The tolerance of brooded Capitella embryos to environmental stress has not been reported.
Females of the marine gastropod Crepipatella dilatata often evict their brooded offspring under hypoxic conditions, possibly as a way of reducing the level of oxygen debt that must eventually be repaid (Segura et al., 2014).
Brooded embryos of Capitella teleta also showed few post-metamorphic consequences (i.e., "latent effects," reviewed by Pechenik, 2006) of early exposure to either reduced salinity or hypoxia, and were, again, even more tolerant of hypoxic conditions than of salinity stress.
Table 2 Number of brood chambers and percentage of filled brood chambers per colony for each treatment Year Treatment Brood chambers P Filled brood P value chambers (%) value 2008 Paired 42.6 ([+ or -]12.0) 0.587 72.2 ([+ or -]3.0) 0.003 Solitary 34.7 ([+ or -]12.1) 38.4 ([+ or -]6.4) 2009 Paired 111.9 ([+ or -]16.7) 0.001 78.3 ([+ or -]3.3) 0.015 Solitary 52.3 ([+ or -] 8.6) 59.2 ([+ or -]4.9) The total number of brood chambers and percentage of filled brood chambers were assessed for each colony about one week after observing the first brooded embryo.
It seems likely, therefore, that the significant difference in brooded embryos between treatments documented in my study was a result of post-zygotic inbreeding depression--specifically, increased embryonic abortion.
Table 4 Results from investigating survival and fecundity of offspring from colonies cultured in each treatment Treatment Transferred Recovered colonies Reproductive colonies metamorphs Paired 61 56 56 Solitary 58 20 13 Treatment Larvae released Initiated Completed metamorphosis metamorphosis Paired 1030 1017 (98.7%) 986 (97.0%) Solitary 3 0 - Sexually mature colonies were collected from the field (Eel Pond, Woods Hole, MA) for larval release 14 d after brooded embryos were observed.
In the Chilean oyster, the particle-catching mechanism was not identified in the present study, but the apparent absence of the second (POC) ring may imply that only one ciliary band is involved, probably because the brooded
larva does not need to concentrate particles since the brooding female is performing this function.
Estimates of instantaneous mortality ([day.sup.-1]) were calculated for pentactulae brooded in female L.
No clear relationships were seen between the percent mortality and features of the mother such as size (drained weight) or number of pentactulae brooded (Table III).
This indicates that smaller adults brood numbers of embryos nearly equivalent to those brooded by larger adults (Rumrill, 1982).
In the latter case, the ability for the brood structure to expand to accommodate the number of fertilized eggs might ensure that, even when fertilization success is high, all the embryos can be brooded. In such cases, a test of the allometry hypothesis may be inappropriate because, in contrast to external brooders or species with a well-defined, solid brood space, there may not be a limit to brood space.