Neighbourhood Society: Nesting Dynamics, Usurpations and Social Behaviour in Solitary Bees (original) (raw)
Related papers
Journal of Theoretical Biology, 1990
In primitively eusocial bee species, Lasioglossum (Evylaeus) malachurum and L. (E.) pauxillum, solitary, overwintered gynes emerge in early spring and find nests. In the nests they provision several brood cells from which the first worker generation emerges several weeks later. During the initial nesting phase the gynes of both species are solitary. Shortly after the first foraging flights in L. malachurum, several gynes can be observed flying about the nest aggregation entering the temporarily empty nests of foraging nest owners. Occasionally, the gyne (the potential usurper) will remain in the nest at the entrance until the nest owner returns. At that time, either the usurper departs immediately, or a fight between the usurper and nest owner ensues. Fights can result in the death or serious injury of one of the combatants. The nest owner wins in most cases, but the usurper does stand a chance of taking over the nest. In contrast, in L. pauxiUum nest takeovers are less common, and no such vicious fighting can be observed. We develop a dynamic simulation model to study the ecological and social conditions that promote nest usurpation of gynes of primitively social bees during the initial, solitary phase of the nesting cycle. The theory of evolutionary stable strategies is used to model the behavioral patterns of the gynes. Nest usurpation is an evolutionary stable strategy under fairly general conditions, but several factors, such as the probability of nest destruction, foraging mortality, the quality of the soil, and owner-intruder asymmetry, affect the time of the emergence of nest usurpation. The results related to the evolutionary stability of nest usurpation are illustrated by simulation examples.
Insectes Sociaux, 2008
Constraints to independent nesting play a key role in the understanding of social evolution in insects, but the source and the magnitude of such constraints are poorly known for many key taxa. In allodapine bees it is known that solitary nesting females have low rates of successful brood rearing and that this drives selection for cooperative nesting. It has been hypothesized that these constraints are due to the presence of enemies-at-thenest, such as ants, but no direct link has been demonstrated between such enemies and colony failure. We set up an experiment in which solitary founded nests of an Australian allodapine bee, Exoneura nigrescens, were either protected from non-flying predators or left unprotected, and compared the resulting colony survival and brood production rates. We found that protected colonies have much higher rates of survival and that the constraints to independent nesting are extreme, with a mean of less than one offspring per nest at the end of the brood rearing period. This means that cooperative nesting is essential for this species to persist in its habitat.
Why Wasp Foundresses Change Nests: Relatedness, Dominance, and Nest Quality
2012
The costs and benefits of different social options are best understood when individuals can be followed as they make different choices, something that can be difficult in social insects. In this detailed study, we follow overwintered females of the social wasp Polistes carolina through different nesting strategies in a stratified habitat where nest site quality varies with proximity to a foraging area, and genetic relatedness among females is known. Females may initiate nests, join nests temporarily or permanently, or abandon nests.
Behavioral Ecology and Sociobiology, 1996
The habitat saturation hypothesis and sociality in an allodapine bee: cooperative nesting is not "making the best of a bad situation" Abstract Several factors thought to be important for the evolution of cooperative breeding in vertebrates have received little attention in facultatively social insects. One of these, the "habitat saturation hypothesis" of Selander (1964), predicts that colony sizes will be greater in breeding units where dispersal opportunities are limited, suggesting that group living is a secondary option to independent reproduction. The Australian allodapine bee Exoneura bicolor exhibits a number of traits that occur in cooperatively breeding bird species, including long life-span, repeated opportunities for reproduction, and vulnerability to brood predation and parasitism. We experimentally examined the effect of a potentially limiting environmental factor, nesting substrate availability, as an agent influencing sociality in E. bicolor. We manipulated nesting substrate availability in two separate locations during a time when foundress dispersal is common. No significant difference was found between colony sizes in cases where dispersal options were abundant and cases where dispersal options were limited. An increase in opportunities for dispersal did not lead to higher rates of independent nesting, suggesting that cooperative nesting is a preferred strategy regardless of distance-related costs of dispersal. Reproductivity per female and brood survival were examined as factors selecting for group living. Low survival of brood in single-female nests has the potential to select for cooperative nesting in this bee.
Ecological constraints on independent nesting in facultatively eusocial hover wasps
Proceedings of The Royal Society B: Biological Sciences, 1998
Recent ¢eld experiments suggest that cooperative breeding in vertebrates can be driven by a shortage of breeding territories. We did analogous experiments on facultatively eusocial hover wasps (Stenogastrinae: Liostenogaster £avolineata). We provided nesting opportunities by removing residents from 39 nests within a large aggregation (1995), and by glueing 20 nests obtained from a distant site into a second aggregation (1996). We prevented nest-less £oaters from competing for these opportunities in 1995 but not in 1996. In both years, helpers in unmanipulated groups were given opportunities to nest independently without having to incur nest-building costs and with a reduced wait before potential helpers emerged. Helpers visited the nests we provided, but adopted only a small proportion (5% of 111 vacancies created in 1995). Others were adopted by £oaters, but a signi¢cant proportion of nests were never adopted (9 out of 20 in 1995, 7 out of 20 in 1996). Helpers that visited nests did not originate from particular kinds of social group. Nests containing older broods were more likely to be adopted, and adopting females rarely destroyed older brood. A general feature of social insect, but not vertebrate life histories, namely the long period of o¡spring dependency relative to the short life expectancy of adult carers, may be a key factor constraining independent nesting.
Demography and relatedness in multiple-foundress nests of the social sweat bee, Halictus ligatus
Insectes Sociaux, 1998
Female sweat bees in the species Halictus ligatus exhibit a wide range of reproductive roles, ranging from typically foundress or queen-like to typically worker-like. Nests are founded in spring and most are haplometrotic, that is, founded by a single foundress. A few (up to 12 %) are pleometrotic, founded by 2-6 foundresses. Variation in the proportion of multifoundress nests from year to year and from place to place suggests an adaptive basis for pleometrosis. We studied the demographic and social characteristics of 23 pleometrotic nests in an aggregation of 250 -300 nests near Victoria, Ontario, in 1984. In pleometrotic associations, dominant foundresses behaved in a manner typical of mid-summer, haplometrotic queens, while subordinates behaved like mid-summer workers. Dominant foundresses tended to be larger than subordinates. Pleometrotic nests were significantly more likely than haplometrotic nests to produce brood, and they also produced more workers. However, this early advantage did not result in the production of more reproductive brood per nest, nor did pleometrotic foundresses experience higher productivity per foundress than did haplometrotic foundresses. Relatively low relatedness among various categories of brood implied that subordinate foundresses were not closely related to dominants. We suggest that pleometrosis most likely results from accidental encounters between spring foundresses as they leave their hibernacula. Once formed, such associations confer a survival advantage on the nest as a whole, but do not result in greater reproductive brood productivity.
Oikos, 2018
Nest-site selection is an important component of species socio-ecology, being a crucial factor in 27 establishment of group living. Consequently, nest-site characteristics together with space-use proxies may 28 reveal the social organization of species, which is critical when direct observation of social interactions is 29 hindered in nature. Importantly, nest-site choice is expected to be under strong selective pressures and the 30 object of intra-and inter-specific competition. Although the bulk of research on sociality focuses on its 31 ecological drivers, our study introduces interspecific competition as a potential factor that could influence 32 social evolution. We investigated the influence of habitat and interspecific competition on the social 33 organization of two sister species of the African four striped mouse (Rhabdomys dilectus dilectus and 34 Rhabdomys bechuanae) in a similar macroenvironment. These species diverged in allopatry and occupy 35 distinct environmental niches. We radiotracked 140 adults to identify their nest-sites, determine nest 36 characteristics and record groups that shared nest-sites. Group cohesion was estimated from nest-site 37 fidelity, group association strength, and home range overlap within versus between group members. We 38 compared the two species in sympatry versus parapatry to determine the impact of species interference on 39 sociality. In parapatry, the two species selected distinct nest-site types, interpreted as different anti-40 predator strategies: R. bechuanae selected fewer, spaced, less concealed nest-sites whereas R. d. dilectus 41 selected clumped and less visible nest-sites. Rhabdomys bechuanae also showed more cohesive and stable 42 social groups than R. d. dilectus. In sympatry, compared to R. bechuanae, R. d. dilectus occupied similar 43 nest-sites, however slightly more exposed and clumped, and displayed similar nest-site fidelity and group 44 association strength. We conclude that although habitat selection may be an important driver of social 45 divergence in Rhabdomys, species interference, by limiting R. d. dilectus movements and forcing nest-site 46 sharing may induce new ecological pressures that could influence its social evolution.
Social information in nest colonisation and occupancy in a long-lived, solitary breeding bird
Oecologia, 2011
Recent work increasingly reveals the importance of social information in individual dispersal decisions, population dynamics and conservation. Much of the knowledge gained to date comes from studies on short-lived and/or densely breeding species. In contrast, our understanding of the processes involved in nest-site selection for long-lived, solitary breeding species is insufficient. We increased nest-site availability by nest-box supplementation over a 5-year period in a population of a long-lived, solitary, secondary-cavity nesting bird, the European roller Coracias garrulus, breeding in natural cavities and human constructions. We tested the nest limitation and the inadvertent conspecific social information hypothesis in order to study the dynamics and mechanisms of abandonment of previously used nests and the colonisation of new ones. Our data lend support to the nest-limitation hypothesis both in terms of quantity—population and the size of breeding clusters increased, and suitability—the majority of pairs used and re-occupied nest-boxes. Nevertheless, the use of natural cavities did not decrease after 5 years. At the between-patch scale, rollers were revealed to colonise nest-boxes based on conspecific social attraction, namely distance to the nearest neighbour in the same season. Despite the unpredictability of patch productivity, at the within-patch scale, the selection of previously unoccupied cavities was consistent with the performance-based conspecific attraction hypothesis. Philopatry could account for the repeated use of cavities, because nests that were used for two successive years were more likely to also be reused in the subsequent season.