Reproductive ecology of three ocypodid crabs II. Incubation sites and egg mortality

Mortality of eggs during incubation was estimated for three ocypodid crabs,Scopimera globosa, Ilyoplax pusillus andMacrophthalmus japonicus, and the influence of incubation sites was discussed. These crabs all lived in isolated burrows and fed on sediments during day time low tide.S. globosa andI. pusillus inhabited the upper intertidal sandflats, whereasM. japonicus inhabited the lower intertidal mudflats. Females of bothS. globosa andI. pusillus remained in their plugged burrows without feeding throughout incubation and the mortality of eggs was low despite large broods relative to body size. On the other hand, females ofM. japonicus fed actively on surface mud during incubation and the mortality of eggs was high despiite small broods relative to body size. InS. globosa andI. pusillus, the ovaries of ovigerous females were small until egg-hatching, whereas inM. japonicus, the ovaries grew rapidly during incubation and females were able to produce consecutive broods. I conclude that incubation of eggs in burrows may be advantageous in species which inhabit the upper interidal sandflats, even though the crabs cannot forage during incubation, since otherwise their eggs would be exposed to strong heat stress and desication during the summer. Furthermore, such species may produce few large broods because of less frequent interruption of feeding than that associated with production of many small broods.     

Primate evolution of a human chromosome 1 hypervariable repetitive element

Summary The clone designated hMF #1 represents a clustered DNA family, located on chromosome 1, consisting of tandem arrays displaying a monomeric length of 40 bp and a repetition frequency of approximately 7×10³ copies per haploid genome. The sequence hMF #1 reveals multiple restriction fragment length polymorphisms (RFLPs) when human genomic DNA is digested with a variety of 4–6-bp recognition sequence restriction enzymes (i.e., Taq I, Eco RI, Pst I, etc.). When hamster and mouse genomic DNA was digested and analyzed, no cross-species homology could be observed. Further investigation revealed considerable hybridization in the higher primates (chimpanzee, gorilla, and orangutan) as well as some monkey species.The evolutionary relationship of this repetitive DNA sequence, found in humans, to that of other primates was explored using two hybridization methods: DNA dot blot to establish copy number and Southern DNA analysis to examine the complexity of the RFLPs. Homology to the hMF #1 sequence was found throughout the suborder Anthropoidea in 14 ape and New and Old World monkey species. However the sequence was absent in one species of the suborder Prosimii. Several discrepancies between established evolutionary relationships and those predicted by hMF #1 exist, which suggests that repetitive elements of this type are not reliable indicators of phylogenetic branching patterns. The phenomenon of marked diversity between sequence homologies and copy numbers of dispersed repetitive DNA of closely related species has been observed inDrosophila mice,Galago, and higher primates. We report here a similar phenomenon for a clustered repeat that may have originated at an early stage of primate evolution.     

Spawning behavior ofChaetodon multicinctus (Chaetodontidae); pairs and intruders

Synopsis Spawning by the banded butterflyfish,Chaetodon multicinctus (Chaetodontidae) was observed on coral reefs off Kona, Hawaii. These fish occurred in male-female pairs during normal daytime activities, a behavior which is typical for the family. Courtship is also a paired male-female activity. During spawning, however, other individuals (males?) may intrude on the spawning pair. Spawning typically takes place at least a meter or two above the bottom. The spawning position consists of the male below and behind the female with his snout against the female's ventral flank or anal fin area. Intruding individuals may join in when the pair is in position and about to spawn. Intruders line-up against the male in the same position as he is against his female. Underwater photographs are included to illustrate these behaviors.     

Interspecific interactions between wild pygmy chimpanzees (Pan paniscus) and red colobus (Colobus badius)

Interspecific interactions accompanied by physical contacts between wild pygmy chimpanzees (Pan paniscus) and red colobus (Colobus badius) were observed on three occasions at Wamba, Republic of Zaire. In all cases, the red colobus initiated the interactions by approaching the pygmy chimpanzees. Most of the pygmy chimpanzees, which were within 5 m of the red colobus, were juveniles or infants but the adult male pygmy chimpanzees never showed any interest in the red colobus. The red colobus groomed the chimpanzees in two cases, but the latter never groomed the former. No true aggressive interactions were observed between the two species. The lack of any evidence of hunting of red colobus through longitudinal studies of the pygmy chimpanzees of Wamba, together with the present observations, suggests that red colobus are probably not targets of hunting by the pygmy chimpanzees.     

Copulatory behavior unaccompanied by ovulation in the Japanese monkey (Macaca fuscata)

Copulatory behavior unrelated to conception is sometimes observed in some non-human primates including the Japanese monkey. In the present study, the authors examined whether a mature follicle or a newly formed fresh corpus luteum was observed in the ovaries of female Japanese monkeys which displayed the copulatory behavior unrelated to conception. Post-conception copulatory behaviors were observed in three out of four females usually kept in individual cages in an air-conditioned room, and in two out of three females without infants kept in an outdoor group cage. However, neither a mature Graafian follicle nor a fresh corpus luteum formed newly after conception was observed in any of these females by laparoscopic examinations conducted immediately after termination of the copulatory behavior. In females with infants born in the preceding birth season, copulatory behaviors were observed in three out of four females kept in the outdoor group cage, and in two out of four females in a free-ranging troop. Ovulation was confirmed in one case out of the three kept in the outdoor group cage, but neither a mature follicle nor a newly formed corpus luteum was observed in the remaining four females. These findings suggest that copulatory behavior in the Japanese monkey is not always controlled by the development of a follicle or ovulation in the ovary.     

Mutational analysis of simian immunodeficiency virus from African green monkeys and human immunodeficiency virus type 2

We constructed ten mutants of simian immunodeficiency virus isolated from African green monkey (SIVAGM), and nine mutants of human immunodeficiency virus type 2 (HIV-2) in vitro. Their infectivity, cytopathogenicity, transactivation potential, virus RNA, and protein synthesis were examined by transfection and infection experiments. Mutations in three structural (gag, pol, env) and two regulator (tat, rev) genes abolished the infectivity of both viruses, but vpx, vpr (HIV-2), and nef were dispensable and mutant viruses were indistinguishable phenotypically from wild type virus. A vif mutant of HIV-2 showed poor infectivity in cell-free condition, whereas SIVAGM mutants grew equally well with wild type virus. In transient transfection assays, rev mutants derived from both viruses produced mainly small mRNA species and no detectable virus proteins and particles. Transactivation potential of tat mutants originated from both viruses was about three- to ten-fold less than that of respective wild type DNAs, generating small amounts of virus.     

Sequence variability of simian immunodeficiency virus in a persistently infected rhesus monkey

A juvenile rhesus monkey that was inoculated intravenously with molecularly cloned SIVmac239 became persistently infected. A modified polymerase chain reaction (PCR) procedure was used to specifically amplify full-length envelope (env) gene sequences from DNA extracted from peripheral blood mononuclear cells (PBMC), lymph node tissue, and cells infected with recovered virus at 69 and 93 weeks post-infection. Extensive sequence variability accumulated in vivo in spite of infection with molecularly cloned virus. In the central portion of env. sequence variability was largely confined to three discrete regions.     

Reactions of wild tamarins,Saguinus mystax andSaguinus fuscicollis to avian predators

During a field study in northeastern Peru, the reactions of a group ofSaguinus mystax on Padre Isla and of a mixed-species troop ofS. mystax andSaguinus fuscicollis at the Río Blanco to raptorial and other birds were observed. Alarms that are specific to flying stimuli were elicited by birds of prey, but other birds that do not represent a threat to the tamarins also caused alarm calls. Alarm events (i.e., instances when one or more alarm calls were given) were observed at rates of 0.3/hr (Padre Isla) and 0.5/hr (Río Blanco). Rates of alarm events significantly increased after the birth of an infant in the Padre Isla group and after the attack of an ornate hawk-eagle (Spizaetus ornatus) on the Río Blanco group. Reactions to alarming stimuli/alarm calls ranged from looking up to falling down from trees. The modification of the tamarins' behavior by the potential presence of aerial predators indicates that raptors represent an important predatory threat to tamarins.     

Lithium in drinking water and the incidences of crimes,suicides, and arrests related to drug addictions

Using data for 27 Texas counties from 1978-1987, it is shown that the incidence rates of suicide, homicide, and rape are significantly higher in counties whose drinking water supplies contain little or no lithium than in counties with water lithium levels ranging from 70-170 micrograms/L; the differences remain statistically significant (p less than 0.01) after corrections for population density. The corresponding associations with the incidence rates of robbery, burglary, and theft were statistically significant with p less than 0.05. These results suggest that lithium has moderating effects on suicidal and violent criminal behavior at levels that may be encountered in municipal water supplies. Comparisons of drinking water lithium levels, in the respective Texas counties, with the incidences of arrests for possession of opium, cocaine, and their derivatives (morphine, heroin, and codeine) from 1981-1986 also produced statistically significant inverse associations, whereas no significant or consistent associations were observed with the reported arrest rates for possession of marijuana, driving under the influence of alcohol, and drunkenness. These results suggest that lithium at low dosage levels has a generally beneficial effect on human behavior, which may be associated with the functions of lithium as a nutritionally-essential trace element. Subject to confirmation by controlled experiments with high-risk populations, increasing the human lithium intakes by supplementation, or the lithiation of drinking water is suggested as a possible means of crime, suicide, and drug-dependency reduction at the individual and community level.     

Demography of agile gibbons (Hylobates agilis)

Demographic processes and the structure of a population of agile gibbons (Hylobates agilis) were investigated over 6 years in the Gunung Palung Reserve, Indonesia. Estimates of population size, density, and biomass revealed a population whose groups were stable in size and composition. Demographic processes place gibbons at risk, however, to short-term changes in their environment. Patterns of survival, fecundity, mortality, and dispersal combined to produce negative rates of growth. In addition, a top-heavy age-class distribution, with adults forming a large fraction of animals, makes it unlikely that this population could recover rapidly from a decline in numbers. Two behavioral factors, territoriality and monogamy, account for the size and stability of gibbon groups. Monogamy imposes limits on group size, while mating patterns and territoriality decrease the impact of sources of high mortality common in other primate species. These relationships underscore the fundamental importance of behavioral influence on demographic processes and social structure.