Establishment Of Colonies Research Articles

Identification and Characterization of Sources of Resistance to Peronospora variabilis in Quinoa

Downy mildew, caused by Peronospora variabilis, is the most important quinoa disease worldwide. However, little is known about the resistance mechanisms acting against this disease. The study goals were to identify quinoa accessions showing resistance to P. variabilis under Spanish field conditions and to characterize the resistance mechanism involved. Towards these objectives, a total amount of 229 accessions of Chenopodium quinoa and one accession of each of the species Chenopodiun berlandieri subs. nutillae, Chenopodium ugandae, and Chenopodium opulifolium were screened for resistance to P. variabilis under field conditions in Córdoba, Spain, during two seasons. The response to P. variabilis in the accessions showed a continuous distribution ranging from complete resistance to high susceptibility. Fifteen resistant and one susceptible accessions were selected for further histological studies. Histological results showed that resistance to downy mildew in quinoa acts mainly at the stage of colony establishment. In resistant accessions, no colonies were formed or success in colony establishment was significantly reduced compared with the susceptible control. Hypersensitive response was associated with colony abortion in a number of the resistant accessions. This work is the first proof of hypersensitive reaction occurrence in quinoa as a response to P. variabilis.

Is regional variability in environmental conditions driving differences in the early body condition of endemic Australian fur seal pups?

Context Good body condition in juvenile marine mammals is crucial for survival and, therefore, population demography. Australian fur seals, endemic to Australia, recently established a breeding colony at the southern edge of their range, at The Needles, a small group of islands in south-west Tasmania (43.6614°S) and a significant distance from their core breeding range in Bass Strait. Aims We aimed to compare pup body condition at two breeding colonies, distinct in time since establishment and latitude. Specific aims were to: (1) establish the timing of peak pupping, to compare condition of known-age pups, and determine a baseline at The Needles; (2) investigate pup body condition over time at an established colony; and (3) gain insight into the effects of environmental conditions on pup body condition. Methods We conducted a colony comparison of pup body condition using condition indices at The Needles and an established breeding colony in Bass Strait, Tenth Island, for the 2019/20 and 2020/21 breeding seasons. Pup body condition was quantified at Tenth Island over 18 years (2003–2020) using a long-term morphometric dataset. To establish breeding phenology at these two colonies, we determined peak pupping date for the 2019/20 breeding season using daily pup counts. We assessed the effect of environmental parameters on body condition for the long-term dataset. Key results Pups from The Needles displayed significantly higher body condition than those from Tenth Island, despite similar peak pupping date. Breeding phenology was consistent with published timing for Australian fur seals. Pup body condition at Tenth Island over the 2-year colony comparison was comparable to the historical average. Environmental drivers that affect maternal foraging efficiency are linked to pup body condition. Conclusions Higher pup body condition at The Needles is likely underpinned by better foraging conditions resulting in increased pup provisioning levels. Our results indicate that south-west Tasmania is a region of foraging and emerging breeding importance for Australian fur seals. Implications Future research to monitor pup body condition, maternal foraging behaviour and ecosystem productivity at The Needles will help to provide greater understanding of likely population trajectories at this southernmost breeding site for Australian fur seals.

Pesticide exposure and forage shortage in rice cropping system prevents honey bee colony establishment

As one of the key stable crops to feed half of the world's population, how rice cropping system affects honey bee health regarding pesticide exposure and forage availability is under investigated. We predicted honey bees were stressed by high pesticide exposure and forage dearth in monoculture rice systems. Providing access to natural habitats is a typical approach to mitigate the negative impact of intensive agriculture on honey bees. We aimed to determine if bee colonies located in landscapes with more cover of forest habitat would collect more forage and be exposed to less pesticides. We selected beekeeping locations in rice dominated landscapes (as control), mosaic landscapes of rice and medium woodland (MW) cover, and landscapes of high woodland (HW) cover, respectively, in July when rice starts bloom and pesticides are commonly used. Colonies were inspected at a biweekly frequency from July to October with population growth and forage (nectar and pollen) availability estimated. Pollen and bees were collected in middle August for pesticide exposure analysis. We did not observe enhancement in forage availability and reduction in pesticide exposure in landscapes with increased forest habitat (i.e., MW or HW cover), and all colonies failed in the end. Other natural habitats that can supplement flower shortage periods in forest can be considered for supporting bee health. Our results suggest that forest should be carefully assessed for being incorporated into beekeeping management or pollinator conservation when forest phenology can be a factor to affect its impact as a natural habitat.

Postcolonialism: Literary Applications of a Decolonizing Tool

Postcolonialism revolves around studying the effects of colonialism on cultures and discloses how European nations controlled "Third World" cultures and how the latter resisted cunning encroachments. It endeavors to decolonize postcolonial states from the political conditions to the cultural ones, as it contests the contemporary legacies of historical colonialism so as to break the present imbalances of power. Postcolonialism also seeks to criticize contemporary colonial ways by seeking powerful substantial change in postcolonial nations while celebrating the lost history of resistance as well. The purpose of this research study is to define postcolonialism and show how postcolonial literary theory is applied to examine texts produced by both the colonized and the colonizing forces. Also, it endeavors to contribute to the body of postcolonial literature and celebrate the lost cultural heritage of the colonized. To meet this end, this research investigation adopts an exploratory research design and uses searching and screening tools to examine, analyze and synthesize relevant first and secondary sources. The findings indicated that postcolonial literary theories, in their multidimensional and multidisciplinary nature, have proven practically useful in scrutinizing western literature, celebrating literary works by the colonized subaltern through giving voice to the tamed, stifled, and disdained intellectuals whose works disclose the truth behind the civilizing mission of colonialism which was nothing but a series of ideas and practices used to legitimize the establishment of overseas colonies to subject people. The results of this research study are significant in the way that they would not only enrich and further advance the existing canon of postcolonial literature but would also raise awareness of everyone investigating the power dynamics of the colonizer and the colonized. In this respect, it is therefore hoped that our dissertation deepens greater understanding and inspires respect, honor, and rehabilitation for the colonized.

Honeybees are buffered against undernourishment during larval stages.

The negative impact of juvenile undernourishment on adult behavior has been well reported for vertebrates, but relatively little is known about invertebrates. In honeybees, nutrition has long been known to affect task performance and timing of behavioral transitions. Whether and how a dietary restriction during larval development affects the task performance of adult honeybees is largely unknown. We raised honeybees in-vitro, varying the amount of a standardized diet (150 µl, 160 µl, 180 µl in total). Emerging adults were marked and inserted into established colonies. Behavioral performance of nurse bees and foragers was investigated and physiological factors known to be involved in the regulation of social organization were quantified. Surprisingly, adult honeybees raised under different feeding regimes did not differ in any of the behaviors observed. No differences were observed in physiological parameters apart from weight. Honeybees were lighter when undernourished (150 µl), while they were heavier under the overfed treatment (180 µl) compared to the control group raised under a normal diet (160 µl). These data suggest that dietary restrictions during larval development do not affect task performance or physiology in this social insect despite producing clear effects on adult weight. We speculate that possible effects of larval undernourishment might be compensated during the early period of adult life.

Studying the historical representation of European religions through 3D digital sculpture art

3D digitization of social legacy has been utilized to safeguard data about colonial legacy items like design, craftsmanship, and trinkets. The 3-d unfolding of gadgets via improvements including elevated reality, augmented reality, and 3-d printing have affected the fields of expertise records and social legacy and features grow to be extra normal. However, concentrates on that go past the specialized parts of 3D innovation and treat such points as their importance for reclamation, protection, commitment, schooling, exploration, and morals scarcely exist. The point of this paper is twofold: from one perspective, it expects to get a superior comprehension of the materialness of every innovation for various purposes gallery show, and, then again, it centers on the discernment of these innovations. This exploration was completed by joining a writing survey with quantitative and subjective investigations of the information procured through a study of SIX inquiries a. Given the analysis of this quantitative and personal information, we give a few measures to utilizing 3D digitized and printed multiplications to upgrade social encounters. The outcomes show the significance of cautiously planning 3D collaborations in the individual and social settings of end-clients and colonial establishments in a request to make genuine social encounters.

Host plant phenology shapes aphid abundance and interactions with ants

Phenological mismatch can occur when plants and herbivores differentially respond to changing phenological cues, such as temperature or snow melt date. This often shifts herbivore feeding to plant stages of lower quality. How herbivores respond to plant quality may be also mediated by temperature, which could lead to temperature‐by‐phenology interactions. We examined how aphid abundance and mutualism with ants were impacted by temperature and host plant phenology. In this study system, aphids Aphis asclepiadis colonize flowering stalks of the host plant, Ligusticum porteri. Like other aphids, abundance of this species is dependent on ant protection. To understand how host plant phenology and temperature affect aphid abundance, we used a multiyear observational study and a field experiment. We observed 20 host plant populations over five years (2017–2021), tracking temperature and snow melt date as well as host plant phenology and insect abundance. We found host plant and aphid phenology to differentially respond to temperature and snow melt timing. Early snow melt accelerated host plant phenology to a greater extent than aphid phenology, which was more responsive to temperature. Both the likelihood of aphid colony establishment and ant recruitment were reduced when aphids colonized host plants at post‐flowering stages. In 2019, we experimentally accelerated host plant phenology by advancing snow melt date by two weeks. We factorially combined this treatment with open top warming chambers surrounding aphid colonies. Greatest growth occurred for colonies under ambient temperatures when they occurred on host plants at the flowering stage. Altogether, our results suggest that phenological mismatch with host plants can decrease aphid abundance, and this effect is exacerbated by temperature increases and changes to the ant–aphid mutualism.

Eusociality and the transition from biparental to alloparental care in termites

AbstractIn eusocial organisms, cooperative brood care within a colony represents a situation where the ancestral parental care duties have shifted away from the reproductive parent(s) towards their offspring. The shift to alloparental care was often instrumental in the initial emergence of eusociality, as it ultimately contributed to the establishment of the reproductive division of labour.Remarkably, eusocial taxa such as ants and termites, which still display an ancestral independent colony foundation phase, must go through an obligatory parental care period, as a temporary subsocial family unit. In termites specifically, an incipient colony inherently remains a woodroach family unit until alloparental care is established. Colony foundation success can then be limited by a series of factors that may include environmental, behavioural, symbiotic and physiological constraints.In this study, 450 incipient termite colonies (Coptotermes gestroi) were established to investigate the timing of physiological changes in founders during the transition from biparental to alloparental care. Results showed that the finite initial internal nutritional resources that alates carry during the dispersal flight are a primary limiting factor for successful colony establishment. TheCoptotermesqueen and king must rapidly establish (<150 days) their first cohort of offspring to reach alloparental care or simply run out of resources and die. Alates, therefore, carry just enough internal resources to produce the first few alloparents (< 15 workers) to prime the system towards colony ergonomic growth, with a definitive shift to solely reproductive functions.Eusocial insect primary reproductive traits were optimized for three successive functions within the life cycle of a colony: alate dispersal (sexual reproduction), colony foundation (parental care) and colony growth (increased egg production towards colony maturity). However, results suggest that trade‐offs involving these functions appear to primarily favour dispersal ones (quantity vs. quality of alates), as founder(s) carry minimal resources and have no room for parental care inefficiency and as they then fully rely on their alloparents for further reproductive output.The transition towards alloparental care during colony foundation of eusocial insects may, therefore, reflect on the initial evolutionary transition from ancestral subsociality to eusociality.Read the freePlain Language Summaryfor this article on the Journal blog.

Archival insights into vulnerability and risk management during the early Spanish colonial period (1598–1680 AD) in New Mexico

Risk and vulnerability are especially acute for colonizing populations due to their limited knowledge of the environment in newly settled areas and constrained social networks. Focusing on the initial settlement of the New Mexico colony, this paper examines the social response of Spanish colonists to vulnerability and risk during the early colonial period (AD 1598–1680). We use historical documents and modern weather records to assess the strategies implemented by 17th-century colonists to mitigate their vulnerability to the effects of unfamiliar, arid environmental conditions. The Spanish Crown had developed risk-reducing practices that encouraged successful establishment of colonies, including technological methods such as irrigation ditches and social methods such as tithing. However, these strategies made certain social and ethnic groups more vulnerable than others, ultimately contributing to the destruction of the New Mexico colony during the Pueblo Revolt in 1680. We argue that vulnerability buffering mechanisms are unevenly distributed across society. Systems of power must be considered when evaluating the effectiveness of social responses to risk.

Bernard Bailyn's Barbarous Modernity

Bernard Bailyn's Barbarous Modernity

Collection and Long-Term Maintenance of Leaf-Cutting Ants (<em>Atta</em>) in Laboratory Conditions

Ants are one of the most biodiverse groups of animals on the planet and inhabit different environments. The maintenance of ant colonies in controlled environments enables an enriched comprehension of their biology that can contribute to applied research. This practice is usually employed in population control studies of species that cause economic loss, such as Atta ants. To cultivate their mutualistic fungus, these leaf-cutting ants collect leaves and for this are considered agricultural pests widely distributed throughout the American continent. They are highly socially organized and inhabit elaborated underground nests composed of a variety of chambers. Their maintenance in a controlled environment depends on a daily routine of several procedures and frequent care that are described here. It starts with the collection of queens during the reproductive season (i.e., nuptial flight), which are then individually transferred to plastic containers. Due to the high mortality rate of queens, a second collection can be carried out about 6 months after the nuptial flight, when incipient nests with developed fungus wad are excavated, hand-picked, and placed in plastic containers. In the laboratory, leaves are daily provided to established colonies, and ant-produced waste is weekly removed along with remaining dry plant material. As the fungus garden keeps growing, colonies are transferred to different types of containers according to the experimental purpose. Leaf-cutting ant colonies are placed in interconnected containers, representing the organizational system with functional chambers built by those insects in nature. This setup is ideal to monitor factors such as waste amount, fungus garden health, and the behavior of workers and queen. Facilitated data collection and more detailed observations are considered the greatest advantage of keeping ant colonies in controlled conditions.

Production of new colonies of Melipona subnitida Ducke (Hymenoptera: Apidae) by reclamation of excess virgin queens

One of the limitations to greater expansion of Meliponiculture and conservation efforts of most stingless bee species is related to the low reproductive rate of colonies, both in the wild and in meliponaries. However, in Melipona, colonies regularly produce an excessive number of virgin queens which are eliminated by the workers. Here, we investigated the use of the excess of virgin queens produced in colonies of Melipona subnitida to produce new colonies using the minimum resources possible from the mother colonies. Virgin queens were evaluated for the acceptance by workers and the establishment of new colonies; the main behaviors they presented and their possible connection to physiological responses were recorded. After that, we evaluated the mating success of the accepted queens and the establishment of new colonies in meliponaries in different environments and with different contexts of male production. The results showed that the age of the virgin queens is not a limiting factor for their acceptance by the workers but the existence of clusters of males is essential for the fertilization and establishment of the new colonies. Under these conditions, the method had a 36.7% success rate, roughly producing a new colony for every three queens that would have been wasted. The method proved to be promising for producing a large number of new colonies descending from virgin queens that are normally eliminated, with little use of resources and in a short period of time. Although only tested on M. subnitida, it can potentially be used for any species of Melipona.

Rearing the green-belly stink bug, Diceraeus furcatus (Fabricius, 1775) (Hemiptera: Pentatomidae) in laboratory

The green belly stink bug, Diceraeus furcatus (Fabricius, 1775) (Heteroptera: Pentatomidae) is an emergent Neotropical crop pest, whose status has progressively changed in the last few years. Diceraeus furcatus is a polyphagous stink bug and its feeding behavior damages corn seedlings, wheat and oat spikes, and soybean pods, causing economic losses. Establishing stock populations of D. furcatus is difficult, and a suitable rearing method is lacking. The establishment of stock colonies is essential to study many aspects of a species, especially economically important ones. In this paper, a method to keep viable stock populations of D. furcatus in the laboratory is described. The periodic asepsis of cages (48 hours), periodical change of diet (48 hours), and mixed diet consisting of bean pods plus peanut and soybean grains, allowed us to obtain adequate biological parameters and population increase of this species. Fertility (251 eggs/female), fecundity (225.91 nymphs/female), and R0 (43 times of increase) show a consistent increase in the population. Additionally, adult survivorship/longevity and weight support the suitability of the method applied. The establishment of stock populations is the first step for a mass-rearing method that is essential to the development of biological control programs and other studies on this emergent pest.

First national-scale evaluation of temephos resistance in Aedes aegypti in Peru

BackgroundThe development of resistance against insecticides in Aedes aegypti can lead to operational failures in control programs. Knowledge of the spatial and temporal trends of this resistance is needed to drive effective monitoring campaigns, which in turn provide data on which vector control decision-making should be based.MethodsThird-stage larvae (L3) from the F1 and F2 generations of 39 Peruvian field populations of Ae. aegypti mosquitoes from established laboratory colonies were evaluated for resistance against the organophosphate insecticide temephos. The 39 populations were originally established from eggs collected in the field with ovitraps in eight departments of Peru during 2018 and 2019. Dose–response bioassays, at 11 concentrations of the insecticide, were performed following WHO recommendations.ResultsOf the 39 field populations of Ae. aegypti tested for resistance to temephos , 11 showed high levels of resistance (resistance ratio [RR] > 10), 16 showed moderate levels of resistance (defined as RR values between 5 and 10) and only 12 were susceptible (RR < 5). The results segregated the study populations into two geographic groups. Most of the populations in the first geographic group, the coastal region, were resistant to temephos, with three populations (AG, CR and LO) showing RR values > 20 (AG 21.5, CR 23.1, LO 39.4). The populations in the second geographic group, the Amazon jungle and the high jungle, showed moderate levels of resistance, with values ranging between 5.1 (JN) and 7.1 (PU). The exception in this geographic group was the population from PM, which showed a RR value of 28.8 to this insecticide.ConclusionsThe results of this study demonstrate that Ae. aegypti populations in Peru present different resistance intensities to temephos, 3 years after temephos use was discontinued. Resistance to this larvicide should continue to be monitored because it is possible that resistance to temephos could decrease in the absence of routine selection pressures.Graphical

Rapid and cost‐effective detection of Fusarium euwallaceae from woody tissues

AbstractThe polyphagous shot hole borer (PSHB) Euwallacea fornicatus is an ambrosia beetle that poses a serious threat to hundreds of tree species in invaded countries. In its invaded range, it relies on a mutualistic fungus, Fusarium euwallaceae, for colony establishment and nutrition. Together, the beetle–fungus complex can cause Fusarium dieback disease that can lead to the death of highly susceptible hosts. The key to mitigation of the spread and control of PSHB is its rapid detection. Current identification relies on DNA extraction and sequencing of barcoding genes of the beetle and/or the fungus, which is expensive and time‐consuming. Often the beetle is not present in a sample, and isolation and purification of the fungus is needed before employing molecular procedures. Because PSHB has a strong association with its fungal symbiont, at least in its invaded range, and the fungus can infect trees without successful PSHB colony establishment, a molecular tool that can rapidly detect F. euwallaceae from infected wood would aid monitoring efforts. Here we developed a PCR amplification protocol that targets a species‐specific gene present in F. euwallaceae from within infected wood of various hosts without prior fungal isolation, DNA purification or sequencing. The technique can detect F. euwallaceae within minimal woody material (c.15 mg) and even from degraded samples of many hosts. Additionally, identification of F. euwallaceae using lysate prepared from mycelia provided a reliable secondary measure. This method drastically reduces the time and costs associated with the identification of F. euwallaceae from field samples.

Laboratory breeding of two Phortica species (Diptera: Drosophilidae), vectors of the zoonotic eyeworm Thelazia callipaeda

BackgroundSome species of drosophilid flies belonging to the genus Phortica feed on ocular secretions of mammals, acting as biological vectors of the zoonotic eyeworm Thelazia callipaeda. This study describes an effective breeding protocol of Phortica variegata and Phortica oldenbergi in insectary conditions.MethodsAlive gravid flies of P. oldenbergi, P. variegata and Phortica semivirgo were field collected in wooded areas of Lazio region (Italy) and allowed to oviposit singularly to obtain isofamilies. Flies were maintained in ovipots (200 ml) with a plaster-covered bottom to maintain high humidity level inside. Adult feeding was guaranteed by fresh apples and a liquid dietary supplement containing sodium chloride and mucin proteins, while larval development was obtained by Drosophila-like agar feeding medium. The breeding performances of two media were compared: a standard one based on cornmeal flour and an enriched medium based on chestnut flour. All conditions were kept in a climatic chamber with a photoperiod of 14:10 h light:dark, 26 ± 2 °C and 80 ± 10% RH.ResultsFrom a total of 130 field-collected Phortica spp., three generations (i.e. F1 = 783, F2 = 109, F3 = 6) were obtained. Phortica oldenbergi was the species with highest breeding performance, being the only species reaching F3. Chestnut-based feeding medium allowed higher adult production and survival probability in both P. oldenbergi and P. variegata. Adult production/female was promising in both species (P. oldenbergi: 13.5 F1/f; P. variegata: 4.5 F1/f).ConclusionsThis standardized breeding protocol, based on controlled climatic parameters and fly densities, together with the introduction of an enriched chestnut-based feeding medium, allowed to investigate aspects of life history traits of Phortica spp. involved in the transmission of T. callipaeda. Obtaining F3 generation of these species for the first time paved the road for the establishment of stable colonies, an essential requirement for future studies on these vectors in controlled conditions.Graphical abstract

Nitrogen fixation by diverse diazotrophic communities can support population growth of arboreal ants

BackgroundSymbiotic ant-plant associations, in which ants live on plants, feed on plant-provided food, and protect host trees against threats, are ubiquitous across the tropics, with the Azteca-Cecropia associations being amongst the most widespread interactions in the Neotropics. Upon colonization of Cecropia’s hollow internodes, Azteca queens form small patches with plant parenchyma, which are then used as waste piles when the colony grows. Patches—found in many ant-plant mutualisms—are present throughout the colony life cycle and may supplement larval food. Despite their initial nitrogen (N)-poor substrate, patches in Cecropia accommodate fungi, nematodes, and bacteria. In this study, we investigated the atmospheric N2 fixation as an N source in patches of early and established ant colonies.ResultsVia 15N2 tracer assays, N2 fixation was frequently detected in all investigated patch types formed by three Azteca ant species. Quantified fixation rates were similar in early and established ant colonies and higher than in various tropical habitats. Based on amplicon sequencing, the identified microbial functional guild—the diazotrophs—harboring and transcribing the dinitrogenase reductase (nifH) gene was highly diverse and heterogeneous across Azteca colonies. The community composition differed between early and established ant colonies and partly between the ant species.ConclusionsOur data show that N2 fixation can result in reasonable amounts of N in ant colonies, which might not only enable bacterial, fungal, and nematode growth in the patch ecosystems but according to our calculations can even support the growth of ant populations. The diverse and heterogeneous diazotrophic community implies a functional redundancy, which could provide the ant-plant-patch system with a higher resilience towards changing environmental conditions. Hence, we propose that N2 fixation represents a previously unknown potential to overcome N limitations in arboreal ant colonies.

Crossing the Alps: Early Urbanism Between Northern Italy and Central Europe (900–400 BC). Edited by Lorenzo Zamboni, Manuel Fernández-Götz, and Carola Metzner-Nebelsick. Leiden: Sidestone Press 2020. Pp. 434. £166.50. ISBN 978-90-8890-961-0 (paper).

<i>Crossing the Alps: Early Urbanism Between Northern Italy and Central Europe (900–400 BC)</i>. Edited by Lorenzo Zamboni, Manuel Fernández-Götz, and Carola Metzner-Nebelsick. Leiden: Sidestone Press 2020. Pp. 434. £166.50. ISBN 978-90-8890-961-0 (paper).

Distribution and Abundance of the Glossy Ibis (Plegadis falcinellus) in Wintering and Breeding Grounds in Northeast Algeria

Atmospheric conditions play an important role in structuring avian communities in space and time. Here we assess the role of weather conditions on the distribution and abundance of the enigmatic glossy ibis (Plegadis falcinellus) in Northeast Algeria in both wintering grounds and in breeding areas in a survey spanning from 2011 to 2019. During the study period, cooler years were wetter and warmer years were drier. The wintering population size in the region could be estimated to 200-300 individuals. The number of individuals in wintering grounds increased in recent years in one site (Berrihane), but it did not show a strong association with weather conditions prior to wintering. Four breeding colonies were detected in highly-vegetated ponds with in-water trees where the number of breeding pairs was the highest. Extinction was recorded for two colonies (50% of colonies) where one permanently disappeared and one exhibited a series of extinctions and recolonizations across years. The estimated colony size was larger at El Dakhla (60–105 pairs) than El Chatt (0–42 pairs), Fezara Lake (25–41 pairs), and Tonga Lake (0–2 pairs). Climate conditions seemed to correlate with the number of pairs in one site (El Chatt) such that warm and dry years were associated with lower number of individuals. We discuss that disturbance and pollution might play a role in colony establishment but the number of pairs is positively related to the extinction of a nearby colony, suggesting that those refuge colonies are crucial for the persistence of the species in the area. This study presents historical data on the occurrence and abundance of a relatively unstudied species and gives new information on its climatic sensitivity which might be helpful for predicting future climate change impacts.

Age-structured model reveals prolonged immigration is key for colony establishment in Gentoo Penguins

AbstractUnderstanding the mechanisms of site colonization and range expansion is crucial to understanding population dynamics, particularly for colonial seabirds that may struggle to shift their breeding ranges under climate change. We provide an alternative and simple approach to estimating the number of migrating individuals among colonies when original mark–recapture datasets are not available for use in more integrated and established methods. Here we fit an age-structured population model with published vital rates and breeding success rates to simple point counts of abundance using rejection-based approximate Bayesian computation (ABC) to estimate the contribution of immigration to four recently colonized Gentoo Penguin (Pygoscelis papua) breeding sites on the Western Antarctic Peninsula. We found that sustained immigration over several years was required to generate the rapid population growth observed, with some sites even showing evidence of an accelerating immigration rate following initial colonization. We demonstrate that our method is capable of estimating the contribution of immigration to population growth in a species where mark–recapture datasets are unavailable. By leveraging census data that are relatively easy to obtain, our approach provides a new method for understanding how range expansions occur in species such as Antarctic penguins whose habitat is undergoing changing climate conditions.