Nest Choice Research Articles

Breeding density affects the movements of gull chicks, the size of their home ranges and their association with neighbours.

Colonies of ground-nesting species often have heterogeneous nest densities and their offspring experience different social conditions depending on the size and location of the breeding territory. For example, unintentional territory crossing by mobile chicks can trigger strong aggression from neighbouring adults, as observed in semi-precocial gulls. This would be expected to shape chicks' movement tendencies, exploratory behaviour and propensity for social contact through aversive feedback learning or pre-natal maternal effects, as mothers may pre-adapt their offspring's behaviour to the expected early life conditions. Therefore, we hypothesize that lesser black-backed gull chicks reared in denser areas of the breeding colony will move less, have smaller home ranges and have fewer social contacts with chicks from neighbouring nests. To test this, we first cross-fostered full clutches between and within high- and low-density parts of the colony, and then used ultra-wideband tags to track free-ranging chicks. In line with our predictions, we found that chicks reared in denser areas had a lower movement activity and smaller home ranges. However, these chicks still had more social contacts, although not necessarily with a higher number of unique individuals. Pre-natal breeding density had no significant effect on any of the parameters. We conclude that parental nest choice strongly affects the early social environment of their chicks, which can shape the development of their (social) phenotype, with potentially long-lasting consequences.

ODCHÓW NORCZ ˛AT POCHODZ ˛ACYCH Z GNIAZD OCIEPLANYCH RÓZNYM MATERIAŁEM

The aim of this study was to compare the rearing of mink in nests insulated with different materials. The study was conducted on a large-scale mink farm located in northwestern Poland. The results of rearing mink from 144 females of the pearl variety, aged one and two years, were analyzed. Four groups were created, taking into account the type of nest lining material and the age of the females. Two weeks prior to the scheduled birth, the nesting houses were lined with two types of insulating material - sawdust from deciduous trees and a mixture of barley straw and hay from meadow vegetation. Data were collected on: the number of born and live-born cubs per litter, the number of reared mink per litter, and the mortality of mink during the rearing period at the mothers. It was found that the material with which mink nests are insulated has an effect on the number of born, live-born and weaned mink. Better reproductive results were reported for females whose nests were insulated with barley straw mixed with meadow hay. They gave birth to larger litters, with more live mink, and raised more young. The mortality rate of young mink was lower in nests insulated with a mixture of straw and hay. The results showed that the use of sawdust as a nest insulating material is associated with a lower survival rate of reared mink. The study shows that the choice of a suitable nest insulating material can favorably affect the number of reared young mink.

Sex determination and optimal development in the Moorish gecko, Tarentola mauritanica

AbstractUnder temperature sex determination (TSD), sex is determined by temperature during embryonic development. Depending on ecological and physiological traits and plasticity, TSD species may face demographic collapse due to climate change. In this context, asymmetry in bilateral organisms can be used as a proxy for developmental instability and, therefore, deviations from optimal incubation conditions. Using Tarentola mauritanica gecko as a model, this study aimed first to confirm TSD, its pattern and pivotal temperature, and second to assess the local adaptation of TSD and variation of asymmetry patterns across four populations under different thermal regimes. Eggs were incubated at different temperatures, and hatchlings were sexed and measured. The number of lamellae was counted in adults and hatchlings. Results were compatible with a TSD pattern with males generated at low and females at high incubation temperatures. Estimated pivotal temperature coincided with the temperature producing lower embryonic mortality, evidencing selection towards balanced sex ratios. The temperature of oviposition was conservatively selected by gravid females. Asymmetry patterns found were likely related to nest temperature fluctuations. Overall, the rigidity of TSD may compromise reproductive success, and demographic stability in this species in case thermal nest choice becomes constrained by climate change.

The emergence of imperfect philopatry and fidelity in spatially and temporally heterogeneous environments

Repeatability in habitat use - often termed site fidelity - is widespread and ubiquitous. Often, used habitat areas may be inherited by offspring in a phenomenon called natal philopatry, leading to intergenerational repeatability in habitat preferences. Both fidelity and philopatry may represent strategies that could optimize fitness in spatially and temporally heterogeneous environments; however, the suite of ecological factors that encourage or discourage fidelity and philopatry remain poorly understood in most taxa. While turtles (Order Testudines) exhibit both fidelity and natal philopatry when selecting nesting areas, emerging evidence suggests that nest choice may be more plastic than previously thought. However, few studies to date have attempted to explore the behavioral choices that may produce deviations from nest site fidelity and philopatry. We used a spatially-explicit, individual-based model to explore how behavioral responses to a heterogeneous landscape can generate population-level patterns of fidelity and philopatry. We demonstrate that this model can dispersal patterns inferred from behavioral and genetic data from a Blanding's Turtle (Emydoidea blandingii) population in central Wisconsin. Reduced philopatry was associated with increasing error rates in habitat discrimination, and reduced site fidelity was associated with decreasing risk tolerance. Unpredictable spatial distributions of risk increased natal philopatry but decreased site fidelity overall, suggesting that strong natal imprinting may sometimes be associated with rapid shifts in habitat preferences in unpredictable environments. Associating risk exposure with increased adult or nest mortality led to increased nest site fidelity in both cases, but with relatively weak effects on natal philopatry. We also demonstrate the utility of this model for other landscapes and species by exploring a simplified seabird system. Our model holds promise for more detailed exploration of the ecological and evolutionary factors that may give rise to fidelity and philopatry.

Behavioral response to heat stress of twig-nesting canopy ants

Tropical forests experience a relatively stable climate, but are not thermally uniform. The tropical forest canopy is hotter and thermally more variable than the understory. Heat stress in the canopy is expected to increase with global warming, potentially threatening its inhabitants. Here, we assess the impact of heating on the most abundant tropical canopy arthropods—ants. While foragers can escape hot branches, brood and workers inside twig nests might be unable to avoid heat stress. We examined nest choice and absconding behavior—nest evacuation in response to heat stress—of four common twig-nesting ant genera. We found that genera nesting almost exclusively in the canopy occupy smaller cavities compared to Camponotus and Crematogaster that nest across all forest strata. Crematogaster ants absconded at the lowest temperatures in heating experiments with both natural and artificial nests. Cephalotes workers were overall less likely to abscond from their nests. This is the first test of behavioral thermoregulation in tropical forest canopy ants, and it highlights different strategies and sensitivities to heat stress. Behavioral avoidance is the first line of defense against heat stress and will be crucial for small ectotherms facing increasing regional and local temperatures.

Don’t listen to mom: no maternal influence on consistent nest and latrine site choice by their offspring in meadow voles

Abstract Where does an animal build a nest? At a large scale, habitat preference can be informed by ‘natal habitat preference induction’, where an animal’s early environment impacts what habitat it finds suitable later in life. Other preferences may be present within a chosen habitat. We tracked the location angle of nests and latrines within the home cages of captive meadow voles, Microtus pennsylvanicus. Nests and latrines were separated from each other by an angle of approximately 180°, perhaps to reduce disease transmission. Meadow voles’ nest and latrine site choices were individually consistent across time. Only nest site choices were consistent between siblings, as assessed by a random effect coefficient, and these choices were repeatable. However, nest site choices at maturity were independent of their mother’s nest choice. We posit that the nest and latrine site choice is a socially learned preference developed through the consensus of siblings after weaning.

Polyandry as a Male Strategy? A Game between Aggressive and Tolerant Males, Arbitrated by Females

AbstractUnrelated males sometimes share their nests and their mates, an example of male-male cooperation that calls for an evolutionary explanation. We developed a game-theoretic model of this situation under the assumption that males could be either "aggressors," attempting to drive off any other arriving male, or "tolerators," willing to share a nest and mates with another tolerator male. We modeled nest dynamics by changing the frequency of the two types in the population and determined how this affected their fitness. We use the sea lamprey as a case study to generate a plausible array of behavioral traits and ecological conditions for the model. Under these conditions, only aggressors or only tolerators could persist, not both, but we also show how exceptions can arise. Aggressors predominated for the standard conditions we chose, but tolerators could take over when females favored them through nest choice or increased mating rate. High nesting densities and high fighting costs also tended to favor tolerators. At moderate to low densities of individuals in the nesting area, female behavior, based on their own costs and benefits, should determine the outcome.

Nest size matters: common cuckoos prefer to parasitize larger nests of Oriental reed warblers.

Avian brood parasites leave parental care of their offspring to foster parents. Theory predicts that parasites should select for large host nests when they have sufficient available host nests at a given time. We developed an empirical experimental design to test cognitive ability of female cuckoos in nest size by studying nest choice of common cuckoos (Cuculus canorus) among nests of its Oriental reed warbler (Acrocephalus orientalis) hosts. We presented three groups of experimental nests: 1) nest dyads tied together including one large and one small artificial nest from reed leaves, 2) nest triads tied together used the old modified warbler's own nests including enlarged, reduced and medium-sized nests, and 3) nest dyads are similar to group 1, but not tied together to elicit parasitism by common cuckoos. We predict that cuckoos prefer larger nest than medium one, the next is smaller nest. Our findings showed that common cuckoo females generally prefer large nests over medium or small sized nests in all three experimental groups. Furthermore, cuckoo parasitism was significantly more common than in previous studies of the same warbler population, implying that larger, higher and more exposed host nests effectively increased the probability of cuckoo parasitism.

Choice of nest attributes as a frontline defense against brood parasitism

AbstractBreeding- and nest-site choice is a behavioral strategy often used to counter negative interactions. Site choices before breeding prevent costs of predation and competition but have been neglected in the context of brood parasitism. For hosts of brood parasites, the earlier brood parasitism is prevented in the breeding cycle the lower the future costs. Suitable nest-sites for cavity-nesting common redstarts (Phoenicurus phoenicurus), a host of the common cuckoo (Cuculus canorus), are a limited resource, but their cavity-nesting strategy could potentially deter predators and brood parasites. We altered the entrance size of breeding cavities and investigated redstart nest-site choice and its consequences to nest predation and brood parasitism risk, although accounting for potential interspecific competition for nest sites. We set-up paired nest-boxes and let redstarts choose between 7 cm and 5 cm entrance sizes. Additionally, we monitored occupancy rates in nest-boxes with 3 cm, 5 cm, and 7 cm entrance sizes and recorded brood parasitism and predation events. We found that redstarts preferred to breed in 5 cm entrance size cavities, where brood parasitism was eliminated but nest predation rates were comparable to 7 cm entrance size cavities. Only in 3 cm cavities both, brood parasitism and predation rates were reduced. In contrast to the other cavity-nesting species, redstart settlement was lowest in 3 cm entrance size cavities, potentially suggesting interspecific competition for small entrance size cavities. Nest-site choice based on entrance size could be a frontline defense strategy that redstarts use to reduce brood parasitism.

No evidence that nest site choice in Pied Flycatchers is mediated by assessing the clutch size of a heterospecific, the Great Tit

Among species that use similar resources, an individual may benefit by observing and copying the behavioural decision of a heterospecific. We tested the hypothesis of heterospecific social learning in passerine birds, namely that a migrant species, the Pied Flycatcher Ficedula hypoleuca, uses external markings on the nest cavities of a resident species, the Great Tit Parus major, as cues when choosing a nest site. Others have suggested that prospecting flycatchers assess the clutch size of tit “demonstrators” by entering their nest boxes and, assuming that a large clutch indicates a high-quality individual, will copy the nest appearance of tits with large, but not small clutches. During a 4-year period in Norway, we designed a similar study but did not find that flycatchers based their nest choice on the clutch size of tits. Neither were there any relationships between clutch size of the tit and its laying date, incubation behaviour, or the number of eggs visible through nest material during egg-laying so Pied Flycatchers did not use these indirect cues to assess quality of the tutor. Filming of tit nests showed that prospecting flycatchers did not enter tit nest boxes to assess the content. Indeed, incubating female tits only left their nest boxes for short bouts of unpredictable duration so there was little opportunity for flycatchers to inspect the nest contents unnoticed. Our study calls into question the mechanism of using the content of tit nests as public information for choosing traits of nest sites based on external characteristics. We suggest that similar studies of nest site choice in relation to possible social information transfer be replicated more widely.

Nest choice in arboreal ants is an emergent consequence of network creation under spatial constraints

Biological transportation networks must balance competing functional priorities. The self-organizing mechanisms used to generate such networks have inspired scalable algorithms to construct and maintain low-cost and efficient human-designed transport networks. The pheromone-based trail networks of ants have been especially valuable in this regard. Here, we use turtle ants as our focal system: In contrast to the ant species usually used as models for self-organized networks, these ants live in a spatially constrained arboreal environment where both nesting options and connecting pathways are limited. Thus, they must solve a distinct set of challenges which resemble those faced by human transport engineers constrained by existing infrastructure. Here, we ask how a turtle ant colony’s choice of which nests to include in a network may be influenced by their potential to create connections to other nests. In laboratory experiments with Cephalotes varians and Cephalotes texanus, we show that nest choice is influenced by spatial constraints, but in unexpected ways. Under one spatial configuration, colonies preferentially occupied more connected nest sites; however, under another spatial configuration, this preference disappeared. Comparing the results of these experiments to an agent-based model, we demonstrate that this apparently idiosyncratic relationship between nest connectivity and nest choice can emerge without nest preferences via a combination of self-reinforcing random movement along constrained pathways and density-dependent aggregation at nests. While this mechanism does not consistently lead to the de-novo construction of low-cost, efficient transport networks, it may be an effective way to expand a network, when coupled with processes of pruning and restructuring.

Movement, Encounter Rate, and Collective Behavior in Ant Colonies.

Spatial patterns of movement regulate many aspects of social insect behavior, because how workers move around, and how many are there, determines how often they meet and interact. Interactions are usually olfactory; for example, in ants, by means of antennal contact in which one worker assesses the cuticular hydrocarbons of another. Encounter rates may be a simple outcome of local density: a worker experiences more encounters, the more other workers there are around it. This means that encounter rate can be used as a cue for overall density even though no individual can assess global density. Encounter rate as a cue for local density regulates many aspects of social insect behavior, including collective search, task allocation, nest choice, and traffic flow. As colonies grow older and larger, encounter rates change, which leads to changes in task allocation. Nest size affects local density and movement patterns, which influences encounter rate, so that nest size and connectivity influence colony behavior. However, encounter rate is not a simple function of local density when individuals change their movement in response to encounters, thus influencing further encounter rates. Natural selection on the regulation of collective behavior can draw on variation within and among colonies in the relation of movement patterns, encounter rate, and response to encounters.

Avian Egg Timers: Female Cowbirds Judge Past, Present, and Future When Making Nest Parasitism Decisions

The cognitive demands associated with brood parasitism are substantial. Not only must female parasites locate nests and assess their suitability for parasitism, they must also time parasitism to correspond with the breeding behavior of the host. Keeping track of the reproductive state of hosts for a variety of nests allows the parasite to select a nest where their egg can be incubated successfully. Thus, nest selection decisions are integral to obligate brood parasites’ reproductive success. In captive breeding flocks of brown-headed cowbirds (Molothrus ater), I studied (1) females’ abilities to time a host nest’s readiness for parasitism and (2) the timing of females’ nest selection decisions. I found that cowbirds can attend to the amount of time that elapsed since a host egg was added to a nest and can use that information to choose a nest for parasitism. Females made their choice of nest during prospecting the day before they laid, and, once decided, they did not update their decisions on the day of laying. Taken together, the results reveal that female cowbirds process substantial amounts of information about location, time, number, and rate in order to plan for future parasitism. This research program reveals that species-typical decisions integrate a variety of general and specialized cognitive abilities to allow females to behave adaptively and maximize reproductive success.

Temporal variation in maternal nest choice and its consequences for lizard embryos

AbstractMicrohabitat choice of nest sites is an important maternal effect that influences the survival and development of embryos in oviparous species. Embryos of many species display a high degree of plasticity in response to developmental environments, which places maternal nesting behavior under strong selective pressure, particularly in temporally changing environments. Nesting behavior varies widely across taxa that exhibit diverse reproductive strategies. The brown anole (Anolis sagrei), for example, lays one egg every 7–10 days across an extended reproductive season from April to October. This aspect of their reproduction provides an opportunity to examine temporal shifts in nesting behavior and its consequences on egg survival and offspring development under seasonally changing climatic conditions. We conducted a two-part study to quantify temporal variation in maternal nesting behavior and its effect on development of A. sagrei embryos. First, we measured nest micro-environments over the nesting season. Second, we “planted” eggs across the landscape at our field site to examine the influence of nest conditions on egg survival and hatchling phenotypes. We also incubated eggs inside chambers in the field to decouple effects of nest moisture from those of other environmental variables (e.g., temperature). Females chose nest sites with higher moisture and lower temperatures relative to what was generally available across the landscape during the nesting season. In addition, eggs exposed to relatively cool temperatures had higher hatching success, and high nest moisture increased egg survival and body condition of hatchlings. Overall, we provide evidence in the field that maternal nesting behavior facilitates offspring survival.

Selective interspecific information use in the nest choice of solitary bees

Abstract Most of the studies on learning in bees have focused on the foraging context; we know little about the preferences and cognitive processes in nest-site selection, especially in solitary bees. The majority of the bee species are solitary and in contrast to eusocial bees, solitary bees’ cognition and social information use have remained largely unstudied. Solitary cavity-nesting mason bees (Osmia spp.) are an ideal system to study interspecific information use in nest choice in the wild as many species share similar nesting requirements. Here, we show that the blue mason bee (O. caerulescens) and the orange-vented mason bee (O. leaiana) examine hallmarks of parasitization of the nests of red mason bees (O. bicornis) before deciding where to establish their own nests. They were also presented with contextual cues (geometric symbols) that could be linked to parasitization by observational learning. Subjects subsequently had the choice of nesting in a nest site marked by the symbol that matched, or did not match, the one seen at the parasitized or healthy nest. We show that the bees copied and rejected the symbol of the examined nest manipulated to exhibit successful and unsuccessful nesting, respectively. We conclude that solitary bees use interspecific information in their nest-site selection. In contrast with current theories of species coexistence, niche overlap between species may dynamically change depending on the observed success of surrounding individuals.

Cheating Cheaters: Social Monogamy but Genetic Polygamy in a Brood Parasite

Understanding the variability of mating systems is central in the study of animal behaviour. The advent of genetic techniques allowed combining social and genetic data, providing a more comprehensive view of reproductive strategies. In obligate avian brood parasites, the lack of constraints derived from offspring care allows for great plasticity of the mating system in response to changes in socio-ecological conditions. This potential for intraspecific variation makes brood parasites ideal model species to investigate the evolution of reproductive behaviour. We simultaneously studied for the first time social and genetic patterns of reproduction of the Great Spotted Cuckoo Clamator glandarius, combining radio-tracking and behavioural observations in the field with genetic parentage analyses. Our results reveal that loose pair bonds can be maintained in this species despite high levels of genetic polygamy and lack of territoriality, possibly because of the need of intra-pair cooperation for finding and parasitising the nests of its large hosts: the Carrion Crow Corvus corone and the Eurasian Magpie Pica pica. We also found that cuckoos mostly ranged around suitable foraging grounds, but females moved larger distances to find host nests to parasitise. Comparison of our results with previous reports on different populations also suggests a plasticity of Great Spotted Cuckoo territorial behaviour that may depend on population density, host choice and distribution of host nests.—Bolopo, D., Roncalli, G., Canestrari, D. & Baglione, V. (2020). Cheating cheaters: social monogamy but genetic polygamy in a brood parasite. Ardeola, 67: 39-56.

Partner choice correlates with fine scale kin structuring in the paper wasp Polistes dominula.

Cooperation among kin is common in animal societies. Kin groups may form by individuals directly discriminating relatives based on kin recognition cues, or form passively through natal philopatry and limited dispersal. We describe the genetic landscape for a primitively eusocial wasp, Polistes dominula, and ask whether individuals choose cooperative partners that are nearby and/or that are genetic relatives. Firstly, we genotyped an entire sub-population of 1361 wasps and found genetic structuring on an extremely fine scale: the probability of finding genetic relatives decreases exponentially within just a few meters of an individual’s nest. At the same time, however, we found a lack of genetic structuring between natural nest aggregations within the population. Secondly, in a separate dataset where ~2000 wasps were genotyped, we show that wasps forced experimentally to make a new nest choice tended to choose new nests near to their original nests, and that these nests tended to contain some full sisters. However, a significant fraction of wasps chose nests that did not contain sisters, despite sisters being present in nearby nests. Although we cannot rule out a role for direct kin recognition or natal nest-mate recognition, our data suggest that kin groups may form via a philopatric rule-of-thumb, whereby wasps simply select groups and nesting sites that are nearby. The result is that most subordinate helpers obtain indirect fitness benefits by breeding cooperatively.

Male and female preferences for nest characteristics under paternal care.

Nests play a critical role for offspring development across the animal kingdom. Nest quality may contribute to the builder's extended phenotype and serve as an ornament during mate choice. We examined male and female nest choice in the common goby (Pomatoschistus microps), a benthic fish with male‐only parental care where females deposit eggs in male‐built nests. Using prebuilt nest models, we independently manipulated two candidate nest quality traits: (a) nest entrance width with a role in oxygen ventilation, and (b) extent of sand cover with a role in camouflage. In simultaneous choice trials, male gobies exhibited no preference for any nest model type. This suggests that initial characteristics of a nesting substrate have minor importance for males, which usually remodel the nest. Females were given a choice between two males occupying either entrance‐ or cover‐manipulated nests. The same pair of males was then exposed to a second female but now with alternated nest types assigned. Most females were consistent in choosing the same, typically the heavier male of the two regardless of nest properties. However, the females that chose the same nest regardless of the male preferred low over high sand coverage and narrow over wide nest entrance. Our results indicate that females base their mating decision on a combination of male phenotype and nest traits. While we found no indication that females are attracted to highly decorated nests, our study is the first in fishes to disentangle a preference for narrow (and thus more protective) nest entrances independent of nest coverage.

To reunite or not: A study of artificially fragmented Diacamma indicum ant colonies

Social insects live together in groups and maintain cohesion to enhance their chances of survival and productivity. Colony cohesion is severely challenged during relocation. We examined the dynamics of colony reunification and the factors affecting nest choice of artificially fragmented colonies of the queenless ant Diacamma indicum. None of the twelve undisturbed colonies fragmented or relocated when a good nest was available in their neighbourhood. When colonies were artificially fragmented, they mostly (25/30) reunified into a single nest unlike in randomized time-ordered network models, indicating that reunification is not the result of random recruitment acts. When the reproductive individual was present in a good nest, the colonies reunified at this address. However, when she was present in a suboptimal nest, colonies relocated her to a better quality nest and reunified there, illustrating that quality of the new nest is more important. The work distribution and relocation dynamics of reunification were comparable to intact colonies relocating to a single new nest. This is made possible by enhanced exchange of information among tandem leaders in the form of increased number of tandem runs among them. We conclude that colony cohesion is very important and is maintained after incorporating the risks of relocation and preference for nest quality during decision making.

The Ecology of Collective Behavior in Ants.

Nest choice in Temnothorax spp.; task allocation and the regulation of activity in Pheidole dentata, Pogonomyrmex barbatus, and Atta spp.; and trail networks in Monomorium pharaonis and Cephalotes goniodontus all provide examples of correspondences between the dynamics of the environment and the dynamics of collective behavior. Some important aspects of the dynamics of the environment include stability, the threat of rupture or disturbance, the ratio of inflow and outflow of resources or energy, and the distribution of resources. These correspond to the dynamics of collective behavior, including the extent of amplification, how feedback instigates and inhibits activity, and the extent to which the interactions that provide the information to regulate behavior are local or spatially centralized.