bluuebunny/crossref_metadata_2025 huggingface dataset:
Site reoccupation in fragmented landscapes: testing predictions of metapopulation theory
Authors: Hames Ralph S. , Rosenberg Kenneth V. , Lowe James D. , Dhondt André A.
Published: September 2010

Populations of formerly continuously distributed species subdivided by habitat fragmentation may show distributions in space and time that are consistent with predictions of metapopulation theory. Local extinctions and recolonizations should result in the most fragmented sites being infrequently occupied and the least fragmented sites being continuously occupied by sensitive species. The probability of extinction is predicted to be negatively correlated with patch size and the amount of habitat in the landscape. Conversely, recolonization is predicted to be negatively correlated with the isolation of the patch, and positively correlated with the amount of habitat in the landscape.

 Data from a 3‐year study of the effect of fragmentation were used to test whether these predictions from metapopulation theory apply to populations of the long‐distance migrant forest birdPiranga olivacea(Scarlet Tanager) in fragmented North American landscapes.

 Principal components analysis was used to derive a composite measure of fragmentation. This measure was used in a logistic regression as a predictor of the number of years that territorial males would occupy a site, given that it was occupied at least once. More fragmented sites were more likely to be occupied only once; the least fragmented sites were more likely to be occupied in all three years. Data on fragmentation were necessary, but not sufficient, to predict site reoccupation, and were poor predictors at medium levels of fragmentation.

 The univariate measures of fragmentation (patch size and isolation, proportion of forest, and forest/non‐forest edge), were also used in logistic regressions to predict the separate probabilities of local extinction or recolonization. Local extinctions were negatively correlated with patch size and amount of forest in the landscape, as predicted. Recolonizations were negatively correlated with isolation of the patch as predicted, and surprisingly, also with the amount of edge in the landscape. This suggests that stochasticity may drive extinctions, but that habitat selection may play an important role in recolonization.

 Demographic data are usually required to establish the suitability of habitat to support persistent populations, but multiple‐year distributional data can provide information on habitat quality far above that obtained from single‐year studies.
Linking patterns in macroecology
Authors: Blackburn Tim M. , Gaston Kevin J.
Published: September 2010

Associated with the development of the field of macroecology has been the recognition and analysis of a number of different patterns in the large‐scale abundance and distribution of species. The mechanistic bases of these patterns have usually been considered in isolation, yet the patterns are necessarily linked, as the same individual animals contribute to all of them.

 Here, a model linking macroecological patterns in abundance, distributional extent and body mass is developed, based on how the finite amount of energy available to the species in a region is divided between them. The energy available to a species is assumed to support some quantity of biomass, which must then be allocated to either many small‐bodied or fewer larger‐bodied individuals. This identifies a necessary link between population size and body mass, which predicts when the variety of relationships between these variables in the published literature are expected to occur.

 Although framed in terms of energy use by species, the model does not assume that energyper seis necessarily limiting populations. How individuals use space determines the form of relationships between population size and distributional extent, distributional extent and body mass, and population density and body mass. The model additionally allows a number of falsifiable predictions about the anatomy of macroecological patterns.

 Support for the assumptions of the model is discussed.
Relative competitive ability does not change over time in blackbirds
Authors: Cresswell Will
Published: September 2010

Individual variation in feeding rate in the absence of competitors (absolute feeding rate) and decline in feeding rate in the presence of competitors (susceptibility to interference) are frequently used as measures of competitive ability or fitness in short‐term foraging studies. They are also crucial parameters of individual‐based population models that predict the distribution of animals across patches. There are, however, few data on whether absolute feeding rate and susceptibility to interference competition remain constant for individuals between years.

 The hypothesis that absolute feeding rate and susceptibility to interference were similar between years was tested by observing 25 European blackbirdsTurdus merulafeeding in seminatural experimental patches, during January to March over a 2–4‐year period 1995–98. Absolute feeding rate was measured as the feeding rates of solitary blackbirds. Susceptibility to interference was measured as the change in feeding rate of a focal bird when it fed in the presence of different numbers of competitors.

 Individuals changed significantly in their feeding rate between years, but most individuals did not change in their feeding rate relative to others in the population. The absolute feeding rate of an individual was significantly positively correlated with its feeding rate in the subsequent year.

 There was no significant variation in susceptibility to interference for individuals between years. Only two of 27 blackbirds showed a significant change in susceptibility to interference between years.

 Relative absolute foraging rate and susceptibility to interference competition were reasonably similar between years in blackbirds. Relative fitness measures derived from short‐term measures of foraging ability may therefore be valid over long periods. In ideal free models that incorporate individual competitive ability, rather than population averages, temporal changes in competitive ability can possibly be ignored.
Models of alternative life‐history strategies, population structure and potential speciation in salmonid fish stocks
Authors: Parker Henry H. , Noonburg Erik G. , Nisbet Roger M.
Published: September 2010

High Arctic landlocked Arctic charr, Salvelinus alpinus L., are used as a reference system to examine the theory of alternative life history strategies in Salmonids and their implication for population structure and potential speciation. In these closed, autonomous systems, Arctic charr are the only fish species present and alternative life history strategies are represented by two distinct size modes, commonly known as ‘dwarf’ and ‘normal’ charr.

 Simple mathematical models are used to caricature the density‐dependent interactions within and between the dwarf and normal components of these bimodal populations. Two different assumptions concerning the genetic relationship between the two alternative life history strategies are investigated: complete reproductive isolation, or a single stock which chooses between the alternative strategies facultatively.

 In constant environmental conditions, the evolutionarily stable strategy (ESS) is not affected by the assumed genetic relationship, and the ESS proportions of dwarfs and normals are shown to depend on environmental parameters. The ESS proportions vary with these parameters along an evolutionarily stable continuum (ESC) and, in particular, a high proportion of normals is associated with high growth rate as a juvenile, and a ‘stunted’ or unimodal population with low growth rate. The predicted ESC for selection of the normal strategy is similar to that observed experimentally in the analogous case of smolting in Atlantic salmon, Salmo salar L.

 A difference in the ratio of fecundity to mortality rate between dwarf and normal sub‐populations is shown to be essential to maintaining bimodal populations, and it is argued that cannibalism is one mechanism which could achieve this difference.

 The model is extended to ask what ecological conditions would favour evolution toward the speciated or reproductively isolated state. It is concluded that short‐term environmental fluctuations select against speciation and it is speculated that most natural bimodal Arctic charr stocks will achieve maximum individual fitness within a ‘semispeciated’ configuration which is maintained by incomplete assortative mating.
Behavioural diversification in brook charr: adaptive responses to local conditions
Authors: McLaughlin Robert L.
Published: September 2010

Recently emerged brook charr (Salvelinus fontinalis Mitchill) foraging in still‐water pools along the sides of streams exhibit conspicuous variation in foraging behaviour. Some charr are sedentary and eat crustaceans from the lower portion of the water column. Others are mobile and eat insects from the upper portion of the water column. This study examines whether this behavioural diversification represents potentially adaptive responses made by individuals to local environmental conditions.

 Four models were constructed to predict how the ratio of mobile to sedentary charr was expected to change with pool morphometry, and how the location and orientation of mobile and sedentary charr were expected to differ within pools. The models assumed the charr forage competitively, but each model differed in assumptions regarding which features of pool morphometry determine the availability of the two main prey types. A spatial constraint hypothesis also was considered.

Findings from this study support the hypothesis that the divergent foraging tactics represent adaptive adjustments made by individual charr in response to competition for spatially separated food sources. Variation in the numbers of sedentary and mobile charr across pools, and spatial distributions of the charr and their crustacean and insect prey within pools, were most consistent with a model assuming that the availability of insect prey, and hence the number of mobile charr, was determined by the pool surface area while the availability of crustacean prey, and hence the number of sedentary charr, was determined by the pool perimeter.

 Parallels between this pool system and polymorphic fish populations in larger lake systems identifies a potential link between the adaptive decision making of individuals and the spatial and phenotypic divergence of populations in response to spatial heterogeneity in food resources.
Habitat suitability and source–sink dynamics of beavers
Authors: Fryxell John M.
Published: September 2010

Theory suggests that territorial species should share many of the same dynamical characteristics as metapopulations, including asynchronous local dynamics, potential for stochastic extinction of the population when rates of successful dispersal fall below mortality risk, and critical importance of the ratio of suitable to unsuitable habitat for long‐term persistence. These propositions were tested on a population of beavers (Castor canadensisKuhl) in Algonquin Provincial Park, Ontario, which has been continuously monitored over 11 years.

 Results showed that the total population was considerably less variable than local abundance at 14 beaver colonies, due to asynchrony among local populations. This suggests that local ecological interactions were more important in determining year‐to‐year variation in beaver numbers than broad‐scale environmental processes, such as weather.

 Of the local colonies, 20% were never abandoned over 11 years, although there was considerable turnover among adults. Offspring production exceeded adult abundance at five source colonies, which did not quite compensate for negative net production at nine sink colonies. These observations were consistent with predictions of spatially structured models of territoriality incorporating local variation in habitat suitability. Mean colony size and probability of recurrence from year‐to‐year were associated with local food availability, indicating that trophic interactions were important in determining local population dynamics.

 The beaver population in Algonquin declined steadily over the study period, however, suggesting that spatial and demographic processes were insufficient to stabilize abundance over time. This is consistent with predictions of spatially structured models of territoriality in which suitable and unsuitable habitats are interspersed. It is hypothesized that long‐term decline in habitat suitability is induced by acceleration of woody plant succession due to selective foraging by beavers.
Adaptive precocial reproduction in voles: reproductive costs and multivoltine life‐history strategies in seasonal environments
Authors: Lambin Xavier , Yoccoz Nigel G.
Published: September 2010

We determined whether reproductive costs associated with precocious or later breeding by female Townsend’s voles (Microtus townsendii) differ and how this relates to the multivoltine life history of microtines. We related the probability of mothers surviving the lactation period to maternal age and the number of pups per litter using logistic models allowing for a threshold value in either explanatory variable below (for litter size) and above (for age) which survival is constant.

 Females born at the beginning of the breeding period were precocious, giving birth for the first time by the time they were 85 days old (min 38 days). Females born at other times delayed sexual maturation by up to 6 months.

 The survival of females who gave birth before a fitted threshold of 85 days old declined precipitously if they gave birth to more than five pups per litter. Survival of older females did not vary in relation to the size of their litters.

 Precocious females had not reached adult size when they conceived their first litter and substantially increased their structural mass during pregnancy. We estimated that young primiparous females gained on average 127 ± 9% of their conception weight during their 21‐day first pregnancy compared to an average increase of 47 ± 2% per pregnancy for all other females. It appears that the low survival during lactation experienced by this cohort alone may be a consequence of the cumulative costs of gestation, lactation and somatic growth.

 We build simple life‐table models to estimate the contribution of very precocious (conception at 25 days), precocious (conception at 50 days) and non‐precocious females (conception > 50 days) to the population as the probability of surviving the spring and summer, plus the total number of females produced and surviving until the end of the summer. We parameterized such models using the empirical survival estimates. Females who conceived five young very precociously made the greatest contribution to the autumn population. Delaying reproduction had a large cost: a very precocious female starting with five young would contribute 7·21 females, while a precocious female with the same initial litter size would contribute only 2·83 females. This advantage stems from both the longer breeding‐life span and from the fact that offspring of very precocious females may themselves reproduce in the year of their birth, such that they compound the precocious investment of their mothers.

 Thus iterated reproduction and the multivoltine nature of microtine life history select for cohort‐specific trade‐off between survival and reproduction.
Multiple predators in the pelagic: modelling behavioural cascades
Authors: FIKSEN ØYVIND , ELIASSEN SIGRUNN , TITELMAN JOSEFIN
Published: September 2010

The behaviour of predators is rarely considered in models of predator–prey interactions, nor is it common to include multiple predators in models of animal behaviour.

We introduce a model of optimal diel vertical migration in zooplankton prey facing predation from two functionally different predators, fish and other zooplankton. Zooplankton predators are themselves subject to predation from larger zooplankton, and all zooplankton face the classical trade‐off between increasing growth rate and predation risk from fish towards the surface. Prey are most vulnerable to zooplankton predators at small sizes, but become more visible to fish as they grow. However, by habitat selection prey continuously manage their exposure to different sources of risk.

We analyse situations with cascading behavioural interactions of size‐structured predator–prey interactions in the pelagic. In particular, we explore how vertical gradients in growth rates and relative abundance of fish and zooplankton predators affect optimal distribution patterns, growth and mortality schedules.

A major model prediction is that prey susceptibility to one functional predator type depends on the abundance of the other predator. Higher abundance of zooplankton predators leads to risk enhancement from fish, minor increases in predation rate from zooplankton and unchanged prey growth rates. Increasing abundance of fish does not alter the risk from zooplankton predators, but reduces growth and development rates. Such asymmetric emergent effects may be common when prey and predators share the same spatial refuge from a common top predator.
Experimentally increased aggressiveness reduces population kin structure and subsequent recruitment in red grouse Lagopus lagopus scoticus
Authors: MOUGEOT FRANÇOIS , PIERTNEY STUART B. , LECKIE FIONA , EVANS SHARON , MOSS ROBERT , REDPATH STEVE M. , HUDSON PETER J.
Published: September 2010

According to the ‘territorial behaviour’ hypothesis, red grouse population cycles are caused by delayed density‐dependent changes in male aggressiveness influencing recruitment. These lagged changes in aggressiveness might be caused by changes in the kin structuring of male populations and differential aggressive behaviour between kin and non‐kin (‘kinship’ hypothesis).

A population‐level manipulation of male aggressiveness in autumn affected the kin structure of male populations, their subsequent aggressiveness, and recruitment of both sexes. On two moors, we implanted the old territorial cocks in autumn with testosterone on an experimental area (T‐areas) and with sham implants on a control area (C‐areas).

Increased aggressiveness in autumn t reduced recruitment in autumns t and t+ 1, and breeding density of both sexes in springs t+ 1 and t+ 2, confirming previous studies elsewhere. A new observation was that cocks on T‐areas had bigger combs (an ornament whose size is testosterone‐dependent) than those on C‐areas for at least 1·5 years after treatment, evidence that they remained more aggressive.

Increased aggressiveness reduced not only subsequent density but also kin structuring among territorial cocks. This is consistent with the ‘kinship’ hypothesis that changes in the kin structure of male populations mediate year‐to‐year changes in male aggressiveness.

Increased aggressiveness did not increase intensity of infection by the dominant intestinal nematode Trichostrongylus tenuis, which might have affected recruitment through reduced breeding success. Moreover, breeding success after treatment was no lower on the T‐ than on the C‐areas.

The results show for the first time that increased aggressiveness affects both kin structure and subsequent recruitment, supporting a key assumption of the kinship hypothesis for red grouse population cycles.
The roles of extinction and colonization in generating species–energy relationships
Authors: EVANS KARL L. , GREENWOOD JEREMY J. D. , GASTON KEVIN J.
Published: September 2010

Positive correlations between energy and species richness are frequently observed, but the causal mechanisms of such species–energy relationships have rarely been identified conclusively.

The more individuals hypothesis (MIH) describes one possible cause of positive species–energy relationships. It suggests that greater resource availability in high‐energy areas increases population sizes, reducing local extinction rates and promoting species richness. It predicts that extinction rates will be lower in high‐energy areas and that, because a given change in population size has a greater influence on extinction risk when initial populations are small, such relationships will be more pronounced in numerically rare species than more abundant ones.

Colonization rates may also influence local species richness, and they may respond positively to the greater resource abundance in high‐energy areas.

We provide the first empirical test of relationships between extinction/colonization rates and energy availability and of the influence of population size on these relationships. We use data on the changing distributions of British birds, in which positive species–energy relationships have previously been documented.

We find that extinction rates are lower in high‐energy areas, but that such patterns are stronger in more abundant species. Spatial variation in colonization rates is influenced less markedly by energy availability, but such patterns are also more marked in numerically abundant species. While these results provide little overall support for the MIH, nor some of its alternatives, they add to increasing evidence that common species drive much of the spatial variation in species richness.
Density‐dependent growth of young‐of‐the‐year Atlantic salmonSalmo salarin Catamaran Brook, New Brunswick
Authors: IMRE I. , GRANT J. W. A. , CUNJAK R. A.
Published: September 2010

While density‐dependent mortality and emigration have been widely reported in stream salmonid populations, density‐dependent growth is less frequently detected. A recent study suggests that density‐dependent growth in stream salmonids occurs at low densities, whereas density‐dependent mortality and emigration occur at high densities.

To test the hypothesis that density‐dependent growth occurs primarily at low rather than at high densities, we examined the relationship between average fork length and population density of young‐of‐the‐year (YOY) Atlantic salmon at the end of the growing season using a 10‐year data set collected on Catamaran Brook, New Brunswick. We tested whether (1) average body size decreases with increasing density; (2) the effect of density on average body size is greatest at low densities; (3) growth rate will decrease most rapidly at low effective densities [Σ(fork length)2]; (4) density‐dependent growth is weaker over space than over time; and (5) the strength of density‐dependent growth increases with the size of the habitat unit (i.e. spatial scale) when compared within years, but not between years.

There was a strong negative relationship between the average body size and population density of YOY Atlantic salmon in the autumn, which was best described by a negative power curve. Similarly, a negative power curve provided the best fit to the relationship between average body size and effective density. Most of the variation in average body size was explained by YOY density, with year, location and the density of 1+ and 2+ salmon accounting for a minor proportion of the variation.

The strength of density‐dependent growth did not differ significantly between comparisons over space vs. time. Consistent with the last prediction, the strength of density‐dependent growth increased with increasing spatial scale in the within‐year, but not in the between‐year comparisons.

The effect of density on growth was strongest at low population densities, too low to expect interference competition. Stream salmonid populations may be regulated by two mechanisms: density‐dependent growth via exploitative competition at low densities, perhaps mediated by predator‐induced reductions in drift rate, and density‐dependent mortality and emigration via interference competition at high densities.
Condition‐specific competition between invasive Argentine ants and Australian Iridomyrmex
Authors: THOMAS MELISSA L. , HOLWAY DAVID A.
Published: September 2010

Biotic interactions and abiotic suitability are often emphasized as factors influencing invasion success. Here we examine how these factors might interact to affect the competitive performance of invasive Argentine ants (Linepithema humile) in Western Australia.

In standardized bait surveys Argentine ants controlled twice as many baits in the morning (ground temperatures: 18–25 °C) compared to the number they controlled in the afternoon (ground temperatures: 30–40 °C). Moreover, Argentine ants displaced native ants from baits only in the morning and were, in turn, displaced by native ants only in the afternoon.

We used a factorial field experiment to test the relative importance of interspecific competition (±) and ground temperature variation [warm (25 °C)/hot (33 °C)] as determinants of competitive performance among established colonies of Argentine ants and two species of native Iridomyrmex (I. bicknelli and I. rufoniger suchieri).

We observed a condition‐specific competitive asymmetry between I. bicknelli and L. humile. In the absence of each other as competitors, these two species responded to ground temperature variation in an opposite manner. I. bicknelli foraged more actively when ground temperatures were hot, whereas L. humile foraged more actively when ground temperatures were warm. In competition with I. bicknelli, Argentine ants monopolized two‐thirds of all baits but controlled more than twice the number of baits under warm conditions than under hot conditions. Iridomyrmex bicknelli dominated 22% of all baits but did so primarily when conditions were hot.

Linepithema humile and I. r. suchieri responded to abiotic variation in a qualitatively similar manner. Both species foraged less actively when ground temperatures were hot than when ground temperatures were warm, but L. humile showed stronger declines when ground temperatures were hot than did I. r. suchieri. In competition with I. r. suchieri, Argentine ants again monopolized two‐thirds of all baits.

Our findings suggest that physical conditions unsuitable for L. humile may combine with interspecific competition from native ants that are more tolerant to hot, dry conditions to reduce the extent to which natural areas in Australia become invaded.
Adaptive sex allocation in relation to life‐history in the common brushtail possum, Trichosurus vulpecula
Authors: ISAAC JOANNE L. , KROCKENBERGER ANDREW K. , JOHNSON CHRISTOPHER N.
Published: September 2010

Maternal control of offspring sex remains a contentious topic in the evolutionary and behavioural ecology of vertebrates. Two models of adaptive sex allocation − the Trivers–Willard (TW) and local resource competition (LRC) hypotheses − have been supported in some studies, but in many other cases the forces shaping offspring sex ratios are unclear. One reason that past studies may not have provided clear support for either model is that the two processes interact, producing complex patterns of sex allocation in relation to the life histories of individual mothers.

The TW hypothesis predicts that in dimorphic, polygynous mammals, females in good condition should be more likely to produce male offspring. The LRC hypothesis predicts an independent effect of age on the offspring sex ratio; females should be more likely to produce sons early in their reproductive lives and daughters later, in order to minimize the duration and reproductive cost of mother–daughter competition. We tested these two predictions in a study of sex allocation in the common brushtail possum, Trichosurus vulpecula.

Offspring sex was strongly dependent on maternal age: females breeding for the first time were likely to produce sons, and at subsequent breeding attempts the sex ratio of offspring was slightly biased towards females. After the first breeding season, sex of offspring was influenced more strongly by body condition than by age, and females in good condition were more likely to have sons. Individual females that showed a between‐year gain in condition were also more likely to produce a male in the subsequent year.

Body mass of male offspring at 5 months was positively correlated with maternal condition. No relationship was found between maternal condition and mass of female offspring.

We conclude that patterns of change in sex allocation in relation to individual life histories of female common brushtail possums can be explained by the interaction of TW and LRC effects.
Association of red‐mark syndrome with a Rickettsia‐like organism and its connection with strawberry disease in the USA
Authors: Metselaar M , Thompson K D , Gratacap R M L , Kik M J L , LaPatra S E , Lloyd S J , Call D R , Smith P D , Adams A
Published: September 2010

Red‐mark syndrome (RMS), a disease seen mostly in rainbow trout, Oncorhynchus mykiss, is of unknown aetiology. The research presented here indicates the presence of an intracellular bacterium in RMS‐affected fish. A positive reaction was observed using immunohistochemistry (IHC) with skin lesions, liver, kidney and spleen of affected fish sampled from several locations within the United Kingdom using two different polyclonal antisera raised against Piscirickettsia salmonis. The same reaction was also seen with a number of different anti‐P. salmonis monoclonal antibodies (MAbs). A disease with similar clinical signs to RMS, referred to as strawberry disease (SD), has been reported in the USA. A Rickettsia‐like organism (RLO) has recently been associated with SD based on analysis of 16S rDNA sequences. Using the same panel of anti‐P. salmonis antibodies used to screen the RMS samples, similar staining was obtained in tissue of SD‐affected fish by IHC. A polymerase chain reaction (PCR) using RLO‐specific primers was also performed on RMS‐affected fish from the United Kingdom, and the samples were positive for the RLO 16S rRNA sequence. These findings suggest that the same aetiological agent may be responsible for RMS in the United Kingdom and SD in the USA.
Motor performance of children with mild intellectual disability and borderline intellectual functioning
Authors: Vuijk P. J. , Hartman E. , Scherder E. , Visscher C.
Published: September 2010

Background  There is a relatively small body of research on the motor performance of children with mild intellectual disabilities (MID) and borderline intellectual functioning (BIF). Adequate levels of motor skills may contribute to lifelong enjoyment of physical activity, participation in sports and healthy lifestyles. The present study compares the motor skills of children with intellectual disability (ID) to the abilities observed in typically developing children. It also aimed to determine whether there is an association between degree of ID and motor performance.

Methods  A total of 170 children between 7 and 12 years old with MID or BIF, who attended schools for special education, were examined on the test component of the Movement Assessment Battery for Children (MABC) test. Both groups were compared with the norm scores of the total score, sub‐scale scores and individual items of the MABC test.

Results  Of the children, 81.8% with MID and 60.0% with BIF performed below the 16th percentile on the total score of the MABC. Both groups demonstrated a relative weakness in the area of manual dexterity. Comparisons between both groups showed small to moderate effect sizes on the total score of the MABC, as well as for all three sub‐scales, favouring the children with BIF.

Conclusions  Children with ID had significantly more borderline and definite motor problems than the normative sample and there was an association between degree of ID and performance of manual dexterity, ball skills and balance skills. This study highlights the importance of improving motor skill performance in both children with borderline and mild ID, and the results support the notion that the level of motor and cognitive functioning are related in children with ID.
Adaptive behaviour in Angelman syndrome: its profile and relationship to age
Authors: Brun Gasca C. , Obiols J. E. , Bonillo A. , Artigas J. , Lorente I. , Gabau E. , Guitart M. , Turk J.
Published: September 2010

Background  Angelman syndrome (AS) is a neurodevelopmental disorder usually caused by an anomaly in the maternally inherited chromosome 15. The main features are severe intellectual disability, speech impairment, ataxia, epilepsy, sleep disorder and a behavioural phenotype that reportedly includes happy disposition, attraction to/fascination with water and hypermotoric behaviour.

Method  We studied the level of adaptive behaviour and the adaptive behavioural profile in the areas of ‘motor skills’, ‘language and communication’, ‘personal life skills’ and ‘community life skills’ in a group of 25 individuals with genetically confirmed AS, to determine whether there is a specific adaptive behaviour profile.

Results and conclusions  None of the individuals, whatever their chronological age, had reached a developmental age of 3 years. A specific adaptive behaviour profile was found, with ‘personal life skills’ emerging as relative strengths and ‘social and communication skills’ as weaknesses.
Age‐dependent antibody response to Plasmodium falciparum merozoite surface protein 2 (MSP‐2)
Authors: KHOSRAVI A. , HOMMEL M. , SAYEMIRI K.
Published: September 2010

Merozoite surface protein 2 (MSP‐2), a very immunogenic malaria antigen, is a highly polymorphic 45–53 kDa merozoite surface protein, which is regarded as a promising vaccine candidate. The highly polymorphic nature of MSP‐2 suggests that the molecule can be involved in protective immunity against malaria. The antibody responses to MSP‐2 antigen are mostly directed against polymorphic and dimorphic regions of the protein. The current study aimed at testing the reactivity of human sera from a malaria‐endemic area of Gambia against MSP‐2 regions 2, 3 and 4 compared to crude schizont extract in a period of 20 years. The age‐dependent immunity was analysed in a manner of cross‐sectional study (the data of the first visit) and also a longitudinal study design (analysing the data at four different time points from 1960 to 1980) testing the sera of 178 individuals randomly selected from the Keneba Serum Collection by using MSP‐2 recombinant protein. The total IgG responses were measured by ELISA. Kolmogorov–Smirnov was used to check the normal distribution of OD, Hb and parasitaemia, and then Spearman correlation was applied to analyse the data. Most sera recognized, predominantly, the variable regions of the MSP‐2, particularly the domain 3. The IgG response against all the antigens increased with age. The IgG responses against domain 3 of MSP‐2 were associated with an increase in haemoglobin levels but a decrease in parasitaemia, suggesting that this immune response may be one of the most useful means for further studies on protective immunity against malaria.
Effect of marking pheromone on clutch size in the Mediterranean fruit fly
Authors: PAPAJ D. R. , ROITBERG B. D. , OPP S. B. , ALUJA M. , PROKOPY R. J. , WONG T. T. Y.
Published: September 2010

Abstract Using acridine orange to selectively stain eggs, we showed that wild‐collected female Mediterranean fruit flies (Ceratitis capitata Wiedemann) laid fewer eggs per clutch in fruit previously infested with eggs than in uninfested fruit. This effect is apparently attributable to marking pheromone deposited by females after oviposition: clutch size on fruit infested with eggs but free of marking pheromone was not statistically different from that on uninfested fruit. Clutch size on uninfested fruit on which marking pheromone was artificially transferred was significantly lower than that on uninfested and untreated fruit. Marking pheromone had a comparable though not statistically significant effect on the clutch size of females originating from a strain maintained in the laboratory for several hundred generations.
The mating‐induced refractoriness of Lucilia cuprina females: manipulating the male contribution
Authors: SMITH P. H. , GILLOTT C. , BROWNE L. BARTON , GERWEN A. C. M. VAN
Published: September 2010

Abstract Three manipulations of the male contribution to copulation were used to investigate what determines the switch‐off of female receptivity that follows mating in Lucilia cuprina.

Multiple matings by males led to a reduction in their effectiveness at switching‐off females: the first twelve matings caused more than 50% of females to be switched‐off 1 day after mating, while the first four matings caused more than 50% of females to be switched‐off for 7 days after mating. Males mated up to twenty‐three times and on average ten times during 10 h of continuous access to virgin females. The number of sperm transferred declined logarithmically through a series of matings as did the quantity of material transferred from the male accessory gland (measured as radiolabeled material) through the first six matings. Overnight isolation of multiply‐mated males led to considerable recovery of their ability to switch‐off females, and to limited renewal of their ability to transfer sperm. Castrated males transferred similar quantities of accessory gland material to females as did sham‐operated males during their first five matings and in their first three matings switched‐off 95% of females for 1 day but only 48% for 7 days.

When normal mating pairs were separated at increasing intervals after coupling, an increasing proportion of females were switched‐off at 1 or 7 days afterward. 7 days after 2 min matings no females were switched‐off though 40% of the number of sperm transferred in a full mating had been transferred by this time.

The proposed explanation for these data is that both the initial switch‐off and its duration are determined by the quantity of a receptivity‐inhibiting substance that normally enters the female haemo‐lymph after being injected by the male into the wall of the bursa copulatrix. It is proposed that when castrated males mate, an absence of sperm results in most accessory gland secretion entering the empty spermathecae (rather than the wall of the bursa as usually occurs) and hence being unable to reach the haemolymph and exert its influence. The effective dose of the receptivity‐inhibiting substance is measured on a logarithmic scale.
The central role of the haemolymph in the regulation of nutrient intake in insects
Authors: SIMPSON S. J. , RAUBENHEIMER D.
Published: September 2010

Abstract. A synthesis is presented for the control of nutrient intake in insects. The haemolymph plays a central role and provides a constantly updated summary of nutritional state. Various ways are discussed in which haemolymph parameters are directly and indirectly linked to the three key aspects of feeding behaviour: food location, food selection and ingestion.
The influence of colony population and brood rearing intensity on the activity of detoxifying enzymes in worker honey bees
Authors: SMIRLE MICHAEL J.
Published: September 2010

Abstract. Cohorts of worker honey bees from a single parental hive, cross‐fostered into colonies which differed in population and other colony parameters, were assessed for activities of enzymes involved in metabolic detoxication. Activities of glutathione S‐transferase and mixed‐function oxidase enzymes were negatively correlated with foster colony population, but positively correlated with the ratio of larvae (brood)/adult workers. Worker bees which had begun foraging had enzyme activity levels higher than any found in bees which were still performing in‐hive duties. Elevated levels of detoxifying enzymes in colonies with low populations and high ratios of larvae/adults may be a protective mechanism to prevent poisoning of larvae by toxins brought to the colony by foragers.
Post‐eclosion diuresis in a flightless insect, the silkmoth Bombyx mori
Authors: STRATHIE LORRAINE W. , NICOLSON SUSAN W.
Published: September 2010

Abstract. Although the silkmoth, Bombyx mori L., has lost the ability to fly, it has retained a post‐eclosion diuresis. In moths removed from their cocoons before eclosion, or in those which failed to spin cocoons as larvae, the weight loss due to diuresis was 14% of the eclosion body weight in males. Moths which used labial fluid to escape from their cocoons showed a correspondingly smaller diuresis (5%). Both urine and labial fluid had high potassium and low sodium concentrations. Unlike post‐eclosion diuresis in butterflies, however, the urine was isosmotic to the haemolymph. In vitro preparations of B.mori Malpighian tubules were stimulated by cyclic AMP, B.mori brain extracts and Manduca sexta diuretic peptide (Mas‐DP I).
On critical night lengths and temperature compensation in the photoperiodic response of two geographical clones of the black bean aphid, Aphis fabae
Authors: Nunes Marlies Vaz , Hardie Jim
Published: September 2010

Photoperiodic response curves were determined for two clones of the black bean aphid, Aphis fabae Scopoli, at three temperatures, 12.5, 15 and 17.5°C. Critical night lengths for the induction of winged females in an English clone (52° N) were 10.5, 11 and 11.5 h, respectively, and 10, 10.5 and 11 h in a Scottish clone (57° N). Critical night lengths for male induction were 10.5, 11 and 11 h at 12.5, 15 and 17.5°C in the English clone, and 10, 10.5 and 10.5 h, respectively, in the Scottish clone. High incidences of winged females and males were observed at all scotophases longer than the critical night length in both clones. In addition, in the English clone, the incidences of winged female and male producers in continuous darkness were 0% at 15 and 17.5°C, and 6% at 12.5°C. In the Scottish clone, however, continuous darkness resulted in high incidences of both winged female and male producers at 12.5 and 15°C, but 0% winged female producers and 6% male producers at 17.5°C. In scotophases shorter than the critical night length, including continuous light, no males or winged females were observed in either clone under the non‐crowded rearing conditions used. The results are discussed in terms of the ‘double circadian oscillator model’ for photoperiodic induction.
Variation in sperm precedence in Chorthippus grasshoppers (Caelifera: Gomphocerinae)
Authors: Reinhardt Klaus
Published: September 2010

Variation in the proportions of offspring fathered by a second male to mate (the P2 value) has been studied in two species of grasshoppers, Chorthippus parallelus (Zetterstedt) and Ch. biguttulus (Linnaeus), by means of the sterile‐male technique. In both species the P2‐values of the first egg pods laid were in the range of 50–100%, and the temporal variation of P2‐values appeared to follow two modes. In one, the P2‐value steadily declined with time, in the other it remained constant at a high level. It is concluded that sperm is passively lost between two matings. The remaining sperm then either mixes within the spermatheca or is stratified. Further variability in sperm precedence can possibly be explained by spermatophore ejection or differential use of stored sperm.
Hormonal control of diapause and overwintering traits in a leaf beetle, Aulacophora nigripennis
Authors: Watanabe Masahiko , Tanaka Kazuhiro
Published: September 2010

To elucidate whether Juvenile Hormone (JH) regulates physiological status in relation to diapause and cold hardiness, we investigated various physiological and biochemical changes in diapause adults of Aulacophora nigripennis after treatment with exogenous pyriproxyfen, an analogue of JH. Topical application of pyriproxyfen at high dose (≥0.05 μg) caused the diapause adults not only to consume more oxygen and mate earlier, but also to suppress enhancement of chill tolerance at 0°C and accumulation of myo‐inositol. By contrast, a lower dose of pyriproxyfen (0.01 μg) did not, suggesting that the amount of pyriproxyfen between 0.01 and 0.05 μg is a critical dose breaking both diapause and cold hardening. Pyriproxyfen‐treated post‐diapause adults lost triacylglycerols, but not glycogen, more rapidly than the acetone control. It is suggested that triacylglycerols are the main energy resource in both diapause and post‐diapause adults, but are consumed more by the latter because of their higher metabolic rate. Glycogen may be converted mainly into myo‐inositol during diapause, but consumed as an energy fuel for basal metabolism during post‐diapause development. Thus, various physiological and biochemical traits in relation to diapause and cold tolerance in this beetle may be at least in part under the control of JH.
Size, peripheral auditory tuning and target strength in noctuid moths
Authors: Norman Alex P. , Jones Gareth
Published: September 2010

We investigated relationships among body size, the frequency of peak auditory sensitivity (best frequency) and acoustic conspicuousness (measured as target strength) to simulated bat echolocation calls in a range of tympanate moths (Lepidoptera: Noctuidae). Audiograms of Amphipyra pyramidea Linnaeus, Agrotis exclamationis Linnaeus, Omphaloscelis lunosa Haworth and Xestia xanthographa Denis and Schiffermüller are described for the first time. Best frequency was inversely related to forewing length, an index of body size. Models predict that target strength falls off rapidly once wavelength (1/frequency) exceeds some defined feature of target size (e.g. circumference for spheres). We investigated how target strength varies in relation to target size and emitted frequency for simple targets (paper discs) and for moths. Target strength fell rapidly when target radius/wavelength < 2 for paper discs of similar size to many noctuid moths. Target strength fell rapidly below wing‐length/wavelength ratios of 2 in relatively small (O. lunosa, wing‐length = 15.2 ± 0.4 mm, best frequency = 45 kHz) and large (N. pronuba, wing‐length = 24.6 ± 0.8 mm, best frequency = 15 kHz) noctuid species, and decreased rapidly at frequencies below 25 kHz in both species. These target strengths were used to predict the detection distance of the moths by bat sonar between 10 and 55 kHz. Predicted detection distances of both species were maximal for fictive call frequencies of 20 kHz, and were reduced at lower frequencies due to decreased target strength and at higher frequencies by excess atmospheric attenuation. Both relatively large and small noctuid moths are therefore strong acoustic targets to bats that echolocate at relatively low frequencies. Bats may emit allotonic calls at low frequency because the costs of reduced detection range are smaller than the benefits of reduced audibility to moths. Because best frequency scales with body size and maximum detection distance is not very sensitive to body size, noctuid moths in the size range examined do not necessarily have best frequencies that would match the call frequencies of bats that may detect the moths at greatest distance precisely. Hence, best frequency may be constrained in part by body size.
Chemical characterization of the alarm pheromone in the venom of Polybia occidentalis and of volatiles from the venom of P. sericea
Authors: Dani F. R. , Jeanne R. L. , Clarke S. R. , Jones G. R. , Morgan E. D. , Francke W. , Turillazzi S.
Published: September 2010

The contents of the venom sacs of the two epiponine species Polybia occidentalis (Olivier) and P. sericea (Olivier) (Hymenoptera: Vespidae) have been analysed by GC‐MS for their volatile constituents. The mixture of volatiles was found to be very diverse in both the species. The spiroacetal (E,E)‐2,8‐dimethyl‐1,7‐dioxaspiro[5.5]undecane, was present in both species and was the major component in P. occidentalis, where it was determined to show (2S,6R,8S)‐configuration. An enantiomerically pure synthetic sample was tested in field bioassays on P. occidentalis colonies and was clearly shown to elicit alarm behaviour.