Ruth Guttman

Activity Patterns of Evolving Mole Rats

Activity patterns were tested in four actively speciating chromosomal forms of blind subterranean mole rats of the Spalax ehrenbergi complex (2n = 52, 54, 58, and 60) which inhabit humid (2n = 52 and 58) and xeric (2n = 54 and 60), as well as cool (2n = 52 and 54) and warm (2n = 58 and 60) environments, respectively. Experimental animals included 98 adult male mole rats representing 9 populations covering the entire species range in Israel. The test apparatus simulated a natural underground territorial runway of a solitary occupant and each test lasted 24 h. The results indicated that (a) the pattern of activity was multiphasic, but activity in all nine populations is remarkably higher during the day than during the night and (b) differences occur among chromosome forms in both levels and patterns of activity. First, the “humid chromosome forms” are more active than the “xeric chromosome forms” and, second, it appears that the activity of the “cool chromosome forms” display a pattern of smaller number of periods as compared with the “warm chromosome forms.” Both results appear to be climatically adaptive and support an optimal activity pattern theory assuming that natural selection maximizes fitness by optimizing net energy gain per unit activity.

The Structure of Spatial Ability Items: A Faceted Analysis.

800 individuals were given a battery of 8 spatial tests which had been assembled with the aid of a mapping sentence of four content facets: rule type, dimensionality, presence or absence of rotation, and test format. An intercorrelation matrix of 49 items from these tests was analyzed by Smallest Space Analysis, SSA-I. All three facets formed distinct regions in a two-dimensional projection of a three-dimensional space. It is suggested that further facets be hypothesized to elaborate on the structure of spatial abilities.

Spouse similarities in personality items: changes over years of marriage and implications for mate selection.

This study examines the variation in similarity between spouses in personality, as assessed by selected items of the Comrey Personality Scales (CPS), over 22 years of marriage. The sample consisted of 138 professional couples in Jerusalem. An analysis of 57 CPS items showed mild convergence for five out of the seven Comrey dimensions over the marriage span investigated and divergence for one Comrey dimension. Convergence and divergence were identified as reduction and increase, respectively, in extreme differences between spouses with length of marriage. These findings underline the necessity of considering the actual scattergrams with marriage length when dealing with assortative mating estimates, in addition to calculating correlation coefficients or comparing means over time. A detailed analysis of spouse correlations for Comrey items in the most recently married subgroup suggests possible mate selection for “self-other centeredness.” Implications for such selection are discussed.

Behavioral correlates of estrous cycle stages in laboratory mice.

Virgin female mice of two inbred strains and an F 1 cross between them displayed rhythmicity in behavior variables with changes in estrous cycle stage. Motor activity in the barrier apparatus, as measured by jumping reached a peak during estrus and decreased between metestrus and diestrus. Anxiety—as expressed by defecation—followed an exactly opposite pattern. “Peeking,” a complex trait including anxiety and exploration, followed no discernible pattern. During the 5 min of the observation period jumping increased with time in the apparatus during all estrous stages, acting as a typically adaptive trait. The peeking pattern was far less clear-cut. It is concluded that, while a clear-cut correlation exists between estrus and locomotor activity, the association is less straightforward with estrus and more diffuse kinds of activity.

Variation in activity scores and sequences in two inbred mouse strains, their hybrids, and backcrosses

Abstract Nine hundred and twenty-two mice, consisting of DBA-1J, C57BL/6J, their F1, F2, and back-cross generations were tested in a barrier activity cage. The exact sequence of acts of each animal in the cage was recorded during a 5-min test period. Observed were two aspects of grooming behaviour, jumping and peeking over the barrier, and a defecation score. The mean number of motor acts per animal was highest in C57BL, lowest in DBA, intermediate in hybrids. Grooming scores gave some evidence of heterosis. Estimates of degrees of genetic determination varied from zero for peeking to 46 per cent for jumping. Typologies of the trajectory of the animal in time have been worked out by means of a nonmetric computer technique, Multidimensional Scalogram Analysis. Examples are presented of three subsamples of profiles, 150 each, showing well-defined DBA and C57BL regions in a two-dimensional space. The behavioural features distinguishing these regions are evaluated by analyses of certain stages in the behaviour sequences as printed by the computer. There is evidence for considerable dominance of the DBA behaviour pattern, with distribution of F2 profiles indicating genetic segregation. Two specific acts in the sequence, the 7th and 23rd, were found to provide optimal discrimination between the DBA and C57BL animals.

Habitat Selection in Evolving Mole Rats

SummaryThe actively speciating four chromosomal species of fossorial mole rats of the Spalax ehrenbergi complex in Israel (2n=52, 58, 54 and 60) which inhabit an increasingly arid environment in this order were tested to determine their habitat preference. The testing apparatus simulated four climatic regimes based on temperature and humidity combinations corresponding to the climatic origins of the four chromosomal species: coolhumid, cool-dry, warm-humid and warm-dry, respectively. The tests involved 175 adults comprising all four chromosome species and representing 10 populations. Out of the 139 analyzed animals 88% selected the warm cages and only 12% selected the cool cages. The four karyotype progressively preferred the warm-dry cage in the following order: 53, 59, 60 and 72% for 2n=58, 52, 54 and 60 respectively, largely in accord with their increasingly arid climatic origins. Even larger differences were found in populations within karyotypes in accord with the local climatic variation within a karyotype range.The results of our analysis indicate that the chromosomal species and populations select their climatic habitat in accord with the climatic conditions of their geographic localities. The humidity index appears to be the prime differentiator of habitat selection and may have been a substantial ecological factor in species differentiation and distribution of the Spalax ehrenbergi complex in Israel.

The relation between motor activity and risk of death in audiogenic seizure of DBA mice

Abstract Evidence is presented for a strong negative relation between a measure of motor activity and subsequent convulsive behavior, particularly fatal seizure, of DBA mice under audiogenic stress. Of three variables tested, sex, defecation and barrier activity, the last provided by far the highest predictive efficiency for both general susceptibility and fatal seizure.

Intrafamilial invariance and parent-offspring resemblance in spatial abilities.

Members of 261 families in Jerusalem were given a battery of eight spatial tests designed in accordance with a mapping sentence containing three major facets of content for the test items. The structure of intercorrelations among scores of tests was found to be the same for fathers, mothers, and children. Patterns of family correlations showed no evidence of X linkage. Compound scores on facet elements (rule inference, rule application, rotation, no rotation) had higher parent-offspring correlations than did simple test scores.

Similarities in test scores and profiles of kibbutz twins and singletons.

Resemblances on five cognitive tests were compared in fifty quartets of school children. Each quartet consisted of a twin pair (MZ or DZ) and a matched singleton pair from the same kibbutz peer group. Similarities of MZs and DZs on test scores essentially replicate those reported previously in other studies. The median correlation for singleton control pairs is 0.29, as compared with that of 0.26 reported in the Texas Adoption Study for unrelated children raised in the same home. In the two spatial tests, control pairs were as similar as the DZ pairs. This suggests a more powerful influence on shared environment in aspects of perceptual performance. A new structural analysis (POSAC) of individual profiles of test scores is presented. Comparison of space diagrams of MZ, DZ, and singleton pair profiles shows systematic differences in structure among the three groups, in accordance with the predicted levels of genetic influences. Such structural differences transcend mere differences in size of correlation, and may give more stringent evidence for the respective roles of genetics and environment.

Spouse similarities in personality traits for intra- and interethnic marriages in Israel

Abstract An abbreviated version of the Comrey Personality Scales (CPS) was administered to 220 Israeli couples, divided ethnically into endogamous Western, endogamous Eastern, and cross-ethnic Eastern x Western background. Two hypotheses were examined: (1) that cross-ethnic couples would show greater similarity in some personality traits than intra-ethnic marriages, and (2) that females and males married cross-ethnically would differ from same-sex, same-ethnicity individuals married within their own ethnic group in certain background and personality characteristics. It was found that cross-ethnic couples had, indeed, higher intra-couple correlations for Empathy than endogamous couples. Western women and Eastern men in interethnic marriages had higher mean scores for Activity and lower means for Conformity than those of same sex and ethnicity in endogamous marriages. Intermarrying Western wives were more extraverted while intermarrying Eastern men were more introverted. On the whole, interethnic marriages were found to be similar to Western marriages in educational level and several attributes of Western lifestyle.