Glasser, T. A. and Markovics, A.

Many Mediterranean brush species have developed a wide array of plant secondary compounds that deter herbivory. In particular, Pistacia lentiscus contains ca. 20% of polyethylene-binding tannins (PEG-b-t), mostly hydrolizable tannins, on DM basis. In contrast, Phillyrea latifolia contains less than 3% of PEG-b-t, mostly flavanoids. In a first study, we showed that, on a yearly basis, P. lentiscus forms 15% of diets ingested by Damascus (Shami) goats, but only 5.6% of diets ingested by Mamber (Baladi) goats, whereas P. latifolia is eaten equally by the two breeds (25% of DM ingested). However, we did not find differences between breeds in the salivary binding capacity of tannins. In a second set of experiments, we found that Damascus goats were more resistant to mixed-species L3 larvae of gastro-intestinal nematodes (GIN) than Mamber goats. Ingesting 1 g kg BW-1 of P. lentiscus tannins reduced fecal egg counts to almost 0 in both breeds but, when subjected to a worm challenge, Mamber goats significantly increased their intake of P. lentiscus, i.e., self-medicated, whereas Damascus goats did not. Intrigued by these behavioral differences, we carried out a cross-fostering experiment, where does from the two breeds raised their own kid or a kid from the other breed, substituted at birth. While kept indoors, does were fed with hay and concentrate, and all kids had equal preference for P. lentiscus and P. latifolia. After does and kids were turned to pasture, kids bred by a Damascus doe increased their preference for P. lentiscus, in contrast with kids which were educated by Mamber does, regardless of their breed. These results indicated that: i. learning (nurture) has a major effect on selective behavior and mothers transmit feeding behaviors to the next generation; ii. pain due to sickness is individual and resistance to sickness has a genetic basis (nature), which may explain the need for self-medication in Mamber but not in Damascus goats; iii. Damascus goat exhibit passive self-medication and Mambers exhibit active self-medication against GIN. Our data suggests a difference between the way foraging habits are acquired in health (nurture) and in sickness (nature).