Extreme allomaternal care and unequal task participation by unmated females in a cooperatively breeding spider

TY - JOUR

T1 - Extreme allomaternal care and unequal task participation by unmated females in a cooperatively breeding spider

AU - Junghanns, Anja

AU - Holm, Christina

AU - Schou, Mads Fristrup

AU - Sorensen, Anna Boje

AU - Uhl, Gabriele

AU - Bilde, Trine

PY - 2017/10

Y1 - 2017/10

N2 - Division of reproductive behaviour and alloparental care are key aspects of many animal societies. In cooperatively breeding species, variation in helping effort and unequal task participation are frequently observed. However, the extent to which the reproductive state of an individual affects the tasks performed during offspring care remains poorly understood. In the social spider Stegodyphus dumicola, approximately 40% of females reproduce, and mothers show extended maternal care including eggsac tending, regurgitation feeding and matriphagy, in which they are consumed by the offspring. We asked whether and to what extent virgin females participate in extreme maternal care and whether they differ from reproducing females in foraging activity. We show that virgin females contributed to all aspects of extended brood care, including regurgitation feeding and matriphagy. This suggests a physiological adaptation in virgin females to cooperative breeding, since in the subsocial Stegodyphus lineatus only mated females provide extended maternal care. Although virgin females and mothers are behaviourally totipotent, we found evidence for task differentiation as virgins engaged less in brood care and more in prey attack than mothers. High relatedness among nestmates and low probability of future reproduction in virgin helpers suggest alignment of reproductive interests between mothers and allomothers. Therefore, extreme allomaternal care by virgin helpers can be considered an adaptation to cooperative breeding in social spiders.

AB - Division of reproductive behaviour and alloparental care are key aspects of many animal societies. In cooperatively breeding species, variation in helping effort and unequal task participation are frequently observed. However, the extent to which the reproductive state of an individual affects the tasks performed during offspring care remains poorly understood. In the social spider Stegodyphus dumicola, approximately 40% of females reproduce, and mothers show extended maternal care including eggsac tending, regurgitation feeding and matriphagy, in which they are consumed by the offspring. We asked whether and to what extent virgin females participate in extreme maternal care and whether they differ from reproducing females in foraging activity. We show that virgin females contributed to all aspects of extended brood care, including regurgitation feeding and matriphagy. This suggests a physiological adaptation in virgin females to cooperative breeding, since in the subsocial Stegodyphus lineatus only mated females provide extended maternal care. Although virgin females and mothers are behaviourally totipotent, we found evidence for task differentiation as virgins engaged less in brood care and more in prey attack than mothers. High relatedness among nestmates and low probability of future reproduction in virgin helpers suggest alignment of reproductive interests between mothers and allomothers. Therefore, extreme allomaternal care by virgin helpers can be considered an adaptation to cooperative breeding in social spiders.

KW - cooperation

KW - reproductive skew

KW - reproductive state

KW - social spiders

KW - sociality

KW - task differentiation

KW - STEGODYPHUS-LINEATUS ARANEAE

KW - SUICIDAL MATERNAL-CARE

KW - SOCIAL SPIDER

KW - ANELOSIMUS-EXIMIUS

KW - DUMICOLA ARANEAE

KW - DEVELOPMENTAL PLASTICITY

KW - GENETICAL EVOLUTION

KW - REPRODUCTIVE STATE

KW - THERIDIID SPIDERS

KW - ANIMAL SOCIETIES

UR - http://www.scopus.com/inward/record.url?scp=85028720009&partnerID=8YFLogxK

U2 - 10.1016/j.anbehav.2017.08.006

DO - 10.1016/j.anbehav.2017.08.006

M3 - Journal article

SN - 0003-3472

VL - 132

SP - 101

EP - 107

JO - Animal Behaviour

JF - Animal Behaviour

ER -