Infection behavior of a parasitoid fly, Emblemasoma auditrix, and its host cicada Okanagana rimosa

Abstract

Males of the cicada Okanagana rimosa (Homoptera: Cicadidae) that produce calling songs are parasitised by the parasitoid fly Emblemasoma auditrix (Diptera: Sarcophagidae). An ethogram of the infection behavior was extracted from videotaped experiments with tethered hosts. The infection behavior can be divided into three phases, each involving different sensory cues: long-range host detection via acoustic signals, visual short-range orientation, and a contact phase with tactile/chemical cues. After phonotaxis by flight, the fly lands on or near the host cicada. It walks around the host to identify the caudal end and squeezes underneath the wings (with a 64–67% preference of the left side). Finally, E. auditrix cuts into the timbal and deposits a larva into the sound producing organ of O. rimosa. This highly specific behavior restricts the host range to cicadas, only two species of which occur simultaneously with the parasitoid. During the infection behavior, the fly does not discriminate between male and female hosts. However, females were not successfully infected during the experiments. The host O. rimosa shows only weak defense behavior (mainly flapping their wings) and seems to rely on parasitoid avoidance. Production of the protest song does not prevent infection.

Influence of habitat structure on the phonotactic strategy of a parasitoid fly Emblemasoma auditrix

“…For E. auditrix , visual orientation is probably important for host attack. The parasitoid usually approaches the host from behind, squeezes underneath its wings, and deposits a larva at the timbal (Schniederkötter & Lakes‐Harlan, 2002). In no case was a larva deposited at the loudspeaker or close to it.…”

“…Thus, walking might be an important part of the host location and attack behaviour. For infection, the parasitoid seems to evaluate the orientation of the cicada's body and approaches the host from behind, squeezing underneath the wings and depositing a larva at the timbal (Schniederkötter & Lakes‐Harlan, 2002).…”

Phonotactic behaviour and vertical sound source localisation of the parasitoid fly Emblemasoma auditrix (Diptera: Sarcophagidae)

“…However, male cicadas seldom try to escape or flick their wings when the fly is crawling under to deposit the larva. Moreover, the flies are very aggressive against flying cicadas and will attack them even in flight (Schniederkötter & Lakes‐Harlan, , Lakes‐Harlan, pers. obs.).…”

“…The females of the parasitoid E. auditrix detect the male calling song of the cicada O. rimosa, which they produce to attract conspecific females. The fly then approaches the singing cicada and deposits a larva inside, which feeds on the host and eventually kills it (Soper et al, 1976;Lakes-Harlan et al, 2000;Schniederkötter & Lakes-Harlan, 2004). The ear of the sarcophagid fly is located at the prosternum (Lakes-Harlan et al, 1999) and mechanical coupling of both ears provides cues for horizontal orientation (Robert et al, 1999).…”

Acoustic radiation patterns of mating calls of the túngara frog (Physalaemus pustuosus): Implications for multiple receivers

“…The larvae burrow into the male cricket and use him as a food source as they develop. 10 Heterospecifics that eavesdrop on the mating signals of their hosts or prey are widespread across taxonomic groups ͑e.g., gecko-cricket, 11 bat-katydid, 12 emblysoma fly-cicada, 13 orminiie fly-bushcricket, in which the signaler and the intended receiver communicate in the horizontal plane while the unintended receiver detects the signal in a vertical plane, the characteristics of the signal available to the different receivers may vary greatly. Thus, beaming patterns of the signal influence its effectiveness at attracting mates and the costs imposed by acoustically orienting predators and parasites.…”