Similar Life History Research Articles

Variations in life history characteristics of the deep-water giant ruby snapper (Etelis sp.) between the Indian and Pacific Oceans and application of a data-poor assessment

The giant ruby snapper, Etelis sp., attains the largest size of any lutjanid in the Indo-Pacific and is one of the most valuable species harvested from deep-water fisheries along the continental and insular shelf margins throughout its broad geographic distribution. Despite this species supporting important commercial, artisanal and subsistence fisheries, quantitative assessments of the status of stocks have been limited by an absence of biological information, unreliable catch and effort statistics, and until recently, misidentification with a cryptic congener. This study aimed, firstly, to describe and compare the age, growth and reproductive characteristics of Etelis sp. between the eastern Indian and western central Pacific Oceans; and secondly, to provide an age-based assessment of the stock in north-western Australia, the only stock for which available data were sufficient to quantify stock status. Although the growth of Etelis sp. differed significantly between sexes and oceans, longevity was similar with a maximum age of 56 years recorded in the Pacific Ocean. Spawning of this species occurred over five months during the austral summer to mid-autumn (i.e. December to April) in the Indian Ocean, but was not well defined in the Pacific Ocean. The estimated ages at 50 % maturity for females and males in the Indian Ocean were similar (i.e. 4–5 years), whereas lengths at 50 % maturity differed (L50mat = 527 and 456 mm fork length, FL, respectively), but were consistent with corresponding differences in growth between sexes. Estimates of the relative female spawning potential ratio for Etelis sp. in north-western Australia suggest the status of this stock remained relatively unchanged from 1997 to 2011, at around 60 % of the unfished level. This assessment provides an example of the relative sustainable exploitation levels for this stock, and potentially other Eteline snappers that exhibit similar life history characteristics, particularly in locations where monitoring and assessments may be data and/or resource limited.

Understanding marine larval dispersal in a broadcast-spawning invertebrate: A dispersal modelling approach for optimising spat collection of the Fijian black-lip pearl oyster Pinctada margaritifera.

Fisheries and aquaculture industries worldwide remain reliant on seed supply from wild populations, with their success and sustainability dependent on consistent larval recruitment. Larval dispersal and recruitment in the marine environment are complex processes, influenced by a multitude of physical and biological factors. Biophysical modelling has increasingly been used to investigate dispersal and recruitment dynamics, for optimising management of fisheries and aquaculture resources. In the Fiji Islands, culture of the black-lip pearl oyster (Pinctada margaritifera) is almost exclusively reliant on wild-caught juvenile oysters (spat), through a national spat collection programme. This study used a simple Lagrangian particle dispersal model to investigate current-driven larval dispersal patterns, identify potential larval settlement areas and compare simulated with physical spat-fall, to inform targeted spat collection efforts. Simulations successfully identified country-wide patterns of potential larval dispersal and settlement from 2012–2015, with east-west variations between bi-annual spawning peaks and circulation associated with El Niño Southern Oscillation. Localised regions of larval aggregation were also identified and compared to physical spat-fall recorded at 28 spat collector deployment locations. Significant and positive correlations at these sites across three separate spawning seasons (r(26) = 0.435; r(26) = 0.438; r(26) = 0.428 respectively, p = 0.02), suggest high utility of the model despite its simplicity, for informing future spat collector deployment. Simulation results will further optimise black-lip pearl oyster spat collection activity in Fiji by informing targeted collector deployments, while the model provides a versatile and highly informative toolset for the fishery management and aquaculture of other marine taxa with similar life histories.

Population-level effects of acoustic disturbance in Atlantic cod: a size-structured analysis based on energy budgets.

Anthropogenic underwater noise may negatively affect marine animals. Yet, while fishes are highly sensitive to sounds, effects of acoustic disturbances on fishes have not been extensively studied at the population level. In this study, we use a size-structured model based on energy budgets to analyse potential population-level effects of anthropogenic noise on Atlantic cod (Gadus morhua). Using the model framework, we assess the impact of four possible effect pathways of disturbance on the cod population growth rate. Through increased stress, changes in foraging and movement behaviour, and effects on the auditory system, anthropogenic noise can lead to (i) increased energy expenditure, (ii) reduced food intake, (iii) increased mortality, and (iv) reduced reproductive output. Our results show that population growth rates are particularly sensitive to changes in energy expenditure and food intake because they indirectly affect the age of maturation, survival and fecundity. Sub-lethal effects of sound exposure may thus affect populations of cod and fishes with similar life histories more than lethal effects of sound exposure. Moreover, anthropogenic noise may negatively affect populations when causing persistent increases of energy expenditure or decreases of food intake. Effects of specific acoustic pollutants on energy acquisition and expenditure should therefore be further investigated.

How and when melanic coloration is an advantage for lizards: the case of three closely-related species of Liolaemus

Body temperature affects various aspects of ectotherm biology. Reptiles, as ectotherms, gain and control their temperature mainly through behavioural adjustments, although some body traits may also be advantageous. According to the thermal melanism hypothesis (TMH) dark colour may be thermally advantageous in cold environments. Additionally, differences in thermoregulatory capacity may also affect performance. We analysed the role of melanism in the thermoregulation and sprint speed performance of three species of Liolaemus lizards from Argentinean Patagonia. Liolaemus shitan, L. elongatus and L. gununakuna are phylogenetically close, with similar body sizes and life history traits, but differ in their melanic colouration, L. shitan being the darkest and L. gununakuna the lightest species. We estimated sprint speed performance curves and heating rates, and recorded final body temperature and sprint speed achieved after a fixed heating time, from two different initial body temperatures, and with and without movement restriction. Performance curves were similar for all the species, but for L. gununakuna the curve was more flattened. Darker species showed faster heating rates, ran faster after fixed heating trials at the lowest temperature, and reached higher body temperatures than L. gununakuna, but this was compensated for by behavioural adjustments of the lighter lizards. Similarity of sprint speed performance may be due to the conservative nature of this character in these species, while variation in heating ability, particularly when starting from low temperatures, may reflect plasticity in this trait. The latter provides support for the TMH in these lizards, as melanism helps them increase their body temperature. This may be especially advantageous at the beginning of the day or on cloudy days, when temperatures are lower.

Preimaginal developmental time of two egg parasitoids and their host searching efficiency

ABSTRACTWhen searching for hosts, parasitoids may experience competition between adults exploiting the same host (extrinsic), or between larvae developing inside the host (intrinsic competition). Differences in competitive abilities like host location and resource utilisation promote coexistence. In this sense, extrinsically superior parasitoids better locate hosts, and intrinsically superior ones can have a shorter preimaginal development, which gives them a competitive advantage in physiological suppression against its competitor. Piezodorus guildinii (Hemiptera: Pentatomidae) is an important soybean pest, and its main natural enemies are egg parasitoids Telenomus podisi and Trissolcus urichi (Hymenoptera: Platygastridae). We compared the ability of wasps to locate host eggs, and larval development time of both parasitoids. Both species took the same amount of time to find and contact eggs, and to start parasitising them. There were no differences in average development time of larvae, pupae, and the entire preimaginal period. Both parasitoid species compared in this study are closely related, having very similar life history strategies. These factors could have covered up other aspects of the host foraging abilities of each species, which can make differences between them when searching for hosts in the field. Moreover, searching abilities of both species could be similar under laboratory conditions but different under field conditions. Understanding competitive interactions between parasitoids is important to improve the biological control of the pest.

Descriptive Analysis of Reasons of Participating Literacy Courses and Effects of Being Literate

The aim of this study is to find out the effects of literacy acquisition on adults’ lives by exploring their background, experiences, and thoughts pertaining literacy’s effect. In order to find effects of literacy, qualitative case study method was used and semi-structured interviews were carried with nine participants. It is found that almost all participants had similar life histories, which triggered them to looking for new solutions in order to cope with life. Age and psychological status of participants were especially powerful inputs in participation process. All participants became able to travel, read and write in order to perform in their daily lives without having relied on others after completion of the course. In addition, all participants in this study felt themselves more confident, improve their communication skills and develop sense of empowerment. As a result, it was found that the literacycoursesshould be separated according to the age and psychological status of the participants as well as content of the curriculum.

Comparative phylogeography of West African amphibians and reptiles.

Comparative phylogeographic studies often support shared divergence times for co-distributed species with similar life histories and habitat specializations. During the late Holocene, West Africa experienced aridification and the turnover of rain forest habitats into savannas. These fragmented rain forests harbor impressive numbers of endemic and threatened species. In this setting, populations of co-distributed rain forest species are expected to have diverged simultaneously, whereas divergence events for species adapted to savanna and forest-edge habitats should be absent or idiosyncratic. We conducted a Bayesian analysis of shared evolutionary events to test models of population divergence for 20 species of anurans (frogs) and squamates (lizards and snakes) that are distributed across the Dahomey Gap, a climate change-induced savanna barrier responsible for fragmenting previously contiguous rain forests of Ghana into two regions: the Togo-Volta Hills and the Southwestern Forests. A model of asynchronous diversification is supported for anurans and squamates, suggesting that drivers of diversification are not specifically related to ecological and life history associations with habitat types. Instead, the wide variability of genetic divergence histories exhibited by these species suggests that biodiversity in this region has been shaped by diversification events that extend beyond the Holocene. Comparisons of the genealogical divergence index, a measure of the genetic divergence between populations due to the combined effects of genetic isolation and gene flow, illustrate that these populations represent a broad sampling of the speciation continuum.

Management, morphological and genetic diversity of domesticated agaves in Michoac\xe1n, M\xe9xico

BackgroundPulque is a fermented beverage prepared with sap of Agave species in Mexico. Management of agaves for this purpose has motivated domestication of some species and high phenotypic variation that commonly causes uncertainty about the taxonomic identity of varieties traditionally managed by people. This study assumed that varieties of crop species continually arise from mutations, sexual reproduction and hybridization, among other processes, and some of them are favoured and maintained by humans. Identifying these varieties may be difficult and a challenging issue for botanists and evolutionary biologists studying processes of domestication. Through a case study, we analysed the traditional varieties of agaves used to produce pulque in Michoacán, Mexico. We aimed at identifying the varieties, analysing the relatedness among them and developing a methodological approach that could help solve taxonomic problems and study variation under domestication of this and other plant groups. We documented (1) the traditional varieties of agave used and their identity, (2) how these varieties are perceived, used and managed by the local people and (3) how management influences phenotypic and genetic variation among varieties.MethodsWe interviewed pulque producers in two localities of the state of Michoacán, Mexico, where we recorded management practices of agaves, the traditional varieties used, the attributes characterizing those varieties, the varieties preferred by people, and features and mechanisms of selection. We conducted multivariate analyses of morphological features of the agave varieties, as well as genetic diversity and genetic distance studies among agave varieties through 11 nuclear microsatellites.ResultsSeven traditional varieties of Agave were recorded in the study area. Multivariate analyses of morphology identified varieties belonging to the species A. salmiana, A. mapisaga and, presumably, A. americana. The preferred varieties have morphological features selected to make easier their management and produce higher sap yields. Genetic diversities (HE = 0. 470 to 0.594) were high compared with other Agave species with similar life history traits and use. Genetic distance analyses grouped the varieties “Verde” and “Negro” (identified as A. salmiana), whereas the varieties “Tarímbaro” and “Listoncillo” (identified as A. mapisaga) formed another group. The varieties “Blanco” and “Carrizaleño” (most probably being A. americana) clustered with varieties of A. salmiana, whereas the variety “Cenizo” appeared as a distinct group. Bayesian analysis indicated that most individuals of varieties of A. salmiana form a group and those of the varieties of A. mapisaga form another, whereas individuals of the varieties putatively belonging to A. americana clustered in similar proportions with both groups.ConclusionsThe traditional pulque production in the study area is an ongoing practice. It is still an important source of products for direct consumption by households and generation of economic incomes and as part of the cultural identity of local people. The most used traditional variety exhibited a marked gigantism, and although these agaves are mainly asexually propagated, populations have high genetic diversity. The local producers promote the maintenance of different traditional varieties. Our study shows the value of an integral research approach including ethnobiological, morphological and genetic information to clarify the state of variation influenced by humans on agaves, but it would be helpful to study other organisms under domestication. In addition, such approach would help to document human and non-human mechanisms generating crop varieties managed by local people.

Invasions of rainbow trout and brown trout in Japan: A comparison of invasiveness and impact on native species

AbstractMany species of salmonids have been stocked into waters outside of their native range. The invasiveness and impact of these species on native species varies depending on their biological traits, and on environmental conditions, such as climate. In Japan, rainbow trout and brown trout, both listed in 100 of the world's worst invasive alien species by the International Union for Conservation of Nature, occur as non‐native species. The invasiveness of these two species is thought to be related to seasonal flooding, given flood waters can physically damage fry and prevent population establishment. Rainbow trout have successfully invaded waters in Hokkaido, northern Japan, where the likelihood of flooding is low between June and July, when their fry emerge, but successful invasions are rare in regions south of Hokkaido. Brown trout, however, have successfully invaded waters not only in Hokkaido, but also other regions. Since brown trout have a similar life history to the native white‐spotted charr and masu salmon, with fry emerging before the flood season, they are more suited to the Japanese climate than Rainbow trout. Rainbow and brown trout interact with native species in various ways, but a common outcome of these interactions is the displacement of native charr species. Legal regulations of non‐native salmonids should be based on understandings of the ecological traits of each invasive species and regional impacts on native species. Given the ongoing nature of climate change, the nature and extent of the effects of rainbow and brown trout on native species might also change.

Growth and longevity of Hawaiian grouper (Hyporthodus quernus) — input for management and conservation of a large, slow-growing grouper

Hawaiian grouper (Hyporthodus quernus) is endemic to the Hawaiian Islands and is regionally important, yet little is known about its life history. This large species is managed within the Deep 7 bottomfish complex, which includes six snapper species that are assumed to have similar life history traits. Previous age estimates were not validated and suggested a maximum age of 34 years. To evaluate the preliminary study and provide a valid basis for life history parameters, we aged otoliths using bomb radiocarbon (14C) dating. Measured 14C values provided ages for smallest to largest fish that differed from the original study. The fundamental information provided here when evaluating Hawaiian grouper conservation status is longevity (valid to 50 years and estimated to 76 years) — no male sampled was <80 cm total length (TL) and younger than 34 years — and age-at-sexual maturity and age-at-sex change, which were indirectly estimated and compared with prior published estimates for this and other groupers. Updated life history parameters (k = 0.078, L∞ = 95.8 cm TL) should be used to improve future management and conservation assessments.

Genetic diversity and structure of Carpinus laxiflora populations in South Korea based on AFLP markers

We applied eight primer-restriction enzyme combinations to investigate genetic diversity, genetic differentiation, and genetic structure of Carpinus laxiflora populations with AFLP markers. The average of effective alleles (Ae), the proportion of polymorphic loci (%P), Shannon’s diversity index (I), and the expected heterozygosity (He) were 1.4, 82.2%, 0.371, and 0.241, respectively. The expected heterozygosity (Hj) from Bayesian method was 0.270. The level of genetic diversity was high compared to those of Carpinus species and other species with a similar life history. The inbreeding coefficient (FIS) from approximated Bayesian method was 0.618, which was smaller than that for Acer pseudosieboldianum (FIS=0.712). Genetic differentiation was 0.060 from AMOVA (ΦST) and 0.056 from Bayesian method (θII). The level of genetic differentiation was very small compared to that of Carpinus species and other species with a similar life history. According to UPGMA and Bayesian clustering, 10 populations were divided into two genetic groups. Except Mt. Chilgap and Minjuji, most of the populations were detected as weak genetic structures according to the geographical distribution such as mountain ranges. We might consider that demographic disturbance, local specific vegetation change history, and forest succession interrupted the genetic structure of C. laxiflora in South Korea.

Potential of marbled crayfish Procambarus virginalis to supplant invasive Faxonius immunis

Biological invasions are a growing threat to global biodiversity due to negative impacts on native biota and ecosystem functioning. Research has expanded from investigating native and alien species interactions to examining relationships among alien species. Invasive crayfish may have similar life histories, niche preferences, and adaptation strategies, but their mutual interactions are little understood. This study aimed to quantify interaction patterns of size-matched calico crayfish Faxonius immunis, established in the Rhine River catchment, and the parthenogenetic marbled crayfish Procambarus virginalis, currently spreading throughout Europe. During agonistic interactions in the absence of shelter, marbled crayfish won a significant majority of fights against calico crayfish, but in the presence of shelter there was no significant difference. When sex of calico crayfish was considered in the analysis without shelter, marbled crayfish won a significantly higher number of fights with female calico crayfish. In the absence of shelter, marbled crayfish dominated calico crayfish females in 83.3% and males in 60% of pairs. With available shelter, the dominance of marbled crayfish was 100% and 54.5% over female and male calico crayfish, respectively. The results suggested that sex and resource availability influence agonistic behaviour in the studied crayfish. Marbled crayfish are confirmed to be competitive against the calico crayfish, which has been shown to be dominant over another serious invader in the Rhine River catchment, the spiny-cheek crayfish Faxonius limosus. In natural sympatric populations, the situation may be affected by factors such as size, reproductive variables, water temperature, and predation pressure.

Internal transcribed spacer sequences analysis of genetic variation among and within populations of Atriplex halimus from different bioclimatic zones in Morocco

The genetic diversity of 12 Atriplex halimus L. populations collected throughout its natural range in Morocco has been studied by using sequences of nrDNA ITS region. Within-population genetic diversity was high in comparison to others species with similar life histories and ecological traits. Most of genetic variation detected by AMOVA resided within populations (94%), relative to the amount of variation among populations (6%). The level of populations differentiation (FST = 0.06) was low, which corresponds with the high level of gene flow (4.00) revealed between populations. Differentiation among ecological groups of populations accounted only for 1.23% of the total ITS variation, which indicates that climatic conditions did not have an effect of population's structuration or that this differentiation is obviously not related to ITS markers. Furthermore, very low genetic differentiation (FCT = 0.015) was observed between regions (Moroccan populations versus American population). Strangely enough, geographic distances were not correlated to genetic differentiation between the populations (r = 0.06, P = 0.5). The structuration of populations in five groups was not operated according to their bioclimatic type. The data obtained in this assay could play a crucial role to establish efficient strategies for genetic resources conservation and to work out the scheme of breeding programs of Atriplex.

Comparative genomic analysis of three co-occurring annual Asteraceae along micro-geographic fragmentation scenarios

This is the first population genomic analysis that examines micro-evolutionary changes in co-occurring plant species, in fragmented habitats, along a precipitation gradient. We applied Genotype-by-Sequencing (GBS) on three different annual Asteraceae on the same sites that share similar life history strategies, but different pollination and dispersal strategies (Catananche lutea, Geropogon hybridus, Urospermum picroides).We tested if the genetic diversity for all species correlates with effective population sizes along the precipitation gradient and whether therefore genetic drift drives evolution at range edges. However, our results support this hypothesis for only one species (C. lutea) but refute it for the other two. Potential genomic signals of adaptation to the high precipitation gradient were found only in one species (U. picroides). We also tested if species with complex pollination and diversified dispersal strategies are less affected by small scale habitat fragmentation, but the opposite is true. Biological differences between the species studied (pollination and dispersal) explain population genetic differences along the precipitation gradient at range edges rather than environmental filters. Pairwise correlation analyses showed no or only weak similarities in the accumulation of mutations in the different species.Our results suggest that the processes driving evolution in different co-occurring species are different, so that most genomic similarities in our investigations may only represent temporary stages in evolution.

Population genetics of Mesembryanthemum crystallinum in Egypt

Genetic diversity plays an important role in any long term management planning of a species. Mesembryanthemum crystallinum has been naturalized in disturbed regions along the Mediterranean coast competing with native plants. The levels and pattern of the genetic variation within and among its populations along Deltaic Mediterranean coast of Egypt was investigated using random amplified polymorphic DNA (RAPD). Forty‐two samples representing nine populations of M. crystallinum were collected. The results showed that %PPB values for a single population ranged from 9.14% to 28.91% with an average of 19.76%. The average of Shannon information index (SI), expected heterozygosity (He) and unbiased expected heterozygosity (uHe) values were 0.098, 0.064 and 0.072, respectively. According to AMOVA analysis, 9% of the total genetic structure was attributable to regional divergences and 38% to population differentiation within regions and 53% differences among individuals within populations. Mantel test showed a low correlation (r2= 0.001) between the studied populations. The dendrogram exhibited two clusters of populations which were confirmed by principal coordinate analysis (PCoA). The study concluded that M. crystallinum has lower levels of diversity than other plant species with similar life history characteristics and high genetic differentiation among population.

Animal life history is shaped by the pace of life and the distribution of age-specific mortality and reproduction.

Animals exhibit an extraordinary diversity of life history strategies. These realized combinations of survival, development and reproduction are predicted to be constrained by physiological limitations and by trade-offs in resource allocation. However, our understanding of these patterns is restricted to a few taxonomic groups. Using demographic data from 121 species, ranging from humans to sponges, we test whether such trade-offs universally shape animal life history strategies. We show that, after accounting for body mass and phylogenetic relatedness, 71% of the variation in animal life history strategies can be explained by life history traits associated with the fast-slow continuum (pace of life) and with a second axis defined by the distribution of age-specific mortality hazards and the spread of reproduction. While we found that life history strategies are associated with metabolic rate and ecological modes of life, surprisingly similar life history strategies can be found across the phylogenetic and physiological diversity of animals.

Differences in dietary niche and foraging behavior of sympatric mule and white‐tailed deer

AbstractMule (Odocoileus hemionus) and white‐tailed deer (Odocoileus virginianus) are congeneric and share similar life histories, yet their distribution is segregated across much of North America. Extensive research on both species within and outside their zone of co‐occurrence has not fully explained these distribution patterns, especially the potential role of diet and foraging behavior. Therefore, we used a common garden experiment to compare diet composition, diet quality, foraging behavior, and intake of tractable mule and white‐tailed deer foraging together within the dry Douglas‐fir (Pseudotsuga menziesii)/ponderosa pine (Pinus ponderosa) forests of northeastern Washington. We sampled at 21 0.5‐ha sites from June to August 2016. We used standard bite count techniques coupled with forage biomass sampling, behavioral observations, and nutritional analyses to compare the foraging ecology of the two species. Mule and white‐tailed deer had similar activity patterns. However, mule deer took larger bites and harvested food faster than white‐tailed deer, and white‐tailed deer consumed more diverse but higher‐quality diets than mule deer. These differences resulted in mule deer acquiring ~25% more dry matter and digestible energy per day. About 90% of the diets consumed by both deer species consisted of deciduous shrubs and forbs, and they selected many of the same plant species. However, overall diet composition was 38% dissimilar, with mule deer consuming diets that were more likely to contain shrubs with higher levels of tannins and lower levels of dry matter digestibility than diets eaten by white‐tailed deer. Dietary overlap was greatest at both very low and very high forage biomass, indicating potential for modest resource competition or partitioning. Our research provides evidence that differences in diet composition of mule and white‐tailed deer do not merely reflect differences in habitat selection, but also suggest the species differ in their fundamental nutritional niches.

Data gaps and opportunities for comparative and conservation biology

Biodiversity loss is a major challenge. Over the past century, the average rate of vertebrate extinction has been about 100-fold higher than the estimated background rate and population declines continue to increase globally. Birth and death rates determine the pace of population increase or decline, thus driving the expansion or extinction of a species. Design of species conservation policies hence depends on demographic data (e.g., for extinction risk assessments or estimation of harvesting quotas). However, an overview of the accessible data, even for better known taxa, is lacking. Here, we present the Demographic Species Knowledge Index, which classifies the available information for 32,144 (97%) of extant described mammals, birds, reptiles, and amphibians. We show that only 1.3% of the tetrapod species have comprehensive information on birth and death rates. We found no demographic measures, not even crude ones such as maximum life span or typical litter/clutch size, for 65% of threatened tetrapods. More field studies are needed; however, some progress can be made by digitalizing existing knowledge, by imputing data from related species with similar life histories, and by using information from captive populations. We show that data from zoos and aquariums in the Species360 network can significantly improve knowledge for an almost eightfold gain. Assessing the landscape of limited demographic knowledge is essential to prioritize ways to fill data gaps. Such information is urgently needed to implement management strategies to conserve at-risk taxa and to discover new unifying concepts and evolutionary relationships across thousands of tetrapod species.

Heterochrony in chimpanzee and bonobo spatial memory development.

The emergence of human-unique cognitive abilities has been linked to our species' extended juvenile period. Comparisons of cognitive development across species can provide new insights into the evolutionary mechanisms shaping cognition. This study examined the development of different components of spatial memory, cognitive mechanisms that support complex foraging, by comparing two species with similar life history that vary in wild ecology: bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Spatial memory development was assessed using a cross-sectional experimental design comparing apes ranging from infancy to adulthood. Study 1 tested 73 sanctuary-living apes on a task examining recall of a single location after a 1-week delay, compared to an earlier session. Study 2 tested their ability to recall multiple locations within a complex environment. Study 3 examined a subset of individuals from Study 2 on a motivational control task. In Study 1, younger bonobos and chimpanzees of all ages exhibited improved performance in the test session compared to their initial learning experience. Older bonobos, in contrast, did not exhibit a memory boost in performance after the delay. In Study 2, older chimpanzees exhibited an improved ability to recall multiple locations, whereas bonobos did not exhibit any age-related differences. In Study 3, both species were similarly motivated to search for food in the absence of memory demands. These results indicate that closely related species with similar life history characteristics can exhibit divergent patterns of cognitive development, and suggests a role of socioecological niche in shaping patterns of cognition in Pan.

Survey design for broad-scale, territory-based occupancy monitoring of a raptor: Ferruginous hawk (Buteo regalis) as a case study.

Given the uncertain population status of low-density, widely-occurring raptors, monitoring changes in abundance and distribution is critical to conserving populations. Nest-based monitoring is a common, useful approach, but the difficulty and expense of monitoring raptor nests and importance of reliable trend data to conservation requires that limited resources are allocated efficiently. Power analyses offer a helpful tool to ensure that monitoring programs have the ability to detect trends and to optimize financial resources devoted to monitoring. We evaluated alternative monitoring designs for raptors to identify appropriate survey effort to detect population trends. We used data collected from a territory-occupancy study of ferruginous hawks throughout Wyoming to guide simulations and evaluate the ability to detect trends in occupancy rates. Results suggest that greater gains in precision of trend estimation may be achieved through the addition of more sites and not more visits; statistical power was ≥80% when monitoring lasted 20 years and population declines were 20%; and probability of detection affected statistical power less than rates of population decline. Monitoring at least 150 sites for 20 years would provide reasonable estimates of trend in occupancy given certain rates of detection and occupancy, but only for population declines of 20%. Removal sampling did not result in substantial changes of any metrics used to evaluate simulations, providing little justification for employing the standard design if territory occupancy is the variable of interest. Initial rates of territory occupancy may be biased high, a problem inherent to many studies that monitor territory occupancy. We explored the effects of lower rates of initial occupancy on the ability to detect trends. Although we present data from a study of ferruginous hawks, our simulations can be applied to other raptor species with similar life history and population dynamics to provide guidance for future trend estimation of territory occupancy.