TY - JOUR
T1 - Parents benefit from eating offspring
T2 - Density-dependent egg survivorship compensates for filial cannibalism
AU - Klug, Hope
AU - Lindström, Kai
AU - St. Mary, Colette M.
PY - 2006/10
Y1 - 2006/10
N2 - Why should animals knowingly consume their own young? It is difficult to imagine many circumstances in which eating one's own young (i.e., filial cannibalism) actually increases an individual's fitness; however, filial cannibalism commonly co-occurs with parental care in fishes. The evolutionary significance of filial cannibalism remains unclear. The most commonly accepted explanation is that filial cannibalism is a mechanism by which caring males gain energy or nutrients that they reinvest into future reproduction, thereby increasing net reproductive success. There is mixed support for this hypothesis and, at best, it can only explain filial cannibalism in some species. A recent alternative hypothesis suggests that filial cannibalism improves the survivorship of remaining eggs by increasing oxygen availability, and thus increases current reproductive success. This theory has received little attention as of yet. We evaluated the hypothesis of oxygen-mediated filial cannibalism in the sand goby by examining the effect of oxygen and egg density on the occurrence of filial cannibalism, evaluating the effects of partial clutch cannibalism on the survivorship of remaining eggs, and comparing potential costs and benefits of filial cannibalism related to the net number of eggs surviving. Indeed, we found that oxygen level and egg density affected the occurrence of cannibalism and that simulated partial clutch cannibalism improved survivorship of the remaining eggs. Additionally, because increased egg survivorship, stemming from partial egg removal, compensated for the cost of cannibalism (i.e., number of eggs removed) at a range of cannibalism levels, filial cannibalism potentially results in no net losses in reproductive success. However, oxygen did not affect egg survivorship. Thus, we suggest a more general hypothesis of filial cannibalism mediated by density-dependent egg survivorship.
AB - Why should animals knowingly consume their own young? It is difficult to imagine many circumstances in which eating one's own young (i.e., filial cannibalism) actually increases an individual's fitness; however, filial cannibalism commonly co-occurs with parental care in fishes. The evolutionary significance of filial cannibalism remains unclear. The most commonly accepted explanation is that filial cannibalism is a mechanism by which caring males gain energy or nutrients that they reinvest into future reproduction, thereby increasing net reproductive success. There is mixed support for this hypothesis and, at best, it can only explain filial cannibalism in some species. A recent alternative hypothesis suggests that filial cannibalism improves the survivorship of remaining eggs by increasing oxygen availability, and thus increases current reproductive success. This theory has received little attention as of yet. We evaluated the hypothesis of oxygen-mediated filial cannibalism in the sand goby by examining the effect of oxygen and egg density on the occurrence of filial cannibalism, evaluating the effects of partial clutch cannibalism on the survivorship of remaining eggs, and comparing potential costs and benefits of filial cannibalism related to the net number of eggs surviving. Indeed, we found that oxygen level and egg density affected the occurrence of cannibalism and that simulated partial clutch cannibalism improved survivorship of the remaining eggs. Additionally, because increased egg survivorship, stemming from partial egg removal, compensated for the cost of cannibalism (i.e., number of eggs removed) at a range of cannibalism levels, filial cannibalism potentially results in no net losses in reproductive success. However, oxygen did not affect egg survivorship. Thus, we suggest a more general hypothesis of filial cannibalism mediated by density-dependent egg survivorship.
KW - Density-dependent egg survivorship
KW - Filial cannibalism
KW - Parent-offspring conflict
KW - Parental care
KW - Paternal care
KW - Pomatoschistus minutus
UR - http://www.scopus.com/inward/record.url?scp=33751324823&partnerID=8YFLogxK
U2 - 10.1554/05-283.1
DO - 10.1554/05-283.1
M3 - Article
C2 - 17133865
AN - SCOPUS:33751324823
SN - 0014-3820
VL - 60
SP - 2087
EP - 2095
JO - Evolution
JF - Evolution
IS - 10
ER -