The development of grooming,sociosexual behavior,play and aggression in captive baboons in their first two years

This paper focuses on the development of behavior in a mixed-longitudinal sample of 77 baboons (Papio sp. — 46 males and 31 females) from birth to 2 years of age. Eleven behaviors measured as frequency of performance and frequency of reception were used to test null hypotheses of gender and rearing differences among thePapio sp. subjects. The behaviors measured included: groom, mount, present, open-mouth threat, hard bite, displace, avoid, grapple, play bite, charge and chase. The data indicate that gender differences exist in the development of grooming, sociosexual behavior and aggression and play. The data also indicate that subjects raised in the nursery environment were behaviorally indistinguishable from mother-reared peers on the basis of the 11 behavioral criteria.     

Loading constraints,body size and mating preference in Gammarus species

Size relationships among pairing Gammarus were examined with reference to two hypotheses for sexual size dimorphism and assortative mating among aquatic Peracarida (Crustacea). The sizes of pairing and non-pairing animals were compared in different experimental conditions where the size of one or both sexes was controlled. The experimental results present a complex picture which suggests that both sexual selection and loading constraints are likely to play a role in determining mating decisions in these animals.Department of Adult & Continuing Education, University of Durham     

Fire induced stem death in an African acacia is not caused by canopy scorching

Abstract The death of smaller stems of trees due to fire is widespread in savannas. There are currently two hypotheses as to how tree stems avoid stem death; by (i) growing tall and enabling the terminal buds to escape being scorched; and (ii) growing a larger stem diameter and thus being buffered against the heat of the fire. Laboratory‐based tests of these hypotheses on one savanna tree species, Acacia karroo Haynes, support the contention that the important parameter is stem diameter. In addition, anatomical evidence of heat impacts to xylem suggests that damage to the xylem of a stem may play a mechanistic role in causing stem death.     

Ploidy of the eusocial beetle Austroplatypus incompertus (Schedl) (Coleoptera, Curculionidae) and implications for the evolution of eusociality

In the hymenopterans, haplodiploidy, leading to high-genetic relatedness amongst full sisters has been regarded as critical to kin selection and inclusive fitness hypotheses that explain the evolution of eusociality and altruistic behaviours. Recent evidence for independent origins of eusociality in phylogenetically diverse taxa has led to the controversy regarding the general importance of relatedness to eusociality and its evolution. Here, we developed a highly polymorphic microsatellite marker to test whether the eusocial ambrosia beetle Austroplatypus incompertus (Schedl) is haplodiploid or diplodiploid. We found that both males and females of A. incompertus are diploid, signifying that altruistic behaviour resulting from relatedness asymmetries did not play a role in the evolution of eusocialty in this species. This provides additional evidence against the haplodiploidy hypothesis and implicates alternative hypotheses for the evolution of eusociality.     

Evolutionary history of rat‐borne Bartonella: the importance of commensal rats in the dissemination of bacterial infections globally

Emerging pathogens that originate from invasive species have caused numerous significant epidemics. Some bacteria of genus Bartonella are rodent‐borne pathogens that can cause disease in humans and animals alike. We analyzed gltA sequences of 191 strains of rat‐associated bartonellae from 29 rodent species from 17 countries to test the hypotheses that this bacterial complex evolved and diversified in Southeast Asia before being disseminated by commensal rats Rattus rattus (black rat) and Rattus norvegicus (Norway rat) to other parts of the globe. The analysis suggests that there have been numerous dispersal events within Asia and introductions from Asia to other regions, with six major clades containing Southeast Asian isolates that appear to have been dispersed globally. Phylogeographic analyses support the hypotheses that these bacteria originated in Southeast Asia and commensal rodents (R. rattus and R. norvegicus) play key roles in the evolution and dissemination of this Bartonella complex throughout the world.     

Seasonal Effects on Play Behavior in Immature <Emphasis Type="Italic">Saimiri sciureus</Emphasis> in Eastern Amazonia

Play behavior is prevalent among most mammalian young, particularly primates. Though several hypotheses address the function of play, researchers have documented information on the potential costs of play and of environmental effects on the occurrence of primate play less well during long-term field studies. I examine seasonal changes in play behavior of immature squirrel monkeys (Saimiri sciureus) across 4 age classes: infants, young juveniles, mid-juveniles, and late juveniles. I observed individuals during 12 mo in Eastern Brazilian Amazonia, an area characterized by highly seasonal rainfall. Play was strongly tied to seasonality, food availability, and changes in diet. The percentage of time spent playing was reduced in the dry season, a period characterized by low fruit availability and an increase in time spent foraging for prey. I suggest that the decrease in play behavior in the dry season is related both to a higher need for energy conservation and to increased time expended in foraging activities.     

A COEVOLUTIONARY ISOMORPHISM APPLIED TO LABORATORY STUDIES OF COMPETITION

Some empirical consequences of an isomorphism between the Lotka-Volterra competitive model and a coevolutionary competitive model are developed. In both the Lotka-Volterra and coevolutionary models, four competitive outcomes are possible: 1) species one wins, 2) species two wins, 3) indeterminate outcome, and 4) stable coexistence. These two models are isomorphic in the sense that the inequalities associated with a particular competitive outcome of the Lotka-Volterra model correspond in a one-to-one manner with similar inequalities associated with the same competitive outcome of the coevolutionary model. The inequalities of the Lotka-Volterra model involve the competition coefficients themselves, while the inequalities of the coevolutionary model involve the genetic variances and covariances of the competition coefficients. The isomorphism suggests some alternative interpretations of the results of classical laboratory studies of competition. The Lotka-Volterra (or ecological) hypotheses postulate that the competition coefficients are constant and that genetic considerations play no role in determining the competitive outcome. By contrast, the evolutionary hypotheses derived from the coevolutionary model postulate that the competition coefficients are variables and that the genetic variances and covariances of the competition coefficients determine the competitive outcome. The isomorphism is applied to competitive exclusion and coexistence, and to competitive indeterminacy in Tribolium. In particular, the evolutionary hypotheses isomorphic to the two classical explanations of competitive indeterminacy, the demographic stochasticity and genetic founder effect hypotheses, are constructed. The theory developed here and in a previous paper (Pease, 1984) provides one perspective on the relation among the Lotka-Volterra competition theory, quantitative genetics, competitive exclusion, the reversal of competitive dominance, coexistence, competitive indeterminacy in Tribolium, and experiments investigating the relation between genetic variability and the rate of evolution of fitness.     

Adult–Adult Play in Primates: Comparative Analyses of its Origin, Distribution and Evolution

Comparative analyses were conducted on a data set derived from the literature so as to test several hypotheses which were developed to explain the distribution of adult–adult play fighting within the order primates. Ratings for play occurring in sexual and non‐sexual contexts were developed. Three hypotheses were evaluated: (i) that play occurring in non‐sexual social contexts is a byproduct of its use in sex; (ii) that the occurrence of play is related to its use for social assessment and manipulation, and so is more likely to be present in species with reduced familiarity between individuals; and (iii) that phylogenetic affiliation influences the likelihood that species within clades engage in play. We used independent contrasts to test the first two hypotheses, and both were significant, with the presence of play in sexual contexts accounting for 14–16% of the variance of play in non‐sexual contexts, and reduced social familiarity accounting for 30–40% of the variance in the occurrence of play in non‐sexual contexts. To test the third hypothesis, we mapped the occurrence of both types of play onto known phylogenies. The overlap was not congruent, indicating that phylogenetic relationships did not account for the distribution of play. Given that play in both sexual and non‐sexual contexts was more likely to occur in species with a social organization involving reduced frequency of contact between the sexes and other social group members, we suggest that the likely adaptive value of play fighting is as a tool for social assessment and manipulation. The possible factors that mitigate the use of play fighting for these purposes, such as the availability of other forms of communication that could serve similar functions, are discussed.     

How internode length,position and presence of leaves affect survival and growth of <Emphasis Type="Italic">Alternanthera philoxeroides</Emphasis> after fragmentation?

Disturbance is common in nature and disturbance-caused fragmentation of clones happens frequently in stoloniferous plants. After fragmentation storage in stolon internodes and leaves may enhance survival and growth of stoloniferous plants. We hypothesize that (1) increasing length of the internode attached to the ramet and (2) presence of leaves will increase ramet survival and growth, and that (3) internode positions (before or after the ramet or both) will also play a role. We tested these hypotheses with the stoloniferous, invasive herb Alternanthera philoxeroides. In one experiment, we measured survival and growth of the ramets either without stolon internode (0 cm in length) or attached with internodes of 2, 4, 6 and 8 cm and either with or without leaves. In the other experiment, we measured survival and growth of the ramets attached with a proximal internode (before the ramet), a distal internode (after the ramet) or both. Increasing internode length and presence of leaves significantly increased the survival rate and growth (biomass, leaf area, number of ramets, stolon length and number of leaves) of the A. philoxeroides plants. All growth measures of A. philoxeroides at harvest were larger when the ramets were attached with a distal internode than when they were attached with a proximal internode, but the survival rate was lower. These results support the hypotheses and suggest that storage in stolons and leaves may be of great significance for clonal plants in frequently disturbed habitats and may contribute greatly to the invasiveness of A. philoxeroides.     

Synaptic fusion pore structure and AMPA receptor activation according to Brownian simulation of glutamate diffusion

 The rising phase of fast, AMPA-mediated Excitatory Post Synaptic Currents (EPSCs) has a primary role in the computational ability of neurons. The structure and radial expansion velocity of the fusion pore between the vesicle and the presynaptic membrane could be important factors in determining the time course of the EPSC. We have used a Brownian simulation model for glutamate neurotransmitter diffusion to test two hypotheses on the fusion pore structure, namely, the proteinaceous pore and the purely lipidic pore. Three more hypotheses on the radial expansion velocity were also tested. The rising phases of the EPSC, computed under various conditions, were compared with experimental data from the literature. Our present results show that a proteinaceous fusion pore should produce a more marked foot at the beginning of the rising phase of the EPSC. They also confirm the hypothesis that the structure of the fusion pore and its radial expansion velocity play significant roles in shaping the fast EPSC time course. Received: 18 March 2002 / Accepted in revised form: 4 November 2002 / Published online: 19 February 2003 Correspondence to: F. Ventriglia (e-mail: franco@biocib.cib.na.cnr.it)     

Avoiding misinterpretation of biotic interactions with the intertype K12‐function: population independence vs. random labelling hypotheses

Abstract. The interactions between plants of different species, age or size play an important role in the dynamics of an ecosystem and can induce specific structures. These interactions can be studied by analysing the spatial structure of the corresponding bivariate patterns. The intertype L₁₂‐function has recently been successfully used in many papers for that purpose. However, when interpreting the results obtained with ecological data, at least two different null hypotheses – independence or random labelling – can be appropriate, depending on the context of the study and the nature of the data. As these two hypotheses correspond to different confidence intervals, an inappropriate choice of the null hypothesis can lead to misinterpretations of biotic interactions when studying ecological data. This problem has rarely been mentioned in the literature. In this paper we clarify the differences between these two null hypotheses, and illustrate the risk of misinterpretation when using an inappropriate null hypothesis. We review the main characteristics of these two hypotheses, and analyse the spatial structure of both real data from forest stands and simulated virtual stands of different structures. We demonstrate that the risk of misinterpretation is quite high, and that extreme misinterpretations, i.e. cases leading to opposite conclusions in terms of spatial interaction, can occur in a significant number of cases. We therefore propose some guidelines to help ecologists avoid such misinterpretations.     

Contrasting latitudinal patterns of life‐history divergence in two genera of new world thrushes (Turdinae)

Several long‐standing hypotheses have been proposed to explain latitudinal patterns of life‐history strategies. Here, we test predictions of four such hypotheses (seasonality, food limitation, nest predation and adult survival probability) by examining life‐history traits and age‐specific mortality rates of several species of thrushes (Turdinae) based on field studies at temperate and tropical sites and data gathered from the literature. Thrushes in the genus Catharus showed the typical pattern of slower life‐history strategies in the tropics while co‐occuring Turdus thrushes differed much less across latitudes. Seasonality is a broadly accepted hypothesis for latitudinal patterns, but the lack of concordance in latitudinal patterns between co‐existing genera that experience the same seasonal patterns suggests seasonality cannot fully explain latitudinal trait variation in thrushes. Nest‐predation also could not explain patterns based on our field data and literature data for these two genera. Total feeding rates were similar, and per‐nestling feeding rates were higher at tropical latitudes in both genera, suggesting food limitation does not explain trait differences in thrushes. Latitudinal patterns of life histories in these two genera were closely associated with adult survival probability. Thus, our data suggest that environmental influences on adult survival probability may play a particularly strong role in shaping latitudinal patterns of life‐history traits.     

Correlates of alternative migratory strategies in western bluebirds

Partial migration occurs when only some animals in a population migrate. While evidence suggests that migratory strategies are partially controlled by genes, individual and environmental conditions which alter the cost‐benefit trade‐off of migration among individuals are also likely to play a role. Three hypotheses have been advanced to explain condition‐dependent partial migration: the arrival time, dominance and body size hypotheses. In this study, we asked whether these hypotheses explained differences in migratory strategy among individuals in a partially migratory population of western bluebirds Sialia mexicana breeding in southern British Columbia, Canada. We used stable hydrogen isotope signatures in claw tissue to determine migratory strategy of individual bluebirds, and examined patterns of migration at both individual and population levels. The proportion of resident bluebirds varied significantly over the three years of the study, and across study sites. Several migrants switched to the resident strategy between years; however, we found no evidence of strategy switching in the opposite direction. Young birds were significantly more likely to be resident than older birds, a pattern which could arise if early arrival is particularly important for birds obtaining a territory for the first time. Furthermore, young females were the most likely of all sex–age classes to be resident, which may reflect a survival advantage of residency for young females. Finally, birds mated assortatively by migratory strategy and isotopic evidence suggests that members of a pair often wintered in the same place. Our results provided no support for the dominance or body size hypotheses, and only limited support for the arrival time hypothesis in bluebirds. However, taken together, we suggest that our findings indicate that social factors may influence migratory strategies in this system.     

Seed predator deterrence by seed-carrying ants in a dyszoochorous plant, <Emphasis Type="Italic">Chamaesyce maculata</Emphasis> L. Small (Euphorbiaceae)

Seeds are often carried by omnivorous ants even if they do not carry elaiosomes. Although many seeds carried by ants are consumed, both seeds abandoned during the seed carrying and leftover seeds are consequently dispersed (dyszoochory). These non-myrmecochorous seeds do not necessarily attract ants quickly. Therefore, these seeds often seem to be exposed to the danger of consumption by pre-dispersal seed predators. We propose the hypotheses, “seed predator deterrence hypothesis” that plants may benefit from seed-carrying ants if they deter seed predators from visiting plants, and seed-carrying ants may play additional roles in plant reproductive success, besides dyszoochory by ants. To test the hypotheses, we investigated the abundance of seed-carrying ants of the species Tetramorium tsushimae Linnaeus and Pheidole noda Smith F., and of the seed predatory stinkbug, Nysius plebeius Distat, on the spotted sandmat, Chamaesyce maculata L. Small, of which the seeds have no elaiosomes but are consumed by both ants and bugs. In the field, ants and stinkbugs seldom encountered each other on the plant. The number of stinkbugs beneath the plants with ants was smaller than that beneath the plants without ants. In laboratory experiments, the number of stinkbugs on the shoot was smaller when ants were present than when they were absent. These results might support the seed predator deterrence hypothesis: the probability of seed predation by stinkbugs seems to be reduced by the ant visits on plants and/or the existence of ants beneath the plants. This study highlights a new ant–plant interaction in seed dispersal by ants.     

Play Behavior in Juvenile Golden Lion Tamarins (Callitrichidae: Primates): Organization in Relation to Costs

Play is a complex behavior that is widespread among vertebrates. Despite the potential benefits for the development of social, cognitive and motor skills, play behavior has costs: energy expenditure, and the risks of injury and predation. As the fitness benefits of play are presumably to be gained as adults, we expect young animals to minimize its immediate costs. Here, we describe play behavior in golden lion tamarins (GLTs) (Leontopithecus rosalia) and test cost-minimizing hypotheses. We collected data on play behavior and adult vigilance in nine groups (four wild and five supplemented, the latter deriving from a reintroduction) of wild-living lion tamarins (16 infants) in Brazil. Results showed that play occupied 3.8% of the activity budget, occurred during the hottest times of the day, and was characterized by being mainly social, involving partners of different ages, and sometimes different species. We found no differences in playing time between wild and supplemented groups. The lion tamarins played less in ‘dangerous’ substrates (canopy branches and forest floor), and more in ‘safe’ substrates (large branches and vine tangles), and favored playing in the center of the group over the periphery. The reproductive animals were vigilant during 78% of the time the infants were playing, and were mostly oriented away from the playing animals. The observed organization of play behavior suggests that juvenile GLTs minimize the risk of predation and accidental injuries, but do not seem to minimize energy expenditure and the risks of social injuries. The social-cognitive benefits acquired from experience of older partners during play may overcome the costs of the latter behavior, and because little time was spent in play, the energetic costs may be inconsequential.     

Social play does not reduce aggression in wild meerkats

Of the numerous hypotheses advanced to explain the adaptive significance of play, several assert that social play increases social harmony, cementing alliances and reducing aggression between group members or littermates. These hypotheses are frequently cited, but their validity remains unknown. We examined the relation between social play and aggression in juvenile meerkats, Suricata suricatta, living in a wild population in the southern Kalahari Desert. We tested the hypothesis that social play reduces aggression, by examining rates of play, play partner choices, the structure of social play and rates of aggressive interactions during foraging. We found no relation between frequency of play and level of aggression, either between individuals or during the course of development. Pups that played together frequently were just as aggressive towards one another as pairs of pups that played infrequently, and play interactions had no subsequent effect on the likelihood of aggression. In contrast, aggressive interactions during foraging inhibited the subsequent likelihood of play, and high levels of aggression during foraging changed the structure of social play, with victimized pups avoiding play wrestling. We conclude that social play does not reduce aggression in young meerkats. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.      

Ovule development: genetic trends and evolutionary considerations

Much of our current understanding of ovule development in flowering pants is derived from genetic and molecular studies performed on Arabidopsis thaliana. Arabidopsis has bitegmic, anatropous ovules, representing both the most common and the putative ancestral state among angiosperms. These studies show that key genetic determinants that act to control morphogenesis during ovule development also play roles in vegetative organ formation, consistent with Goethe’s “everything is a leaf” concept. Additionally, the existence of a common set of genetic factors that underlie laminar growth in angiosperms fits well with hypotheses of homology between integuments and leaves. Utilizing Arabidopsis as a reference, researchers are now investigating taxa with varied ovule morphologies to uncover common and diverged mechanisms of ovule development.     

Phylogenetic identification of symbiotic protists of five Chinese Reticulitermes species indicates a cospeciation of gut microfauna with host termites

Symbiotic protists play important roles in the wood digestion of lower termites. Previous studies showed that termites generally possess host-specific flagellate communities. The genus Reticulitermes is particularly interesting because its unique assemblage of gut flagellates bears evidence for transfaunation. The gut fauna of Reticulitermes species in Japan, Europe, and North America had been investigated, but data on species in China are scarce. For the first time, we analyzed the phylogeny of protists in the hindgut of five Reticulitermes species in China. A total of 22 protist phylotypes were affiliated with the family Trichonymphidae, Teranymphidae, Trichomonadidae, and Holomastigotoididae (Phylum Parabasalia), and 45 protist phylotypes were affiliated with the family Pyrsonymphidae (Phylum Preaxostyla). The protist fauna of these five Reticulitermes species is similar to those of Reticulitermes species in other geographical regions. The topology of Trichonymphidae subtree was similar to that of Reticulitermes tree. All Preaxostyla clones were affiliated with the genera Pyrsonympha and Dinenympha (Order Oxymonadida) as in the other Reticulitermes species. The results of this study not only add to the existing information on the flagellates present in other Reticulitermes species but also offer the opportunity to test the hypotheses for the coevolution of symbiotic protists with their host termites.     

Genetic characterisation of Cylindrospermopsis raciborskii (Nostocales, Cyanobacteria) isolates from Africa and Europe

The invasive cyanobacterium Cylindrospermopsis raciborskii is increasingly spreading in temperate freshwater habitats worldwide and is of major concern due to its ability to produce potent toxins. It is, therefore, important to understand the mechanisms behind the dispersal of this species. Different hypotheses have been proposed to explain the phylogeography and mechanisms underlying the recent expansion of C. raciborskii into temperate latitudes, but there is still no conclusive evidence whether the obvious ecological success of C. raciborskii is due to selection mechanisms, physiological tolerance, climatic change or radiation after the last ice age. In the present study, new isolates of C. raciborskii from Europe and Africa were genetically characterised by sequencing the ITS1, PC-IGS, nifH and rpoC1 genes and compared to corresponding sequences of C. raciborskii available in GenBank in order to test different phylogeographical hypotheses. The strains were also morphologically examined and screened for production of the hepatotoxic cylindrospermopsin (CYN). We clearly demonstrate a variation among the populations of C. raciborskii from different geographical regions. The phylogenetic analyses revealed a clustering of the strains due to geographic origin. The ITS1 and nifH genes separated into American, European and Australian–African groups, whereas the PC-IGS and rpoC1 separated into American and European/Australian/African groups. An analysis of concatenated data supported the division into American, European and African/Australian groups, and even indicated a subdivision into an African and an Australian group. Our findings do not strongly support any of the existing hypotheses on the phylogeography of C. raciborskii, and most likely a combination of these hypotheses is the best approach to understand the evolution and dispersal of this species.