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Hawthorn Pollinator Examination Jessica Snow Biol 320 Sec 001 08 VI 2015 All photos by Jessica Snow Data Collected by Anna Wan, Sam Walker, and Jessica Snow
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Table of Contents:
Introductions_______________________________________________________________________________________3 Methods_____________________________________________________________________________________________3 Results_______________________________________________________________________________________________4 Discussion___________________________________________________________________________________________6 Key for Basic Identification________________________________________________________________________7 Conclusion_________________________________________________________________________________________10 References_________________________________________________________________________________________11 Appendix A________________________________________________________________________________________12
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Introduction Pollination, primarily by insects, is one of the most important ecological services
provided by a group of organisms. Pollination is key to sexual reproduction in many
flowering plants, and allows for the continued introduction of variation by genetic
recombination (Clancy). This genetic variation is vital to stable communities, and with
variation comes the ability to survive environmental changes. In addition, pollination is
needed for the production of 35% of the crops used for food worldwide (Insects &
Pollinators). With this in mine, it becomes apparent how crucial it is to support native
pollinator species. Genus Crataegus, or commonly called, Hawthorn trees have multiple
species native to Michigan (Michigan Flora Online). Many of these trees are known to help
support other species by providing food and shelter. In our study, we surveyed the
individuals visiting Hawthorn trees while in bloom. This survey shows Hawthorn tree’s
ability to support local pollinator species by providing them with a seasonal food source.
Methods To learn about the diversity of
pollinators that visit the Hawthorn trees in
Jensen’s meadow, collections were made on
four days from two sites. Both sites of
collection were adult Hawthorn trees found
in Jensen’s meadow on the University of
Dearborn Campus Natural Area (figure 1).
Collection periods were conducted in late
morning to achieve best collection condition.
Goal conditions were full sun, calm, and
warm. Due to natural weather variation, not
all collections could be made in these prime conditions (table 1). On May 22, collection
techniques were practiced and no specimens were analyzed. Specimens were collected
using fine mesh nets, transferred into plastic transfer containers and stored in a shaded
region until the collection was complete. During collection, repeat specimens were not
collected if possible. Collection focused on examining the diversity, not quantity, of
Figure 1: Map of Collection Area
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pollinators visiting the Hawthorn trees. After collection was competed, specimens were
refrigerated for 20-‐35m and then transferred to individual vials for observation. These
vials were kept refrigerated or in ice water when not being analyzed to inhibit movement
and stress of specimens collected. They were then observed under a dissecting microscope
and photographed. A record was taken of each identified pollinator. To help in
identification, Kaufman’s Field Guide of Insects and BugGuide.net were used. Collection
ended with the end of the blooming period for the Hawthorn trees, which bloomed for just
over one week. Organisms were identified to their family, a few were identified to genus,
some were tentatively identified to genus, and two were identified to species. In analysis of
diversity, different specimens in the same family were only considered different if they
were morphologically unique. In this case, they were given a number after their name to
denote this difference (table 2, appendix A).
Results From four days of collection, 25 unique organisms were identified to be visiting the
Hawthorn trees. Of these species, not all are known to collect pollen or nectar, instead
using the Hawthorn for other purposes such as feeding on plants and insects. These will be
considered secondary pollinators and are denoted in table 2 with an asterisk. Kaufman’s
Filed Guide to insects was used to make this determination (Kaufman). To see further
details about behaviors that qualified organisms as primary or secondary pollinators, refer
to Appendix A. In total, 17 commonly considered pollinators, which we will call primary
pollinators, were identified. 8 secondary pollinators were collected. Many secondary
pollinators accidentally pollinate flowers while performing their own feeding behavior.
Day Test A B C D Date 22 V 2015 23 V 2015 27 V 2015 29 V 2015 01 V1 2015 Time (EST) 1230-‐0130 1046-‐1130 0905-‐1005 0920-‐1020 1220-‐1250 Hawthorn sampled A A A A B Temperature (°C) N/A 25.9 26.0 25.6 13 Humidity (%) N/A 32 61 78 58 Sky cover N/A Clear Clear Full cloud Full cloud Wind N/A Calm Calm Calm 1.5mph Analysis Time N/A 1130-‐0300 1205-‐0305 1210-‐0310 1250-‐0150 Bloom Stage Early Middle Middle Fading Late Table 1: Collection Information
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This fact was determined from the visible presence of pollen grains on many of these
individuals. Day B, May 27th had the best collecting conditions and was the time of fullest
flower blooms. This day had sunshine and high temperatures, which seemed to encourage
pollination behavior. Day B was a diverse collection day, and the majority of species
collected were known pollinators. On day B, 10 different types of pollinators were collected
and 90% were primary pollinators (table 2). On day C, 12 types of pollinators were
collected, but only 50% were primary pollinators. Day A was much less diverse with only 6
types collected, 80% of them being primary pollinators. The day of lowest diversity was
day D, with only two individuals collected, both being primary pollinators. This could be
due both to cold cloudy weather and the end of bloom conditions. Mining bees were
23 V 2015 27 V 2015 29 V 2015 01 V1 2015 Small Carpenter Bee II Mining Bee IIII III I Asian Multicolored Lady Beetle* I Spotted Lady Beetle I Metallic Sweat Bee II Flesh Fly I I Muscid Fly* I Bee Fly I Bumble Flower Beetle I Large Carpenter Bee I Red Admiral Butterfly I I Sweat Bee I II Honey Bee I Flower Fly 1 I Flower Fly 2 I Plant Bug* I Spread-‐winged Damselfly* II Rove Beetle 1* I Rove Beetle 2* I Assassin Bug* I Yellowjacket I Bumble Flower Beetle 1 I Thread-‐waisted Wasp* I Ichneumon Wasp I Syrphid Fly I Table 2: Collection Results *Secondary Pollinator
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collected on three of the four collection days, making them a common pollinator of
Hawthorns. Flesh flies, Red Admiral butterflies, and Sweat bees were all collected on two
occasions, meaning that they may be somewhat common pollinators for Hawthorn trees.
Discussion The taxa richness observed at the Hawthorn trees during the 4 days of collection
show that they are host to many different pollinators. It can be surmised that Hawthorn
trees are capable of helping to support a largely diverse population of pollinators. This
allows for the opportunity to introduce Hawthorn trees to an area where the pollinators
found in this study would be a positive addition. In habitat management, this data can be
used as a guide to look at benefits and drawbacks of adding Hawthorn trees into an
environment.
Methods of identification were learned by trial and error during the 4 days of
collection. The Key below was created as a summary of the best techniques acquired. In
our identification, the first necessary step was to isolate the invertebrates into broad
categories. After that was determined more specific classifications were made.
Key For Basic Identification
1. Can haltêres (small knob structures) be identified behind the front wing?
a. If yes, you have a fly. Flies only have one set of wings which often fold in.
Example of a fly (left) and close-‐up of haltêre (right)
b. If no, continue to question two.
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2. Can elytra (hardened wing cover) be observed in rest, often concealing wings?
a. If yes, you have a beetle.
Examples of two types of beetles with hard wing-‐covers (above)
b. If no, continue on to question three.
3. Are there broad wings, more than 3 times the size of body?
a. If yes, you have a butterfly, or moth.
Examples of a Red Admiral Butterfly (above)
b. If no, continue on to question four.
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4. Is the abdomen very narrow, 2 pairs of wings long, and body often blue or green?
a. If yes, you have a damselfly or pondhawk
Example of Spread-‐winged Damselfly (above)
b. If no, continue on to question five.
5. Are legs much longer than body, highly jointed, or body with highly angular shape?
a. If yes, you may have a plant bug, assassin bug or other secondary pollinator.
Example of plant bug (left) and assassin bug (right)
b. If no, continue on to question six.
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6. Is connection between thorax and abdomen very narrow or hourglass shaped?
a. If yes, you may have a wasp or similar family
Example of Thread-‐Waisted (Left) and Ichneumon Wasp (right)
b. If no, you may have a bee if it fits these criterion: hairy or not, shiny or not,
compound eyes on sides of head, antennae usually moderately long, legs
thicker, joined and shorter than body length. Holds wings to body when at
rest. Yellowjackets have yellow and black distinct patterning on abdomen.
Example of sweat bee (left) and yellowjacket (right)
This experience showed that insect identification is not black and white, which is
why identification keys are tricky to make. The purpose of the above dichotomous key is to
help identify common pollinators found at Hawthorn trees, and was the approach
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developed during identification. The key can be used as a good way to start figuring out
what type of arthropod you are dealing with. The rules above will have exceptions and
won’t be accurate in all cases. It is hoped that with resources for easier identification,
important pollinators will be recognized and appreciated for their high ecological value as
well as for intrinsic value.
This study was completed in hopes that further research will be conducted on the
same and other local species that support diverse and beneficial pollinator populations.
This study should be followed up with the following considerations. The collection may
have been biased to attractive, moving, loud pollinators and therefore a representative
sample may not have been collected. Repeat observations need to be conducted to see if the
recorded pollinator population is consistent on a yearly basis. Further analysis of identified
pollinators should occur to further classify and understand the diversity of pollinators
supported by Hawthorn trees.
Conclusion
The survey of pollinators at Hawthorn trees shows signs of high diversity,
suggesting that Hawthorns are important members of a community that is able to support
pollinators. By supporting many pollinating organisms, addition of Hawthorn trees into
meadow environments is recommended when other flower plants exist to support the
pollinator population for the 355 days of the year when Hawthorn’s are not in bloom. In
this way, Hawthorns can contribute to a healthy community and provide a stable food
source for these pollinators. This study can help initiate further research into local
pollinator populations and the plant species that support them, helping us understand the
biotic relationships that support the communities and populations we live in. This will
allow us to make educated and responsible decisions about habitat management.
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References Kaufman, Kenn, and Eric R. Eaton. Kaufman Field Guide to Insects of North America. New
York, NY: Houghton Mifflin, 2007. Print.
BugGuide. Iowa State University, Department of Entomology, 2015. Web. 08 June 2015.
<http://bugguide.net/>.
Michigan Flora Online. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University
of Michigan. Web. June 8, 2015. http://michiganflora.net/genus.aspx?id=Crataegus.
Clancy, S. (2008) Genetic recombination. Nature Education 1(1):40 <
http://www.nature.com/scitable/topicpage/genetic-‐recombination-‐514>.
"Insects & Pollinators." Natural Resources Conservation Service. United States Department
of Agriculture, 2015. Web. 08 June 2015. <http://www.nrcs.usda.gov/wps/portal/
nrcs/main/national/plantsanimals/pollinate/>.
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Appendix A: Behavior Information used to Determine Primary vs. Secondary Pollinators Diet or Behavioral Trail
Small Carpenter Bee Thistles and other flowers Mining Bee Pollen and nectar from specific flowers Asian Multicolored Lady Beetle* Aphids Spotted Lady Beetle Eats aphids and pollen Metallic Sweat Bee Known to pollinate flowers Flesh Fly Adults eat flower nectar Muscid Fly* Adults feed on living plant or animal tissue Bee Fly Eats nectar of lilac, plum and other flowers Bumble Flower Beetle Feed on pollen, nectar, fruit and plant juices Large Carpenter Bee Pollinate apples, pears and other fruit Red Admiral Butterfly Adults eat fruit, sap, bird droppings and nectar Sweat Bee Known to pollinate flowers Honey Bee Pollinate flowers Flower Fly 1 Feed on many flower parts Flower Fly 2 Feed on many flower parts Plant Bug* Feed on plants, some are predatory Spread-‐winged Damselfly* Feed on insects Rove Beetle 1* Mostly insect eaters Rove Beetle 2* Mostly insect eaters Assassin Bug* Eat insects Yellowjacket Adults collect flower nectar Bumble Flower Beetle 2 Feed on pollen, nectar, fruit and plant juices Thread-‐waisted Wasp* Eat flies Ichneumon Wasp Some are parasites, others visit flowers Syrphid Fly Feed on flower parts *Gray and asterisks means the organism has been determined to be a secondary pollinator.
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Appendix B: Species List Methods of Collection
1. Collected specimens only that landed on Hawthorn tree near flower or hover nearby 2. Moths and caterpillars released 3. Smallest insects could not be captured using our methods 4. Repeat specimen collections for a day were avoided when detected 5. Stored in plastic containers in shade during collection 6. Collections limited to one hour 7. Specimen were stored in refrigerator 20min or more before analysis 8. Identified used dissecting microscopes and a camera 9. Identified specimens were released S. of EIC
A1 Small Carpenter Bee Family: Apidae Genus: Ceratina
ID: 7cm long, ID: head and thorax iridescent dark green, almost black ID: very few hairs on head, abdomen and thorax ID: Distinguished from small sweat bees because less hair and lobed back wing Pollen hairs on 3rd pair of legs only Slender body Small mouthparts Long slender wings (Kaufman p.348)
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A2 Mining Bee Family: Andrenidae Genus: Andrena
ID: hairs between compound eyes and antennal base ID: very long hairs on 3rd pair of legs (Kaufman p.340) A3 Mining Bee Family: Andrenidae Genus: Andrena
ID: hairs between compound eyes and antennal base Long, slender wings Yellow hairs on full body and legs 10mm long (Kaufman p.340)
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A4 Mining Bee Family: Andrenidae Genus: Andrena
ID: hairs between compound eyes and antennal base (Kaufman p.340) A5 Small Carpenter Bee Family: Apidae Genus: Ceratina
ID: slender full iridescent green body ID: very few hairs on head, abdomen and thorax Pollen in long hairs on 3rd leg pair 8.5mm long (Kaufman p.348)
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A6 Mining Bee Family: Andrenidae Genus: Andrena
ID: hairs between compound eyes and antennal base (Kaufman p.340) A7 Asian Multicolored Lady Beetle Family: Coccinellidae Species: Harmonia axyridis
ID: Black M-‐shaped pattern on white pronotum ID: Elytra orange, shiny with black spots ID: a beetle due to hardened elytra (Kaufman p.156)
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A8 Spotted Lady Beetle Family: Coccinellidae Species: coleomegilla maculata
ID: Elytra orange with 12 large black spots, pronotum orange with two black spots ID: flattened back, long abdomen, black legs ID: a beetle due to hardened elytra (Kaufman p.154) A9 Metallic Sweat Bee Family: Halictidae Genus: probably Augochlora or Augochlorella
ID: Entire body metallic green and hairy Fine yellow hairs on all legs Abdomen slender, curved down 9.5mm long (Kaufman p.340) A10 Released, Not a Pollinator
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A11 Flesh Fly Family: Sarcophagidae
ID: one pair wings, white large haltêres ID: short antennae Red-‐brown eyes, thorax with black and silver vertical stripes, hairy Feet with two pads, wings lay flat (Kaufman p.306) A12 Metallic Sweat Bee Family: Halictidae
ID: Entire body metallic green and hairy, two sets of wings Abdomen eaten by other insect (Kaufman p.340)
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B1 Mining Bee Family: Andrenidae Genus: Andrena
ID: hairs between compound eyes and antennal base (Kaufman p.340) B2 Muscid Fly Family: Muscidae
ID: three segmented antennae with a hair protruding from end (aristate) ID: brown calypters (reduced hind wing) just in front of small light haltêres Other: long proboscis, red large compound eyes, small clubbed antennae with red tip Other: White and black abdomen curled downward Other 9mm long (Kaufman p.306)
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B3 Bee Fly Family: Bombyliinae Genus: Bombylius
ID: Clearly a bee mimic, thick yellow fur on thorax and abdomen ID: long, stiff proboscis like a hummingbird’s bill ID: long, thin, delicate legs Other: Large brown club-‐shaped haltêres, 10mm long, 17mm wingspan Other: dark on top of wings and translucent below (Kaufman p.294) B4 Bumble Flower Beetle Family: Scarabaeidae Genus: Euphoria
ID: broadly oval, yellow hairs covering body, dark pattern, loud buzz in flight ID: Antennae end with three fingerlike projections Other: 8-‐8mm long Known pollinators, feed at flowers (Kaufman p.138)
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B5 Large Carpenter Bee Family: Apidae Genus: Xylocopa
ID: large size and hair placement, black dot on center of thorax Other: 20mm long Other: Furry yellow thorax w/ black spot in center, furry black legs Other: Hairless, shiny black abdomen, black head, segmented antennae Other: Quickly agitated, buzzes loudly, shakes abdomen (Kaufman p.344) B6 Mining Bee Family: Andrenidae Genus: Andrena
ID: hairs between compound eyes and antennal base Other: flattened black hairless abdomen, hair on thorax and back legs (Kaufman p.340)
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B7 Red Admiral Butterfly Family: Nymphalidae Genus: Vanessa Species: Vanessa atalanta
ID: Wing coloration, dark with orange streaks and white dots at tips of top pair Bottom wings brown, top has orange, black and white, long antennae 20mm body length, 1 wing is 30mm head to tail (Kaufman p. 234) B8 Sweat Bee Family: Halictus Genus: Halictidae
ID: Thickened yellow back legs, yellow hairs on part of thorax, mostly hairless Fuzzy yellow hind legs, yellow fuzz between eye and antennae 12mm long, body black and shiny Wings same length as body, long thin antennae (Kaufman p.340)
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B9 Honey Bee Family: Apidae Species: Apis mellifera
ID: body is the color of honey with black stripes on abdomen Other: hair on thorax, pollen packets on hind legs (Kaufman p.347) B10 Mining Bee Family: Andrenidae Genus: Andrena
ID: hairs between compound eyes and antennal base Other: shaking abdomen, rubbing hind legs together (Kaufman p.340)
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B11 Flower Fly 1 Family: Syrphidae Genus: Unknown, possibly Mallota
ID: spurious vein which is found parallel to fourth longitudinal wing vein Bee mimic, 15mm long, 2 short antennae with terminal black hair Other: Lower mandible protrudes, slight downward carve to abdomen (Kaufman p.300) B12 Flower Fly 2 Family: Syrphidae Genus: Unknown, somewhat like Platycherius & Xylota but wider abdomen
ID: : spurious vein which is found parallel to fourth longitudinal wing vein 9mm long body, short antennae ending in a hair, black eyes, white face Rubbing front legs, very flat abdomen slightly curved down Thorax has fine hairs, two light spots on both abdomen sides (Kaufman p.302)
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C1 Plant Bug Family: Miridae
ID: distinct membrane and corium, cuneus present Other: 5mm long, not a pollinator (Kaufman p. 113) C2 Spread-‐winged Damselfly Family: Lestidae
ID: arculus is broader than narrow-‐winged damselfly Other: 33mm long, black and pale blue vertical stripes, wings slightly spread while resting (Kaufman p.52)
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C3 Sweat Bee Family: Halictidae
ID: ID: Entire body metallic green and slightly hairy Other: three caught, only one recorded Other: Fuzzy legs, short hairs, 10mm long 1 sub-‐antennal suture under each antennal socket, basal vein arched (Kaufman p.340) C4 Mining Bee Family: Andrenidae
ID: fellow hairy patch between eye and antenna Other: hairy yellow thorax, shiny black abdomen, 12 mm long (Kaufman p.340)
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C5 Rove Beetle 1 Family: Staphylinidae
ID: Antennae longer than body, filamentous, slender body, shortened elytra ID: antennae not clubbed, narrow waist, noticeable claws Other: 6mm long (Kaufman p.200) C6 Rove Beetle 2 Family: Staphylinidae Genus:
ID: very small elytra, no projections on antennae, narrow waist, distinctive claws ID yellow legs with thick knees, black body Other 8.5mm long (Kaufman p.200)
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C7 Assassin Bug Family: Reduviidae
ID: black wings, green body, long antennae, 6 legs, black spot on joints Other red eyes, some white on belly, 13mm long (Kaufman p. 116) C8 Yellowjacket Family: Vespidae Genus: Vespula
ID: Dark wings, thorax has 2 yellow bars and 2 yellow spots on bottom ID: antennae are black with 2 segments, smoothed stinger (female?) ID: body is smooth no fuzz Most likely Eastern Yellowjacket, Vespula maculifrons, due to pattern and range (Kaufman p.357)
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C10 Bumble Flower Beetle 2 Family: Scarabaeidae Genus: Trichiotinus
ID: end of antennae are a club with 3 parts, pronged ID: elytra very short, does not cover body Other: 7.5mm (Kaufman p.139) C11 Sweat Bee Family: Halictidae Genus: Lasioglossum
ID: Body is slightly metallic green, hairy yellow legs, slender, flat abdomen, glossy Other: 7mm long (Kaufman p. 341)
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C12-‐ Spread-‐winged Damselfly, released without further documentation C13-‐ Red Admiral, released without further documentation C14 Flesh Fly Family: Sarcophagidae
ID: one pair wings, hairy thorax with black and silver vertical stripes Other: large brown eyes, pale face, 10mm long (Kaufman p.306) C15 Thread-‐Waisted Wasp Family: Sphecidae Genus: Crabro
ID: small, slender ID: yellow stripes on black abdomen, yellow shapes on black thorax, hourglass shape body ID: yellow neck ring, yellow hairs on forehead, dark patch on outer wing Other: 9mm long (Kaufman p.338)
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D1 Ichneumon Wasp, Scorpion Wasp Family: Ichneumonidae
ID: antennae>10mm, body<10mm, back leg pair>10mm ID: yellow back legs with black joints, honey brown abdomen thinly connected to thorax ID: many antennal segments, all black (Kaufman p. 326) D2 Syrphid Fly Family: Syrphidae Genus: Toxomerus Species: Toxomerus germinatus
ID: Very distinctive arrow pattern on back matches Toxomerus germinatus, within range ID: White, small club haltêres ID: Wing pattern exactly matches this species ID: extremely short antennae with hair Other: pale underside, large eyes fill face (Kaufman p.298, 303)
