Infection behavior, life history, and host parasitism rates of Emblemasoma erro (Diptera: Sarcophagidae), an acoustically hunting parasitoid of the cicada Tibicen dorsatus (Hemiptera: Cicadidae)

Abstract

Background: 'Eavesdropping' parasitoids find their hosts by homing in on the communication signals of other insects. These parasitoids often exploit chemical communication, but at least some species of the sarcophagid genus Emblemasoma eavesdrop on the acoustic communications of cicadas. Despite considerable scientific interest in acoustic parasitoids, we know remarkably little about most species of Emblemasoma. To better understand the ecology and behavioral diversity of these flies, I used a combination of field and laboratory techniques to elucidate the infection behavior and life history of E. erro, which uses the cicada Tibicen dorsatus as a host, and I also investigated parasitoid loads and parasitism rates of T. dorsatus in multiple host populations in the central United States.Results: Female E. erro used the acoustic signals of male T. dorsatus as the primary means of locating hosts, but they also required physical movement by the host, usually either walking or flight, to provide visual cues for the final larviposition attack. Larvae were deposited directly on the host's integument and burrowed through intersegmental membrane to enter the host's body. On average, E. erro larvae spent 88.0 h residing inside their host before leaving to pupariate, but residence time was strongly dependent on both ambient temperature and effective clutch size. Adult flies eclosed about 18 days after pupariation. Across all study sites, the mean parasitoid load of infected male T. dorsatus was 4.97 larvae/host, and the overall parasitism rate was 26.3%. Parasitism rates and parasitoid loads varied considerably among host population samples, and high parasitism rates were usually associated with high parasitoid loads. Conclusions: Previously, detailed information about the infection behavior, life history, and host parasitism rates of sarcophagid acoustic parasitoids was only available for one species, E. auditrix. This study reveals that the infection behavior of E. erro is quite different from that of E. auditrix and, more broadly, unlike that known for any other species of acoustic parasitoid. The life histories of these two Emblemasoma are also divergent. These differences suggest that sarcophagid acoustic parasitoids are more behaviorally and ecologically diverse than previously recognized and in need of further study.

Eavesdropping to Find Mates: The Function of Male Hearing for a Cicada-Hunting Parasitoid Fly,Emblemasoma erro(Diptera: Sarcophagidae)

“…Details of the methods used to construct these signals are provided in Stucky (2015) . Briefly, the calling songs of 20 different male N. dorsatus were recorded and analyzed to determine the values of three acoustic parameters: peak frequency, chirp length, and chirp rate (here, “chirp” is equivalent to the term “pulse group” defined in Stucky (2015) ; see Cole (2008) for a spectrogram and oscillograms of the N. dorsatus calling song). The mean values of these parameters were used to construct representative “model calls” that represented the average mating call of male N. dorsatus from the general study area.…”

“…At least six species of flies of the tachinid tribe Ormiini (Diptera: Tachinidae) and two species of flies of the sarcophagid genus Emblemasoma (sensu Pape 1990 ; Diptera: Sarcophagidae) are parasitoids with an unusual method of finding their hosts: Female flies have highly sensitive ears that allow them to listen for, and home in on, the airborne acoustic signals of their host crickets, katydids, and cicadas ( Cade 1975 ; Soper et al 1976 ; Burk 1982 ; Fowler and Kochalka 1985 ; Lakes-Harlan and Heller 1992 ; Walker 1993 ; Allen 1998 ; Stucky 2015 ). Females perform rapid, positive phonotaxis to the mating calls of their hosts, but all previous studies have found that males are not attracted to these sounds in the field ( Fowler 1987 ; Walker 1993 ; Farris et al 2008 ; Lakes-Harlan et al 2014 ).…”

“…Here, I present the results of an investigation of the function of male hearing in the sarcophagid parasitoid Emblemasoma erro Aldrich. Emblemasoma erro is an acoustic eavesdropping parasitoid of the cicada Neotibicen dorsatus (Say) (Hemiptera: Cicadidae) in the central Great Plains region of North America, and as with other sarcophagid and tachinid acoustic parasitoids, females of E. erro orient to the mating calls of their hosts for larviposition ( Stucky 2015 ). After informally observing that male E. erro were also attracted to the acoustic signals of cicadas, I hypothesized that both male and female E. erro might use the calling songs of their hosts as a means for locating potential mates.…”

First mitogenome for the subfamily Miltogramminae (Diptera: Sarcophagidae) and its phylogenetic implications

“…It is a young lineage within the schizophoran super-radiation of Diptera (Wiegmann et al, 2011;Cerretti et al, 2017) with diverse life habits, e.g. kleptoparasitism of Hymenoptera (Spofford et al, 1989), predators of other insects, spider egg sacs and reptile eggs (Pickens, 1981;Lopes, 1982;Mullen et al, 1984;Trauth & Mullen, 1990;Pape, 1996), parasitoids of insects and snails (Pape, 1994;McKillup et al, 2000;Stucky, 2015) and necro/coprophagy (Bänziger & Pape, 2004). Thus, the Sarcophagidae are of important ecological, medical and forensic importance.…”

Adaptive Strategies in Life-History of Bushcrickets (Orthoptera) and Cicadas (Homoptera) to Parasitoids Pressure on Their Acoustic Communication Systems—A Case for Sociality?

“…Such adaptations could be realized by satellite males and other alternative behavior (Zuk et al, 1993) and have mainly been reported for crickets and their parasitoids, especially Ormia ochracea. Within the Emblemasomatini some parasitoids have multiple host species (Stucky, 2015), whereas the wellinvestigated Emblemasoma auditrix seems to be more selective as it has almost exclusively been found in the cicada Okanagana rimosa (Lakes-Harlan et al, 2000). E. auditrix shows several host specific adaptations, from ecological preferences to tuning to the auditory cue for host localization and a highly specific host infection behavior (Schniederkötter and Lakes-Harlan, 2004).…”