08 September, 2023

Online images for braod-scale fly-floral interactions and biodiversity

 by Blakeman et al.

 

Flies, belonging to the Order Diptera and recognized by their two wings, play a vital role as pollinators, yet their interactions with flowers are not as well understood compared to bees and other more frequently studied pollinators. To bridge this knowledge gap, we compiled a dataset of 1,275 images of fly-flower interactions, contributed by photographers worldwide through internet repositories. From each image, taxonomic details were extracted for both flies and flowers, along with information about flower characteristics (color, shape) and fly activities (foraging, pollen carrying). While the resulting dataset does exhibit taxonomic and other biases, it nonetheless offers an initial panoramic view of the factors influencing pollination by Diptera. We identified 22 families of flies, with blow flies (Family Calliphoridae) and hover flies (Family Syrphidae) being the most abundant, and 63 families of flowers, with sunflowers (Family Asteraceae) and flowers in the carrot / celery family (Family Apiaceae) being the most abundant. Notably, our study found that fly behavior, such as pollen carrying and foraging, is influenced by flower color and shape. We found flies were more likely to be pollen carrying on elongate cluster flowers that were yellow and foraging on yellow and white flowers. Although some biases exist in the citizen science data, our findings shed light on pollinator-flower relationships and demonstrate the value of citizen science in documenting fly pollination amidst global insect declines.

Read the scientific publication in JPE!

18 July, 2023

Comparing levels of geitonogamous visitation by honey bees and other pollinators

By Travis and Kohn

A honey bee foraging on White Sage (Salvia apiana)

Honey bees (Apis mellifera) can be found on all continents exlcuding Antarctica, and are the most common flower visitor in both agricultural and natural settings worldwide. Pollinator importance and effectiveness has been historically calculated as the number of pollen grains deposited or the number of fruits or seed produced after a single visit by a pollintor onto a previously unvisited flower. However, the number of flower visits per plant a floral visitor makes before moving onto another plant (geitonogamous visitation) may also be of interest for successful reproduction in both self-compatible and -incompatible plants. Here we show that on average, honey bees visit more flowers per plant compared to the average among all pollinators, and as honey bees become more numerically abundant, non-honey bee flower visitors visit less flowers per plant. This study provides evidence that while the number of pollen grains depostited or the number of fruits/seeds produced informs a pollinator's importance and/or effectiveness, the number of flower visits per plant should also be taken into account. 

Read the scientific publication in JPE.

07 June, 2023

Observing bees and wasps

 by Graham et al.

A Halictus bee visiting a cactus flower

Bees and wasps perform many vital ecological roles. They provide pollination services to native plants and crops and can be used as indicators of habitat quality. Furthermore, wasps can control pest insects. Understanding which bees and wasps visit certain plants and crops (e.g., plant-pollinator interactions) can help identify insects that provide important crop pollination services, that may serve as biological control agents, and that have threatened populations. In order to understand potential environmental threats that may affect wild crop pollinators, managed pollinators, and pest control insects, monitoring programs and surveys need to be undertaken. In this review, we discuss the importance of 1) evaluating populations of threatened and endangered bee and wasp species, 2) identifying and evaluating pollinators of crops, 3) documenting wasp species for use as biological control agents, 4) surveying the ranges of non-native bees and wasps, and 5) utilizing bees and wasps as biological indicators of habitat quality. In addition to these topics, we also provide different methods or strategies that can be used to monitor bees and wasps. We hope that the information in this review can be used to begin or add to existing surveys and monitoring programs conducted by researchers, land managers, and citizen scientists.

 

Read the scientific publication in JPE!

23 May, 2023

Pollenkitt steht im Zusammenhang mit der Sammelbarkeit von Malvoideae-Pollen für corbiculate Bienen

von Sabine Konzmann, Mona Neukirchen, Dagmar Voigt, Christoph Neinhuis & Klaus Lunau

Eine Hummel sammelt den pinken Pollen
von
Malope trifida an ihren Hinterbeinen (oben);
Eine Hummel ist dicht mit blassgelbem Pollen
von
Hibiscus syriacus bedeckt, kann
ihn aber nicht sammeln (unten)

Bienen bringen Pollenkörner von Blüte zu Blüte, aber sammeln auch Pollen der dadurch nicht mehr zur Bestäubung dienen kann. Blüten aus der Familie der Malvaceae besitzen typischerweise große und stachelige Pollenkörner, die nicht von corbiculaten Bienen wie Honigbienen und Hummeln gesammelt werden können. Allerdings gibt es ein paar Ausnahmen die zeigen, dass Pollengröße und Stacheln nicht allein dafür verantwortlich sind, die Sammelbarkeit des Pollens zu verhindern. Zusätzlich könnte die Klebrigkeit des Pollenkitts die Sammelbarkeit von Malvenpollen entscheidend beeinflussen. Diese Klebrigkeit wurde hier in einem Zentrifugen-Experiment gemessen. Wurden Pollenkörner mit Hexan gewaschen, war der gesamte Pollenkitt entfernt. Wurden sie aber mit Wasser gewaschen, entfernte das nur den Pollenkitt von den sammelbaren Pollenkörnern von Malope trifida, nicht aber von nicht-sammelbaren Pollenkörnern von Hibiscus syriacus. Pollenkitt könnte die starke Klebrigkeit verursachen, wodurch Pollen hervorragend an blütenbesuchenden Insekten haften bleibt, aber auch das Sammeln des Pollens durch corbiculate Bienen verhindert. Konsequenterweise werden solche Blüten lediglich von Nektar sammelnden corbiculaten Bienen besucht - welches die Fortpflanzung der Pflanzen begünstigt.

Link zur wissenschaftlichen Publikation in JPE