A fresh torrent of tears burst from their lachrymal ducts and the vast concourse of people, touched to the inmost core, broke into heartrending sobs


The parent-offspring conflict theory delineates a zone of conflict between the mother and her offspring over weaning. We expect that the mother would try to wean her offspring off a little earlier than the offspring would be ready to wean themselves, thereby entering the zone of conflict for a short span of time. Though the theory was originally formulated in the context of weaning, it is also relevant in other contexts where a parent and his/her offspring have conflicting interests. Conflict has been reported over feeding, grooming, traveling, evening nesting, and mating in various species.

There are several theoretical models that address parent-offspring conflict in different contexts like reproduction, intra-brood competition, sexual conflict, and parental favoritism toward particular offspring. Though relatedness between parents, offspring and siblings can be measured easily, it is not easy to measure precisely parental investment and the costs and benefits to the concerned parties in nature. In some studies attempts have been made to quantify parental care in terms of milk ingested by offspring, sometimes as a correlate of weight gain by the individual pups, and sometimes by the duration of suckling. However, we have to accept that there is considerable variation in the suckling rates of individual pups, and in hunger levels of individuals, and hence such measures can only provide a rough estimate of parental investment. It is therefore not surprising that empirical tests of the theory in a field set up are sparse, especially in the original context of weaning. The parent-offspring conflict theory has in fact been claimed to be one of the most contentious subjects in behavioral and evolutionary ecology and also one of the most recalcitrant to experimental investigation.

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