Abstract: The landing patterns of horse flies on the human body were observed in Croatia. A total of 386 horse flies belonging to 22 species were sampled. The five most commonly collected species were used in the analysis. The stochastic linear connection is tight among the landings of the species Tabanus bromius, Tabanus maculicornis, Tabanus tergestinus, and Philipomyia graeca on the human body regions (matrix R). The preferred feeding area for these four species was the lower leg, whereas for the species Haematopota pluvialis it was the head and neck. Of the total number of horse flies that landed 44.81% were on the lower leg. Only 0.26% landed on the forearm. Chi-square analysis indicated non random landing patterns on human by these horse flies.

Abstract: Intraspecific allometric calculations of the brain to body size relation revealed distinct differences between 127 (67; 60) ancestral wild cavies and 82 (37; 45) guinea pigs, their domesticated relatives. The dependency of both measures from one another remained the same in both animal groups but the brains of guinea pigs were by 14.22% smaller at any net body weight. Consistent with results in other species the domestication of Cavia aperea is also characterized by a decrease of brain size. Fresh tissue sizes of the five brain parts medulla oblongata, cerebellum, mesencephalon, diencephalon and telencephalon were determined for 6 cavies and 6 guinea pigs by the serial section method. Additionally the sizes of 16 endbrain structures and those of the optic tract, the lateral geniculate body and the cochlear nucleus were measured. Different decrease values resulted for all these structures concomitant with domestication as was calculated from the amount of total brain size decrease and average relative structure values in the wild as well as the domesticated brain. The size decrease of the entire telencephalon (-13.7%) was within the range of the mean overall reduction as similarly was the case for the total neocortex (-10.7%) whereas the total allocortex (-20.9%) clearly was more strongly affected. The size decrease of the olfactory bulb (-41.9%) was extreme and clearly higher than found for the secondary olfactory structures (around -11%). The primary nuclei of other sensory systems (vision, audition) were decreased to less extent (lateral geniculate: -18.1%; cochlear nucleus: -12.6%). Mass decreases of pure white matter parts were nearly twice as high in contrast to associated grey matter parts (neocortex white versus grey matter; tractus opticus versus lateral geniculate body). The relatively great decrease values found for the limbic structures hippocampus (-26.9%) and schizocortex (-25.9%) are especially notable since they are in good conformity with domestication effects in other mammalian species. The findings of this study are discussed with regard to results of similar investigations on wild and domesticated gerbils (Meriones unguiculatus), the encephalization of the wild form, the special and species-specific mode and duration of domestication and in connection with certain behavioral changes as resulted from comparative investigations in ethology, socio-biology, endocrinology and general physiology.

Abstract: In a previous study, Kuroshima and colleagues demonstrated that capuchin monkeys (Cebus apella) learned to discriminate between a “knower” who inspected a box for food, and a “guesser” who did not. The aim of the present study was to specify whether the subjects learned a simple conditional discrimination or a causal relationship that seeing leads to knowing. In experiment 1, we introduced five types of novel containers to two subjects. Each container was of different shape and color. The subjects gradually learned to reach toward the container the knower suggested. In experiment 2, we diversified the behavior of the knower and the guesser. In experiment 3, in order to eliminate the possibility of discrimination based on differences in the magnitude and the complexity of two trainers, we equated their behaviors. One subject adapted to the novel behaviors of the knower and the guesser, successfully discriminating the two trainers. Thus this monkey clearly learned to use the inspecting action of the knower and the non-inspecting action of the guesser as a discriminative cue to recognize the baited container. This result suggests that one capuchin monkey learned to recognize the relationship between seeing and knowing.

Abstract: This study investigated post-conflict (PC) behavior among wild chimpanzees (Pan troglodytes) of the M-group in the Mahale Mountains, Tanzania, and examined what types of behavior characterize the PC situation in this group, and the factors that influence the occurrence of PC affiliation between opponents soon after the end of an aggressive conflict (i.e., reconciliation). We found that the opponents affiliated selectively soon after the end of aggression, suggesting that reconciliation occurred in this group. The mean individual corrected conciliatory tendency (CCT) (Veenema et al. 1994 in Behav Proc 31:29-38) was 14.4%, which is similar to or lower than frequencies observed in studies of captive and wild chimpanzees. The valuable relationship hypothesis predicts that the CCT is higher among individuals who share valuable relationships (e.g., males or affiliative dyads) than among individuals who do not (e.g., females or less-associative dyads). However, the analysis based on data for aggression between unrelated individuals (including one incident between an adult and non-adult) and aggression between unrelated adults, did not uncover this difference. Affiliation by a previously uninvolved individual with the victim (“consolation”) and with the aggressor (“appeasement”) occurred more frequently following aggression than in the control condition. The results are compared with previous studies of captive and wild chimpanzees.

Abstract: Fluctuations of ovarian hormones across the menstrual cycle influence a variety of social and cognitive behaviors in primates. For example, female rhesus monkeys exhibit heightened interest for males and increased agonistic interactions with other females during periods of high estrogen levels. In the present study, we hypothesized that females' preference for males during periods of high estrogen levels is also expressed at the level of face perception. We tested four intact females on two face-tasks involving neutral portraits of male and female rhesus monkeys, chimpanzees and humans. In the visual preference task (VP), monkeys had to touch a button to view a face image. The image remained on the screen as long as the button was touched, and the duration of pressing was taken as an index of the monkey's looking time for the face stimulus. In the Face-Delayed Recognition Span Test (Face-DRST), monkeys were rewarded for touching the new face in an increasing number of serially presented faces. Monkeys were tested 5 days a week across one menstrual cycle. Blood was collected every other day for analysis of estradiol and progesterone. Two of the four females were cycling at the time of testing. We did not find an influence of the cycle on Face-DRST, likely due to a floor effect. In the VP however, the two cycling individuals looked longer at conspecific male faces than female faces during the peri-ovulatory period of the cycle. Such effects were absent for human and chimpanzee faces and for the two noncycling subjects. These data suggest that ovarian hormones may influence females' preferences for specific faces, with heightened preference for male faces during the peri-ovulatory period of the cycle. Heightened interest for stimuli of significant reproductive relevance during periods of high conception risk may help guide social and sexual behavior in the rhesus monkey.