A conspectus of the Cladocera of the subterranean waters of the world

A synthesis of current knowledge of the Cladocera living in non-surface waters is provided. For all 94 species and subspecies recorded (Dec. 1994) we give information on their ranges, ecological characteristics, and a review of literature data. We also give a historic survey of the development of concepts, identify categories among groundwater-dwelling species, and discuss their adaptations and the evolutionary lines present. Of the estimated total of c. 450 non-marine Cladocera of the world, c. 20% may occur in underground aquatic habitats, but true groundwater forms (stygobionts or stygobites) are relatively few, possibly not more than 10 species (c. 2.5% of the total). This number may increase, as attention is given to subterranean habitats outside Europe.     

Demography and Life Histories of Sympatric Patas Monkeys, <Emphasis Type="Italic">Erythrocebus patas</Emphasis>, and Vervets, <Emphasis Type="Italic">Cercopithecus aethiops</Emphasis>, in Laikipia,Kenya

Mortality patterns are thought to be strong selective forces on life history traits, with high adult mortality and low immature mortality favoring early and rapid reproduction. Patas monkeys (Erythrocebus patas) have the highest potential rates of population increase for their body size of any haplorhine primate because they reproduce both earlier and more often. We report here 10 yr of comparative demographic data on a population of patas monkeys and a sympatric population of vervet monkeys (Cercopithecus aethiops), a closely related species differing in aspects of social system, ecology, and life history. The data reveal that 1) adult female patas monkeys have significantly higher mortality than adult female vervets; 2) infant mortality in patas monkeys is relatively low compared to the norm for mammals because it is not significantly different from that of adult female patas monkeys; and 3) infant mortality is significantly higher than adult female mortality in vervets. For both species, much of the mortality could be attributed to predation. An epidemic illness was also a major contributor to the mortality of adult female patas monkeys whereas chronic exposure to pathogens in a cold and damp microenvironment may have contributed to the mortality of infant vervets. Both populations experienced large fluctuations during the study period. Our results support the prediction from demographic models of life history evolution that high adult mortality relative to immature mortality selects for early maturation.     

Correlated evolution of sex and reproductive mode in corals (Anthozoa: Scleractinia)

Sexuality and reproductive mode are two fundamental life-history traits that exhibit largely unexplained macroevolutionary patterns among the major groups of multicellular organisms. For example, the cnidarian class Anthozoa (corals and anemones) is mainly comprised of gonochoric (separate sex) brooders or spawners, while one order, Scleractinia (skeleton-forming corals), appears to be mostly hermaphroditic spawners. Here, using the most complete phylogeny of scleractinians, we reconstruct how evolutionary transitions between sexual systems (gonochorism versus hermaphrodism) and reproductive modes (brooding versus spawning) have generated large-scale taxonomic patterns in these characters. Hermaphrodites have independently evolved in three large, distantly related lineages consisting of mostly reef-building species. Reproductive mode in corals has evolved at twice the rate of sexuality, while the evolution of sexuality has been heavily biased: gonochorism is over 100 times more likely to be lost than gained, and can only be acquired by brooders. This circuitous evolutionary pathway accounts for the prevalence of hermaphroditic spawners among reef-forming scleractinians, despite their ancient gonochoric heritage.     

Life history evolution in cichlids 2: directional evolution of the trade-off between egg number and egg size

The negative relationship between offspring number and offspring size provides a classic example of the role of trade-offs in life history theory. However, the evolutionary transitions in egg size and clutch size that have produced this negative relationship are still largely unknown. Since body size may affect both of these traits, it would be helpful to understand how evolutionary changes in body size may have facilitated or constrained shifts in clutch and egg size. By using comparative methods with a database of life histories and a phylogeny of 222 genera of cichlid fishes, we investigated the order of evolutionary transitions in these traits in relation to each other. We found that the ancestral large-bodied cichlids first increased egg size, followed by a decrease in both body size and clutch size resulting in the common current combination of a small-bodied cichlid with a small clutch of large eggs. Furthermore, lineages that deviated from the negative relationship between clutch and egg size underwent different transitions in these traits according to their body size (large bodied genera have moved towards the large clutch/small egg end of the continuum and small bodied genera towards the small clutch/large egg end of the continuum) to reach the negative relationship between clutch size and egg size. Our results show that body size is highly important in shaping the negative relationship between clutch size and egg size.     

Modelling Primate Behavioral Ecology

Models play an important role in any mature science because they force us to make explicit our assumptions about how a phenomenon works and allow us to explore the way in which different variables influence a complex biological system. I review the principal kinds of models that could be used to study primate behavior and ecology: linear programming models, systems models, optimality models, stochastic dynamic programming models and agent-based simulation models. Although less use has been made of modelling in primatology than in some other areas of behavioral ecology, there is considerable scope for exploiting the predictive and explanatory power of models in the field.     

An interplay between forest and non‐forest South American avifaunas suggested by a phylogeny of lepidocolaptes woodcreepers (dendrocolaptinae)

Very few South American avian superspecies or species groups are composed of both forest and non‐forest taxa. The genus Lepidocolaptes comprises 8–9 species of woodcreepers, most of which are forest birds, but two species, L. angustirostris and L. souleyetii, inhabit open vegetations. Therefore, this genus should play an important role in the discussion about the relationships between forest and non‐forest South American avifaunas. Nucleotide sequences from two mitochondrial genes, cytochrome b and ND2, suggest that: (i) L. fuscus should be removed from the genus since its association with other members of this genus is poorly supported. This view has been pointed out also by morphological and behavioural data; (ii) the phylogenetic position of the open‐vegetation species within the Lepidocolaptes radiation indicate that the split between forest and non‐forest elements within this genus took place as recently as two million years ago. This result suggests that the evolutionary relationships between forest and non‐forest biotas in South America may have been more dynamic than previously thought.     

Evolution of human growth spurts

This study investigates subadult growth spurts in a large sample of anthropoid primates, including humans. Analyses of body mass growth curves show that humans are not unique in the expression of female and male body mass growth spurts. Subadult growth spurts are observed in both New World and Old World anthropoid primates and are more common in males than in females. Allometric analyses of growth spurts indicate that many aspects of primate growth spurts are strongly correlated with species size. Small species tend not to exhibit growth spurts. Although male and female scaling patterns for velocity and size measures are comparable, scaling relations of variables that measure the timing of growth spurts differ by sex. These patterns can he related to sexual differences in life histories. Scaling analyses further show that humans do not depart substantially from patterns that describe other anthropoid primates. Thus, in relative terms, human growth spurts are not exceptional compared to this sample of primates. The long absolute delay in the initiation of the human growth spurt may be of substantial evolutionary importance and serves to distinguish humans from other primates. In essence, humans exhibit growth spurts that are comparable to other primates in many respects. However, human growth spurts are shifted to very late absolute ages. © 1996 Wiley-Liss, Inc.     

稻族的系统发育及其研究进展

稻族Oryzeae是禾本科Poaceae中包含多种经济植物的重要类群, 现有大约12个属, 广布全球的热带和温带地区。由于其重要的经济价值和在理论研究上的代表性, 稻属Oryza及其近缘属的研究受到了广泛关注。虽然形态学和初步的分子证据表明稻族是一个单系类群, 但稻族内各属的分类处理和属间系统发育关系以及稻族的起源、地理分布式样和机制等方面仍存在许多悬而未决的问题。本文简要回顾了稻族系统学研究的历史, 包括稻族的建立及其在禾本科中的系统位置、稻族的族下划分、稻族各属的界定及其系统发育关系。目前已有的研究结果表明: 稻族是单系类群, 可分为两个主要分支, 相当于传统的两个亚族(Zizaniinae和Oryzinae), 但稻族单性花小穗是多次起源的, 不宜作为划分亚族的依据; 一些单型属(Hydrochloa、Porteresia和Prosphytochloa)的建立得不到分子证据的支持; 根据分子钟原理估计稻族两个主要分支(亚族)的分歧时间在大约2000万年前, 而稻属和近缘属假稻属Leersia的分歧时间为1400万年; 稻属内主要类群的分歧时间在900万年前左右。此外, 本文还对稻族的生物地理学问题进行了初步探讨, 对稻族系统发育和进化研究中存在的问题及未来研究方向进行了讨论。     

The niche, biogeography and species interactions

In this paper, I review the relevance of the niche to biogeography, and what biogeography may tell us about the niche. The niche is defined as the combination of abiotic and biotic conditions where a species can persist. I argue that most biogeographic patterns are created by niche differences over space, and that even ‘geographic barriers’ must have an ecological basis. However, we know little about specific ecological factors underlying most biogeographic patterns. Some evidence supports the importance of abiotic factors, whereas few examples exist of large-scale patterns created by biotic interactions. I also show how incorporating biogeography may offer new perspectives on resource-related niches and species interactions. Several examples demonstrate that even after a major evolutionary radiation within a region, the region can still be invaded by ecologically similar species from another clade, countering the long-standing idea that communities and regions are generally ‘saturated’ with species. I also describe the somewhat paradoxical situation where competition seems to limit trait evolution in a group, but does not prevent co-occurrence of species with similar values for that trait (called here the ‘competition–divergence–co-occurrence conundrum’). In general, the interface of biogeography and ecology could be a major area for research in both fields.