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Miriam H Richards - One of the best experts on this subject based on the ideXlab platform.

  • ergonomic skew and reproductive queuing based on social and seasonal variation in foraging activity of eastern Carpenter Bees xylocopa virginica
    Canadian Journal of Zoology, 2015
    Co-Authors: Miriam H Richards, Christopher Course
    Abstract:

    Reproductive division of labour in social Carpenter Bees differs from that in classically eusocial insects because reproductive output and ergonomic inputs are positively correlated—dominant females monopolize both foraging and reproduction. We quantified ergonomic skew in the facultatively social Bee Xylocopa virginica (L., 1771) (eastern Carpenter Bee) based on detailed observations of foraging activity by individually marked females in 2009. Unusually for a univoltine Bee, this species exhibits a spring foraging phase during which females feed pollen to other adults, probably as part of behavioural interactions to establish dominance hierarchies. During brood-provisioning, foraging in social nests was dominated by one female at a time, with replacement by a succession of foragers as dominants disappeared and were succeeded by a subordinate. The principal foragers (individuals that did the largest share of foraging in each colony) did 85%–100% of all pollen trips, so contributions to pollen-provisioning...

  • reproductive aggression and nestmate recognition in a subsocial Bee
    Animal Behaviour, 2013
    Co-Authors: Sandra M. Rehan, Miriam H Richards
    Abstract:

    In social contexts, the ability to recognize and discriminate among individuals is advantageous, because it allows individuals to adjust their behaviour so as to enhance both individual and group fitness. Eusocial insects have finely developed mechanisms of discrimination that promote many kinds of social interactions, but discrimination may also be adaptive in noneusocial species, including solitary ones. Physical traits such as reproductive status influence rates of aggression and discrimination, permitting individuals to share common resources and nesting sites and to cooperatively care for offspring, while excluding potential aggressors or social parasites. In this study, we examined reproductive aggression and nestmate recognition in a subsocial species of small Carpenter Bee, Ceratina calcarata , using circle tube behavioural assays. Not only does this subsocial Bee show nestmate recognition, but there is seasonal variation in aggression that correlates with seasonal variation in reproductive status, illustrating that both aggressive behaviour and the consequences of nestmate recognition are context dependent. Females that were actively reproductive (ovaries fully developed) were more aggressive than pre-reproductive (ovaries undeveloped) or post-reproductive females (ovaries resorbed). Females altered their behaviour when interacting with nestmates versus non-nestmates. As in most social Hymenoptera, agonistic behaviour was observed to be greatest between unfamiliar, reproductively active individuals. However, post-reproductive females were tolerant towards unfamiliar females. During the natural adult cohabitation phase of the nesting cycle (the mature brood phase), mothers were aggressive towards daughters, whereas same generation pairs of nestmates or non-nestmates showed no signs of aggression. These results indicate that this subsocial Bee species does possess the ability to recognize nestmates but the consequences of recognition vary seasonally, sometimes resulting in greater aggression towards nestmates than towards non-nestmates.

  • colony social organisation and alternative social strategies in the eastern Carpenter Bee xylocopa virginica
    Journal of Insect Behavior, 2011
    Co-Authors: Miriam H Richards
    Abstract:

    The eastern Carpenter Bee, Xylocopa virginica, can nest either solitarily or in groups. In southern Ontario, Canada, near the northern edge of the range, most nests are social, containing groups of two to five adult females. Although social nests were much more frequent than solitary ones, they produced no more brood, so per capita brood productivity was actually lower for social females. Social females exhibited several reproductive strategies inferred from wing wear patterns, which reflect flight activity, and mandibular wear patterns, which reflect nest construction activity. Primary females accumulated a large degree of wing and mandibular wear and were presumed to be the primary reproductives in social nests. Secondary females accumulated less wing and mandibular wear and were probably subordinates awaiting opportunities to supersede primaries as dominant foragers and egg-layers. Tertiary females remained inactive, apparently deferring reproduction to the subsequent year. Social nesting, serial replacement of dominant females in social nests, and deferred reproduction are probably responses to severe competition for nests and nesting substrate.

  • knowing who s who nestmate recognition in the facultatively social Carpenter Bee xylocopa virginica
    Animal Behaviour, 2010
    Co-Authors: Marianne Peso, Miriam H Richards
    Abstract:

    When animals live in groups, the ability to discriminate group members from nonmembers allows individuals to adjust their behaviour in ways that enhance both individual and group fitness. In social insects, especially Bees, this kind of recognition has mainly Been studied with reference to colony-based social interactions, but they also interact in other kinds of group contexts. In the facultatively social Carpenter Bee, Xylocopa virginica, individuals of both sexes interact repeatedly, in such activities as cooperative brood raising by females, territorial competition by males, and matings near nest entrances. In light of these varied interactions, in which the ability to discriminate familiar from unfamiliar individuals might be advantageous, the aim of our study was to determine whether X. virginica adults are capable of nestmate recognition. Nestmates were defined operationally as Bees that were caught at the same nest entrance after spending the night together, whereas non-nestmates were from different nests. We used circle tube assays of male–male, female–female and male–female dyads to compare rates of aggressive (pushing, biting and C-postures) and tolerant/cooperative (head-to-head touching and passing) behaviour in nestmates versus non-nestmates. In general, aggression occurred sooner and more frequently among non-nestmates than among nestmates, whereas tolerance was more common among nestmates. This indicates that male and female Bees can recognize familiar individuals of both sexes and adjust their behaviour accordingly. Since tested individuals may have Been nestmates for less than 24 h, this further suggests that both female and male Bees may learn the identities of their nestmates quickly.

  • body size and shape of the large Carpenter Bee xylocopa virginica l hymenoptera apidae
    Journal of the Kansas Entomological Society, 2009
    Co-Authors: Dimitri A Skandalis, Sean M Prager, Glenn J Tattersall, Miriam H Richards
    Abstract:

    In Bees, both body size and shape may show considerable variation associated with differences between females and males, among populations, and due to local environmental variation. We studied multiple parameters of body size and shape of the large Carpenter Bee Xylocopa virginica, to understand how body size and shape are influenced by sex, and by seasonal and annual variation. In addition, we compared Bees from a population near the northern edge of the range (southern Ontario, ON) which experience relatively severe winters, to Bees from the central portion of the range (Maryland, MD), which experience milder winters. Overall, males and females differed in linear dimensions but were more or less the same mass. Seasonal variability was investigated using ON Bees. In winter, females and males had the same overall mass, but male thoracic volume and linear dimensions such as head capsule width, intertegular width, and costal vein length, were all larger for a given mass. In summer, males weighed less than females, due to loss of mass from the abdomen. Year-to-year differences in size and shape were indicated in MD Bees, which exhibited significant differences in linear dimensions and dry mass, but not wet mass. In addition, northern Bees were smaller than southern Bees in terms of linear dimensions, but it is not entirely clear if overwintering mass differs. We suggest that seasonal and sex differences in size are related to the different flight activity patterns of males and females in summer, and that geographic differences between the two populations are related to the length and duration of winters.

Remko Leys - One of the best experts on this subject based on the ideXlab platform.

  • molecular phylogeny and historical biogeography of the large Carpenter Bees genus xylocopa hymenoptera apidae
    Biological Journal of The Linnean Society, 2002
    Co-Authors: Steve J B Cooper, Remko Leys, Michael Schwarz
    Abstract:

    The biogeographical history of major groups of Bees with worldwide distributions have often Been explained through hypotheses based on Gondwanan vicariance or long distance dispersal events, but until recently these hypotheses have Been very difficult, if not impossible, to distinguish. New fossil data, comprehensive information on Mesozoic and Cenozoic coastline positions and the availability of phylogenetically informative DNA markers now makes it feasible to test these hypotheses for some groups of Bees. This paper presents historical biogeographical analyses of the genus Xylocopa Latreille, based on phylogenetic analyses of species belonging to 22 subgenera using molecular data from two nuclear genes, elongation factor-1α (EF-1α) and phosphoenolpyruvate carboxykinase (PEPCK), combined with previously published morphological and mitochondrial data sets. Phylogenetic analyses based on parsimony and likelihood approaches resulted in several groups of subgenera supported by high bootstrap values (>85%): an American group with the Oriental/Palaearctic subgenera Nyctomelitta and Proxylocopa as sister taxa; a geographically diverse group (Xylocopa s.l); and a group consisting of African and Oriental subgenera. The relationships among these three clades and the subgenus Perixylocopa remained unresolved. The Oriental subgenus Biluna was found to be the sister group of all other Carpenter Bee subgenera included in this study. Using a relaxed molecular clock calibrated using fossil Carpenter Bees, we show that the major splits in the Carpenter Bee phylogeny occurred well after the final breakup of Gondwanaland (the separation of South America and Africa, 100 Mya), but before important Miocene fusion events. Ancestral area analysis showed that the genus Xylocopa most likely had an Oriental-Palaearctic origin and that the present world distribution of Xylocopa subgenera resulted mainly from independent dispersal events. The influence of Pleistocene glaciations on Carpenter Bee distributions is also discussed. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 77, 249–266.

  • The superseded female's dilemma: ultimate and proximate factors that influence guarding behaviour of the Carpenter Bee Xylocopa pubescens
    Behavioral Ecology and Sociobiology, 1993
    Co-Authors: Katja Hogendoorn, Remko Leys
    Abstract:

    Both solitary and primitively social nests of the facultatively social Carpenter Bee Xylocopa pubescens can be found throughout most of the breeding season. In social nests there is reproductive division of labour between a dominant forager and a guarding female. Two types of guarding females can be discerned: the young pre-reproductive guards, and older, formerly reproductive guards. The latter type of guard is found when, after a take-over of reproductive dominance either by a nestmate (mostly a daughter) or an intruder, the defeated female stays in the nest instead of leaving to try and found or usurp another nest. She is then manipulated into the role of a guard. The dominant female profits from the presence of the guard since she protects the nest against pollen robbery by conspecifics (Hogendoorn and Velthuis 1993). We have studied why superseded females might “prefer” to remain as a guard, rather than try their luck somewhere else. The hypotheses investigated pertain to (1) the difficulty for the defeated female of finding a new nest and of restarting reproductive activities due to (a) ecological constraints (nest and pollen shortage) and (b) the effect of age and wear on the defeated female; (2) the effects of guarding in terms of inclusive fitness. We found that superseded females remained as guards significantly more often when a nestmate (not necessarily close kin) took over reproductive dominance than when an intruder did so. Other factors associated with the decision of the defeated female to stay or leave were her age and the number of her own young still present after the supersedure. The probability of finding or constructing a new nest was lower for old than for young females. After finding a nest, old females produced less brood than young foundresses. As a result of these two factors old superseded females gained, in terms of inclusive fitness, by staying as guards, whereas young females profited from leaving the nest. We interpret these results as an indication that guarding behaviour has evolved due to kin selection. However, kin discrimination apparently did not occur. Therefore we conclude that in this species kin selection is not, in the proximate frame of reference, based on kin recognition and preference for helping kin.

John Alcock - One of the best experts on this subject based on the ideXlab platform.

  • the evolution of the mating system of the Carpenter Bee xylocopa varipuncta hymenoptera anthophoridae
    Journal of Zoology, 2009
    Co-Authors: Larry D Marshall, John Alcock
    Abstract:

    The Carpenter Bee, Xylocopa varipuncta, appears to have evolved a dispersed lek mating system. Males leave the natal nest in the late afternoon in March and April to hover for periods of up to two hours in the crowns of non-flowering trees growing in desert washes. Females and other males occasionally visit a hovering male, probably drawn by a sex pheromone. Resident males repel intruders of the same sex and attempt to induce females to alight on foliage, where mating occurs. The hovering territories do not contain nests, or potential nest sites, or food resources for females. Lek territoriality may have evolved in this species because nests are difficult to locate and the food-plants are evenly dispersed over a large area, making economical defence of patches of this resource unfeasible. Males are left with the option of demonstrating social dominance to potential mates through control of a superior landmark territory.

  • differences in site fidelity among territorial males of the Carpenter Bee xylocopa varipuncta hymenoptera anthophoridae
    Behaviour, 1993
    Co-Authors: John Alcock
    Abstract:

    Lekking males of the Carpenter Bee Xylocopa (Neoxylocopa) varipuncta compete for landmark territories, where they are occasionally visited by receptive females. In a study conducted over three flight seasons, less than 10% of marked males qualified as long-term residents (i.e. Bees that held the same hovering station for 90 min or more on at least two afternoons). However, among the small minority of long-term residents were some Bees that returned to the same landmark for up to 3 hr every afternoon for several weeks. These males defeated many intruders in aerial combat during each afternoon. The hypothesis that site-faithful males were individuals of unusual resource-holding power is not supported. Long-term residents were not larger on average than short-term territory holders. Moreover, the frequency of mating by long-term residents was very similar to that of males in the general population, suggesting that long-term residents did not hold territories that were exceptionally attractive to females. Thus, the basis for site fidelity in this species remains elusive. The rarity of site-faithful males in this species may be related to great daily fluctuations in the numbers of potentially receptive females visiting the landmark territories, which may make the timing of male mate-attracting behavior far more important than regularly returning to defend any one site.

Mariano Lucia - One of the best experts on this subject based on the ideXlab platform.

Sandra M. Rehan - One of the best experts on this subject based on the ideXlab platform.

  • Range expansion of an already widespread Bee under climate change
    Elsevier, 2019
    Co-Authors: Rebecca M. Dew, Daniel Paiva Silva, Sandra M. Rehan
    Abstract:

    Climate change is a key threat to pollination networks and has already caused shifts in the distribution and phenology of many Bee species. Predictions based on species distribution models forecast that most Bee species will continue to decline as climate change progresses, the few exceptions to this being common, widespread species with large dispersal capabilities. Most of the Bees studied so far are temperate or tropical species but many ecosystems are predicted to experience increased aridification under climate change. Therefore, we need to understand how pollinator species are likely to respond. Here we present species distribution models for the arid-adapted Australian small Carpenter Bee, Ceratina australensis Perkins, 1912 (Apidae: Xylocopinae) under Intergovernmental Panel on Climate Change (IPCC) climate change conditions predicted for 2070 (Representative Carbon Pathway 8.5). We applied Maximum Entropy, Generalized Linear Models, Generalized Additive Models and Random Forest methods. Overall, our models predict that this Bee will have an increased area of suitable habitat as climate change progresses, including an increased range within protected areas. However, its potential range will shift further into coastal areas, that are highly human populated and urbanised. Our results suggest that wild Bee taxa may be able to cope with the predicted scale of future aridification under climate change. Finally, this species is predicted to increase in urban environments, which highlights the need for city planning, suitable habitats and green spaces to support wild Bee species. Keywords: Climate change, Species distribution modelling, Pollinator, Wild Bee, Arid zone, Ceratin

  • sociodemographic variation in foraging behavior and the adaptive significance of worker production in the facultatively social small Carpenter Bee ceratina calcarata
    Behavioral Ecology and Sociobiology, 2017
    Co-Authors: Cullen Franchino, Michael Mikat, Sandra M. Rehan
    Abstract:

    Provisioning for young offspring is an archetypical form of parental investment. Ceratina calcarata Bees provide extended maternal care to their young and demonstrate an unusual strategy of dual-phase pollen provisioning. Most Bees first gather provisions as they establish nests in spring. However, C. calcarata mothers will also feed their newly eclosed young a second time, perhaps ensuring their survival during a long winter diapause. Some mothers rear a small, worker-like daughter to assist them during this second provisioning phase. We studied provisioning behavior in C. calcarata to examine patterns of maternal investment and foraging dynamics throughout the breeding season. Mothers typically made a high number of short-duration foraging trips each day, whereas late-season females tended to make fewer and longer trips. This difference in foraging duration may indicate a lower risk of brood loss in those nests where mature offspring are present. Nest demographic data revealed that an offspring laid in the first brood cell position is typically female and usually smaller than her siblings. In 29% of the nests, this small daughter was observed to adopt a forager role at maturity and provisioned for her siblings. Dwarf daughters had a higher number of active days and foraging trips per day in orphaned nests than in nests where a mother was present. The foraging behaviors of worker-like daughters were similar in length of foraging trip and handling time to mothers during this second provisioning period. We hypothesize that incipiently social foraging by this smallest daughter may act as a form of insurance against brood loss during occasions when a mother is unable to sufficiently provision for her eclosed offspring during the second phase. Parental investment in the size and sex of offspring is under strong selection for assured fitness returns. For example, many social insect mothers make an initial investment in small offspring to take on risky foraging behavior while they specialize on future reproduction. Solitary and facultatively social species provide an important baseline to understand the evolution of social complexity from natural variation in maternal care and foraging behavior. Here, we characterize the parental investment strategies of a subsocial small Carpenter Bee and reveal the potential adaptive significance of prolonged maternal care and worker production in this species. Mothers provide an initial investment that is extended by workers providing alloparental care to siblings. Maternal manipulation of dwarf eldest daughters may serve as an insurance mechanism in the event of maternal mortality to assure the survival of siblings.

  • reproductive aggression and nestmate recognition in a subsocial Bee
    Animal Behaviour, 2013
    Co-Authors: Sandra M. Rehan, Miriam H Richards
    Abstract:

    In social contexts, the ability to recognize and discriminate among individuals is advantageous, because it allows individuals to adjust their behaviour so as to enhance both individual and group fitness. Eusocial insects have finely developed mechanisms of discrimination that promote many kinds of social interactions, but discrimination may also be adaptive in noneusocial species, including solitary ones. Physical traits such as reproductive status influence rates of aggression and discrimination, permitting individuals to share common resources and nesting sites and to cooperatively care for offspring, while excluding potential aggressors or social parasites. In this study, we examined reproductive aggression and nestmate recognition in a subsocial species of small Carpenter Bee, Ceratina calcarata , using circle tube behavioural assays. Not only does this subsocial Bee show nestmate recognition, but there is seasonal variation in aggression that correlates with seasonal variation in reproductive status, illustrating that both aggressive behaviour and the consequences of nestmate recognition are context dependent. Females that were actively reproductive (ovaries fully developed) were more aggressive than pre-reproductive (ovaries undeveloped) or post-reproductive females (ovaries resorbed). Females altered their behaviour when interacting with nestmates versus non-nestmates. As in most social Hymenoptera, agonistic behaviour was observed to be greatest between unfamiliar, reproductively active individuals. However, post-reproductive females were tolerant towards unfamiliar females. During the natural adult cohabitation phase of the nesting cycle (the mature brood phase), mothers were aggressive towards daughters, whereas same generation pairs of nestmates or non-nestmates showed no signs of aggression. These results indicate that this subsocial Bee species does possess the ability to recognize nestmates but the consequences of recognition vary seasonally, sometimes resulting in greater aggression towards nestmates than towards non-nestmates.