Robert M. Woollacott

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Larvae and adults of the marine bryozoan Watersipora cucullata invariably possess numerous extracellular mycoplasma-like, organisms. Mesodermally encapsulated groups of these atypical bacteria occur in the visceral coeloms of all colony members. In contrast, thousands of the symbionts are externally attached to each larva along a unique superficial groove;(More)
Adult colonies of the bryozoan Bugula neritina release short-term anenteric larvae that initially are strongly photopositive. Over the course of several hours larvae lose their initial photopositivity and either become photonegative or alternate between positive and negative phototaxis. We report that newly released photopositive larvae rapidly become(More)
Elevation of the K+ concentration in seawater (added as KC1) induces larval settlement and metamorphosis in Bugula simplex, B. stolonifera, and B. turrita. All three of these bryozoan species have similar bell-shaped dose-response curves: 5 mM excess K+ is sufficient to increase settlement and metamorphosis significantly over seawater controls in all the(More)
Larvae of the bryozoans Bugula neritina and Bugula stolonifera exhibit an apparent negative geotaxis under conditions of darkness and constant temperature. This behavior cannot be accounted for by buoyancy since the larvae are negatively bouyant, nor is it a consequence of gradients in the partial pressures of dissolved gases since the response occurs under(More)
Pigmented spots have been implicated as potential photoreceptors in many bryozoan larvae which display phototactic behavior. Larvae ofScrupocellaria bertholetti, initially photopositive on release from the brood chambers, have a pair of identical posterolateral pigmented spots and a third morphologically different spot in the anteromedian line. The presumed(More)
The free swimming larvae of many marine invertebrates actively respond to light. Light cues can be used to regulate position in the water column and to facilitate encountering sites suitable for metamorphosis. We examined the ontogeny of larval phototaxis and the ontogeny of metamorphic competency in larvae from three congeneric species of bryozoans. Larvae(More)
The pigmented spots of bryozoan larvae have often been implicated in photoreception due to their preferential occurrence in larvae with positive phototactic behavior. Results of light and electron microscopic studies of Bugula neritina show that the larvae possess two spots, each with a basal sensory cell situated at the base of a pit-like depression. The(More)
Origin and formation of the body wall epidermis of the ancestrula in three species of gymnolaemate bryozoans were analyzed by scanning and transmission electron microscopy. In the ctenostome Bowerbankia gracilis, the aboral pallial epithelium forms the entire cystid epidermis, whereas in the anascan cheilostome Bugula neritina, the wall and roof regions of(More)
Conspecific aggregations in terrestrial and aquatic organisms can have a significant effect on an individual's survival, growth and reproductive fitness, particularly if these aggregations are composed of closely related individuals. Such aggregations can form passively, as a consequence of dispersal, or actively, as a consequence of kin recognition. In(More)