Identifying �Floral Visitors and Pollinators�and Utilizing the Citizen Science Platform iNaturalist

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Weber Lab of SIU

Training for Citizen Scientists for pollinator observation and identification a curriculum by

Kate Tillotson, Dr. Jenn Weber and Kim Sasan

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All photos courtesy of Kim Sasan of

Texas Master Naturalists

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Most flowering plants are dependent on mutualisms with insects to move their pollen from one flower to another, these insects are called pollinators

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To successfully identify pollinators and other floral visitors it’s important to understand the interactions of flowering plants and insects

These mutualisms are often complex and can be studied from the perspective of either participant in the mutualism- the plant or the pollinator

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Categorizing both parts of the mutualism contributes observations that give researchers a better sense of these unique relationships

Pollinators are insects that, in visiting flowers, are capable and efficient at moving pollen from the flower of one plant to another, as you can see below this bee is covered in hairs that collect pollen as it forages for nectar and pollen. These hairs are located all over a bees body and ferry pollen from one flower to another.

Pollinators act as unwitting vectors for the movement of pollen

Many insects visit flowers and may utilize flowers beyond collecting nectar or pollen. Scientists often want to understand and characterize all the visitors that come to a flower, not just the pollinators. 

Here you can see two floral visitors- They're both utilizing this flower, but for different ends.

the flower fly or pollinator 

and the crab spider, its predator 

Here we see some of the floral visitors that may use flowers for ends other than pollination

Spiders are common predators on flowers. They often wait to ambush their prey by hiding beneath flowers and leaves. 

Wasps are predatory meat eaters and use flowers to find prey. They also sometimes use flower nectar as a supplement to their diets. 

Ants and beetles are a common sight on flowers. Generally, they are very poor pollinators and are only on or in flowers to steal nectar, that is why we consider them nectarivores.

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Both groups have bodies mostly without hairs that would pick-up pollen (like bees have) as they feed on the flower's nectar

This limits the ability of these groups to facilitate pollen movement between flowers

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Additionally, most ants are wingless and their ability to disperse pollen is even more limited

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These herbivores often eat more than leaves and will bore their way into flowers, causing damage to the floral structures and stealing floral resources

Herbivores may be very tiny like these scale insects

Some of the most interesting herbivore interactions are those of pollinating species that depend on the same plants for feeding their larvae, such as the butterfly larvae pictured here 

Herbivores may feed on flowers or other parts of the flowering plant, which can affect the resources a plant can utilize for flowering and reproduction.

A bee or not a bee?

Some bee mimics are hairy and similar in size to bees.

Many pollinators are very small, and it can be hard to distinguish the difference between flies and bees without careful observation.

Similarly, some bees may look like one another but have different roles as pollinators.

Even when we’re just observing pollinators, it may not be clear who is who. Some insects that visit or pollinate flowers may imitate or mimic bees in their coloration, such as flower flies, beetles, and predators such as wasps, which share similar coloration.

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This is also a fly

This is a fly

Honeybees (Apis)

Unlike Bumble Bees, Honeybees are a non-native species that was naturalized from Europe

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Honeybees have stripes that are orange-yellow and black which distinguishes them from native bumblebee and bee species which have yellow or light-yellow coloration

 Bumblebees (Bombus)

Bumblebee stripes which are black and vivid yellow 

Generally furrier and larger

 Carpenter Bees (Xylocopa)

Bumblebees have a hairy abdomen

Carpenter Bees have a shiny abdomen and much larger heads

Bumblebees (Bombus)

Small Bees

While some small bees are larger and easily seen some of the species in the genus Lasioglossum (Sweat Bees) can be as small as 3-4 mm

They can be an important part of a pollinator community for different species of flowers

It's important to keep your eyes peeled and try to differentiate these from small flies!

Small bees do not belong to the same genus as Bumblebees (Bombus) and can be the size of Honeybees or smaller. These are native bees that are locally adapted and can be very diverse.

Flower Flies

Flies have only one pair of wings and generally hold them at a 45-degree angle at rest

Bees have two pairs of wings, with the second pair shorter than the first 

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Flies have a "thick-waist" and the thorax connects to the abdomen

Bees have a defined "waist" with a distinct separation between thorax and abdomen

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Flies have no pollen collecting hairs on their back legs like bees do

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Fly species can have very similar markings to bees, but their flight is distinct from bees in that they can hover

Antennae of bees vary from other insects in that they have elbowed antennae

Flies have much shorter antennae than bees

With large forward-facing eyes that often touch the top of their head

Bees have eyes on the side of their head

Wasps

Wasps have skinny bodies with a narrow waist and are generally hairless with long, thin legs

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As a general rule, wasps are predators and eat other organisms but may come to flowers to feed on pollen or nectar to aid their development. However, they’re considered poor pollinators because of their hairlessness.

Wasps resemble bees in color and may be plentiful in flowering areas

Moths 

Moths may resemble bees in that they have hairy bodies, and their coloration may be similar

But bees have very different mouthparts than moths and butterflies as well as different movement in flight

Beetles

Beetles resemble bees in coloration only and as we covered earlier in the presentation, they are generally poor pollinators

Their antennae, body shape, and the fact that their wings are covered should give away that these beetles are just posing as bees!

We have discussed the differences between pollinators and floral visitors such as predators. We are also familiar with different groups of bees that could be observed visiting flowers as well as some of the ways other insects' mimic bees to protect themselves while they visit flowers.

Building on this knowledge, we’ll learn about functional groups and the relationships between flowers and pollinators that we could characterize.

What is a functional group?

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Birds

Large Bees

Small Bees

Flies

Moths and Butterflies

Each group tends to interact with plant species differently

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Pollinators can be subdivided into "functional groups"

Pollinator Assembly

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This refers to the unique relationships between different pollinators and plants. Some flowers may have many pollinators, while others may have very few specialist pollinators.

Scientists can map these interactions at the ecological level.

Flower Generalists

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If a flowering plant species is visited by two or more functional groups of pollinators, it is considered a generalist

Other characteristics include accessible pollen, and lots of nectar

Generalist flowers tend to have a shape that is open, radial, bowl shaped or flat and often are white, cream, or yellow-green colored

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Insect Generalists and Foraging

If a pollinator is a generalist, it visits several to many plant species, generally in one foraging trip

Generalist pollinators are common and are often essential parts of pollinator assemblies for flowering plants

Most of the functional groups of pollinators visit species of flowers regularly in a non-random pattern. This is important for the plants because it means pollen is moved between plants. Scientists attribute this to a type of learning on the insect's part.

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Pollinator and Floral Specialization

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Often scientists define specialization through behavior (interaction with a flowering plant) and range of a certain pollinator

Defining pollinator specialism is a little trickier...

Floral constancy is a type of “specialization”. During a foraging trip insects may visit flowers from only one species of plant. This behavior is easily observed.

Plants that are reliant on one functional group or very few species for reliable pollination are said to be “specialized”. These flowering species have evolved certain characteristics that attract specific pollinators

Flower Shape and Form

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Radial Symmetry

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Bilateral Symmetry

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Often reflects whether a flowering species is a specialist 

Dish Shaped

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Tubular Form

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Radial symmetry and an open shape indicate a flower that may be visited by generalist pollinators

Shapes or forms such as bilateral symmetry or an enclosed or tubular form may indicate more specialized pollinators or different pollinator syndromes.

Pollination syndromes are a set of traits that generally indicate certain functional groups of pollinators and have been selected for over time.

Pollination Syndromes

Plant Communities and Markets

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Plant communities are defined by the species present and their density and abundance

Communities are groups of species that commonly occur together. We can define this on several levels: the flowering plant community, the pollinators and visitors, or all together

If one species is particularly dense, we may expect to see a different pollinator make-up or insects only visiting these flowers. These can be seen as "markets" 

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Community Change

Through time: throughout the day, a community may change, and the density or species of open flowers may change

Weather: as temperature or weather events within a day occur, a community may change as some flowers close at certain temperatures or with rainfall

Introduction to Observational Research and Citizen Science

You may have never personally participated in an observational study of pollinators BUT you've probably reported data

Now, more than ever, citizen observations can impact scientific research by contributing scientific data that can be collected in a repeatable method.

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Through apps like iNaturalist Citizen Scientists can share their results directly with researchers.

Observational Research

Taking data in a repeatable method is the backbone of scientific experimentation. This allows you, the researcher, to understand under what circumstances the data was taken and to account for discrepancies and anomalies

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To take repeatable observational data on pollinators and floral visitors follow the steps below

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Start by picking a spot that is "uniform" meaning that it has one type of habitat

You'll measure and observe an area the same distance as your arms outstretched , forming a square, about 1 meter by 1 meter

Record your observations for 30 minutes

When?

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Spring

Early Fall

Bees and other pollinators dislike cloudy, windy or cold and cool days 

Take observations when it's nice and sunny out

Ensure that flowers are open and not closed due to time of day or weather

Take observations in mid- morning or afternoon depending on the heat of the day

What to record?

1. Record data about where you're observing

Record the habitat features

-grassland?

-woodland?

-one large bush with many blooms?

2. Record the time, date and geographic location

This information you can gather from your phone

3. Record plant characteristics or species present

"Patchy purple flowers"

You may even want to identify plant species using the Seek app by iNaturalist

What to record?

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Record the functional groups of pollinators that are present and how many. If species look distinct you can record how many different species you think are present. Make notes of their habit- are they visiting many flowers or just a few?

Other Records

You can leave your observations as is or take it a step further...

Record visitors that aren't pollinators, such as predators or herbivores

Maybe you want to ID insects you see but you don't know what species?

You can upload a clear, close-up photo of your pollinator/visitor to iNaturalist

This allows other citizen scientists the ability to check and see what you may have found and ID it!

You can also use Seek by iNaturalist- it uses image recognition technology to identify natural life around you. No registration is needed and it doesn't collect user data. 

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iNaturalist

iNaturalist is a powerful tool that connects people around the world in characterizing and collecting data on biodiversity

Just by uploading photos you can give scientists a chance to understand the species you're observing through metadata

iINaturalist is an open forum where people can discuss what species is present in your observations

Where your observation goes after it’s uploaded

RESEARCH GRADE

Academic researchers can then use all this data to understand natural history questions in many fields

If enough people agree on the identification or your organism on iNaturalist then your observation can be used for research!

You're a Citizen Scientist!

By participating, you can be an important part of increasing our knowledge and awareness of pollinators and other aspects of the natural world

These natural interactions are also ones that are crucial to humans and our food sources

Characterizing functional groups and pollinator species in an area deepens our understanding of the ecological services those insects play a part in