Flower-visiting insects of genus Melastoma (Myrtales: Melastomataceae) at the Fushan Botanical Garden, Taiwan

We investigated the diversity and behaviour of insects that visit flowers of four native Melastoma (Family Melastomataceae) species of Taiwan and a horticultural hybrid Melastoma species at the Fushan Botanical Garden, Taiwan biweekly from May to August 2020. Visits of flower-visiting insects were classified into seven behavioural categories, based on the insects' behaviour and positions on the flower. The data are further assigned into four insect-flower interactions, namely pollination, herbivory, commensalism and neutralism. Our goal is to provide baseline data of insect-plant interactions of Melastoma, which is a common, but understudied plant genus in the country. A total of 1,289 visits to flowers were recorded by at least 63 insect morphospecies belonging to seven orders. The number of insect species recorded per Melastoma species ranged from 9 to 39. Visiting, sonication and passing were the three most frequently recorded types of behaviour, collectively accounting for 90.2% (n = 1,240) of the total observations. Pollination was the most dominant insect-flower interaction, accounting for 70.2% of the total observations, followed by neutralism (20.0%), herbivory (6.3%) and commensalism (3.5%). Sweat bees of the genera Lasioglossum and Maculonomia (Hymenoptera: Halictidae) are considered key pollinators to Melastoma species in Fushan Botanical Garden, based on their high number of visits and sonication behaviour. Our study provides the first list of insects that visit the flowers of all Taiwan's known Melastoma species and description of their interactions with the plants.

The ‘red-tailed’ Lasioglossum (Dialictus) (Hymenoptera: Halictidae) of the western Nearctic

Sweat bees in the subgenus Lasioglossum (Dialictus) are one of the most diverse and abundant bee taxa, and a critically important component of bee biodiversity. Yet, the most basic taxonomic knowledge of these bees is lacking in many regions. As a step towards a better understanding of the L. (Dialictus) of the western Nearctic region, a revision of the ‘red-tailed’ L. (Dialictus) species was completed. Thirty-six species were revised, 20 of which are described as new, and two names are treated as junior subjective synonyms. Descriptions, figures, distribution maps, floral hosts, and keys to species for females and males are provided. The following 20 species are described as new: Lasioglossum (Dialictus) arenisaltans sp. nov., L. (D.) argammon sp. nov., L. (D.) austerum sp. nov., L. (D.) cactorum sp. nov., L. (D.) cembrilacus sp. nov., L. (D.) clastipedion sp. nov., L. (D.) clavicorne sp. nov., L. (D.) decorum sp. nov., L. (D.) festinum sp. nov., L. (D.) imbriumbrae sp. nov., L. (D.) julipile sp. nov., L. (D.) lilianae sp. nov., L. (D.) meteorum sp. nov., L. (D.) miltolepoides sp. nov., L. (D.) minckleyi sp. nov., L. (D.) perditum sp. nov., L. (D.) rufornatum sp. nov., L. (D. ) spivakae sp. nov., L. (D.) tessellatosum sp. nov., and L. (D.) torrens sp. nov. Previously unknown males of L. (D.) clematisellum (Cockerell, 1904), L. (D.) droegei Gibbs, 2009, L. (D.) kunzei (Cockerell, 1898), and L. (D.) pallidellum (Ellis, 1914) are described and figured for the first time. Lasioglossum (Dialictus) clarissimum (Ellis, 1914) (= Halictus clarissimus Ellis, 1914) and L. (D.) perexiguum (Sandhouse, 1924) (= Halictus (Chloralictus) perexiguus Sandhouse, 1924) are new subjective junior synonyms of L. mesillense (Cockerell, 1898) (= Halictus nymphalis var. mesillensis Cockerell, 1898). A lectotype specimen is newly designated for L. mesillense, for which the location of the type material has not previously been known. The following five new records for Mexico are reported: L. clematisellum, L. droegei, L. eophilus (Ellis, 1914), L. kunzei, and L. pallidellum.

Bee visitation and fruit quality in berries under protected cropping vary along the length of polytunnels

Wild and managed bees provide effective crop pollination services worldwide. Protected cropping conditions are thought to alter the ambient environmental conditions in which pollinators forage for flowers, yet few studies have compared conditions at the edges and centre of growing tunnels. We measured environmental variables (temperature, relative humidity, wind speed, white light and UV light) and surveyed the activity of managed honeybeesApis mellifera, wild stingless beesTetragonula carbonariaand sweat beesHomalictus urbanusalong the length of 32 multiple open-ended polyethylene growing tunnels. These were spaced across 12 blocks at two commercial berry farms, in Coffs Harbour, New South Wales and Walkamin, North Queensland, Australia. Berry yield, fresh weight and other quality metrics were recorded at discrete increments along the length of the tunnels. We found a higher abundance and greater number of flower visits by stingless bees and honeybees at the end of tunnels, and less frequent visits to flowers toward the middle of tunnels. The centre of tunnels experienced higher temperatures and reduced wind speed. In raspberry, fruit shape was improved with greater pollinator abundance and was susceptible to higher temperatures. In blueberry, per plant yield and mean berry weight were positively associated with pollinator abundance and were lower at the centre of tunnels than at the edge. Fruit quality (crumbliness) in raspberries was improved with a greater number of visits by sweat bees, who were not as susceptible to climatic conditions within tunnels. Understanding bee foraging behaviour and changes to yield under protected cropping conditions is critical to inform the appropriate design of polytunnels and aid pollinator management within them.

Mass-length Relationships for 3 Bee Species in Northwest Ohio

The ability to accurately estimate bee mass through measurements of intertegular distance (ITD) is an important tool for field biologists. ITD is the distance between the bases of the 2 wing tegulae on the bee’s thorax. However, the relationship between ITD and bee mass can vary based on species and sampling region. A collection of 92 bees—representing 3 species—was examined to assess the accuracy of ITD in estimating dry mass for bees in northwest Ohio. The focus was on 3 species: silky striped sweat bees (Agapostemon sericeus), honey bees (Apis mellifera), and common eastern bumble bees (Bombus impatiens). Overall, there was a positive correlation between ITD and dry mass across all individuals sampled (R2 = 0.77), but within species the degree of correlation varied significantly. The results suggest that ITD accurately estimates dry mass in silky striped sweat bees (R2 = 0.93), but the correlation weakens in common eastern bumble bees (R2 = 0.54) and is non-existent in honey bees (R2 = 0.39). Field biologists interested in using ITD to estimate bee mass should take preliminary measurements when investigating bumble bees, and should avoid ITD estimates in honey bees.