Fig. 1. Extensive actin filament loss from bundle modules is seen in maturing Drosophila bristles. Wild-type bristles of increasing age were stained with rhodamine-labeled phalloidin and imaged by confocal microscopy. Images of bristles at the indicated age (32-56 hours after puparium formation) were examined for smooth bundles with no gaps (a), bundles with overlapping modules (c), bundles with gaps (e), apically tapering modules (g) and for bundles with extensive filament ghosts remaining (i). The percentage of bristles with bundles of each type was plotted as a function of developmental time. Note that individual bristles could contain more than one type of bundle. For example, 43-hour bristles often contain bundles with overlapping modules and bundles with gaps (see text for details). A total of 195 thoracic bristles were examined. Portions of bristles illustrating smooth bundles (b), bundles with overlapping modules (indicated with arrowheads) (d), and bundles with gaps (indicated with arrowheads) (f) are shown to the right. A portion of a bristle illustrating tapering modules is shown in (h). Arrowheads indicate alignment of modules. A portion of a bristle illustrating extensive filament ghosts is shown in (j). Arrowheads indicate two bundles with ghost connections. Bars, 2 µm.