Squash Bees

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Three Squash Bees
Peponapis pruinosa
Copyright © 2009 Jim Cane

At long last we are enjoying full summer, and with it, the bounty of our gardens. Last August on this program, you learned about our native squash bees. Unlike honeybees and bumblebees, Squash bees are not social. Each female excavates a simple vertical tunnel in the dirt the diameter of a pencil. Lateral tunnels terminate in tiny chambers where she caches pollen and nectar to feed her progeny. She lays one egg per chamber. These nests are well concealed.

But you can readily see the feverish activity of males and females at squash, pumpkin and gourd flowers soon after sunrise, often before honeybee activity. Squash bees are the size of honey bees, but earlier, faster and more deliberate in their flight. Males have a yellow spot on the face. Unlike honeybees, female squash bees carry squash pollen dry in a brush of hairs on their hind legs.

Both sexes of squash bee are valuable pollinators, indeed they are the unheralded pollinators of most of the nations squash and pumpkins. But there is more to their story in Utah. Their native hosts, the wild gourds, only grow in the hot low deserts. Native Americans domesticated and cultivated squashes and gourds, but the practice did not spread north of the red rock country. Across most of Utah and the northern US in general, we have squash bees because we grow squash. In Utah, European settlers first grew squashes only 150 years ago. Each annual generation of squash bees spread further north, hopscotching from homestead to homestead, reaching as far north today as Boise Idaho. As you pick your zucchinis, butternuts and pumpkins, realize that your squash’s flowers also fed the descendants of our squash bee pioneers.

This is Linda Kervin for Bridgerland Audubon Society.


Photo: Courtesy and © Copyright 2009 Jim Cane

Text: Jim Cane, Bridgerland Audubon Society

Additional Reading:

Our Native Squash Bees, Wild About Utah, 12 August 2008, https://wildaboututah.org/squash-bees/

Squash Pollinators of the Americas Survey (SPAS), James Cane, USDA Pollinating Insect Research Unit, Utah State University

2009: https://www.ars.usda.gov/Research/docs.htm?docid=16595

2005: https://www.ars.usda.gov/Research/docs.htm?docid=12041

Perfect Pumpkin Pollinators: The Squash Bees!, James Cane, Frank A. Eischen, Blair J. Sampson, USDA-ARS, https://www.ars.usda.gov/is/AR/archive/nov08/bees1108.htm Also published in Agricultural Research magazine Nov/Dec 2008 https://www.ars.usda.gov/is/AR/archive/nov08/

Across the Americas, Squash and Gourd Bees Are Superb Pollinators, Marcia Wood, Dec 30, 2008, https://www.ars.usda.gov/is/pr/2008/081230.htm

Celebrating Wildflowers, Pollinator of the Month, Squash Bees, Jim Cane, USDA ARS, Bee Biology & Systematics Lab, Logan, Utah https://www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/squash_bees.shtml

Crop domestication facilitated rapid geographical expansion of a specialist pollinator, the squash bee Peponapis pruinosa, Margarita M. López-Uribe, James H. Cane, Robert L. Minckley, Bryan N. Danforth
Proc. R. Soc. B 2016 283 20160443; DOI: 10.1098/rspb.2016.0443. Published 22 June 2016https://rspb.royalsocietypublishing.org/content/283/1833/20160443.abstract

The Migratory Locust in North America; a post mortem

The Migratory Locust in North America; a post mortem
Rocky Mountain Locust were similar
to this Large Grasshopper
Melanoplus sanguinipes
Copyright © 2008 Lynette Schimming
As found on www.bugguide.net

Vast migratory swarms of flying grasshoppers, or locusts, have periodically scoured arid parts of Africa and the Middle East since Biblical times, devastating crops and causing famine. But did you know that during the 19th century, American homesteaders were likewise plagued by migratory swarms of grasshoppers? The largest swarm passed through Nebraska in June of 1875; it was 110 miles wide, 1800 miles long and more than a 1/4 mile thick, taking five days to pass overhead. It remains the world’s largest recorded insect outbreak.

Here in Utah, at the time of the transcontinental railroad, migratory locusts periodically descended on the homesteads of Mormon settlers, laying up to 1 billion eggs per acre. These ravenous swarms devoured crops, vegetation, even laundry hung out to dry. Around the Great Salt Lake, drowned pickled grasshoppers would wash ahore in vast drifts. Native peoples gathered these salty, sun-dried hoppers for food, a rich source of protein and fat.

Why are we no longer plagued by locust swarms? It appears that the Rocky Mountain locust, went extinct at the turn of the 20th century. Entomologist Jeffrey Lockwood reports that the DNA of specimens preserved in the ice of glaciers in the Wind River Range are like no other grasshopper alive today. The cause of the locust’s abrupt extinction may never be known with certainty, but Lockwood believes that these outbreaks originated in the mountain meadows of the northern Rockies. By the 1880s, these public lands were packed with cattle and sheep, far more than the land could sustain. In a few short years, livestock stripped bare the very core habitats needed by the Rocky Mountain locust, leading to its abrupt extinction and the end of locust swarms in North America.

This is Linda Kervin for Bridgerland Audubon Society.


Photo: Courtesy & Copyright © 2008 Lynette Schimming (As found on www.bugguide.net)

Text: Jim Cane, Bridgerland Audubon Society
Additional Reading:

Locust: The Devastating Rise and Mysterious Disappearance of the Insect that Shaped the American Frontier, Jeffrey Lockwood, Basic Books, 2004,ISBN:9780738208947, https://www.amazon.com/Locust-Devastating-Mysterious-Disappearance-American/dp/0465041671

Read more: 1. https://historyphilosophybooks.suite101.com/article.cfm/locust_by_jeffrey_lockwood#ixzz0IVh4qXFR&C

First and annual report of the United States Entomological commission for the year 1877 relating to the Rocky Mountain locust and the best methods of preventing its injuries and of guarding against its invasions Digitized by Google Books from Harvard University


Pestiferous Ironclads: The Grasshopper Problem in Pioneer Utah, Davis Bitton and Linda P Wilcox, Utah Historical Quarterly, 46 #4 as found on “Utah History to Go” https://historytogo.utah.gov/utah_chapters/pioneers_and_cowboys/pestiferousironclads.html

USA National Phenology Network

Courtesy USA National Phenology Network

The study of recurring plant and animal life cycle events is phenology. It is the calendar of nature. This includes when plants flower, when birds migrate and when crops mature. Phenology is relevant to interactions between organisms, seasonal timing and large-scale cycles of water and carbon. Phenology is important to us for many reasons. Farmers need to know when to plant and harvest crops and when to expect pests to emerge. Resource managers use it to monitor and predict drought and assess fire risk. Vacationers want to know when the best fall colors will be or when the wildflower blooms will peak. Timing varies but we can discern patterns.

The USA National Phenology Network monitors the influence of climate on the phenology of plants, animals and landscapes. They encourage people to observe phenological events such as flowering, migrations and egg laying. The Phenology Network provides a place to enter, store and share these observations, which are then compiled and analyzed nationwide. Participants range from individual observers in their own backyards to professional scientists monitoring long-term plots. My husband and I monitor leafing and flowering of lilacs, a key species in the program.

These observations support a wide range of decisions made routinely by citizens, managers, scientists and others. This includes decisions related to allergies, wildfires, pest control, and water management.

I urge you to participate. The National Phenology Network has many public, private and citizen partners. It is a great way to become involved in a nation-wide effort to better understand our environment. All this information and much more is available at the National Phenology website, to which there is a link from our Wild About Utah website.

This is Linda Kervin for Bridgerland Audubon Society.


Text: Linda Kervin, Bridgerland Audubon Society
Additional Reading:

Linda Kervin’s pieces on Wild About Utah

Phenology Tools for Community Science
USA National Phenology Network, https://www.usanpn.org/
Nature’s Notebook Education Program, US National Phenology Network, https://www.usanpn.org/nn/education

North American Bird Phenology Program, USGS Patuxent Wildlife Research Center, https://www.pwrc.usgs.gov/bpp/BecomeAParticipant.cfm

eBird, https://www.ebird.org/

iNaturalist, https://www.inaturalist.org/

Bark Beetle Mania

Bark Beetle Mania: Pine beetle damage to ponderosa pine in Dixie National Forest 2000 Courtesy USDA Forest Service
Pine beetle damage to ponderosa pine
in Dixie National Forest
2000 USDA Forest Service

Hi, I’m Holly Strand of Stokes Nature Center in beautiful Logan Canyon.

For a creature that’s typically less than six millimeters in size, bark beetles certainly have a mammoth footprint. Outbreaks of the tiny insects in forests across western North America have changed millions of trees into shriveled, rust-colored sentinels of a changing ecosystem. In Utah alone, between 1990 and 2005, wood-boring beetles ate their way through more than 466,000 acres which equals 3% of Utah’s total forested area.

Bark beetles are native to our forests and evolved together with their respective hosts. For example, the Douglas-fir beetle evolved with Douglas firs, and the spruce beetle with Engelmann spruce. The mountain pine beetle is the least discriminating. It attacks lodgepole pine, ponderosa pine and, more recently, high elevation species such as whitebark pine, limber pine, and bristlecone pine.

Douglas fir beetle galleries
beneath the outer bark
2000 USDA Forest Service

At healthy population levels, bark beetles renew forests by killing older and declining trees, allowing young, more productive ones to flourish. Female beetles initiate the assault, simultaneously attracting males using pheromones. Within hours the tree becomes the site of a “mass attack” of thousands of beetles. Then the females begin to reproduce. An individual female may lay over 100 eggs. As eggs hatch, larvae construct feeding galleries in the inner bark of the tree. These galleries eventually girdle and kill the tree by cutting off the exchange of nutrients between the roots and the crown of the tree.

Some of the biggest outbreaks in Utah have occurred in the Dixie and the Manti La Sal National Forests. The spruce beetle is responsible for thousands of acres of dead Engelmann spruce trees in both of these forests. The Piñon Ips beetle also thrives in piñon pines in southern UT. Meanwhile, on the other end of the state, the mountain pine beetle is causing serious outbreaks in the Uintas. The Wasatch Range forests have yet to experience extensive diebacks but the mountain pine beetle, Douglas fir beetle and spruce beetle are all causing higher mortality rates than they have in the past.

Certain forestry management practices are partially responsible for the unprecedented bark beetle outbreaks. Dense, homogenous forests with repressed fire regimes are more susceptible to attack. On the other hand, uncrowded, variable age stands composed of lots of different species are healthy and resilient.

Warming climate conditions have also contributed to the severe bark beetle outbreaks. Early fall and late spring freezes, and extremely cold temperatures help repress bark beetle populations. I’ll try to keep this in mind when it’s snowing in June here in Cache Valley. At least our pine trees will be healthy and safe from the bark beetle.

Barbara Bentz, research entomologist with the USDA Forest Service Rocky Mountain Research Station and adjunct faculty member with Utah State University’s Department of Wildland Resources, provided the scientific information for this piece.

Thanks to the USU College of Natural Resources and the Rocky Mountain Power Foundation for supporting research and development of this Wild About Utah topics. For Wild About Utah and Stokes Nature Center, I’m Holly Strand.


Images: UDSA Forest Service: Assessment and response to bark beetle outbreaks in the Rocky Mountain aea. Report to Congress from Forest Health Protection (see below)

Text: Mary-Ann Muffoletto, Holly Strand

Sources & Additional Reading

Bentz B, Allen CD, Ayres M, Berg E, Carroll A, Hansen M, Hicke J, Joyce L, Logan J,MacFarlane W, MacMahon J, Munson S, Negr?n J, Paine T, Powell J, Raffa K, Régnière J, Reid M, Romme W, Seybold S, Six D, Tomback D, Vandygriff J, Veblen T, White M, Witcosky J, Wood D (2009) Bark Beetle Outbreaks in Western North America: Causes and Consequences. University of Utah Press, ISBN 978-0-87480965-7, 42 p.

Logan, J.A., Powell, J.A. 2001. Ghost forests, global warming, and the mountain pine beetle (Coleoptera: Scolytidae). Am. Ent. 47(3): 160-172.

Samman, Safiya, Logan, Jesse tech eds. 2000. Assessment and response to bark beetle outbreaks in the Rocky Mountain aea. Report to Congress from Forest Health Protection, Washington Office, Forest Service, U.S. Department of Agriculture. Gen. Tech. Rep. RMRS-GTR-62. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 46 p.
https://www.usu.edu/beetle/documents/2000186_5Samman_Logan.pdf (accessed June 22, 2009)

Morgan, Kory, Racing the clock to stem the spread of the mountain pine beetle, USDA Forest Service, May 11, 2021, https://www.fs.usda.gov/features/racing-clock-stem-spread-mountain-pine-beetle