The effects of nurse eggs and sibling interactions on the larval development of the poecilogonous annelid Boccardia proboscidea (Spionidae)

Abstract

In poecilogony, different types of larvae are produced within the same species. Previous studies have suggested maternal control of the production of larval types; however, it is not clear which factors or mechanisms generate contrasting developmental patterns among siblings. The spionid polychaete Boccardia proboscidea produces within the same capsule adelphophagic larvae that eat nurse eggs and siblings and complete all or most of their development inside the capsule (Type A larvae), and larvae with little growth until they hatch as planktotrophic larvae (Type B larvae). In this study, we manipulated capsule content to explore the factors determining larval type in B. proboscidea and the role of extra‐embryonic maternal nutrition and sib–sib interaction in the developmental fate of offspring. When early larval stages were grown individually in vitro, with nurse eggs as the only food source, some of them remained small, while others continue developing into larger pre‐competent larvae by feeding on nurse eggs. This suggests that larval types in B. proboscidea are determined very early in development and are not solely the product of sib–sib interaction inside the capsule. However, our data also suggest that hatching size variability within larval types of a clutch depends on nurse egg availability. Type B larvae grew normally to metamorphosis when phytoplankton was available, but suffered high rates of cannibalism by Type A larvae. These results are consistent with the hypothesis that individual larval fates are determined very early in development and that once their fate is determined, hatching size and intracapsular survival are affected by maternal food provisioning and sibling interaction.

Evolutionary Developmental Biology (Evo‐Devo) Research in Latin America

“…The effects of nurse eggs and sibling interactions on the larval development of the poecilogonous annelid Boccardia proboscidea (Spionidae) (Oyarzún and Brante, )…”

Molecular analysis and new records of the invasive polychaete Boccardia proboscidea (Annelida: Spionidae)

“…The reproduction and larval development of B. proboscidea have been described from California and Washington, USA, and British Columbia, Canada (Hartman, 1940(Hartman, , 1941Woodwick, 1977;Gibson, 1997;Smith & Gibson, 1999;Gibson & Smith, 2004;Oyarzun & Strathmann, 2011;Gibson & Carver, 2013;Oyarzun & Brante, 2014), Australia (Blake & Kudenov, 1981), South Africa (David & Simon, 2014), and Argentina (Jaubet et al, 2015). The species exhibits development that varies both within a single brood and among broods produced by different females.…”

Bioenergetics of parental investment in two polychaete species with contrasting reproductive strategies: The planktotrophicBoccardia chilensisand the poecilogonicBoccardia wellingtonensis(Spionidae)

“…Poecilogony (i.e., a species having more than one type of larval development) is infrequent in nature and only found in polychaetes and gastropods. This type of reproduction results in broods containing offspring hatching either as planktonic larvae, as juvenile individuals, or as a combination of both (Krug, ; Krug, Gordon, & Romero, ; McDonald, Collin, & Lesoway, ; Oyarzun & Brante, , ). These intra‐specific differences are often related to the amount and source of energy provided by females for larval nutrition and the capacity of the larvae to use that nutritional source.…”

“…Life history trade-offs between reproductive investment, fecundity, and the survival probability of the offspring often lead to a decrease in female fecundity (i.e., egg number per brood) in parallel with an increase in the amount of energy invested per offspring and vice versa (Fenchel & Christiansen, 1979;Thorson, 1950). On the one hand, embryos with high energy reserves grow to advanced stages of development within the capsule and hatch with a larger body size, which may increase survival specially during periods of low food availability (Ito, 1997;Moran & Emlet, 2001;Oyarzun & Brante, 2014). On the other hand, those embryos with less energy hatch at smaller sizes, which are subjected to high mortality by predation and starvation and are highly dependent on planktonic food availability for survival (Fenchel & Christiansen, 1979;Jablonski & Lutz, 1983;Thorson, 1950).…”