The Phoridae is known as 'scuttle flies' because they walk in rapid bursts of movement with short pauses between. In this study, larval locomotive behavior and development was characterized in the phorid, Megaselia scalaris. Comparison was made with the well-characterized fruit fly model, Drosophila melanogaster. Developmentally, the rate of maturation was consistently slower for Megaselia than Drosophila. This disparity was exaggerated at lower temperatures, particularly during larval development. In addition to slower growth, movements in Megaselia were also slower, as evidenced by reduced rates of larval body wall contractions and mouth hook movements. Megaselia larvae also displayed a unique behavior of swallowing air when exposed to a small pool of liquid. This permitted floating upon immersion and, therefore, might prevent drowning in the natural environment. The anatomical and physiological properties of a neuromuscular junction in the phorid larvae were also examined. The innervation of the motor nerve terminals on the ventral abdominal muscle (m6) is innervated by Type Ib and Is axons, similar to Drosophila. As in Drosophila, the Is terminals produce larger excitatory postsynaptic potentials (EPSPs) than the Ib. The amplitudes of the EPSPs in M. scalaris were reduced compared to those of D. melanogaster, but unlike D. melanogaster the EPSPs showed marked facilitation when stimulated with a 20 Hz train. We conclude that there may be differences in synaptic structure of the nerve terminals that could account for the different electrophysiological behaviors.
|Number of pages||13|
|Journal||Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology|
|State||Published - Oct 1 2003|
Bibliographical noteFunding Information:
We thank Mr Ryan Ball (University of KY) and Ms Racennah Braxton (Talladega college, AL) for helping to conduct behavioral assays used in this study. Dr Susan Harrison assisted with photography. Funding was provided by NSF grants IBN-0091535 (DH), IBN-9808631 (RLC) and NSF-ILI-DUE 9850907 (RLC). We thank Mr Mike Sharkey (Department of Entomology, University of Kentucky) and Dr Brian Brown (Associate Curator of Entomology, Natural History Museum of Los Angeles County, CA) for species identification.
- Neuromuscular junction
ASJC Scopus subject areas
- Molecular Biology