DOI: 10.5061/dryad.bg79cnppm
title: Data from: Full compensation of parental care after partner loss in an annelid

description: In species with biparental care, each parent would benefit by exploiting
 its partner and reduce its investment over offspring care. The conflict is
 especially apparent when one parent deserts or reduces its investment,
 forcing the remaining parent to either abandon the brood or compensate for
 the loss of partner-care effort; however, compensation is expected to be
 partial for the evolutionary stability of biparental care. We investigated
 the level of parental care compensation in the simultaneously
 hermaphroditic annelid worm, Ophryotrocha diadema, where both parents care
 for egg clutches. We removed one parent and found that widowed parents
 fully compensated for the loss of their partner; the number of scan
 observations widows spent in clutch attendance was statistically
 equivalent to that of paired parents. Consistently, individually, widowed
 parents attended their clutch significantly more often than focal worms
 among paired parents. We discuss how full compensation can be compatible
 with evolutionary stability of biparental care in a rare species with
 sparse population and whose adaptations suggest that mate encounter might
 be rare. In this condition, nest attendance might be valuable as it
 promotes clutch protection from predators as well as mate encounters thus
 mitigating the conflict of interests over parental care.
description: # Data from: Full compensation of parental care after partner loss in an
 annelid Marie Kauffmann, Lula Insel, Maria-Cristina Lorenzi*  *Laboratoire
 d'Ethologie Expérimentale et Comparée (LEEC), Université Sorbonne
 Paris Nord, Villetaneuse, France* **Corresponding author:*
 *[mariacristinalorenzi@gmail.com](mailto:mariacristinalorenzi@gmail.com)*
 Dataset DOI:
 [10.5061/dryad.bg79cnppm](https://doi.org/10.5061/dryad.bg79cnppm) ##
 Description of the data and file structure ### Files and variables ####
 File: individual_clutch_attendance.csv **Description:** The file contains
 the data collected during the lab experiment on compensation for partner
 loss in parental care in the annelid *Ophryotrocha diadema*, a marine worm
 with biparental care. As the number of behavioral observation scans varied
 among paired and widow worms, the data sheet contains empty cells
 (indicated with "NA"). ##### Variables * ID: code of
 identification of the 213 pairs * developmental.environment: factor with
 two levels (Competitive environment/Non competitive environment). This
 variable describes the two developmental regimes the experimental worms
 experienced before entering the experiment: 1) lab mass cultures (200-300
 worms in 200 mL water), where worms experience high mating opportunities
 and high reproductive competition, thereafter: competitive developmental
 regime; or 2) separate bowls containing siblings, i.e., the offspring of
 30 pairs of worms isolated from the lab mass cultures and kept in separate
 bowls (10-40 offspring in 60 mL water; n = 280 individuals) until they
 were newly sexually mature, thereafter: non-competitive developmental
 regime. * condition: factor with two levels (paired/widow). In the
 condition “widow”, we removed one of the two worms from the bowl; either
 the mother or the father, resulting in n = 54 bowls where the clutch was
 only cared for by the father, and n = 53 bowls where the clutch was cared
 for by the mother. In the condition “paired”, the pair was kept intact,
 and either the mother (n = 51) or the father (n = 55) was considered as
 the focal worm in the subsequent behavioral observations. *
 parental_role: factor with two levels (mother/father), which describes
 whether the simultaneously hermaphroditic worm was the mother or the
 father of the offspring which it cared for. * focal_size: body size of the
 focal worm at the start of the experiment (number of body segments). *
 partner_size: body size of the partner of the focal worm at the start of
 the experiment (number of body segments). * clutch_size: number of eggs in
 the clutch. The eggs are sealed into a jelly envelop. * time: day of the
 behavioral observation (the eggs were laid on day 0, behavioral
 observation performed on day 1 or 2). This variable was entered as a
 factor in the statistical analysis. * n_obs: number of observation scans.
 * focal_care: factor with two levels 1/0: the focal worm performed/did not
 perform parental care at the observation scan. * partner_care: factor with
 two levels 1/0: the partner of the focal worm performed/did not perform
 parental care at the observation scan. * total_care: total number of times
 the clutch was attended by any parent. * removal_2nd \_clutch: factor with
 two levels 1/0: whether a second clutch was present/absent. In case it was
 present, we removed it before behavioral observations. ## Dates and
 Location of data collection (incl. time zone) April-May 2024, Laboratoire
 d'Ethologie Expérimentale et Comparée (LEEC), Université Sorbonne
 Paris Nord, Villetaneuse, France
 ([UTC+01:00).](https://en.wikipedia.org/wiki/UTC%2B01:00
 "UTC+01:00") ## Code/software SOFTWARE VERSIONS Statistical
 analyses were done in R version 4.4.1 (R Core Team 2024). We ran the GLMM
 using the package lme4 (Bates et al. 2015). The equivalence test was
 performed using the packages onewaytests and TOSTER (Caldwell, 2022).
 REFERENCES Bates, D., Mächler, M., Bolker, B., & Walker, S. (2015).
 Fitting Linear Mixed-Effects Models Using lme4. Journal of Statistical
 Software, 67, 1–48. Caldwell A.C. (2022). Exploring Equivalence Testing
 with the Updated TOSTER R Package. PsyArXiv,
 [https://doi.org/10.31234/osf.io/ty8de](https://doi.org/10.31234/osf.io/ty8de).