Cintia Pamela Fraysse, Analía Fernanda Pérez, Ayelén Mattenet, Malena Pfoh, Claudia Clementina Boy

Oral brooding (Anasterias antarctica) versus internal brooding (Diplopteraster verrucosus): Contrasting strategies of the brooded juveniles for full development

Introduction

Oral brooding (anasterias antarctica) versus internal brooding (diplopteraster verrucosus): contrasting strategies of the brooded juveniles for full development. Explore contrasting oral (Anasterias antarctica) and internal (Diplopteraster verrucosus) brooding in South Atlantic sea stars. Study analyzes offspring oxidative metabolism, energy, and development.

Abstract

Both sea star species in this study are brooders from the South Atlantic. Anasterias antarctica displays a complex reproductive cycle involving incubation during eight or nine months and it broods its offspring over the mouth, while Diplopteraster verrucosus displays continuous reproduction and broods its offspring in nidamental chambers under the dermis. We collected A. antarctica in May, August, and November (beginning, mid and late incubation) from Parque Nacional Tierra del Fuego (Tierra del Fuego AeIAS, Argentina), while D. verrucosus was collected at three Oceanographic Research Cruises at Namuncurá Marine Protected Area/ Burdwood Bank I and II. We measured general parameters of oxidative metabolism (reactive oxygen species “ROS” and total antioxidant capacity “TAC”), energy density, and energy content in three different stages during offspring development. In the case of A. antarctica, energy depletion, increasing ROS and constant TAC levels at the late development stage could act as a developmental constraint and trigger the independence of juveniles. Similarly, in D. verrucosus juveniles, which exhibit extra embryonic maternal nutrition, despite the continued increase in energy, the antioxidants present in this kind of nutrition do not counteract the ROS generated by the metabolic rise.

Review

This study offers a compelling comparative analysis of two distinct brooding strategies in South Atlantic sea stars, *Anasterias antarctica* (oral brooding) and *Diplopteraster verrucosus* (internal brooding). The research aims to elucidate the physiological challenges and developmental triggers for independence in brooded juveniles, a critical area for understanding parental investment and life-history evolution in marine invertebrates. By focusing on oxidative metabolism and energy dynamics, the paper promises valuable insights into how different maternal care strategies influence offspring development and the subsequent timing of their release. A significant strength of this work lies in its direct comparative approach, meticulously tracking key physiological markers (ROS, TAC, energy density, energy content) across different developmental stages in offspring from two species with fundamentally different brooding environments. The findings for *A. antarctica* are particularly insightful, suggesting that energy depletion combined with an increase in reactive oxygen species (ROS) and a static antioxidant capacity (TAC) could serve as a crucial developmental constraint, ultimately triggering juvenile independence. Similarly, the observation in *D. verrucosus* that even with continuous maternal energy supply, antioxidants from extra-embryonic nutrition fail to fully counteract metabolic ROS, underscores a common physiological hurdle across diverse brooding strategies. While the abstract presents intriguing initial findings, a more detailed elaboration within the full manuscript would significantly enhance the paper's impact. For instance, a deeper discussion of the specific "three different stages" for each species, outlining clear developmental milestones, would strengthen the interpretation of physiological changes. Future research could also benefit from exploring the genetic and molecular underpinnings of the observed ROS generation and antioxidant responses, as well as the long-term ecological consequences of these contrasting developmental pathways for juvenile survival and fitness post-independence. Further contextualization of environmental factors at the collection sites and their potential influence on brooding physiology would also add valuable depth.

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