Differences in winter activity,courtship, and social behavior of two captive family groups of Mexican wolves (Canis lupus baileyi)

The purpose of this study was to determine differences in activity patterns and social behavior of two groups of endangered Mexican wolves maintained at two quite different facilities and to determine some of the variables that should be considered when making specific behavioral comparisons among wolves in this binational captive breeding program. Quantitative measurements of an Activity Index and social behaviors were obtained for three individuals in each pack. Within each age/sex category, activity, aggression, and play were more frequent in the pack at a zoo facility, compared to the pack at a field station facility. Frequency of courtship interactions and scent marking were significantly higher in the field station pack. The packs were similar in the frequency of active submission, but differed significantly in the pattern of this behavior. Given the large number of interacting variables and small number of individuals in this study, we recommend caution in generalizing results to other packs or facilities. Zoo Biol 16:435–443, 1997. © 1997 Wiley-Liss, Inc.     

Juvenile hormone-mediated reproduction in burying beetles: From behavior to physiology

The burying beetle, Nicrophorus orbicollis, is the first beetle exhibiting parental care for which endocrinological studies have been initiated. Burying beetles bury and prepare small vertebrate carcasses as a breeding resource for their offspring. After emergence as an adult, hemolymph titers of juvenile hormone and ovarian size increase in concert for 2–3 weeks, and both plateau until an appropriate resource is discovered. Upon finding a suitable carcass, titers of juvenile hormone increase extremely rapidly (<20 min), and within 18 h ovarian mass increases threefold and oviposition begins. This rapid reproductive development is hypothesized to be selected by the intense competition for these protein-rich but quickly deteriorating resources. Burying beetle females exhibit an additional juvenile hormone surge at the time young hatch. This peak in juvenile hormone is hypothesized to be associated with either the considerable behavioral demands which accompany care of young larvae or with a female's willingness to oviposit a replacement clutch should brood failure occur early in the care-giving phase. Parental care has evolved in at least 16 additional families within the Coleoptera. Comparative studies of nonparental and parental groups will be important for understanding how the physiology of ancestral groups affects the evolution of complex social behavior. Arch. Insect Biochem. Physiol. 35:479–490, 1997. © 1997 Wiley-Liss, Inc.     

Juvenile hormone in earwigs: Roles in oogenesis,mating, and maternal behaviors

The role of juvenile hormone (JH) in courtship, mating, maternal behavior, and the ovarian cycle was studied in the ring-legged earwig, Euborellia annulipes (Lucas). The single, median corpus allatum makes and secretes JH III. JH III production was low in newly eclosed adult females, increasing as oocytes developed, maximal at about the time of oviposition, and low again in brooding females. Application of 35 or 122 μg JH III to newly eclosed females hastened the onset of courtship behavior, but had no effect on the age at which females first mated nor on the duration of mating, though the trend is toward advanced onset. Hormone treatment advanced the age of first oviposition and reduced clutch size and the proportion of eggs hatching but did not affect the interval from oviposition of the first clutch to oviposition of the second clutch, nor the size and proportion hatching of the second clutch. Acetone treatment and treatment with 6 μg JH III did not affect these parameters. Application of 50 μg JH III to females on the day of oviposition shortened the duration of maternal care and advanced the onset of the second gonadotropic cycle, compared with that of acetone-treated and precocene II-treated females. The duration of maternal care was positively correlated with the proportion of eggs hatching. JH titer analysis confirmed JH III to be the predominant hormone in this species and clearly demonstrated the absence of other homologues. This work also confirmed our hypothesis that intermediate to high levels of JH are associated with oocyte growth, mating, and cessation of maternal care; low levels of JH are associated with the period of maternal behavior and slow ovarian development. We are currently investigating factors which might regulate corpus allatum activity during the reproductive cycle and the subsequent period of maternal care. Arch. Insect Biochem. Physiol. 35:427–442, 1997. © 1997 Wiley-Liss, Inc.     

The China Productivity Project: Results and conclusions

Experiments were conducted to determine what factors cause variation in individual work output (economic productivity). Forty-five young male Chinese cycle haulers from Beijing were assessed for physiological work capacity, size and body composition, health, nutritional status, cold resistance, household social environment, and motivation. Experiments were conducted in the laboratory as well as under actual working conditions; ethnographic observations were made in the household and on the job during the Beijing winter of 1992. Overall work motivation correlated to actual monthly distance/load measures of productivity the most strongly (r = 0.518), followed by physiological capacity estimated by heart rate:speed ratio during field experiments (r = −0.473). Alcohol consumption (a negative factor), household health, and carbohydrate intake were all moderate predictors. Maximum oxygen uptake showed lower correlation (r = 0.261), and among anthropometric values only relatively long lower legs were predictive (r = 0.298). Since many of these variable categories were relatively independent of each other, multiple regression analysis showed that together they explained 61.6% of the work output variance. Simultaneous prediction by FASEM (LISREL) is also very strong. Am J Phys Anthropol 103:295–313, 1997. © 1997 Wiley-Liss, Inc.     

Hormone measures in finger-prick blood spot samples: New field methods for reproductive endocrinology

Comparative endocrine studies have notably advanced understanding of ecological factors that contribute to variation in human reproductive function. Such research has relied on methodological advances that permit hormone determinations in samples that are easily and safely collected, stored, and transported, most recently on measurement of steroids in saliva. This report seeks to further expand the scope of endocrine research by demonstrating the value of blood spot samples collected by finger prick. As a sampling strategy, finger-prick blood spot collection offers the advantages of short collection time, low invasiveness, repeatability, absence of postcollection processing, low biohazard risk, and ease of sample storage and transport. We document good sample stability and present sensitive assay methods for a range of steroids and proteins (FSH, LH, PRL, T, E2, DHEAS, androstenedione, cortisol, SHGB) in blood spots that require sample volumes of 3–12 μl and display good reliability, specificity, precision, accuracy, and convertibility of results to plasma/serum equivalent concentrations. Laboratory evaluation was augmented by a feasibility study at a remote site in Papua New Guinea that confirmed validity and stability of blood spot collections under field conditions. Research applications of blood spot sampling are illustrated with a series of studies, including cross-sectional surveys for developmental and life span endocrinology, a longitudinal, population-based developmental epidemiologic study of puberty, and serial sampling in a dynamic study of neuroendocrine response to suckling. We conclude that the sampling features and wide range of measurable biomolecules of blood spots do constitute a methodological advance for endocrine research. Am J Phys Anthropol 104:1–21, 1997. © 1997 Wiley-Liss, Inc.     

Hindlimb suspension and hind foot reversal in Varecia variegata and other arboreal mammals

The foot, perhaps more than any other region of the primate body, reflects the interaction of positional behaviors with the geometric properties of available supports. The ability to reverse the hind foot during hindlimb suspension while hanging from a horizontal support or descending a large diameter vertical trunk has been noted in many arboreal mammals, including primates. Observations of Varecia variegata in the wild and under seminatural conditions document hindlimb suspension in this lemurid primate. The kinematics and skeletal correlates of this behavior are examined. Analogy is made with the form and function exhibited by nonprimate mammalian taxa employing this behavior. Examples of carnivores and rodents display very similar adaptations of the tarsals while other mammals, such as the xenarthrans, accomplish a similar end by means of different morphologies. However, a suite of features is identified that is shared by mammals capable of hind foot reversal. Hindlimb suspension effectively increases the potential feeding space available to a foraging mammal and represents a significant, and often unrecognized, alternative adaptive strategy to forelimb suspension and prehensile-tail suspension in primates. Am J Phys Anthropol 103:85–102, 1997. © 1997 Wiley-Liss, Inc.     

Seasonal and diel patterns in Pacific white-sided dolphin (Lagenorhynchus obliquidens) pulsed calls near Barkley Canyon

Evaluation of temporal patterns in offshore marine mammal activity through visual data collection can be impaired by light and weather conditions and the cost of ship time. The conditions-independence and cost-efficacy of acoustic data collection make it popular for researching the temporal patterns of wild dolphins. However, Pacific white-sided dolphins (PWSDs) north of Southern California remain under-researched. This study evaluates diel and seasonal patterns in PWSD communication signals detected in 480 days of near-continuous passive acoustic data collected over 20 months from the Barkley Canyon node of Ocean Networks Canada's NEPTUNE observatory, offshore Vancouver Island, British Columbia, Canada. In this study, a random forest classifier is used to identify PWSD pulsed calls and false positives are manually removed. The resulting acoustic presence-absence data set is evaluated for seasonal and diel patterns using generalized additive mixed models, considering masking effects from ambient noise. PWSDs are found to be vocally active during all diel periods year-round, with high summer and low spring activity. Seasonally dependent diel patterns are identified, with PWSD pulsed calls exhibiting no diel pattern in spring, a slight increase in vocal activity during dusk and night in fall and winter, and a notable increase during night and dawn in summer.     

Assessing spatial patterns and density of a dolphin population through signature whistles

Some dolphin species produce signature whistles, which may allow the identification of individual dolphins using passive acoustic monitoring (PAM). Identifying individuals by their sounds may enhance the opportunities for monitoring and addressing biological and ecological questions about these species. Here, we explored the potential of signature whistles to investigate ecological aspects of a resident bottlenose dolphin population. Using a limited data set, with few individuals recognized by signature whistles, combined with spatial capture-recapture (SCR) methods, we investigated how effective such approach is describing spatial use patterns and estimating density for this population. The data were collected using 4–6 stationary bottom-moored recorders. Since only eight signature whistles were identified, our density estimate may represent a subset of the entire population. However, even with only a few signature whistles identified, our results confirmed the center of the core area used by these dolphins as the area with the highest encounter probability. In addition, our results provided evidence that these dolphins have the same spatial use pattern at night as during the day. This study shows that SCR analysis of signature whistle data can improve our ecological knowledge and understanding of dolphin populations.     

Temporal distribution of PBAN‐like immunoreactivity in the hemolymph of Mamestra brassicae females in relation to sex pheromone production and calling behavior

A direct enzyme‐linked immunosorbent assay has been developed and applied to the analysis of PBAN immunoreactivity in female hemolymph of the cabbage armyworm, Mamestra brassicae. PBAN‐IR determinations have been carried out with third scotophase insects at different times of the photoperiod. The rhythm of calling and the pattern of pheromone production by third scotophase females at different times of the photoperiod have also been determined. PBAN‐IR and calling are well correlated. However, whereas pheromone titers decrease, both PBAN‐IR levels and percentage of calling females remain high in the last hours of the scotophase. These results are discussed in the context of the regulation of sex pheromone biosynthesis in M. brassicae. Arch. Insect Biochem. Physiol. 40:80–87, 1999. © 1999 Wiley‐Liss, Inc.     

Studies on fertilization in the teleost. III. The relationship between nuclear behavior and the histone H1 kinase activity in anesthetized medaka eggs

To investigate the mechanisms of fertilization in the teleostean egg, the relationship between the nuclear behavior and the activity of histone H1 kinase was examined in medaka, Oryzias latipes, eggs that were anesthetized at sperm penetration. Inseminated in the anesthetized state, most eggs failed to undergo the propagative waves of increase in cytoplasmic Ca²⁺ and exocytosis of cortical alveoli (CABD). The sperm‐penetrated eggs that exhibited no or partial CABD only around the animal pole underwent a transient contraction of the cortical cytoplasm toward the animal pole region and were designated nonactivated eggs. Temporary compaction of the second meiotic metaphase (MII) chromosomes was accompanied by contractile movement of the cortical cytoplasm, but not by completion of the second meiotic division. The activity of histone H1 kinase in nonactivated eggs remained high, although it decreased slightly concurrent with sperm penetration. Cyclin B and cdc2 levels remained unchanged as well. The nonactivated eggs began to transform the penetrated sperm nucleus into metaphase chromosomes in the cortical cytoplasm facing the inner end of micropylar canal within 20 min postinsemination (PI). Two figures of typical metaphase chromosomes were found in the animal pole area at ≤40 min PI. Chromosome condensation in nonactivated eggs was not inhibited by actinomycin D, nor was the high activity of histone H1 kinase reduced. In the presence of cycloheximide or 6‐dimethylaminopurine (6‐DMAP), however, the compact sperm nucleus and the MII chromosomes transformed to interphase nuclei without CABD or extrusion of the polar body, although the activity of histone H1 kinase remained high. These results suggest that in the fish egg, transformation of MII chromosomes to an interphase nucleus may not be caused by loss of MPF activity, but rather than by the loss of activity of a short‐lived protein kinase(s), sensitive to 6‐DMAP that is independent of CABD in the cascade reactions triggered by increased cytoplasmic calcium. Dev. Genet. 25:137–145, 1999. © 1999 Wiley‐Liss, Inc.