Vol. 54, 2015
Infection behavior, life history, and host parasitism rates of Emblemasoma erro (Diptera: Sarcophagidae), an acoustically hunting parasitoid of the cicada Tibicen dorsatus (Hemiptera: Cicadidae)
Brian J Stucky
Department of Ecology and Evolutionary Biology, University of Colorado, Campus Box 334 UCB, Boulder, CO 80309, USA
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
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.
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.
Key words: Eavesdropping; Emblemasoma; Host defense; Host location; Infection behavior; Parasitoid; Parasitoid load; Phonotaxis; Superparasitism; Tibicen.
*Correspondence: E-mail: firstname.lastname@example.org