Abstract:  【Aim】 Sclerodermus parasitoids cooperate among foundresses (mated female wasps) in parental care, being an unique group performing quasi-social behavior in parasitoids. By cooperation foundresses can effectively exploit large sized hosts with stronger defenses, yet it is unclear if kinship among foundresses plays a role in this cooperation. This study aims to examine the effects of foundress-offspring kinship on maternal care behavior and offspring developmental performance in S. guani attacking the pupae of the host Tenebrio militor. 【Methods】 Maternal care provided by either a birth or adoptive foundress was evaluated by observing larva-translocation behavior using video camera and examining the developmental performance including larval survival, pupation, sex ratio, and body weight. 【Results】 The larva-recognition time by birth foundresses (32.73 s) was not significantly different from that by adoptive foundresses (19.64 s), but the number of larvae examined by birth foundresses with antenna-tapping (176 during 12 h) was twice as many as that by adoptive ones. The time for a bout of translocation did not differ between birth (27.31 s) and adoptive (41.55 s) foundresses. The interval in time between two bouts of translocation differed between two types of foundresses, of which birth foundresses had a shorter interval (60% of that by adoptive ones). The survival rate of offspring larvae tended by a birth foundress (90%) was not different from that by an adoptive foundress, yet the adult emergence rate from pupae was slightly higher for birth foundresses (95.5%) than that for adoptive foundresses (91.4%). The offspring sex ratio was female biased (90%) and did not differ between birth and adoptive foundresses. The body weight of adult female offspring was not significantly different between two kinds of foundresses. 【Conclusion】 The results of this study suggest that foundress-offspring kinship has a discernible effect on larvatranslocation behavior, but a negligible effect on offspring development.  

Key words: Sclerodermus guani, Tenebrio militor, quasi-social behavior, kinship, parental care, kin selection