Phylogenetic analysis of twinning in Callitrichinae

• The callitrichines are known for twinning and for a communal rearingsystem in which all or most group members help care for the offspring.The origin of twinning has been the subject of much speculation. In thisstudy predictions from earlier hypotheses are tested on the basis of twoalternative phylogenetic trees. From this analysis we infer that helpingbehavior and male care preceded the origin of twinning, and that thesetraits did not coevolve with, but might have been important prerequisitesfor twinning in callitrichines. Small body size does not necessarilyresult in twinning, although it might still have been a prerequisite forits evolution. Gum feeding was an ecological change which evolved alongwith twinning. If nutrition was a limiting factor in the number of offspringproduced, then the use of a new feeding resource could have beencrucial for the origin of twinning in callitrichines. According to one of thetwo alternative solutions inferred by the total evidence tree, and in accordancewith the morphological tree, semi-annual breeding appears inthe marmosets together with specialization in gum feeding. The fact thatgums are available for these monkeys all year may have facilitated semiannualbreeding. We suggest that the exploitation of gums as a feedingresource could have been the decisive factor in the increase of the reproductiverate by twinning and by semi-annual breeding.

Subject headings

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

Keyword

Ethology and behavioural ecology

Etologi och beteendeekologi

Biologi med inriktning mot zooekologi

Biology with specialization in Animal Ecology

Publication and Content Type

ref (subject category)

art (subject category)