Senescence in Acartia tonsa (Copepoda, Calanoida): male’s reproductive performance preliminary results from a southern population

ABSTRACT

The effect of age on fertilization capacity and reproductive potential were examined in males from a laboratory population of Acartia tonsa over their life time providing new empirical data for a foundational estuarine species. The reproductive functions spermatophore production (SPR), number of fertilized females (NFF), percentage of males that effectively fertilized females (M), egg production rate (EPR), and hatching success (EHS) were evaluated during the adult life of male A. tonsa, from maturation until advanced age (38 d) under controlled laboratory conditions. The ageing process of the male was manifested occurred as a general decrease in most of the reproductive functions, but these followed specific patterns: SPR did not decay significantly with advanced male age, as it did happen with NFF, M and EPR; EHS increased at an intermediate age. Those changes were out of phase: while EPR declined already at intermediate age, NFF and M evidenced a decline at more advanced ages. Results suggest that reproductive senescence in copepod males involves the interaction of several mechanisms whose study will require comprehensive approaches.

KEYWORDS:

• Reproductive senescence
• spermatophore production rate
• vital rates

Acknowledgments

We thank M Martínez, L Santos, V Gutiérrez, A Denicola and G García for their support during this project. The present study was conducted at Centro Universitario Regional del Este (CURE), Universidad de la República.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The present study was performed within the framework of the research project ‘Implicancias de la senescencia sobre la biología reproductiva y eco-fisiología de copépodos marinos’ and funded by Agencia Nacional de Investigación e Innovación (ANII), Uruguay, Grant number [FCE_1_2011_1_6872].