On ablation of the zooids
, the remaining vascular tissue initially loses a small volume of hemolymph but quickly contracts its peripheral vessels to halt the oozing, and hemocytes start to aggregate (Fig.
En Santa Fe se marcaron tres colonias y cada cuatro horas durante 24 horas, se recolectaron cinco zooides
de forma aleatoria de cada colonia.
Comparison of the two genera shows an increase in larval size at hatching, a decrease in the number of eggs per zooid
, and an increase in development time between Botryllus and Botrylloides species.
Colonies also vary in total sperm production because they vary in size (number of zooids
), which in turn varies during colony ontogeny.
Colonies include three blastogenetic generations represented by mature, filter-feeding zooids
, primary buds on zooids
, and secondary buds (budlets) emerging from the primary buds (Manni et al., 2007).
Assessment of the number of colonies and zooids
of Zoothamnium per substrate area showed that this genus was the dominant peritrich from April 15th to April 21st, but was outnumbered by Vorticella spp.
To examine the repeatability of sampling only the five longest spines from each colony, spine length was measured for 10 haphazardly chosen zooids
in each of four regions of the colony.
In both treatments, [approximately equal to] 85% of the Bugula larvae used in these assays developed two zooids
within 24 h, and a paired t test indicated no difference in the number of individuals reaching this stage after 24 h (P = 0.66, N = 18, Fig.
The oldest class, Stenolaemata, has only one extant order: the marine calcified Cyclostomatida with characteristic tube-shaped zooids
forming colonies that vary from encrusting to branched to massive.
The mean number of zooids
per colony (proliferation rate) of Z.
Jackson and McKinney (1990) found that, in the Mesozoic and Cenozoic, communication among zooids
was more extensive in cheilostomes than in cyclostomes and that cheilostomes largely replace cyclostomes, which implies a trend in mean degree of individuation for bryozoans as a whole.
Other studies have confirmed higher concentrations of bryostatins on larvae (~10 X), as well as in zooids
with ovicells (~3 X) compared to zooids
with no ovicells (Lopanik et al., 2004, 2006).