The Auditory System of the Dipteran ParasitoidEmblemasoma auditrix(Sarcophagidae)

Abstract

Several taxa of insects evolved a tympanate ear at different body positions, whereby the ear is composed of common parts: a scolopidial sense organ, a tracheal air space, and a tympanal membrane. Here, we analyzed the anatomy and physiology of the ear at the ventral prothorax of the sarcophagid fly, Emblemasoma auditrix (Soper). We used micro-computed tomography to analyze the ear and its tracheal air space in relation to the body morphology. Both tympana are separated by a small cuticular bridge, face in the same frontal direction, and are backed by a single tracheal enlargement. This enlargement is connected to the anterior spiracles at the dorsofrontal thorax and is continuous with the tracheal network in the thorax and in the abdomen. Analyses of responses of auditory afferents and interneurons show that the ear is broadly tuned, with a sensitivity peak at 5 kHz. Single-cell recordings of auditory interneurons indicate a frequency- and intensity-dependent tuning, whereby some neurons react best to 9 kHz, the peak frequency of the host’s calling song. The results are compared to the convergently evolved ear in Tachinidae (Diptera).

New data on acoustic signals of Stauroderus scalaris (Orthoptera: Acrididae) from different local populations with a note about its parasite from the genus Blaesoxipha (Diptera: Sarcophagidae)

“…In this regard, information on the biology of this species and its interrelations with other insects (in particular with parasitic flies, which are natural regulators of insect abundance) from different areas is relevant. Concerning a parasite-host relationship, we should say that some parasitic flies from families Sarcophagidae and Tachinidae are able to find acoustically active insects by their sound signals (Leonide, 1969;Lehmann, 2003;Hedwig & Robert, 2014;Tron et al, 2016). This interesting fact was confirmed by using sound traps in nature as well, when parasites were caught by playback of acoustic signals of their hosts, in particular crickets (Orthoptera: Gryllidae) (Cade, 1975) and mole crickets (Orthoptera: Gryllotalpidae) (Fowler, 1987).…”

“…After infestation, males lose the ability to further emission of sounds, that makes them inaccessible to other parasites and prevents multiple parasitism. Analyses of responses of auditory afferents and interneurons show that the tympanal organ of E. auditrix is broadly tuned, with a sensitivity peak at 5 kHz (Tron et al, 2016.). Single-cell recordings of auditory interneurons indicated a frequencyand intensity-dependent tuning, whereby some neurons react best to 9 kHz, the peak frequency of the host's calling signal.…”

Analysis of fixation materials in micro-CT: It doesn’t always have to be styrofoam

“…For many specimens that are stored in solution, the contrast can be greatly improved if they are also temporarily removed from the solution and dabbed. If moist samples can be taken from the medium, parafilm fixation [ 30 , 33 , 36 ] is particularly suitable to prevent drying out during the scan duration ( Fig 2E ). In this case, it has proven useful to seal the parafilm with wide tweezers ( Fig 2E ).…”

“…For many specimens that are stored in solution, the contrast can be greatly improved if they are also temporarily removed from the solution and dabbed. If moist samples can be taken from the medium, parafilm fixation [30,33,36] is particularly suitable to prevent drying…”