tulip poplar windfall, other spring flowers and phenology '24

Click on the image and notice that ants have discovered the tulip poplar flower. These ants are not thought of as pollinators just clever at finding sweets.

Based on my Atlanta backyard observations and record keeping, I found this year's first Tulip Popular flower windfall right on time (day 97) - see my table below.  I'm curious how my first tulip poplar windfall observations correlate with other spring surrogates?  The National Phenology Network leaf out model is another way to determine if spring is early, on time, or late.

Spring Leaf Index Anomaly Map uses the first leaf out of cloned lilac and honeysuckle cultivars as these woody plants are among the first to leaf out or bloom and are common across much of the country.  The model also uses temperature and weather events beginning January 1 of each year.  The current spring is compared with a 1991-2020 average. The map shows that the 2024 Georgia Piedmont region's first leaf out day of the year is similar to the 19-year average - spring is on time in the Georgia Piedmont region and surrounding regions show that spring is a few days early.

Other Atlanta nectar sources at this time (not shown):

• Chinese Wysteria (invasive)
  
• White Clover
• Spiderwort
• Amur Honeysuckle (invasive)
• Dandelion
  

1st Windfall	day of year
April 10, 2011	100
March 27, 2012	87
April 19, 2013	109
April 12, 2015	102
April 15, 2017	105
April 5, 2018	95
April 11, 2019	101
April 7, 2021	97
April 6, 2022	96
March 24, 2023	83
April 6, 2024	97
median	97

Made with HTML Tables

MABA swarm hotline

For me, collecting swarms or attracting swarms to bait hives is the most exciting part of my beekeeping.  Possibly making spring my favorite beekeeping season.  

 

Sunday at 1PM I received a text from the MABA "swarm commander" - a homeowner has called the swarm hotline about a swarm in their yard.   The best part of the text details...the swarm address is 3 miles away and the swarm is just a foot or two above the ground.  I'm all in and arrive in the next half hour.

 

I strongly relate to E.O. Wilson's connection to nature as not outgrowing his childhood bug phase. Knowing everyone does not share this view, I consciously met the homeowner's insect concerns with lots of listening about the swarm of bees. The re-framing education moment comes next - I say "that huge ball hanging from the tree canopy is a wasp nest, these bees likely have their nest in a cavity, like a tree."   

A few weeks ago, I patched up and painted my old wood nucleus box.  Wow, I'm ready for the swarm call-out, or so I thought.  Good - my bee toolbox has a bag of gloves. Bad - the gloves are too small, too old - they split and I quickly gave up wearing gloves.   The bees don't like the brushing or the hand attached to the yellow brush - my poor hand!

I added a swarm lure to the nucleus box entrance, brush, brush, brush again...and I'm nearly there.    I leave the nucleus box for collection just before dusk, 7:30PM.   So proud of myself to discover no bees returned to the trunk of the shrub.

mason bee sex

I sent these backyard photos to a few computer vision tools with results ranging from wrong to interesting.  I also asked questions using a conversational search engine about the size of male mason bees.
 

iPhone Visual Look Up is for identifying all objects (food, objects and living things too) in photos and videos on the iPhone.  For these photos Visual Look Up produced wrong or slightly wrong answers - Western Honey Bee and Osmia Rufa.

iNaturalist is for recording observations of individual living things, particularly things that can be tied to a species name.  iNat uses photos with a date, location, and crowdsourced identification. iNat's response to the last photo was Genus Osmia (139 native species of mason bee in North America). 

Perplexity AI is a conversational search engine that answers queries using natural language predictive text.  Perplexity's response to, "Are male mason bees smaller or larger than female mason bees?"  Click on the small numbers that link the response to a reference.

Male mason bees are smaller than female mason bees. Females are larger than males, with shorter, thicker antennae. Mason bees are generally much smaller than honey bees or bumblebees, measuring only about 1/4 inch long1

This size difference is a notable characteristic of mason bees, with males being noticeably smaller than females, typically around 7-15 millimeters long in most North American species3

winter-flowering ornamental cherry tree 2024

Year after year, this tree has produced great bee photos foraging on winter-flowering cherry tree.   The time was 2 PM, the temperature was 57°F (13.9°C), blue sky, sunshine, and a loud buzz of bees on this quiet street.

What's next?  Crabapple trees (thanks to Trees Atlanta) are beginning to leaf-out and those flowers will be here soon and attracting honey bees too.

does the cluster provide insulation?

I discovered 2 interesting articles by Derek Mitchell (PhD Candidate in Mechanical Engineering at the University of Leeds), one is intended for a general honey bee audience, the other a hard-core engineering-science article.  This blog post contains 2 images from those articles.

• Honeybees cluster together when it’s cold – but we’ve been completely wrong about why
• Honeybee cluster—not insulation but stressful heat sink 
  

 Facts about bees wintering in thin-wall wood hives:

• bees move from the hive edges towards the center of the hive to form a cluster
• as temperatures fall, the cluster shrinks - see the image from Derek's article
  
• the cluster core is hot compared to the cluster periphery.  
• bees in the core consume honey and keep bees in the periphery warm.
• in extreme winter temperatures, bees on the periphery risk death by hypothermia
• the cluster periphery is denser than the core

Derek writes, "Since the early twentieth century, the outer layer (mantle) of honeybees (Apis mellifera) in the winter cluster has been said to insulate the cluster core."  

A shrinking cluster increases density, reduces porosity, and increases heat loss. Here I'm using porosity to describe the amount of empty (air) space, or porosity = empty space ÷ total space.  Typically a thermal insulator reduces heat loss by trapping air and is therefore low in density.  The higher density cluster periphery is not a thermal insulator - has never been a insulator.  Beekeepers need not stress bees in extremely cold temperatures when insulation is readily available. 

• take a quick look in beekeeping catalogs and you'll discover flexible hive wraps - flexible wraps roll-up for easy storage and reusable next winter
  
• solid foam board insulation for home improvement is available for purchase or free as building waste

Bees have evolved to live in trees (a nest with extremely thick wood walls) that provide real insulation - see the image from Derek's article. To those protecting popular opinion, to the skeptic, to the frugal beekeeper, consider winter insulation using a side-by-side test.

Winter Top Ventilation

If you turn to page 116 of Seeley's book The Lives of Bees, you'll find a reference to Derek Mitchell a PhD Candidate in Mechanical Engineering at the University of Leeds.   With web-based searching, I discovered Derek's 2017 article in the American Bee Journal (Vol. 157 No. 8) Honey Bee Engineering: Top Ventilation And Top Entrances.   The article illustrates that adding top ventilation significantly reduces humidity and the depth of the heat pool when compared to an uninsulated hive.  Why?  Warmer air is more buoyant and flows faster through the top vent.

Providing hive insulation in winter reduces bee-generated heat loss and this increases the temperature of the heat pool found at the top of the hive - see the image from Derek's article.  I'm using the word heat pool as temperatures measured relative to the top of the hive -- I recognize, pool is commonly used with liquids that fill upwards from the bottom of containers. I currently use insulated hive wraps in winter and plan to close my top vent moving forward.

In email conversation, Derek recommends adding more hive insulation above the hive compared to the hive sides to discourage condensation from raining down on the bees.

Derek has simulated the heat flow of a winter bee cluster in a thin-walled wooden hive and compared those results with measurements collected by other researchers.  I plan to discuss this article in an upcoming blog post.

nematodes as a biologic control

On December 24, 2022, Atlanta experienced a historic single digit 8°F (-13.3°C) minimal temperature.  This cold snap turned green ground cover brown and likely pushed small hive beetles (SHB) deeper into hives and compost piles. 

My bee yard has high shade, good soil moisture, and summer soil temperatures for SHB reproduction.  I used biological control, Beneficial nematodes (Heterorhabditis Indica), to treat the soil for SHB larvae.   At dusk, I watered the liquid nematode suspension onto the soil.  Direct sunlight (UV light) is fatal to nematodes.

It's one thing to see and squash adult SHBs with my hive tool and another stranger thing to take a leap of faith releasing after dark 'The Smallest Show on Earth' -  Step Right Up! Step Right Up!

• Moved the insulated FedEx mailer with 2.5 million microscopic nematodes to the refrigerator. 
• Removed the leaf litter at the hive locations and then wet the soil.  
• The next step was washing nematodes from gel transport material - small gel pieces can clog the watering can.   I used a large strainer with a fine mesh to remove and rinse the numerous gel pieces.
• Added more water to the bucket and stirred it to keep the nematodes from settling to the bottom.
• At dusk, I watered the biologic control onto the soil.