Variations in maternal behavior in the rat as a function of sex and gonadal state

Performance of major components of maternal care was evaluated quantitatively in several test situations for various groups of rats. Maternal behavior of concaveated ovaríectomized virgin females and castrated males was inferior on a variety of measures to that of concaveated intact virgin females. However, concaveated intact virgin females were markedly inferior to natural mothers on measures of nest building and responsiveness to an intruder. Thus, it was found that test situations other than the standard homecage test revealed previously undetected group differences and that the occurrence of pup retrieval is not a valid predictor of the performance of some major components of maternal care. In addition, it was concluded that gonadal hormones partially determine the quality of maternal responsiveness displayed by virgin females, but that gonadal hormones characteristic of the cycling female are not sufficient to increase maternal responsiveness to the level seen with natural mothers. Possible relationships between pup-induced maternal behavior and that of natural mothers are discussed.     

Leaf chemistry and the biomass of folivorous primates in tropical forests

Summary Recent results have suggested that the biomass of folivorous arboreal primates per unit area in Africa and Asia is positively correlated with the average quality of leaves, expressed as the ratio of protein to fiber concentrations in a given forest. This hypothesis has been tested in different forests of Madagascar. Leaf selection of all folivorous femus species was studied in relation to leaf chemistry. Except for two populations ofLepilemur subspecies all other folivorous lemur species (including two other subspecies ofLepilemur) select leaves with high concentrations of easily extractable protein or low concentrations of fiber, or both. This confirms the prominent role of these two components in leaf selection by folivorous lemurs. The average quality of mature leaves in a given forest, expressed as the ratio of protein to fiber concentrations, is positively correlated with the biomass of folivorous lemurs. This confirms the hypothesis tested and suggests rather uniform selection processes for arboreal folivorous primates across the world.     

Effects of prostaglandin E2 and indomethacin on sexual behavior in the female rat

Prostaglandin E₂ (PGE₂) facilitated sexual behavior in estrogen-primed ovariectomized or ovariectomized-adrenalectomized rats. Administration of indomethacin, an inhibitor of prostaglandin synthesis, attenuated the effectiveness of estrogen and progesterone in inducing sexual receptivity in ovariectomized rats. Concurrent administration of PGE₂ with indomethacin restored sexual behavior only when administered early in the estrogen-priming period but not if administered along with the progesterone. Our studies support the likelihood of a role of prostaglandins in the control of sexual behavior in the female rat.     

Nonhuman primates and the acquired immunodeficiency syndrome: a union of necessity

Because of the close phylogenetic relationship, nonhuman primates are highly susceptible to human pathogens, including infection of chimpanzees by the human immunodeficiency virus (HIV), the causative agent of AIDS. This, and the existence of a highly related simian virus, SIV, which causes an AIDS-like disease in macaques, emphasizes the continued importance of using nonhuman primates as model systems for identifying and developing prophylaxis and therapy for infectious agents and, in particular, for fighting the pandemic AIDS.     

Predation and primate evolution

This paper presents the results of a general review of predation on nonhuman primates as a selective force in primate evolution. Testable hypotheses derived from the literature on predation on primates, concerning sexual dimorphism, male defense, group size, solitaries, transfer, subgrouping, and sex ratio, were applied to the available data on populations with varying predation rates in search of significant correlations. All seven hypotheses were supported, indicating that predation is and has been an important determinant of primate evolutionary history. Suggestions for accumulating a larger and more accurate body of information on predation rates on primates are offered.     

Secretory proteins and growth factors of the baboon (Papio anubis) uterus: potential roles in pregnancy.

The primate endometrium undergoes distinct morphological changes during the menstrual cycle. These alterations are regulated by the steroid hormones, estrogen and progesterone. Several lines of evidence suggest that some of these hormonally induced changes may be modulated by growth factors. Our studies have focused on characterizing the secretory activity of the uterine endometrium associated with these hormonally regulated morphological changes during the menstrual cycle and pregnancy in the baboon. Additionally, we have also attempted to study the regulation of specific growth factors and their receptors. In this review we present evidence to indicate that growth factor receptors for insulin-like growth factor-I (IGF-I) and epidermal growth factor (EGF), and secretory proteins, insulin-like growth factor binding protein-1 (IGFBP-1) and retinol binding protein (RBP), which are present in the glandular epithelium during the menstrual cycle, undergo cell-specific changes in gene expression at the implantation site during pregnancy. We postulate that these alterations in growth factor receptor and secretory protein expression are conceptus modulated and may play important regulatory roles during trophoblast invasion and decidualization.     

The primate origins of female sexuality,and their implications for the role of nonconceptive sex in the reproductive strategies of women

In many species of monkeys and apes, sexual solicitations of males by females are more facultative and opportunistic than generally realized. Although female sexual solicitations peak at midcyle, solicitations and copulations are not necessarily confined to the days just around ovulation. Human female sexuality, and the physiological underpinnings of this sexuality evolved in prehominid contexts in which female primates solicited and copulated with multiple males on a situation-dependent basis. Such sexual behavior became increasingly costly to females in the course of hominid evolution, and women's sexuality today must be viewed as an imperfect compromise between formerly adaptive organs (such as the female clitoris) and the chronic challenges mothers face in eliciting and insuring male protection and investment in offspring.