)

“…The ephemeral nature and patchy distribution of some habitats of developing filth flies poses a challenge for newly emerged, adult pupal parasitoids to locate hosts. Odors emanating from host habitats can serve as long-range stimuli that are often highly detectable, whereas odors directly from hosts are a more reliable indication of host presence, but are generally less detectable from a distance (Laing 1937, Vet et al 1991, Voss et al 2009). …”