Lasioglossum Species Research Articles

New and little-known Canadian Lasioglossum (Dialictus) (Hymenoptera: Halictidae) and an emended key to species

Abstract A revised key to the 94 species of Lasioglossum (Dialictus) currently known to occur in Canada is presented, incorporating new species and taxonomic updates since the publication of the first key in 2010. Two new species, Lasioglossum (Dialictus) immigrans and Lasioglossum (Dialictus) onuferkoi, are described from Canada. Lasioglossum (D.) ascheri, L. (D.) stictaspis, and L. (D.) tegulariforme are reported or confirmed from Canada for the first time. Lasioglossum (D.) gaudiale (Sandhouse, 1924) and L. (D.) helianthi (Cockerell, 1916) are resurrected from synonymy with L. (D.) tegulariforme (Crawford, 1907). The following five new synonymies are established: L. (D.) stictaspis (Sandhouse, 1923) (= L. (D.) albuquerquense (Michener, 1937)); L. (D.) ascheri Gibbs, 2011 (= L. (D.) curculum Gibbs, 2011); L. (D.) helianthi (Cockerell, 1916) (= L. (D.) imbrex Gibbs, 2010); L. (D.) megastictum (Cockerell, 1937) (= L. (D.) punctiferellum (Cockerell, 1937)); and L. (D.) obnubilum (Sandhouse, 1924) (= L. (D.) lilliputense Gibbs, 2010). Previously undescribed males of L. (D.) helianthi, L. (D.) reasbeckae, L. (D.) tegulariforme, and L. (D.) weemsi are diagnosed and figured.

Floral Scent and Pollinators of Cypripedium calceolus L. at Different Latitudes

Floral scent is an important trait in plant–pollinator interactions. It not only varies among plant species but also among populations within species. Such variability might be caused by various non–selective factors, or, as has been shown in some instances, might be the result of divergent selective pressures exerted by variable pollinator climates. Cypripedium calceolus is a Eurasian deceptive orchid pollinated mainly by bees, which spans wide altitudinal and latitudinal gradients in mainly quite isolated populations. In the present study, we investigated whether pollinators and floral scents vary among different latitudes. Floral scents of three C. calceolus populations in the Southern Alps were collected by dynamic headspace and analyzed by gas chromatography coupled to mass spectrometry (GC/MS). These data were completed by previously published scent data of the Northern Alps and Scandinavia. The scent characteristics were compared with information on pollinators recorded for present study or available in the literature. More than 80 scent compounds were overall recorded from plants of the three regions, mainly aliphatics, terpenoids, and aromatics. Seven compounds were found in all samples, and most samples were dominated by linalool and octyl acetate. Although scents differed among regions and populations, the main compounds were similar among regions. Andrena and Lasioglossum species were the main pollinators in all three regions, with Andrena being relatively more abundant than Lasioglossum in Scandinavia. We discuss natural selection mediated by pollinators and negative frequency–dependent selection as possible reasons for the identified variation of floral scent within and among populations and regions.

The floral ecology and breeding system of Veratrum virginicum (Melanthiaceae)1

We analyzed the floral biology of a population of the threatened/endangered Veratrum virginicum (L.) W.T. Aiton at the Shaw Nature Reserve (Missouri, USA), comparing our results to the first and only study of this species by Charles Robertson (1896). We confirmed most of Robertson's original descriptions regarding floral presentation, protandry, and insect pollination but found the following new information. Each flower lived 9–11 days and smelled of raw liver and latex. We discerned four floral stages based on gradual changes in style and stamen orientation, which might assist in insect-mediated pollination. We determined that stigmas became receptive by the fifth day of anthesis. The generalist pollination system included three Lasioglossum species (Halictidae) and the beetle Chauliognathus marginatus Fabr. (Cantharidae). Most floral foragers showed a geometric mean of body dimensions between 2–3 mm. Approximately 40% of foraging insects carried heterospecific pollen loads, combining the host flower's pollen with grains from up to seven co-blooming taxa. Field observations suggest that all bees foraged on multiple inflorescences whereas beetles remained on the same inflorescence for hours. Larger Apidae species showed symptoms of nectar poisoning. Epifluorescence showed that flowers exposed to visiting insects contained < 5 pollen tubes per gynoecium. Fruit set was 3% for bagged flowers and 51% for exposed flowers. However, the conversion rate of ovules into seeds was low in both bagged (2%) and exposed (6%) flowers. We interpret low reproductive success as one explanation for current declines in populations of this species.

Three new species of Lasioglossum (Hymenoptera: Halictidae) from Mexico, with comments on the biogeography of Mexican species of the subgenus Lasioglossum

Three new species of Lasioglossum (Lasioglossum) from Mexico, L. manantlense sp. nov., L. tacanense sp. nov. and L. colimense sp. nov., are described and figured. McGinley’s (1986) key to species south of the US-Mexican border is emended to include the new species. Comments on the biogeography of Mexican species of the subgenus are provided. An interesting feature of the femoral scopa found in 2 of the new species is described and illustrated.

New Island Records for Lasioglossum (Hymenoptera: Halictidae) from the Virgin Islands, West Indies.

The halictid bee fauna of the West Indies is poorly documented, especially for species of LasioglossumCurtis, 1833. More information regarding the ranges and distributions of these species among the islands is needed for understanding historical biogeography and for bee conservation efforts. Here we report new distributional records in the U.S. and British Virgin Islands for three species of Lasioglossum: L. dispersumGibbs, 2018, L. enatumGibbs, 2018, and L. rufopanticis (Engel, 2001). We also provide information on new host-plant associations and describe specimens with atypical wing venation and unusual facial markings, which add to our understanding of basic biology and variation within species.

Canopy thinning, not agricultural history, determines early responses of wild bees to longleaf pine savanna restoration

Longleaf pine savannas are highly threatened, fire‐maintained ecosystems unique to the southeastern United States. Fire suppression and conversion to agriculture have strongly affected this ecosystem, altering overstory canopies, understory plant communities, and animal populations. Tree thinning to reinstate open canopies can benefit understory plant diversity, but effects on animal communities are less well understood. Moreover, agricultural land‐use legacies can have long‐lasting impacts on plant communities, but their effects on animal communities either alone or through interactions with restoration are unclear. Resolving these impacts is important due to the conservation potential of fire‐suppressed and post‐agricultural longleaf savannas. We evaluated how historical agricultural land use and canopy thinning affect the diversity and abundance of wild bees in longleaf pine savannas. We employed a replicated, large‐scale factorial block experiment in South Carolina, where canopy thinning was applied to longleaf pine savannas that were either post‐agricultural or remnant (no agricultural history). Bees were sampled using elevated bee bowls. In the second growing season after restoration, thinned plots supported a greater bee abundance and bee community richness. Additionally, restored plots had altered wild bee community composition when compared to unthinned plots, indicating that reduction of canopy cover by the thinning treatment best predicted wild bee diversity and composition. Conversely, we found little evidence for differences between sites with or without historical agricultural land use. Some abundant Lasioglossum species were the most sensitive to habitat changes. Our results highlight how restoration practices that reduce canopy cover in fire‐suppressed savannas can have rapid benefits for wild bee communities.

Pollination ecology of Tetratheca species from isolated, arid habitats (Banded Iron Formations) in Western Australia

Pollination and reproductive ecology of arid zone species in Australia are neglected topics. This is particularly true of rare species, some of which are threatened by mining operations. The bee community at Windarling Range in southern Western Australia and the pollination ecology of four rare Tetratheca taxa with distributions restricted to Banded Iron Formation inselbergs in the arid south-west were examined in winter and spring to understand if pollination rate was affecting the reproductive ecology of the plants. The bee fauna on the Windarling Range was sampled using coloured pan traps at three landscape positions of ridge (where Tetratheca paynterae subsp. paynterae occurs), slope and flats and the insect visitors to T. paynterae subsp. paynterae were quantified by direct observation. The bee fauna varied over the two years with average richness higher in 2010 than 2011 and was higher on the ridge compared with the slope and flats below the inselberg. The Tetratheca species are buzz pollinated and T. paynterae subsp. paynterae is only visited by a subsection of the bee fauna, mainly Lasioglossum species, which were shown to be relatively faithful to the species in terms of the pollen they carried. Flowering mainly occurs after the winter wet season, but may occur at other times when there has been substantial rain. This may not coincide with bee activity. In the winter flowers may be poorly serviced if maximum daytime temperatures are below 20°C. However, in spring when temperatures are higher the majority of flowers were pollinated and there was no significant difference in proportion of pollinated flowers between the four taxa examined. As T. paynterae is outcrossing the propensity for bees to attend few flowers on a visit to each plant, often on the outer part of the plant canopy, will likely ensure a high success rate for seed formation. High seed set in such an arid environment with few suitable sites for seedling establishment is essential so some propagules can find safe sites for establishment to maintain population numbers.

Local population density affects pollinator visitation in the endangered grassland daisy Rutidosis leptorhynchoides (Asteraceae)

The spatial arrangement of plants has implications for their pollination. Dense patches of flowering plants can result in increased pollinator attraction and, consequently, higher pollination and seed set per flower. We investigated this effect in the endangered, self-incompatible Australian daisy Rutidosis leptorhynchoides F.Muell. (Asteraceae) by quantifying the effect of plant density on pollinator visitation and seed set in a wild population. Pollinator activity was investigated by direct observation of insect behaviour, by examining the pollen carried on candidate insect species, by video monitoring of visitation, and by tracking the movement of dye as a pollen analogue. Two native Lasioglossum species (Hymenoptera: Halictidae) were identified as the most frequent pollen-carrying visitors to inflorescences. Their visitation was significantly higher where plants were dense, but no statistical correlation between seed set and plant density was found. Florivory was identified as potentially having a substantial negative influence on seed set, but without any clear relationship to plant density. Given that R. leptorhynchoides has declined substantially across its range, and previous reintroduction attempts have often failed, our findings provide key information pertaining to knowledge of pollinator and florivore behaviour in relation to plant density. To maximise success of future management strategies, these animal-plant interactions should be captured in species recovery designs.

Bees of the genus Lasioglossum (Hymenoptera: Halictidae) from Greater Puerto Rico, West Indies

The species of Lasioglossum from Greater Puerto Rico are reviewed. Nine species are recognized, including five new species described herein: Lasioglossum (Dialictus) genaroi sp. nov., L. (D.) dispersum sp. nov., L. (D.) enatum sp. nov., L. (D.) monense sp. nov. and L. (D.) amona sp. nov. The latter two are known only from Mona Island. Keys and images are provided to assist in identification. Details of nesting biology, floral hosts and distribution are provided where available. Three species, L. (D.) parvum (Cresson, 1865), L. (D.) busckiellum (Cockerell, 1915), and L. (D.) mestrei (Baker, 1906) are removed from the list of species for Puerto Rico. Details on their revised distribution are provided. Three new records for Haiti, L. (D.) gundlachii (Baker, 1906), L. (D.) ferrerii (Baker, 1906) and L. (D.) busckiellum are documented. Notes on other species in the Greater Antilles are provided, including the synonymy of Lasioglossum bruesi (Cockerell, 1912) and L. jamaicae (Ellis, 1914) under L. gemmatum (Smith, 1853).

Combination of reclaimed and unreclaimed sites is the best practice for protection of aculeate Hymenoptera species on brown coal spoil heaps

The study focused on aculeate Hymenoptera recorded at 114 study plots on seven brown coal spoil heaps (reclaimed and under spontaneous succession) situated in the North Bohemian Brown Coal Basin, Czech Republic. In total, 2706 individuals of 212 species from 13 families were collected using Moericke traps. Of this number, 46 rare species (2 regionally extinct, 7 critically endangered, 14 endangered, and 23 vulnerable), 5 species protected by law, and 3 other rare species were recorded. Species typical of sand banks and open landscape were most numerous. The communities were dominated by Lasioglossum species, Diodontus minutus and Bembecinus tridens on unreclaimed sites, and Apis mellifera, Lasioglossum pauxillum, and Osmia rufohirta on reclaimed sites. Unreclaimed sites hosted twice as many rare species at four times greater abundances. Rare species occurred there more frequently than at reclaimed sites. Species known as regionally extinct, Evagetes littoralis and Nomada minuscula, were found only on unreclaimed sites. Redundancy analysis showed that especially threatened species are connected with sandy sites small in area and with sparse vegetation cover. The number of rare species slowly increased with age, but young sites, too, could be very rich. It is recommended to combine succession and reclamation approaches to create suitable nesting habitats, refuges, and food resources. It is essential to maintain a fine mosaic of habitats in various (above all young) successional stages.

Seasonal Cycles, Nests, and Social Behavior of Some Colombian Halictine Bees (Hymenoptera; Apoidea)

This papel contains descriptions of nests and information on seasonal cycles and social behavior of four halictine bees, Habralictus bimaculatus, Caenohalictus eberhardorum, Lasioglossum (Dialictus) seabrai, and L. (D.) breedi. Data are also included on two parasitic halictine bees, both of the genus Microsphecodes. The Habralictus and Caenohalictus nest in aggregations; individual nests are occupicd by one to several bees. There are no castes and within a nest containing two el more bees the relationships are communal or possibly quasisocial. The two species of Lasioglossum (Dialictus) nest in diffuse and often small aggregations. The colonies have mean populations of little over two bees, but there are weakly differentiated queens and workers, especially in L. seabrai. Activities were similar in both wet and dry seasons, so far as known.

Do wild bees complement honeybee pollination of confection sunflowers in Israel?

Complementarity between species in the use of flower resources can enhance the pollination services of diverse pollinator communities. To test for complementarity, we studied fine-scale patterns of flower visitation and contribution to seed set of the three locally dominant bee species (commercially managed honeybees and two wild, non-managed Lasioglossum species) visiting confection (non-oil) sunflower in central Israel. The three species differed in their temporal (time of day) and phenological (head bloom stage) visitation patterns but generally showed niche redundancy. Moreover, honeybees strongly outperformed the wild species in both visitation rates and single-visit contributions to seed set. We conclude that the present communities and densities of wild bees do not complement honeybee sunflower pollination in the studied system. Sunflower seed production in central Israel is currently dependent solely upon the high stocking rate and pollination efficiency of honeybees.

A Duna-Tisza közi homoki sztyepprétek vadméh-közösségének hosszú távú változásai

Between 2006 and 2008, 972 Apoidea specimens have been collected that belonged to 93 species. Within the wild bee community the ratio of the Halictus and Lasioglossum species (19,45%), and the Megachile species (23,36%) are significant and also the density of the bumble bees (Bombus species) with 19,65%. During the collection in the years of 1977-78-79, 102 taxa were found in the Kis-Bugac barren. In the samples of six years, 141 species and one variation were shown. Having compared to the samples of 1977-78- 79, the results of the collection conducted 29 years later proved 53 species to be coommon. Faunal similarity of the two periods according to the Jaccard-index is 0,373. The most important community components found were the holomediterranean (24 species) and palearctic (21 species) in the years of 2006-2008. In the years of 1977-1979 the palearctic (33 species) and european (17 species) taxa were the most important fauna elements. According to the climate-tolerance assessment - during both collecting periods - the ratio of the Thermophile species was the most significant. According to the frequency index in the second collecting period, the ratio of the rare and very rare species have increased. In both collecting periods, the most important community component was the medium flying period Apoidea species.

Diversity and distribution of nematodes associated with wild bees in Turkey

AbstractThe diversity and distribution of nematodes associated with soil-dwelling bees in Turkey were examined. A total of 9456 wild bees were collected and dissected to detect nematodes and 173 female and 22 male bees were positive for an overall association level of 2.1%. Halictus resurgens was the most commonly collected bee found with nematodes with 82 and 19 nematode-infested female and male bees, respectively. Sixty-four of the nematode isolates were recovered from the Black Sea region (32.8%), 59 from Central Anatolia (30.3%), 35 from the Mediterranean (17.9%), 24 from the Aegean (12.3%), six from Eastern Anatolia (3.1%) and seven from Southeast Anatolia (3.6%). In 3.9% of all bees of the family Halictidae (173/4417), nematodes were observed in the Dufour's gland, poison sac, oviduct, bursa copulatrix and abdominal cavity of dissected female bees and from the genital capsule of male bees. Only abdominal glands of 0.6% (21/3279) of female bees from the family Andrenidae were observed with nematodes. Nematodes were isolated from the genital capsule of one male bee from the family Melittidae. The poison sac was the organ where nematodes were most often observed but the highest number of nematodes occurred in the abdominal cavity. Most nematodes were in the dauer juvenile stage making identification difficult. Sequence analysis using LSU D2/D3 domains and a fragment of mitochondrial cytochrome oxidase I (mtCOI) allowed for putative identification of nematode isolates. Two or three species of Bursaphelenchus (B. anatolius, B. debrae, and potentially one or more cryptic species closest in morphology to B. anatolius) were isolated from six different halictid species (two genera; Halictus and Lasioglossum) from different geographical regions in Turkey. An additional four species of diplogastrid were recovered from the abdominal glands of andrenids; a new species of Koerneria from Andrena limata and a separate sister clade to Mononchoides composed of three other possible species from four Andrena species. An additional unknown species in the order Tylenchida (near Allantonematinae) was recovered from three species of Lasioglossum. No molecular data were obtained from three mermithid juveniles from two Andrena and one Halictus species because samples were lost in transit. The associations of most nematode isolates with bees of the families Halictidae and Andrenidae were hypothesised to be phoretic, whereas the tylenchid and mermithids were parasites.

Pollination of the lady's slipper Cypripedium henryi Rolfe (Orchidaceae)

The pollination ecology of Cypripedium henryi Rolfe, a slipper orchid endemic to west China, was investigated, and its floral shape, size, colour, and scent were analysed. Examination of the breeding system suggests that the flowers are self-compatible, but need pollen vectors for successful reproduction. The flower is rewardless; over 15 insects belonging to Araneida, Hymenoptera, Diptera, Lepidoptera, and Coleoptera were recorded as flower visitors, but most only alighted or rested on the flower. In the total 32 h of observations over 2 years, female Lasioglossum bees were found to be the most frequent visitors and the only pollinators. They showed a high visitation frequency and, surprisingly, re-visited the same flowers frequently. Cypripedium henryi probably attracts pollinators visiting the flowers through general food deception (odour components, colour, false nectar guides), as well as special structures (slippery labellum, slippery staminode). Although three Lasioglossum species visited the flowers, only L. sauterum Fan et Ebmer was found with pollen. Lasioglossum flavohirtum Ebmer was large and climbed out from the entrance. Morphologically, L. sichuanense Fan et Ebmer could be considered as a potential pollinator, but the collected specimens were found to have no pollen of C. henryi on their bodies. It was speculated that the particular floral scent of C. henryi discouraged the entrance of L. sichuanense bees. Lasioglossum sauterum was matched morphologically to the flower, but not all of the visitations resulted in effective pollinations, as some flowers of C. henryi were frequently re-visited and the pollen mass had been taken away by bees on previous visitations. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 156, 491‐499.

Phylogeny of the bee genus Lasioglossum (Hymenoptera: Halictidae) based on mitochondrial COI sequence data

SummaryThe bee genus Lasioglossum Curtis is a model taxon for studying the evolutionary origins of and reversals in eusociality. This paper presents a phylogenetic analysis of Lasioglossum species and subgenera based on a data set consisting of 1240 bp of the mitochondrial cytochrome oxidase I (COI) gene for seventy‐seven taxa (sixty‐six ingroup and eleven outgroup taxa). Maximum parsimony was used to analyse the data set (using paup*4.0) by a variety of weighting methods, including equal weights, a priori weighting and a posteriori weighting. All methods yielded roughly congruent results. Michener’s Hemihalictus series was found to be monophyletic in all analyses but one, while his Lasioglossum series formed a basal, paraphyletic assemblage in all analyses but one. Chilalictus was consistently found to be a basal taxon of Lasioglossum sensu lato and Lasioglossum sensu stricto was found to be monophyletic. Within the Hemihalictus series, major lineages included Dialictus + Paralictus, the acarinate Evylaeus + Hemihalictus + Sudila and the carinate Evylaeus + Sphecodogastra. Relationships within the Hemihalictus series were highly stable to altered weighting schemes, while relationships among the basal subgenera in the Lasioglossum series (Lasioglossum s.s., Chilalictus, Parasphecodes and Ctenonomia) were unclear. The social parasite of Dialictus, Paralictus, is consistently and unambiguously placed well within Dialictus, thus rendering Dialictus paraphyletic. The implications of this for understanding the origins of social parasitism are discussed.

Behavioral Interactions of Two Solitary, Halictine Bees with Comparisons among Solitary, Communal and Eusocial Species

AbstractLaboratory behavioral experiments were conducted with two solitary, halictine bee species, in the genus Lasioglossum, to examine the nature of behavioral interactions between non‐nestmate females. The experimental design of this study was identical to previous work on both a communal (Kukuk 1992) and a eusocial Lasioglossum species (Breed et al. 1978), thereby providing data for comparison of female‐female interactions in species within a single, very large genus that exhibit different sociality. Both solitary species exhibited low levels of aggressive behavior yet nearly all females were reproductively active, as determined by subsequent dissections. Neither ovarian width nor size was associated with aggression in either species. Interspecific comparisons reveal large differences in cooperation and aggression among the four congeneric species. The communal species exhibits significantly more cooperative and less aggressive behavior than all other species suggesting that communal social behavior in Lasioglossum is not phenetically intermediate between the behavior of solitary and eusocial species.

Survey of native bees (Hymenoptera: Colletidae and Halictidae) in the Mackenzie Basin

This paper records the presence of 10 native bee species in the Mackenzie Basin, South Canterbury. In the family Colletidae 6 species of Leioproctus and 2 Hylaeus were found, and in the family Halictidae 2 species of Lasioglossum were found. Nests were located for 5 species (3 Leioproctus species, 1 Hylaeus species, and 1 Lasioglossum species).

Sociality and seasonal size variation in Halictine bees

For species ofLasioglossum, subgenusDialictus, the amount of seasonal body size variation of worker bees is correlated with indicators of the level of sociability attained by the species, such as queen longevity. Interspecific comparison of the amount of variation gives a simple measure of the level of sociality of the species. Different patterns of seasonal body size variation can be controlled by factors such as temperature and day length which are exogenous to the colony but in species with higher levels of sociality these patterns may be controlled endogenously.