Kinship alters the effects of forced cohabitation on body weight,mate choice and fitness in the rat-like hamster Tscheskia triton

It has been documented that social isolation imparts deleterious effects on gregarious rodents species, but caging in group imparts such effects on solitary rodents. This study was attempted at examining how kinship to affect body weight, behavioral interaction, mate choice and fitness when we caged male and female rat-like hamsters Tscheskia triton in pair, a solitary species. We found that females paired with nonsibling males became heavier than the females paired with sibling males, but both agonistic and amicable behavior between paired males and females did not differ between sibling and nonsibling groups. This indicated that kinship might reduce females＇ obesity in response to forced cohabitation, and dissociation might exist between physiological and behavioral responses. Furthermore, binary choice tests revealed that social familiarity between either siblings or nonsiblings decreased their investigating time spent in opposite sex conspeeifie of cage mates and/or their scents as compared with those of nonmates, suggesting effects of social association on mate and kin selection of the hamsters. On the other side, both females and males caged in pair with siblings show a preference between unfamiliar siblings or their scents and the counterparts of nonsiblings after two month separation, indicating that the kin recognition of the hamsters might also rely on phenotype matching. In addition, cohabitation （or permanent presence of fathers） elicited a lower survival of pups in nonsibling pairs than sibling pairs, but did not affect litter size, suggesting that kinship affects fitness when housing male and female ratlike hamsters together. Therefore, inbreeding might be adapted for rare and endangered animals.

A thelytokous predatory mite is more cannibalistic towards distant kin

Kin recognition has been widely observed in various taxa.Cannibalism avoidance may be a strong driver for the evolution of kin recognition,as it may avoid a reduction in inclusive fitness.Kin recognition has recently been observed in a generalist phytoseiid,Amblyseius herbicolus(Acari:Phytoseiidae).This study experimentally examined the degree of relatedness needed between prey larvae and cannibal adults of A.herbicolus for the occurrence of kin discrimination.The adults were individually placed in enclosed arenas with two prey,a daughter and a more distant related larva,to observe their cannibalizing choice.The adults of A.herbicolus did not discriminate between close relatives(daughter versus niece)but preferably cannibalized more distant kin(i.e.,first and second cousins once removed).Phenotype matching and familiarization seem prominent as recognition mechanisms used by A.herbicolus adults.The effect of learning on kin recognition through prior contact in A.herbicolus requires further investigation.Studies on other adaptive functions of kin recognition of A.herbicolus,such as cooperation and parental care,may provide meaningful insights.

Kin Interactions of Arabidopsis Based on the Integrated Performance of Plants

Mechanisms of kin selection have been studied to explain how siblings grow together, but the findings remain controversial. This can be ascribed to the use of single indicators without considering other factors. Three ecotypes of Arabidopsis were used to examine kin responses of siblings growing together. Plant traits of leaves, plant shape, reproductive activity, and roots were investigated. We found that Arabidopsis recognized their kin neighbors, showed selective responses to distinct plant traits among ecotypes, and modes of responses were dependent on neighbor＇s growing distance. If single traits were used to judge kin response performance, the results were chaotic. However, by developing and studying an integrated performance value based on multiple traits, we determined that Ler showed similar integrated performances at all planting distances, while the integrated performance of Col was ranked mainly as medium distancedistance small distance large distance, which suggested kin cooperation. However, in comparison to medium and small distances, at which performance was consistent with kin recognition, we found that at large distance, strangers of Ws performed better than kin plants, which suggested competition. Thus, we conclude that kin recognition could be affected by plant competition conditions that are the result of growing distance, and that the integrated performance of individuals was more suitable to evaluate kin interactions of plant species.