The first documented migration of a potter wasp, Ancistrocerus adiabatus (Hymenoptera: Vespidae: Eumeninae)

Eumenine wasps are not known to be migratory and have never been proposed as migrants, let alone documented as such. We document a large-scale migration of a common eumenine, Ancistrocerus adiabatus, during which 44 000–68 000 wasps moved through a known migration corridor in southwestern Ontario, Canada, in less than an hour. Evidence for migration of another eumenine, Pachodynerus erynnis, six species of flower flies (Diptera, Syrphidae), and two dragonflies (Odonata) is also provided. We hope that this note encourages naturalists to focus their attention on insects at known migration concentration sites to learn more about this grossly understudied aspect of animal behaviour.

Overall and repeated floral visitation by insects suggests flower flies (Syrphidae) as the major pollinator group of Alaska Wild Rhubarb (Koenigia alaskana var. glabrescens; Polygonaceae) in Northwest Territories, Canada

Alaska Wild Rhubarb (Koenigia alaskana var. glabrescens; Polygonaceae) is a native Arctic, subarctic, and alpine plant of northwestern North America. Although the plant has some economic and ecological importance, its biology is poorly known. At 11 sites in the northeast corner of its range in Northwest Territories, we found that 87% of its floral visitors were flies, mostly Syrphidae, a diverse family known to be important pollinators. Insects visiting consecutive flowers on different plants and, thus, likely effecting pollination were also flies (78.6%) and also mostly Syrphidae (72.7%) followed by Hymenoptera (20%). Although syrphids were the dominant potential pollinators at most sites, there was some variation among sites. Our results provide quantitative support for pollinator diversity and the major role of Syrphidae in pollination of Alaska Wild Rhubarb. We suggest that pollination is not a limiting factor in this plant’s spread, nor its rare and local occurrence and restricted distribution, because the majority of its pollinators are widespread.

Eristalis flower flies can be mechanical vectors of the common trypanosome bee parasite, Crithidia bombi

Flowers can be transmission platforms for parasites that impact bee health, yet bees share floral resources with other pollinator taxa, such as flies, that may be hosts or non-host vectors (i.e., mechanical vectors) of parasites. Here, we assessed whether the fecal-orally transmitted gut parasite of bees, Crithidia bombi, can infect Eristalis tenax flower flies. We also investigated the potential for two confirmed solitary bee hosts of C. bombi, Osmia lignaria and Megachile rotundata, as well as two flower fly species, Eristalis arbustorum and E. tenax, to transmit the parasite at flowers. We found that C. bombi did not replicate (i.e., cause an active infection) in E. tenax flies. However, 93% of inoculated flies defecated live C. bombi in their first fecal event, and all contaminated fecal events contained C. bombi at concentrations sufficient to infect bumble bees. Flies and bees defecated inside the corolla (flower) more frequently than other plant locations, and flies defecated at volumes comparable to or greater than bees. Our results demonstrate that Eristalis flower flies are not hosts of C. bombi, but they may be mechanical vectors of this parasite at flowers. Thus, flower flies may amplify or dilute C. bombi in bee communities, though current theoretical work suggests that unless present in large populations, the effects of mechanical vectors will be smaller than hosts.

New record of Cepa apeca (Diptera, Syrphidae, Eristalinae, Merodontini) in the Andean-Amazonian region of Colombia and expansion of its geographic range

ABSTRACT Flower flies of the genus Cepa are endemic to the Neotropical region and Cepa apeca is currently known only from Costa Rica. Here we report the first record of C. apeca in Colombia based on a single female collected using a canopy trap in a dense secondary forest in a mountainous ecosystem in the locality of Vereda San Francisco, municipality of Florencia-Caquetá, at an altitude of 643 m.a.s.l. This finding constitutes the first record of the genus Cepa in Colombia and expands the geographic range of Cepa apeca by approximately 1,500 km (straight line) southwards to South America. Our finding represents the southernmost occurrence of the species and contributes to the incipient knowledge on the Diptera diversity in the Colombian Andean-Amazonian region.

Eristalis (Diptera: Syrphidae) Flower Flies are Potential Non-host Vectors of the Common Trypanosome Bee Parasite, Crithidia Bombi

Flowers can be transmission platforms for parasites that impact bee health, yet bees share floral resources with other pollinator taxa, such as flies, that could be hosts or non-host vectors (i.e., mechanical vectors) of parasites. Here, we assessed whether the fecal-orally transmitted gut parasite of bees, Crithidia bombi, can infect Eristalis tenax flower flies. We also investigated the potential for two confirmed solitary bee hosts of C. bombi, Osmia lignaria and Megachile rotundata, as well as two flower fly species, Eristalis arbustorum and E. tenax, to transmit the parasite at flowers. We found that C. bombi did not replicate (i.e., cause an active infection) in E. tenax flies. However, 93% of inoculated flies defecated live C. bombi in their first fecal event, and all contaminated fecal events contained C. bombi at concentrations sufficient to infect bumble bees. Flies and bees defecated inside the corolla (flower) more frequently than other plant locations, and flies defecated at volumes comparable to or greater than bees. Our results demonstrate that Eristalis flower flies are not hosts of C. bombi, but they may be mechanical vectors of this parasite at flowers. Thus, flower flies may amplify or dilute C. bombi in bee communities.

Updating the knowledge of the flower flies (Diptera: Syrphidae) from Chile: Illustrated catalog, extinction risk and biological notes

Syrphidae, more commonly known as flower flies, are considered one of the most important Diptera families worldwide because of their critical role in pollination, biological control and decomposition of organic matter. The study of these flies in Chile has stagnated due to a lack of local experts as well as the absence of an updated catalog of species. This study is an attempt to remedy the latter of these issues by providing an illustrated and updated catalog to the Syrphidae of Chile. Species are presented under currently accepted names, with synonyms and previous combinations listed and original references. Type localities, world and Chilean distribution by geopolitical Chilean regions, taxonomic and biological notes, a complete record of bibliographic references and extinction risk under IUCN Red List criteria are provided. This catalog recognizes 132 species of Syrphidae, belonging to four subfamilies (Eristalinae, Microdontinae, Pipizinae and Syrphinae), 13 tribes and 47 genera. A total of 46 species (34.84 %) is restricted to the geopolitical territory of Chile. Eight species are considered exotic, one is considered incertae sedis and three are based on doubtful records. Seventeen species of 10 different genera (Copestylum Macquart, 1846; Dolichogyna Macquart, 1842; Eosalpingogaster Hull, 1949b; Eupeodes Osten Sacken, 1877; Meromacrus Rondani, 1848; Palpada Macquart, 1834; Paragus Latreille, 1804; Sphiximorpha Rondani, 1850; Sterphus Philippi, 1865 and Toxomerus Macquart, 1855) are reported from Chile for the first time. A total of 44 species (33.33 %) reported from Chile are directly threatened by human activities such as agriculture, forestry, mining and/or urbanization and indirectly by climate change. The gaps found in the geographic distribution of Chilean flower fly species and what it means for its use by disciplines such as ecology, floral biology and agronomy, are discussed. In addition, the use of this illustrated catalog for biological conservation, the potential definition of priority areas and ecosystem management plans based on this group of Diptera are also discussed.

Aneriophora aureorufa (Philippi, 1865) (Diptera: Syrphidae): a fly specialized in the pollination of Eucryphia cordifolia Cav. (Cunoniaceae R. Br.), an endemic species of South American temperate forest

The order Diptera is the second most important group of pollinators worldwide. Many flies are considered generalist pollinators, but specialist flower flies’ associations are rare or uncommon. The present study aimed to determine the level of specialization in pollination for Aneriophora aureorufa (Philippi, 1865) (Diptera: Syrphidae), an endemic species of the South American temperate forests. The study evaluates also the species abundance in different sampling sites and environments. Our data suggest that Aneriophora aureorufa has an exclusive and extremely narrow association with the flowers of Eucryphia cordifolia Cav.¸ an endemic Chilean species. We reviewed the literature on Chilean pollinator species searching for information about Aneriophora Stuardo & Cortés 1952 and compared its exclusive association with other specialist flies. We conducted long-term fieldwork for 22 years in one location during the flowering season and over a period of one to six years in five additional locations. In our field study we recorded all insects which had contact with stigma and/or stamens of 25 plant species. We found that Aneriophora visits flowers of E. cordifolia in both low absolute abundance and low relative percentage, and occasionally visits flowers of two other species. In the northern distributional range of A. aureorufa, where E. cordifolia is absent, the hoverfly was recorded in flowers of Laurelia sempervirens (Ruiz & Pav.) Tul. (Chilean laurel, Atherospermataceae), but in low frequency (0.01 flowers/min). In a site where we have a long-term study, A. aureorufa represented only 0.2% of all flower visitors, and its abundance was higher in canopy forests, visiting 0.03 flowers/min. Based on our observations and the literature review we propose that (1) Aneriophora is one of the most specialized pollinator flies described until now; (2) the species is more frequent in old-growth forests than in forest edges or isolated trees.

A new species of the flower fly genus Criorhina Meigen (Diptera: Syrphidae) from mainland China

The genus Criorhina consists of honey-bee and bumblebee mimic flower flies with a strongly produced face. It is widespread in the Holarctic and Oriental Regions. Criorhina adults are usually found flying near white spring flowers in woodlands and shrubs. The Chinese Criorhina fauna is poorly known and includes seven species. In our flower fly collection of Henan Province, northern China, an eighth new species was discovered: Criorhina rostrata Li, Huo & Li sp. nov. This new species is here described and illustrated. The new species possess a very long proboscis, unique amongst the Criorhina species from mainland China. In addition, during the course of this study, Criorhina brevipila Loew, 1871 was also found to be present in mainland China, based on a specimen from our collection. A key to the species of Criorhina from mainland China is given.

Abundance and Distribution of Korean Flower Flies (Diptera: Syrphidae): Dominant Influence of Latitude on Regional Distribution

Studies on abundance and distribution at different scales are rare. We examined whether the abundance of flower flies at a site in South Korea was related to the national occupancy and global distribution (distributional extent or range size) and whether the national occupancy was related to global distribution. In global distribution, the influence of two dimensions (latitude and longitude) was analyzed separately. Flower flies were collected by malaise and pitfall traps at a forest gap in South Korea. Data regarding national occupancy and global distribution were obtained from a Korean Flower Fly Atlas. We collected 46 species from the field survey and obtained a list of 119 species from the Korean Flower Fly Atlas. Our results showed that abundance at a site was positively correlated with national occupancy, but not global distribution, and the national occupancy was positively correlated with global distribution, mainly by the latitudinal range size. Finally, our results indicated that the regional distribution of flower flies was influenced by its one-dimensional global distribution.