Platyrrhine juvenile mortality in captivity and in the wild

I reviewed literature on juvenile mortality in the Platyrrhini in order to evaluate reproductive success in captive breeding. Juvenile mortality includes abortion, premature mortality, stillbirth and death of the unweaned young. The highest losses occur in the Callitrichidae (31% through 3 months of age; 86% through 6 months of age) and in Lagothrixspp. (around 50% through 1 month of age) among the Cebidae. High abortion rates occur in Saguinusand Aotus.High stillbirth incidences are reported for the Callitrichidae (Callithrixand Saguinus)and for the Cebidae (Saimiriand Aotus).Although most mortality occurs in the first week for most species, a considerable proportion of deaths occurs in the period from week 1 until weaning. Important causes of death are trauma and aberrant parental behavior. Prematurity plays an important role in perinatal death among the Callitrichidae. Dystocia is a major cause of stillbirth in Saimiri. Congenital malformations occur in Callithrix, Saguinus, Leontopithecus,and Saimiri.Infectious diseases play a secondary role in mortality, particularly during the first period of life. A higher mortality risk is present if the infant is male, if the litter size is different from two (Callitrichidae), if the mother is primiparous, captive born, or inexperienced, or if the group is small (Callitrichidae) or unstable (Cebidae).     

Catarrhine juvenile mortality in captivity,under seminatural conditions,and in the wild

Juvenile mortality is an important problem in the development of captive populations. I compiled data from published literature on abortion, premature mortality, stillbirth, and death of unweaned young. Cumulative mortality incidences (CMI) during the first month in captive populations (CP) of Cercopithecoidea range between 13 and 51%, and CMI in the first year between 28 and 56%. Mortality rate during the first year ranges between <4 and 48% in free- ranging populations (FRP) and between 10 and 60% in wild populations (WP). Much of the juvenile mortality in CP appears to occur in the first month, whereas in FRP and WP mortality is more scattered throughout the juvenile period. High mortality rates occur in both CP and WP of nonhuman Hominoidea. Mortality rate during the first month in CP is between 12 and 36% for the Hylobatidae and between 18 and 31% for the Pongidae. If the entire juvenile period is considered, gorilla CP and WP have comparable CMI, while CMI is higher in WP than CP for chimpanzees. Most of the juvenile mortality in CP of chimpanzees occurs before the age of 1 year. Trauma, including infanticide and maternal inadequacy, seems to be a more important factor in infant mortality of Cercopithecoidea than infectious disease is. Relatively frequent reports of congenital, hereditary, and/or genetically determined malformations in the Cercopithecoidea may be related to the long use of animals in this group for laboratory purposes. Infectious disease is the most important cause of nonhuman hominoid juvenile mortality, followed by trauma and maternal disorders, particularly related aberrant maternal behavior. Cercopithecoid juvenile mortality risk factors most frequently mentioned in the literature are sex of the infant and rank of the mother: dominant females produce more female offspring, and juvenile males suffer higher mortality than females do. The female skewed sex ratio at birth in gorillas and chimpanzees could be explained by the local resource competition theory. Higher male mortality rates occur in nonhuman Hominoidea, except in two Hylobatesspp. and Pan paniscus,which have higher female mortality. Parity and rearing history of the mother are very important risk factors in nonhuman hominoid infant mortality.     

An analysis of chewed food particle size and its relationship to molar structure in the primatesCheirogaleus medius andGalago senegalensis and the insectivoranTupaia glis

The chewed food particle size and shearing capacity of the lower molars of two primate species, the fat-tailed dwarf lemur,Cheirogaleus medius and the bushbabyGalago senegalensis, and an insectivoran, the tree shrew,Tupaia glis, were compared. Differences in the shearing design of the lower molars correlate strongly with the chewed food particle size in these species: the greater the shearing capacity, the smaller the chewed food particles. These three species are of comparable size but differ greatly in diet in the wild.C. medius primarily eats fruit and nectar, whileG. senegalensis andT. glis are largely insect-eaters. The lower molars ofG. senegalensis andT. glis show a much greater shearing capacity than do those ofC. medius. The average length of chewed food particles ofC. medius is significantly larger than that ofG. senegalensis, while that ofT. glis is intermediate between the two primates but is closer to that ofG. senegalensis. Our findings that insect-eating species grind their food more finely than do fruit- and resin-eating species can be correlated with digestibility of foods: finely chewing foods such as fruits which are low in relatively undigestible cell wall components would not greatly improve their digestibility, so a highly efficient food processing apparatus would be less important to the animal's survival. Insect-eaters much more finely chew their foods, implying that there is some constituent of insect bodies difficult to digest, and that grinding increases its digestibility. We suggest that this constituent is chitin.     

Effects of inbreeding on infant mortality in captive primates

Breeding records for 16 primate colonies representing six families and both suborders were obtained from 10 institutions breeding primates in captivity and from the international studbook on one endangered species. Inbreeding coefficients relative to the founding population were calculated for each individual born. Individuals with an inbreeding coefficient of zero were classified as “noninbred” those with inbreeding coefficients greater than zero, as “inbred.” Infant mortality was defined as all deaths prior to the age of 6 months. Infant mortality of inbred young was higher than that of noninbred young in 15 of the 16 colonies surveyed (P =0.0003, one-tailed sign test). The higher mortality rate of the inbred young was significant by a Fisher’s exact test with a probability less than or equal to 0.05 in five of the individual colonies: Lemur fulvus, Saguinus fuscicollis illigeri, Saguinus fuscicollis, Leontopithecus rosalia,and Mandrillus sphinx.     

Social pressures have selected for an extended juvenile period in primates

Primates are highly social animals. As such, they utilize a large repertoire of social skills to manage their complex and dynamic social environments. In order to acquire complex social skills, primates require an extended learning period. Here I perform a comparative analysis using independent contrasts to show that social pressures have favored an extension in the proportion of time primates spend as juveniles.     

Canine perinatal mortality: a cohort study of 224 breeds

Canine perinatal mortality is known to be relatively high. However, the literature on perinatal mortality in dogs is still sparse and often refers to a single or only a few breeds. The aim of this large-scale observational study was to describe the perinatal mortality in purebred dogs of various breeds at both puppy and litter level. In addition, the influence of breed, breed size, litter size, age of the bitch, litter number and season for whelping on the risk of perinatal mortality at litter level was studied and the mean litter size at eight days and eight wks after birth was calculated. A retrospective cohort study was performed by studying 10,810 litters of 224 breeds registered in the Norwegian Kennel Club in 2006 and 2007. Perinatal mortality was defined as the sum of stillborn puppies and puppies that died during the first wk after birth (early neonatal mortality) and was present in 24.6% of the litters. Eight percent of the puppies died before eight days after birth, with 4.3% as stillbirth and 3.7% as early neonatal mortality. For most breeds the perinatal mortality was low, but for some breeds a higher perinatal mortality was found. The mean litter size at eight days and eight wks after birth was 4.97 (±0.02) and 4.92 (±0.02) puppies, respectively. Of all puppies born, only 1% died during the period from eight days to eight wks after birth. Random effects logistic regression analysis indicated that increasing litter size and age of the bitch were associated with an increased risk of stillbirth, early neonatal mortality and total perinatal mortality at the litter level (P < 0.001). The random breed effect was significant for all outcomes. Litter number also had a significant effect on stillbirth, early neonatal mortality and total perinatal mortality at the litter level, with the highest risk of perinatal mortality found in the first litter (P < 0.001). Further, the risk of early neonatal mortality was doubled in litters with stillborn puppies. No significant effect of whelping season on perinatal mortality at litter level was found. An interaction existed between the age of the bitch and litter number and the risk of stillbirth was three times as high (odds ratio = 3.00) in litters from bitches having their first litter after the age of six y. Breed was a more important determinant of perinatal mortality in litters than breed size. However, more than 90% of the variation in perinatal mortality was found at the individual litter level and efforts to minimize puppy mortality should be targeted at the management of the individual litter rather than at the breed level.     

Infant mortality in Armenia, 1992–2003

Health system reforms have been taken in Armenia during a time of dramatic economic and fiscal distress. It is important to assess trends in health indicators and ascertain if the changes in socio-economic systems affected the health status of infants as the most vulnerable part of the population. We find that infant mortality has fallen during the period c. 1992-2003 in spite of the difficult economic circumstances because of health-care procedures that were introduced. Particular attention is paid to the underreporting of infants' death cases in the state registration system as well as to estimating the role of different factors influencing infant mortality in Armenia.     

Bias in calculating growth rates in cod (Gadus morhua L.) due to size selective growth and mortality

Size selective growth and size selective mortality strongly biased the calculation of specific growth rates among juvenile cod in a feeding experiment.     

Airport and city-centre temperatures in the evaluation of the association between heat and mortality

A variety of ambient exposure indicators have been used to evaluate the impact of high temperature on mortality and in the identification of susceptible population sub-groups, but no study has evaluated how airport and city centre temperatures differ in their association with mortality during summer. This study considers the differences in temperatures measured at the airport and in the city centre of three Italian cities (Milan, Rome and Turin) and investigates the impact of these measures on daily mortality. The case-crossover design was applied to evaluate the association between daily mean apparent temperature (MAT) and daily total mortality. The analysis was conducted for the entire population and for subgroups defined by demographic characteristics, socioeconomic status and chronic comorbidity (based on hospitalisation during the preceding 2 years). The percentage risk of dying, with 95% confidence intervals (95% CI), on a day with MAT at the 95th percentile with respect to the 25th percentile of the June-September daily distribution was estimated. Airport and city-centre temperature distributions, which vary among cities and between stations, have a heterogeneous impact on mortality. Milan was the city with the greatest differences in mean MAT between airport and city stations, and the overall risk of dying was greater when airport MAT (+47% increase, 95%CI 38-57) was considered in comparison to city MAT (+37% increase, 95%CI 30-45). In Rome and Turin, the results were very similar for both apparent temperature measures. In all cities, the elderly, women and subjects with previous psychiatric conditions, depression, heart and circulation disorders and cerebrovascular disease were at higher risk of dying during hot days, and the degree of effect modification was similar using airport or city-centre MAT. Studies on the impact of meteorological variables on mortality, or other health indicators, need to account for the possible differences between airport and city centre meteorological variables in order to give more accurate estimates of health effects.     

Lipoprotein-associated phospholipase A2, and subsequent cardiovascular events and mortality among patients with coronary heart disease

Objective: The objective of this study is to evaluate the relevance of Lp-PLA₂ to risk prediction among coronary heart disease (CHD) patients.

Methods: Lp-PLA₂ activity was measured in 2538 CHD patients included in the Bezafibrate Infarction Prevention (BIP) study.

Results: Adjusting for patient characteristics and traditional risk factors, 1 standard deviation of Lp-PLA₂ was associated with a hazard ratio (HR) of 1.12 (95% confidence interval (CI): 1.00–1.25) for mortality and 1.03 (0.93–1.14) for cardiovascular events. Lp-PLA₂ did not significantly improve model discrimination, or calibration nor result in noteworthy reclassification.

Conclusions: Our results do not support added value of Lp-PLA₂ for predicting cardiovascular events or mortality among CHD patients beyond traditional risk factor.     

The effects of larval abundance, settlement and juvenile mortality on the depth distribution of a colonial ascidian

The colonial ascidian Didemnum candidum (Savigny) is more abundant at shallow depths on floating docks than at greater depths along pilings in Pearl Harbor, Oahu, Hawaii. To compare the effects of selective settlement and postsettlement mortality on adult distribution, I determined if settlement was nonrandom relative to depth, if differences in adult abundance were responsible for the depth distribution of settlement, and if juvenile mortality varied with depth. A plankton pump was used to measure variation in larval abundance with depth. Acrylic settling plates were suspended at different depths and sampled nondestructively to measure settlement intensity and juvenile mortality. Settlement and mortality of the didemnid ascidians Diplosoma listerianum Milne-Edwards and Diplosoma sp. were also measured in the field and compared to that of D. candidum. Settlement of D. candidum was indeed nonrandom over depth. Both planktonic larvae and settled juvenils were more numerous at 0.5 than 3 or m. Settlement intensity on vertical plates was greatest within 1–2 cm of the water surface in the laboratory and within 2–3 cm in the field. Directly adjacent to the floating dock, where adults were equally abundant, settlement on horizontal plates was greater at shallow depths, suggesting directed movement of larvae upward. However, the ratio of settled juveniles to planktonic larvae (number of settlers: number of larvae) did not significantly differ with depth, suggesting that larvae were not more likely to settle at a particular depth. Settlement of the Diplosoma species was also heaviest near the surface. Juvenile mortality was greater at 0.5 than at 3 or 6 m for both D. candidum and the Diplosoma species. Experimental settlement showed that mortality, per se, of D. candidum was independent of depth. Rather, mortality was density-dependent, and the higher mortality near the surface was due to the greater number of larvae settling there. At this location, nonrandom settlement appears to determine the adult distribution of D. candidum, despite greater juvenile mortality at shallow depths. The pattern of settlement over depth is largely determined by adult proximity, rather than active larval behavior.     

The relationship between body weight and natural mortality in juvenile and adult fish: a comparison of natural ecosystems and aquaculture

The relationship between body weight and natural mortality in juvenile and adult fish was analysed for different aquatic ecosystems: lakes, rivers, the ocean, and pond, cage and tank aquaculture systems. Mortality was modelled as a power function of weight, and the parameters b (exponent) and M_u (mortality at the unit weight of 1 g) estimated for fish in the six ecosystems, as well as within selected populations, species and families. At the ecosystem level, no significant differences in parameters were found between lakes, rivers and the ocean and a joint mortality-weight relationship for all natural ecosystems was estimated with parameters b=?0.288 (90% CL[?0.315, ?0.261]) and M_u=3.00 (90% CL[2.70, 3.30]) year^?1. Among the culture systems, mortality-weight relationships in ponds and cages were not significantly different and a joint relationship was estimated. The weight exponents of mortality in ponds/cages and tanks were very similar at about b=?0.43, and significantly more negative than in natural ecosystems. Mortalities at unit weight were significantly lower in tanks (0.91 year^?1) than in ponds/cages (2.24 year^?1), and both were significantly lower than in natural ecosystems. No systematic differences were found between the mortality-weight relationships determined for individual populations, species or families, and fish in the respective ecosystems. It is hypothesized that aquaculture mortality-weight relationships indicate the allometric scaling of non-predation mortality, which is therefore more strongly size dependent than predation mortality. If non predation mortality in natural ecosystems shows a similar scaling with body weight, then the allometric exponent of predation mortality must be less negative than that observed for total natural mortality. Implications of the established mortality-weight relationships for aquaculture and culture-based fisheries are discussed.     

A novel geminal diol as a highly specific and stable in vivo inhibitor of insect juvenile hormone esterase

Thio-containing and acetylenic trifluoromethyl ketones were potent inhibitors of insect juvenile hormone (JH) esterase with greater inhibitory activity than aliphatic and α,β-unsaturated homologs. Octylthio-1,1,1-trifluoropropan-2-one was the most potent inhibitor with the greatest equilibrium hydration constant in pure water. However, a keto/hydrate equilibrium was not necessary for JH esterase inhibition. The carbonyl tautomer of 1-octyl [1-(3,3,3-trifluoropropan-2,2- dihydroxy)] sulfone (OTPdOH-sulfone) was not detectable, and yet OTPdOH-sulfone was a potent in vitro inhibitor of JH esterase with an I₅₀ of 1.2 nM. The mechanism of JH esterase inhibition by these compounds is discussed. OTPdOH-sulfone inhibited JH esterase with minimal activity toward insect 1-naphthyl acetate esterase and electric eel acetylcholinesterase. The inhibitor was also active in vivo, selective for JH esterase, and persistent for over 32 h. OTPdOH-sulfone when topically applied to larval and adult cabbage loopers, Trichoplusia ni, elicited juvenoid activity apparently because of the specific in vivo inhibition of JH metabolism. Arch. Insect Biochem. Physiol. 36:165–179, 1997. © 1997 Wiley-Liss, Inc.     

Age-specific, density-dependent and environment-based mortality of a short-lived perennial herb

Density-independent and density-dependent processes affect plant mortality. Although less well understood, age-specific mortality can also play an important role in plant mortality. The goal of this study was to analyse several factors accounting for mortality in the Mediterranean short-lived perennial herb Lobularia maritima. We followed three cohorts of plants (from emergence to death) during 4 years in field conditions. We collected data on plant mortality of the effect of biotic agents (moth larvae and mycoplasma-like organisms, MLOs) and environmental variables. We also estimated density-dependent relationships affecting the fate of seedlings and adults. Results show that cohorts differed in their survival curves and ageing significantly increased mortality risk. Seedling mortality was density-dependent whereas adult mortality was not affected by density. MLO infection led to higher plant mortality whereas moth larvae attack did not affect plant mortality. In general, seedlings and adult plants experienced the highest mortality events in summer. We found, however, weak relationships between weather records and plant mortality. Age and size structures were not correlated. Overall, this study provides a comprehensive review of age-specific, density-dependent and density-independent factors that account for mortality of L. maritima plants throughout their life cycle in field conditions, highlighting the fact that age is an important factor in determining plant population dynamics.     

The nature and titre of juvenile hormone in the Colorado potato beetle, Leptinotarsa decemlineata

This paper describes the nature and titre of juvenile hormone at different developmental stages of the Colorado potato beetle, Leptinotarsa decemlineata Say, determined by a selective mass-spectroscopic detection technique, High levels of juvenile hormone III were observed in long-day beetles, whereas low titres occurred in pre-diapause and diapause adults. The level of juvenile hormone III in larvae was low compared with reproductive adults, whereas hardly any juvenile hormone could be detected in pupae. We were not able to detect juvenile hormones I or II. The results agree well with previously reported data using the Galleria bioassay.     

The source and action of head factors regulating juvenile hormone esterase in larvae of the cabbage looper, Trichoplusia ni

Brain (median or lateral regions) or suboesophageal ganglion (SOG) homogenates of Day 1 fifth instar larvae of Trichoplusia ni induced the appearance of haemolymph juvenile hormone esterase (JHE) when injected into Day 1, Day 2 or early Day 4 fifth instar ligated hosts. Brain and SOG homogenates of late fourth instars also induced JHE when injected into Day 1 hosts, whole late fifth instar and pupal tissue did not. The pattern of JHE induction by early fourth through Day 3 fifth instar brain and SOG homogenates correlated with natural haemolymph JHE activity occurring at these times. Implantation of late fourth and Day 1 fifth instar brains and/or SOG into similar age hosts similarly induced JHE activity while prothoracic and abdominal ganglia did not. The relative levels of induction following implantation were SOG<brain<brain+SOG. JHE activity which appears in the haemolymph following injection of brain homogenates appears to be largely due to a single enzyme which has an isoelectric point indistinguishable from that of the natural haemolymph enzyme. Evidence is presented which suggests that inhibitory as well as stimulatory brain factors are involved in JHE regulation.     

Juvenile hormone-binding protein and juvenile hormone esterase activity in hemolymph from last-instar nymphs of Leucophaea maderae

The concentration of the juvenile hormone-binding protein (JHB) in hemolymph was determined throughout the last nymphal instar. It was found to be 3.9 μM at the molt to the instar, rising to 13 μM by mid-instar, and dropping to 6.7μM the day before emergence. Endocrine control of its production during the last nymphal instar could not be established. The apparent juvenile hormone esterase (JHF) activity was low at the molt to the last instar, but rose about fivefold by mid-instar, and then modestly declined. On the day of emergence, JHF activity rose to the highest level observed. A four- to fivefold increase in absolute JHF activity was determined during the first half of the last nymphal instar. This increase is not regulated by JH. Removal of the JHB from hemolymph samples by precipitation with a polyclonal specific antibody increased the JHF activity up to 1,000-fold. Thus, changes in the concentrations of JHB can affect the apparent activity of JHE, which is unrelated to the production or degradation of the JHF.